Enhanced assessment of technological factors for Ti-6Al-4V and Al-Cu-Mg strength properties

OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 23 No. 4 2021 Sample data and comparison of simulation and experiment results Sample material Sample type Sample dimensions Stress concen- trator dimen- sions, mm Stress Amplitude in the experiment exp a  , MPa Stress amplitude in simulation num a  , MPa h , mm b , mm VT6 /( Ti-6Al-4V ) without a hole 2.1 9 – 348 351 with a hole Ø 1.5 245 223 D16 / ( Al-Cu-Mg ) without a weld 1.5 12 – 130 132 without a weld □ 1.5 80 118 Conclusions 1. Experimental dependences of temperature and total strains on the magnitude of the stress amplitude are obtained for homogeneous and inhomogeneous stress-strain state in the region of concentrators, which simulate the in fl uence of technological factors on the strength of samples made of titanium ( VT6 ) and aluminum ( D16 ) alloys. 2. It is established that: a) the amplitude of critical stresses for samples made of VT6 alloy with a stress concentrator in the form of a hole is less by 30 % or more than that of samples without holes; b) the amplitude of critical stresses of samples made of alloy D16 with a concentrator in the form of a weld is 38 % less than that of samples without weld. 3. Veri fi cation fatigue tests of the samples con fi rmed the validity of the accelerated assessments and conclusions 2. 4. The simulation results for fl at samples with a hole and with a weld showed satisfactory agreement of the stress amplitudes between the experimental data and the simulation results. This correspondence makes it possible to carry out qualitative numerical estimates of the onset of accumulation of inelastic strain in structures with stress concentrators during cyclic deformation with an increasing stress amplