Vol. 25 No. 4 2023 3 EDITORIAL COUNCIL EDITORIAL BOARD EDITOR-IN-CHIEF: Anatoliy A. Bataev, D.Sc. (Engineering), Professor, Rector, Novosibirsk State Technical University, Novosibirsk, Russian Federation DEPUTIES EDITOR-IN-CHIEF: Vladimir V. Ivancivsky, D.Sc. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Vadim Y. Skeeba, Ph.D. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Editor of the English translation: Elena A. Lozhkina, Ph.D. (Engineering), Department of Material Science in Mechanical Engineering, Novosibirsk State Technical University, Novosibirsk, Russian Federation The journal is issued since 1999 Publication frequency – 4 numbers a year Data on the journal are published in «Ulrich's Periodical Directory» Journal “Obrabotka Metallov” (“Metal Working and Material Science”) has been Indexed in Clarivate Analytics Services. Novosibirsk State Technical University, Prospekt K. Marksa, 20, Novosibirsk, 630073, Russia Tel.: +7 (383) 346-17-75 http://journals.nstu.ru/obrabotka_metallov E-mail: metal_working@mail.ru; metal_working@corp.nstu.ru Journal “Obrabotka Metallov – Metal Working and Material Science” is indexed in the world's largest abstracting bibliographic and scientometric databases Web of Science and Scopus. Journal “Obrabotka Metallov” (“Metal Working & Material Science”) has entered into an electronic licensing relationship with EBSCO Publishing, the world's leading aggregator of full text journals, magazines and eBooks. The full text of JOURNAL can be found in the EBSCOhost™ databases.
OBRABOTKAMETALLOV Vol. 25 No. 4 2023 4 EDITORIAL COUNCIL EDITORIAL COUNCIL CHAIRMAN: Nikolai V. Pustovoy, D.Sc. (Engineering), Professor, President, Novosibirsk State Technical University, Novosibirsk, Russian Federation MEMBERS: The Federative Republic of Brazil: Alberto Moreira Jorge Junior, Dr.-Ing., Full Professor; Federal University of São Carlos, São Carlos The Federal Republic of Germany: Moniko Greif, Dr.-Ing., Professor, Hochschule RheinMain University of Applied Sciences, Russelsheim Florian Nürnberger, Dr.-Ing., Chief Engineer and Head of the Department “Technology of Materials”, Leibniz Universität Hannover, Garbsen; Thomas Hassel, Dr.-Ing., Head of Underwater Technology Center Hanover, Leibniz Universität Hannover, Garbsen The Spain: Andrey L. Chuvilin, Ph.D. (Physics and Mathematics), Ikerbasque Research Professor, Head of Electron Microscopy Laboratory “CIC nanoGUNE”, San Sebastian The Republic of Belarus: Fyodor I. Panteleenko, D.Sc. (Engineering), Professor, First Vice-Rector, Corresponding Member of National Academy of Sciences of Belarus, Belarusian National Technical University, Minsk The Ukraine: Sergiy V. Kovalevskyy, D.Sc. (Engineering), Professor, Vice Rector for Research and Academic Aff airs, Donbass State Engineering Academy, Kramatorsk The Russian Federation: Vladimir G. Atapin, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Victor P. Balkov, Deputy general director, Research and Development Tooling Institute “VNIIINSTRUMENT”, Moscow; Vladimir A. Bataev, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Vladimir G. Burov, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Aleksandr N. Korotkov, D.Sc. (Engineering), Professor, Kuzbass State Technical University, Kemerovo; Dmitry V. Lobanov, D.Sc. (Engineering), Associate Professor, I.N. Ulianov Chuvash State University, Cheboksary; Aleksey V. Makarov, D.Sc. (Engineering), Corresponding Member of RAS, Head of division, Head of laboratory (Laboratory of Mechanical Properties) M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences (Ural Branch), Yekaterinburg; Aleksandr G. Ovcharenko, D.Sc. (Engineering), Professor, Biysk Technological Institute, Biysk; Yuriy N. Saraev, D.Sc. (Engineering), Professor, Institute of Strength Physics and Materials Science, Russian Academy of Sciences (Siberian Branch), Tomsk; Alexander S. Yanyushkin, D.Sc. (Engineering), Professor, I.N. Ulianov Chuvash State University, Cheboksary
Vol. 25 No. 4 2023 5 CONTENTS OBRABOTKAMETALLOV TECHNOLOGY Akintseva A.V., Pereverzev P.P. Modeling the interrelation of the cutting force with the cutting depth and the volumes of the metal being removed by single grains in fl at grinding........................................................................................................................................ 6 Sharma S.S., Joshi A., Rajpoot Y.S. A systematic review of processing techniques for cellular metallic foam production................. 22 Karlina Yu.I., Kononenko R.V., Ivantsivsky V.V., Popov M.A., Deryugin F.F., Byankin V.E. Review of modern requirements for welding of pipe high-strength low-alloy steels.......................................................................................................................................... 36 Startsev E.A., Bakhmatov P.V. The infl uence of automatic arc welding modes on the geometric parameters of the seam of butt joints made of low-carbon steel, made using experimental fl ux......................................................................................................................... 61 Martyushev N.V., Kozlov V.N., Qi M., Baginskiy A.G., Han Z., Bovkun A.S. Milling martensitic steel blanks obtained using additive technologies................................................................................................................................................................................ 74 Loginov Yu.N., Zamaraeva Yu.V. Evaluation of the bars’ multichannel angular pressing scheme and its potential application in practice................................................................................................................................................................................................... 90 EQUIPMENT. INSTRUMENTS Rajpoot Y.S., SharmaA.K., Mishra V.N., Saxena K., Deepak D., Sharma S.S. Eff ect of tool pin profi le on the tensile characteristics of friction stir welded joints of AA8011.................................................................................................................................................... 105 Chinchanikar S., Gadge M.G. Performance modeling and multi-objective optimization during turning AISI 304 stainless steel using coated and coated-microblasted tools........................................................................................................................................................ 117 Ghule G.S., Sanap S., Chinchanikar S. Ultrasonic vibration-assisted hard turning of AISI 52100 steel: comparative evaluation and modeling using dimensional analysis........................................................................................................................................................ 136 Pivkin P.M., Ershov A.A., Mironov N.E., Nadykto A.B. Infl uence of the shape of the toroidal fl ank surface on the cutting wedge angles and mechanical stresses along the drill cutting edge...................................................................................................................... 151 MATERIAL SCIENCE Sokolov R.A., Muratov K.R., Venediktov A.N., Mamadaliev R.A. Infl uence of internal stresses on the intensity of corrosion processes in structural steel....................................................................................................................................................................... 167 Klimenov V.A., Kolubaev E.A., Han Z., Chumaevskii A.V., Dvilis E.S., Strelkova I.L., Drobyaz E.A., Yaremenko O.B., Kuranov A.E. Elastic modulus and hardness of Ti alloy obtained by wire-feed electron-beam additive manufacturing................... 180 Vorontsov A.V., Filippov A.V., Shamarin N.N., Moskvichev E.N., Novitskaya O.S., Knyazhev E.O., Denisova Yu.A., Leonov A.A., Denisov V.V. In situ crystal lattice analysis of nitride single-component and multilayer ZrN/CrN coatings in the process of thermal cycling.......................................................................................................................................................................................... 202 Rubtsov V.E., Panfi lov A.O., Kniazhev E.O., Nikolaeva A.V., Cheremnov A.M., Gusarova A.V., Beloborodov V.A., Chumaevskii A.V., Grinenko A.V., Kolubaev E.A. Infl uence of high-energy impact during plasma cutting on the structure and properties of surface layers of aluminum and titanium alloys................................................................................................................... 216 Bobylyov E.E., Storojenko I.D., Matorin A.A., Marchenko V.D. Features of the formation of Ni-Cr coatings obtained by diff usion alloying from low-melting liquid metal solutions..................................................................................................................................... 232 Burkov А.А., Konevtsov L.А., Dvornik М.И., Nikolenko S.V., Kulik M.A. Formation and investigation of the properties of FeWCrMoBC metallic glass coatings on carbon steel.......................................................................................................................... 244 Sharma S.S., Khatri R., Joshi A. A synergistic approach to the development of lightweight aluminium-based porous metallic foam using stir casting method........................................................................................................................................................................... 255 Strokach E.A., Kozhevnikov G.D., Pozhidaev A.A., Dobrovolsky S.V. Numerical study of titanium alloy high-velocity solid particle erosion.......................................................................................................................................................................................... 268 EDITORIALMATERIALS 284 FOUNDERS MATERIALS 295 CONTENTS
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Elastic modulus and hardness of Ti alloy obtained by wire-feed electron-beam additive manufacturing Vasiliy Klimenov 1, a*, Evgeny Kolubaev 2, b, Zeli Han 1, c, Andrey Chumaevskii 2, d, Edgar Dvilis 1, e, Irina Strelkova 1, f, Ekaterina Drobyaz 3, g, Oleg Yaremenko 4, h, Aleksandr Kuranov 4, i 1 National Research Tomsk Polytechnic University, 30 Lenin ave., Tomsk, 634050, Russian Federation 2 Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, 2/4, pr. Akademicheskii, Tomsk, 634055, Russian Federation 3 Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russian Federation 4 Opton Engineering Limited Liability Company Ugreshskaya str., 2, p. 53, Moscow, 115088, Russian Federation a https://orcid.org/0000-0001-7583-0170, klimenov@tpu.ru; b https://orcid.org/0000-0001-7288-3656, eak@ispms.tsc.ru; c https://orcid.org/0000-0001-6502-6541, hanzelizy@gmail.com; d https://orcid.org/0000-0002-1983-4385, tch7av@gmail.com; e https://orcid.org/0000-0002-6853-6448, dvilis@tpu.ru; f https://orcid.org/0000-0002-2222-2865, strelkova@tpu.ru; g https://orcid.org/0000-0002-5364-3574, ekaterina.drobyaz@yandex.ru; h https://orcid.org/0009-0002-8193-8027, oy@opton.ru; i https://orcid.org/0009-0001-5593-9053, ak@opton.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2023 vol. 25 no. 4 pp. 180–201 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2023-25.4-180-201 ART I CLE I NFO Article history: Received: 17 July 2023 Revised: 10 August 2023 Accepted: 18 September 2023 Available online: 15 December 2023 Keywords: Wire-feed electron-beam additive manufacturing Titanium alloys Elastic modulus Indentation Ultrasonic control Hardness Funding Research was supported by Grant No. 23-7900066 from the Russian Science Foundation, https://rscf.ru/project/23-79-00066/. Acknowledgements The authors like to express their gratitude towards the management of the Academic Innovative Center of National Research Tomsk Polytechnic University for equipment employed in these studies, financially supported by the Ministry of Education and Science of the Russian Federation (Project No. 075-15-2021-710). These studies also employed equipment of the Core Facility Centre “Structure, Mechanical, and Physical Properties of Materials” of Novosibirsk State technical University. We thank S. Yu. Nikonov (Institute of Strength Physics and Materials Science SB RAS) for 3D printing of specimens. ABSTRACT Introduction. The development and application of additive manufacturing depends on many factors, including the printing process performance and buy-to-fly ratio. Wire-feed electron-beam additive manufacturing (EBAM) is attracting more and more attention from research teams. Moreover, the use of electron beams is the most effective and competitive for additive manufacturing of parts from alloys possessing high oxidation characteristics, e.g., titanium, stainless steels, since selective laser melting occurs in vacuum. Welding titanium wire VT6sv is the most preferable choice due to its availability and a wide range of thickness. This alloy, however, has fewer alloying elements than VT6 (Ti–6Al–4V) alloys. The high performance of wire-feed 3D printing and the VT6sv alloy composition affect the structure, phase composition, and properties of the fabricated alloy. As is known, the elastic modulus and hardness of alloys are important parameters, which can be measured rapidly also using non-destructive testing. The purpose of this work is to study the application of different approaches to measuring the elastic modulus and hardness of products obtained by wire-feed EBAM using the equipment of the Institute of Strength Physics and Materials Science SB RAS. Research methods. The structure of VT6sv titanium alloys fabricated by 3D printing and VT10 (Grade 2), VT6 (Ti–6Al–4V) alloys, was investigated by different methods such as metallography, ultrasonic gauging, instrumented indentation technique, macro- and micro-indentation, indentation hardness testing. Results and Discussion. Titanium alloy fabricated from VT6sv titanium wire under different thermal conditions has a typical columnar structure throughout the forging height. The structure formation determines the elastic modulus and hardness at various points of the forging. It is found that the elastic modulus is higher than that of as-delivered Ti–6Al–4V alloys, while the hardness is lower. Micro-indentation shows lower values of the elastic modulus than macro-indentation, which approach to values obtained by ultrasonic gauging and in other works. Different values of the elastic modulus at different points of the 3D printed forging indicate its sensitivity to the structure and phase composition of the material and demonstrate capabilities of measuring techniques used in this work. For citation: Klimenov V.A., Kolubaev E.A., Han Z, Chumaevskii A.V., Dvilis E.S., Strelkova I.L., Drobyaz E.A., Yaremenko O.B., Kuranov A.E. Elastic modulus and hardness of Ti alloy obtained by wire-feed electron-beam additive manufacturing. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2023, vol. 25, no. 4, pp. 180–201. DOI: 10.17212/19946309-2023-25.4-180-201. (In Russian). ______ * Corresponding author Klimenov Vasiliy A., D.Sc. (Engineering), Professor National Research Tomsk Polytechnic University, 30 Lenin ave., 634050, Tomsk, Russian Federation Tel.: +7 (3822) 701-777, e-mail: klimenov@tpu.ru
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Introduction Titanium (Ti) and titanium alloys are widely used in biomedicine due to its biocompatibility, corrosion resistance, and high specific strength. In the case with titanium prosthetic implants, its fatigue strength, tensile strength, and elongation are important in a substitution of load-bearing hard tissues [1]. Strength and hardness of parts fabricated by conventional techniques can be controlled rather easily, as its mechanical properties are almost the same as forgings it is obtained from. However, for example, when milling parts, some of materials go to waste. That is why additive manufacturing (AM) becomes more preferable both in medicine and other production activities based on expensive and hard-to-machine materials [2]. While, AM process parameters such as heat source power and velocity, surface power density, scanning mode, affect the melt pool shape and dimensions during the process. This determines the thermal cycle, cooling rate, temperature gradient, and solidification rate affecting the structure formation and properties of printed parts [3]. Mechanical properties of the material fabricated by selective laser melting (SLM) or directed energy deposition (DED), depending on the structure formation, determined by thermal conditions, are widely discussed by research teams. These studies are focused on the understanding of AM processes and its optimization [4–9], since the properties of fabricated products should satisfy standard requirements [10]. Both methods of material physics and mechanical strength testing accompanied by specimen disintegration are widely used. And interest in applying non-destructive testing, capable to detect and measure strength properties of the material, is understandable. Among mechanical properties that are most often measured by non-destructive testing methods, the elastic modulus and hardness, measured by ultrasonic testing [11–14], and elastic modulus, measured by instrumental indentation techniques [15–18], should be highlighted. When ultrasonic method is used to control the quality, the specimen retains its integrity. But the determination of the elastic modulus requires specific specimen geometry due to the structural performance and sensor dimensions. Only indentation techniques can therefore be really discussed as a prospect application of nondestructive testing method. A comparison of the elastic modulus, measured by indentation techniques and ultrasonic gauging, is very useful and informative [19].Although GOST R 8.748-2011 gives the requirements for the macro- and micro-indentation loads, the obtained test results require thorough discussion and comparison [20]. It should be noted that elastic modulus is a key parameter in the material design and engineering. According to Zolotarevsky [21], the elastic modulus of pure metals is a low-sensitive parameter of the structure. In works [22, 23] it is found that this parameter changes during the transition of pure metals from coarse- to nano-crystalline state. Of great importance is the problem of the elastic modulus stability after different thermal treatment of Ti alloys, most of which consist of two phases [24]. According to numerous studies, elastic modulus, for example, for the VT6 (Ti-6Al-4V) alloy, ranges between 90 and 145 GPa [24]. It is shown that it depends on many factors, namely structure, its homogeneity, forging shape, and size of area to be measured. Elastic modulus of Ti alloys used in medicine, is an important parameter, which determines biocompatibility of implants. Its reduction to the elastic modulus of bone tissue is gained by additional doping of alloys, which leads to significant changes in its structure and phase composition [25, 26]. Controlling the values of the elastic modulus of alloys, especially at the stage of technology development, is of great importance. Ti alloys for additive manufacturing are exposed to a specific influence leading to the formation of inhomogeneous and anisotropic structures and phases. SLM or electron-beam additive manufacturing (EBAM) provide the formation of products with required properties [27]. The improvement of the economic efficiency of additive manufacturing, for example, increasing the wire-feed 3D printing performance, is associated with a complicated control for thermal conditions, and the alloy acquires a specific structure and phase composition [28, 29]. In the literature on AM-fabricated Ti alloys, information about the elastic modulus is obtained after processing tensile/compressive strain curves or after nanoindentation [29] and, to a lesser extent, after ultrasonic gauging [30]. In studying alloys with a complex structure and phase composition, it is expedient to apply several methods to measure the elastic modulus [31].
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Today, the widespread instrumental indentation technique allows measuring the elastic modulus in real conditions, which also provides detection of other strength properties such as tensile strength, yield strength, crack resistance [32, 33]. This work presents studies on measuring the elastic modulus and hardness using ultrasonic gauging and macro- and micro-indentation of VT6sv titanium plates. The latter are fabricated by wire-feed EBAM and its properties are compared to those of VT1-0, VT6 and Ti-6Al-4V alloys obtained by conventional techniques. Discussion of measurement results obtained for the elastic modulus and hardness by various techniques assists in further understanding of the obtained values on the structure and phase composition of AM-fabricated Ti alloys. Methodology Materials In our experiments, the Ti alloy was fabricated by wire-feed EBAM using the welding titanium wire VT6sv with a diameter of 1.6 mm. The chemical composition of this wire met the requirements of GOST 27265. It differed from the VT6 alloy in that the content of alloying elements corresponds to the lower limit of alloying values. Also, VT1-0 (Grade 2), VT6 and Ti-6Al-4V titanium rolled sheets were investigated. The chemical composition of VT1-0 and VT6 alloys matched GOST 19807–91, whereas the composition of the Ti-6Al-4V alloy corresponded to the China national standard GB/T 3620.1-2016. This is summarized in Table 1. Ta b l e 1 Chemical composition of titanium alloys Alloys Ti Al V Zr Si Fe O H N C Impurities VT1-0 (Grade 2)* Base – – – 0.10 0.25 0.20 0.010 0.04 0.07 0.10 VT6* Base 5.3–6.8 3.5–5.3 0.30 0.10 0.60 0.20 0.015 0.05 0.10 0.30 Ti-6Al-4V** Base 5.5–6.75 3.5–4.5 – – 0.3 0.20 0.015 0.05 0.08 0.4 VT6sv*** Base 3.5–4.5 2.5–3.5 – 0.10 0.15 0.12 0.003 0.04 0.50 0.30 * GOST 19807–91 ** GB/T 3620.1-2016 *** GOST 27265–87 Alloy specimens were fabricated on a laboratory EBAM system developed in the Institute of Strength Physics and Materials Science SB RAS [34]. The EBAM process was performed in vacuum, at a pressure ranging between 10–3 and 10–2 Pa. The 150×60×2.5 mm3 titanium VT1-0 substrate was positioned on a 160×60×5 mm3 protective layer made of stainless steel. All this was mounted to a triaxial working table via metal clamps. The working table was equipped with liquid cooling, and during printing the temperature was maintained at 13–15 ℃. After the 20th layer, the beam current was reduced from 55 to 40 mA to decrease the heat input. CAD-assisted 3D printing provided the fabrication of 100×60×8 mm3 plate, one plate is demonstrated in Fig. 1, а. The obtained plates were milled and polished for ultrasonic gauging, indentation, and hardness measurement in 89×39×3 mm3 areas indicated in Fig. 1, b. Ultrasonic gauging In order to detect the elastic modulus and hardness by ultrasonic gauging, instrumental indentation and metallography, the electric discharge machining was used for cutting test specimens from different sectors of the plate. Cutting was performed according to the requirements for specimen dimensions in these measuring techniques.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 а b Fig. 1. General view of 3D printed specimen (a): I – VT1-0 substrate, II – wire-feed EBAM plate, III – cut area for testing; indentation measurement segments (b): 0 – in XY plane, 1 –6 – in XZ plane The ultrasonic thickness gauge 38DL PLUS (Olympus), presented in Fig. 2, а, was used to measure the elastic modulus. The requirements for the specimen dimensions were determined by the size of the shear wave probe V156 (5 MHz) and longitudinal wave probe V112 (10 MHz). The specimen height should exceed the probe diameter (Fig. 2, b). The mean thickness value was obtained after 10 measurements of each specimen. The wave velocity was obtained by measuring the specimen thickness and the time of the wave propagation. Poisson’s ratio ν and elastic modulus E were calculated from (1) and (2): 2 2 1 2( / ) ; 2 2( / ) T L T L V V V V − ν = − (1) 2 (1 )(1 2 ) , 1 L V E ρ + ν − ν = − ν (2) where VT is the shear acoustic velocity; VL is the longitudinal acoustic velocity equaling the doubled thickness divided by the time of back and forth propagation; ρ is the density. The elastic modulus was calculated according to ASTM E494-15 [35]. а b Fig. 2. Photograph of ultrasonic thickness gauge 38DL PLUS (a); schematic ultrasonic gauging (b): 1 – probe, 2 – specimen
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Indentation elastic modulus Macro-indentation Measurement of the elastic modulus during macro-indentation of a Ti alloy plate fabricated by 3D printing was carried out by the instrumental indentation system AIS3000 HD (FRONTICS, Korea) [32, 33, 36] presented in fig. 3, а, b. The procedure is schematically illustrated in fig. 3, c, d. b а c d 2 1 5 mm R = 0.25 m m Fig. 3. General view of the AIS3000 HD (a); indentation assembly (b): 1 – Vickers indenter (Dia. 0.5/1.0 mm), 2 – specimen; schematic indentation (c): 1 – rounded tip, 2 – specimen; points of indentation (d) The AIS3000 HD operating principle is based on the penetration of an indenter into the inspected object under a gradual loading and subsequent periodic partial unloading followed by complete unloading after reaching the maximum penetration depth. Firmware controls the system operation and displays control parameters such as load, depth, loading rate. External software is installed on a PC to control the system operation and display, store, communicate, and statistically process results of measurement. External software detects such properties as elastic modulus, hardness, residual stress, tensile strength, and crack resistance (fracture toughness) based on the load-penetration curve. The indentation load is measured by a strain gauge, and the indentation depth is determined by a displacement sensor. The system operation is based on instrumented indentation, i.e., indentation of the tip (indenter) into the inspected material according to both GOST R 8.748-2011 [17] and ASTM E2546-15 [15]. The instrumental indentation technique helps to determine the dependence between the penetration force and depth at its gradual variation. The AIS3000 HD provides fast and easy inspection not only of parts, but also various products. A WC spherical indenter with a radius of 250 mm was used for indentation at a load of 600 N. Each test included 15 “loading →partial loading → intermittent unloading” cycles at a loading rate of 0.3 mm/ min. Load-penetration curves were continuously obtained during indentation and then converted into “true stress-true strain” curves. All indentation tests were performed at room temperature. The elastic modulus is determined by the contact stiffness S (the slope of the tangent to the unloading curve when the force F is removed, shown in fig. 4). The straight section of the unloading curve describes the elastic recovery of the material. The unloading curve can be expressed as: ( )m f F k h h = − , (3) where m and k are correlation constants.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 max 1 max 2 ( ) , m f r c h h dF S km h h E A dH − = = = − = π (4) 2 2 1 1 1 , i r i E E E − ν − ν = + (5) where v and vi are Poisson’s ratios for the material and indenter, respectively; Er is the reduced elastic modulus; Ei is the elastic modulus of the indenter tip. The equation that describes the reduced elastic modulus is as follows: 1 , 2 r c E S A π = (6) where Аc is the actual contact area of the spherical indenter tip with regard to the height of the plastic pile-up hpile and the elastic contact depth hd. The real contact area Аc is determined with respect to the actual contact radius а and is the function hc of the contact depth and the material: ( ). c c À f h = (7) The contact depth at the current penetration force can be obtained from the analysis of the unloading curve (fig. 4) using the indenter geometry, elastic strain, and morphology of deformed surface. In figs. 4 and 5, the following notations are used: Fmax: Maximum penetration force; hp: Residual indentation depth after Fmax removal from the specimen; hr: Point of intersection of the tangent to curve at Fmax with the indentation depth-axis; Fig. 4. Schematic “loading/unloading” curves of indentation for a single cycle
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Fig. 5. Morphology of deformed surface of the material hmax: Maximum indentation depth at Fmax; hc: Depth of the contact of the indenter with the test piece at Fmax; hpile*: Height of plastic pile-up; hd: Depth of elastic contact; R: Radius of spherical tip; а: Actual contact radius; а*: Contact radius without pule-up. We thus obtain: * * * max , c c pile d pile h h h h h h = + = − + (8) max max ( ) 0, 75 / , d r h h h F S = ω − = (9) where ω is the indenter shape index equaling 0.75 for spherical tip. Therefore, * * * max max (0, 7 , 5 / ) c pile pile h h h F S h + = − + (10) * max * , . pile IT c h h f n R h = (11) The plastic pile-up can be expressed through the constant с and connected with the strain hardening n of the material by the empirical relation 2 2 *2 5(2 ) , 2(4 ) à n ñ n à − = = + (12) where a is the actual contact radius; а* is the contact radius without pile-up. Based on the geometry of the spherical indenter, the actual contact radius is expressed as hc and the indenter radius R: ( ) 2 * *2 5(2 ) 2 . 2(4 ) c c n à Rh h n − = − + (13) The actual contact area Ac is determined by the actual contact depth hc correlating with hpile* and hc*: ( ) 2 2 . c c c A Rh h = π − (14)
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Micro-indentation The elastic modulus and microhardness testing was performed on a DUH-211S Dynamic Ultra Microhardness Tester (Shimadzu, Japan) fitted with a Berkovich three-sided pyramid indenter with α = 65.03°. The maximum test force was 2,000 mN (fig. 6). The indentation elastic modulus is calculated from (5), where Poisson’s ratio for diamond is 0.07, the elastic modulus for diamond is 1.14‧106 N/mm2, in this case the reduced elastic modulus in the indentation region Er is determined as follows: , 2 r p S E A π = (15) where Ар is the cross-sectional area of the contact surface between the tip and specimen, which is determined by the load curve on F–h diagram and the tip area function. For the Berkovich tip, Ар is calculated as follows: 4.8 . 96 p c A h = (16) The DUH-211S provides a continuous measurement of the material stiffness along with loading and displacement as a continuous function of the penetration depth. The hardness and elastic modulus are calculated at each data point recorded during testing. Microhardness measurement A DuraScan-10 hardness tester (EMCO-TEST, Austria) for high load range testing was used to measure the hardness under 100 g load for 3 s. Measurement was conducted in the XZ plane, on the left side at point 0 (see fig. 1, b). Fig. 6. General view of a DUH-211S Dynamic Ultra Microhardness Tester (a); test section (b): 1 – probe, 2 – specimen; schematic loading (c): 1 – Berkovich indenter, 2 – specimen; point of indentation (d) b а c d 2 1 20 µm
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Metallography and elemental analysis The preparation of specimens for metallographic studies and elemental analysis was carried out by cutting it from various sections of the printed plate and then grinding the surfaces using sandpaper with a consistently decreasing grain size of the abrasive. Final polishing was carried out using diamond paste. The microstructure of the specimens was investigated using an Axio Observer A1m Inverted Microscope (Carl Zeiss, Germany) after chemical etching with Kroll’s reagent consisting of 10 mL HNO3, 3 mL HF, and 87 mL H2O. An Oxford Instruments INCA X-Act Energy dispersive X-ray (EDX) spectroscopy on the scanning electron microscope Zeiss EVO 50 XVP (Germany) was carried out to investigate the fine structure and chemical composition of the structural elements. The EDX analysis was performed in two planes with a scanning step of 0.25 µm. Results and discussion Structure and elemental composition Materials fabricated by selective laser melting (SLM) or wire-feed EBAM are characterized by the heterogeneous and anisotropic structure and properties [28], determined by layer-by-layer fusing by the electron beam. It is well known that cooling rates in the majority of conventional casting techniques can range from several tens to a thousand of kelvin per second, which induces significant changes in the structure and properties of the manufactured material. In additive manufacturing, cooling rates of the melt can range from 103 to 108 K/s. Moreover, temperature gradients reach 106 K/cm [37] in some regions. The structural features and its effects on the properties of titanium alloys were most often evaluated using metallography methods and mechanical tests for hardness and strength, mainly under tension, for specimens obtained by selective laser melting [38, 39]. In wire-feed EBAM, when the layer thickness is considerably higher than in SLM, temperature conditions conform with lower cooling rates, that is proven by the columnar structure, presented in fig. 7, а, and the cross-section of columnar crystals in the form of polygons with diagonals of a b c d Fig. 7. SEM images with EDX analysis in XZ (a) and XY (b) planes; microhardness distribution (c); elemental analysis (d)
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 1 to 2.0 mm in the beam scanning plane, as shown in fig. 7, b. The nature of the change in microhardness values in the presented planes also indicates structural inhomogeneities in the forming grains (fig. 7, c). The average microhardness values calculated for XZ and XY planes differ from each other, viz. 334±14 HV0.1 and 304±16 HV0.1, respectively. Unlike the EDX analysis of the microhardness distribution, the EDX analysis of the elemental distribution in weight percentage (fig. 7, d) at different points shows no significant change, which indicates the leading role of inhomogeneity of the structure, rather than the phase. Ultrasonic gauging of elastic modulus and Poisson’s ratio The elastic modulus and Poisson’s ratio for specimens prepared from different alloys are presented in table 2. Ta b l e 2 Elastic properties determined by the 38DL PLUS Alloys → Properties↓ VT1-0* VT6* Ti-6Al-4V* 3D printed VT6sv Elastic modulus E, GPa 109±1 120±1 130±1 131±1 Poisson’s ratio, ν 0.33±0.03 0.32±0.03 0.31±0.03 0.27±0.03 * As-rolled alloys As reported in early research [40] on the values of elastic moduli of commercially pure Ti alloy and Al- and V-doped Ti alloys, this parameter for cast alloys was 92 and 108 GPa at 160 and 294 HV, respectively. At the same time, the sensitivity of the elastic modulus to the phase composition and crystal structure was observed. The structure formation and properties of such alloys were investigated in [34, 41]. The structure consisted of lamellas and a + b phase colonies of different length and width. β-phase lamellas were smaller and located between a-phase lamellas, as presented in fig. 7а, b. It is very important that the presence of the β-phase provided its hardness growth even in the presence of the martensitic α’-phase. That indicated the predominant role of the solid solution hardening. The elastic modulus decreased with increasing content of the β-phase [42]. It was important to compare the data of titanium master alloys and commercially pure titanium, since the latter possessed a homogeneous structure unlike binary master alloys [43]. According to reference data in recent research, the elastic modulus is 100 to 110 GPa for pure titanium and Ti-6Al-4V system alloys, either cast or rolled [43] and 120 to 125 GPa at 400 to 420 HV hardness of the master alloy, respectively [27]. At the same time, the elastic modulus measured by ultrasonic gauging is 120 GPa for pure titanium in the initial state [43]. As can be seen from table 2, the elastic modulus for VT1-0 and VT6 alloys is in good agreement with that obtained in [27, 43], whereas the elastic modulus for the Ti-6Al-4V alloy significantly differs due to, probably, significant difference in its structure and phase composition. Instrumental indentation [19, 22, 33, 36, 43] and nanoindentation [27] measurements of the elastic modulus for Ti alloys obtained by both conventional methods and additive manufacturing, are more common than ultrasonic gauging [19, 43]. Macro-indentation of elastic modulus and microhardness The macro-indentation depth is ~150 mm, indentation point diameter is 0.5 mm (fig. 3d), which does not violate the integrity of the sample material and does not change its physical properties. At the same time, the dimensions of the material involved in the measurements exceed those analyzed during nanoindentation by more than an order of magnitude and are commensurate with the grain sizes. The elastic modulus is detected using the load-unload curves obtained by the above-described procedure and presented in fig. 8. The indenter penetration in the material induces its stress-strain state.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Fig. 8. Load-penetration curves of instrumental indentation using the AIS3000 HD Indentation with multiple intermittent unloading results in a set of parameters in a wide indentation range, i.e., at different depth of penetration with gradually increasing penetration force. Using these parameters, the reduced elastic modulus is calculated in the whole range of elastoplastic deformation in the indentation zone. The elastic modulus and microhardness, obtained in XZ and XY planes, are shown in fig. 9. As can be seen in fig. 9, а, b, absolute hardness values at different points with the structure shown in fig. 7, а, differ insignificantly, while in-plane hardness values matching structures shown in fig. 7, b, are slightly lower. Similar findings are presented in many works. As for absolute values of the elastic modulus, it differs from each other at different points and planes. As in the case with rolled alloys, the elastic modulus is different in the scanning plane and growth plane (fig. 9, b, c). And its absolute values are considerably lower than those obtained by ultrasonic testing. Micro-indentation of elastic modulus and hardness Load-depth curves in fig. 10 are obtained for four alloys. Great difference in the residual penetration depth indicates different resistance to deformation or hardness of alloys. One can see that after unloading, the residual depth for the VT1-0 alloy is higher than for other alloys. It means that this alloy is softer, while for other alloys, the tangent slope is close to the unloading curve. Table 3 presents the elastic modulus and hardness for Ti alloys measured by various indentation techniques in different planes. In this table, terms longitudinal and vertical mean that the indentation load is applied in XZ and XY rolling planes, respectively. The obtained hardness values correspond to the values inherent in the alloys under study and show a difference depending on the measurement plane, both for rolled material VT1-0 and printed VT6cv. Values of the elastic modulus demonstrate its dependence on the structure and phase composition of Ti alloys. According to Lutfullin et al. [24], in Ti alloys consisting of a hexagonal α-phase and body centered cubic
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 c Fig. 9. Elastic modulus and hardness measured by the AIS3000 HD at different points: a – points 1, 2, 3; b – points 4, 5, 6; с – point 0 (XY plane) a b Fig. 10. Load-depth curves
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Ta b l e 3 Physical and mechanical properties of Ti alloys Alloys → / Measurement methods and properties↓ VT1-0* Ti-6Al-4V* 3D printed VT6sv VT6* Macro-indentation E, GPa Longitudinal 110±8 110±13 XZ 103–131 108±4 Vertical 102±3 111±10 XY 90–100 Micro-indentation DuraScan-10 HV0.1 Longitudinal 168±5 370±23 XZ 334±14 339±6 Vertical 170±6 375±25 XY 304±16 DUH-211S EIT = 0.5 GPa 99±3 94±1 90–100 90±2 HIT = 0.5 N/mm2 1930±152 3913±129 3552±259 3660±105 Note. EIT: Indentation elastic modulus, HIT: Indentation hardness *As-rolled alloys β-phase (VT6, Ti-6Al-4V and VT6sv), the elastic modulus may depend on the ratio between these phases, as the elastic modulus for the α-phase is higher than for the β-phase. Lutfullin et al. attribute changes in the elastic modulus not only to the structure and phase composition of the 3D-printed VT6sv alloy, but also to the crystallographic texture. The latter plays an important role for the single-phase VT1-0 alloy. As reported in [43], this alloy predictably manifests a homogeneous structure and is often used as a standard material for nanoindentation measurements of the elastic modulus for Ti alloys. As for the welding titanium wire VT6sv subjected to remelting and thermal treatment during 3D printing, we observe changes in its structure and phase composition (see fig. 7). In addition, phases and texture modified by temperature conditions in different parts of the specimen, also affect the elastic modulus [34]. It should be noted that temperatures below the β-transus temperature, induce the formation of several structural types in the SLM Ti-6Al-4V alloy, namely: allomorphic crude lamellas, small lamellas/aciculae, and α-phase grains [44]. The formation of these structures can be observed in SLM titanium alloys [27, 30]. Structural elements include a finer grain structure and martensite. The grain size and martensitic component depend on the 3D printing mode, which determines the hardness and elastic modulus of the product. Its hardness significantly exceeds that of the product fabricated from the rolled alloy, i.e., 5 or 6 and 3 or 4 GPa, respectively. As for the elastic modulus, it is slightly lower than that of the product fabricated from cast or rolled Ti alloys, i.e., 107 to 119 GPa and 110 to 125 GPa, respectively. In wire-feed EBAM, the layer thickness is much higher than in SLM forgings, and temperature conditions approach to those of casting. In wire-feed EBAM, the well-defined columnar structure appears throughout the forging height and equiaxial grain structure in the scanning plane (see fig. 7, а, b). Such an alloy structure provides its hardness common to cast alloys, which slightly differs from the hardness in planes of forming and scanning. The elastic modulus obtained for all specimens, is much lower than that measured by ultrasonic gauging (see table 2). The highest difference in its values is conditioned by micro-indentation. The same difference is observed in [43], where the elastic modulus is measured by ultrasonic gauging and nanoindentation; besides the attention was drawn to the fact that the accuracy should be expected to be higher if the indentation covers a larger volume. All findings of the elastic modulus and hardness for the VT6sv alloy fabricated by wire-feed EBAM and Ti-6Al-4V and VT6 alloys in various states are presented in fig. 11, а. According to this figure, the elastic modulus obtained by ultrasonic testing for the printed material and rolled Ti-6Al-4V alloy, is slightly higher than that of initial cast and rolled alloys and those fabricated by EB-PBF in other works. Micro-indentation of the elastic modulus shows lower values than macro-indentation and findings of other researchers. Notably, the hardness of specimens printed from the VT6sv wire is lower than that of the Ti-6Al-4V alloy. This is explained by the VT6sv alloy composition, structure (see fig. 7), and microstructure [34]. The data presented in fig. 11, b correspond to cast alloys.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Conclusions 1. Elastic modulus and hardness are obtained for the Ti alloy fabricated by wire-feed EBAM with use of the VT6sv wire. These parameters were measured by using three techniques: ultrasonic gauging, macro-, and micro-indentations. The obtained values are compared to those obtained for different rolled Ti alloys and those described in other works. 2. The elastic modulus of Ti alloys with different structure and phase composition are in range of 90– 100 GPa (macro-indentation) and 103–131 GPa (macro-indentation). These values correspond to the values for the initial and EBAM-fabricated alloys. 3. The elastic modulus for the alloy fabricated by wire-feed EBAM, are slightly higher than the known values presented in the literature, namely 131 and 125 GPa, respectively. On the contrary, the hardness is lower and matches the hardness of respective cast alloys. 4. Micro-indentation of the elastic modulus shows lower values than that when using macro-indentation; it is close to the elastic modulus obtained by ultrasonic gauging and in other works. 5. The difference between values of the elastic modulus at various points of the forging indicates its sensitivity to the structure and phase composition and demonstrated capabilities of described measurement techniques. a b Fig. 11. Elastic modulus (a) and hardness (b) for Ti alloys. Abbreviations: SLM – selective laser melting; EB-DED – electron beam directed energy deposition; EB-PBF – electron beam powder bed fusion; L-DED – laser directed energy deposition. Values obtained in this work are marked with an asterisk* References 1. Niinomi M. Mechanical properties of biomedical titanium alloys. Materials Science and Engineering: A, 1998, vol. 243 (1–2), pp. 231–236. DOI: 10.1016/s0921-5093(97)00806-x. 2. Milewski J.O. Additive manufacturing of metals: from fundamental technology to rocket nozzles, medical implants, and custom jewelry. Cham, Springer, 2017. 343 p. ISBN 3319863487. DOI: 10.1007/978-3-319-58205-4. 3. DebRoy T., Mukherjee T., Wei H.L., Elmer J.W., Milewski J.O. Metallurgy, mechanistic models and machine learning in metal printing. Nature Reviews Materials, 2021, vol. 6 (1), pp. 48–68. DOI: 10.1038/s41578-02000236-1. 4. Murr L.E., Gaytan S.M., Ramirez D.A., Martinez E., Hernandez J., Amato K.N., Shindo P.W., Medina F.R., Wicker R.B. Metal fabrication by additive manufacturing using laser and electron beammelting technologies. Journal of Materials Science and Technology, 2012, vol. 28 (1), pp. 1–14. DOI: 10.1016/S1005-0302(12)60016-4.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 5. Murr L.E., Esquivel E.V., Quinones S.A., Gaytan S.M., Lopez M.I., Martinez E.Y., Medina F., Hernandez D.H., Martinez E., Martinez J.L., Stafford S.W., Brown D.K., Hoppe T., MeyersW., Lindhe U., Wicker R.B. Microstructures and mechanical properties of electron beam-rapid manufactured Ti–6Al–4V biomedical prototypes compared to wrought Ti–6Al–4V. Materials Characterization, 2009, vol. 60 (2), pp. 96–105. DOI: 10.1016/j.matchar.2008.07.006. 6. Facchini L., Magalini E., Robotti P., Molinari A. Microstructure and mechanical properties of Ti‐6Al‐4V produced by electron beam melting of pre‐alloyed powder. Rapid Prototyping Journal, 2009, vol. 15 (3), pp. 171– 178. DOI: 10.1108/13552540910960262. 7. Gong X., Lydon J., Cooper K., Chou K. Beam speed effects on Ti–6Al–4V microstructures in electron beam additive manufacturing. Journal of Materials Research, 2014, vol. 29 (17), pp. 1951–1959. DOI: 10.1557/ jmr.2014.125. 8. Pushilina N., Stepanova E., Stepanov A., Syrtanov M. Surface modification of the EBM Ti-6Al-4V alloy by pulsed ion beam. Metals, 2021, vol. 11 (3), p. 512. DOI: 10.3390/met11030512. 9. Fedorov V.V., Rygin A.V., Klimenov V.A., Martyushev N.V., Klopotov A.A., Strelkova I.L., Matrenin S.V., Batranin A.V., Deryusheva V.N. Strukturnye i mekhanicheskie svoistva nerzhaveyushchei stali, sformirovannoi v usloviyakh posloinogo splavleniya provoloki elektronnym luchom [Structural and mechanical properties of stainless steel formed under conditions of layer-by-layer fusion of a wire by an electron beam]. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2021, vol. 23, no. 4, pp. 111–124. DOI: 10.17212/1994-6309-2021-23.4-111-124. 10. Suo H., Chen Z., Liu J., Gong S., Xiao J. Microstructure and mechanical properties of Ti-6Al-4V by electron beam rapid manufacturing. Rare Metal Materials and Engineering, 2014, vol. 43 (4), pp. 780–785. DOI: 10.1016/ s1875-5372(14)60083-7. 11. ASTMD2845-08. Standard test method for laboratory determination of pulse velocities and ultrasonic elastic constants of rock (Withdrawn 2017). ASTM International, 2008. 12. GB/T 38897-2020. Non-destructive testing – Measurement method for material elastic modulus and Poisson’s ratio using ultrasonic velocity. StateAdministration for Market Regulation, National StandardizationAdministration. China, 2020. 20 p. (In Chinese). 13. State Standard 25095–82. Sintered hardmetals. Method of determination of elastic modulus (of Young’s modulus). Moscow, Standards Publ., 1982. 10 p. (In Russian). 14. GOST R 57862–2017. Composites. Determination of dynamic young’s modulus, shear modulus and Poisson’s ratio by sonic resonance. Moscow, Standartinform Publ., 2017. 15 p. (In Russian). 15. ASTM E2546-15. Standard practice for instrumented indentation testing. ASTM International, 2015. 16. ISO 14577-1:2015. Metallic materials – Instrumented indentation test for hardness and materials parameters – Part 1: Test method. ISO, 2015. 46 p. 17. GOST R 8.748–2011. Metallic materials – Instrumented indentation test for hardness and materials parameters – Part 1: Test method. Moscow, Standartinform Publ., 2011. 28 p. (In Russian). 18. GB/T 21838.1-2019. Metallic materials – Instrumented indentation test for hardness and materials parameters – Part 1: Test method. State Administration for Market Regulation, National Standardization Administration. China, 2019. 40 p. 19. Wu S.-J., Chin P.-C., Liu H. Measurement of elastic properties of brittle materials by ultrasonic and indentation methods. Applied Sciences, 2019, vol. 9 (10), p. 2067. DOI: 10.3390/app9102067. 20. Broitman E. Indentation hardness measurements at macro-, micro-, and nanoscale: A critical overview. Tribology Letters, 2017, vol. 65 (1), art. 23. DOI: 10.1007/s11249-016-0805-5. 21. Zolotorevskii V.S. Mekhanicheskie svoistva metallov [Mechanical properties of metals]. 3rd ed.Moscow, MISIS Publ., 1998. 400 p. 22. Fougere G.E., Riester L., Ferber M., Weertman J.R., Siegel R.W. Young’s modulus of nanocrystalline Fe measuredbynanoindentation. Materials ScienceandEngineering:A, 1995, vol. 204 (1–2), pp. 1–6.DOI: 10.1016/09215093(95)09927-1. 23. Noskova N.I., Mulyukov R.R. Submikrokristallicheskie i nanokristallicheskie metally i splavy [Submicrocrystalline and nanocrystalline metals and alloys]. Ekaterinburg, UrO RAN Publ., 2003. 279 p. 24. Lutfullin R.Ya., Trofimov E.A., Kashaev R.M., Sitdikov V.D., Lutfullin T.R. Young’s modulus of titanium alloy VT6S and its structural sensitivity. Letters on Materials, 2017, vol. 7 (1), pp. 12–16. DOI: 10.22226/24103535-2017-1-12-16. 25. Sumner D.R., Turner T.M., Igloria R., Urban R.M., Galante J.O. Functional adaptation and ingrowth of bone vary as a function of hip implant stiffness. Journal of Biomechanics, 1998, vol. 31 (10), pp. 909–917. DOI: 10.1016/ S0021-9290(98)00096-7.
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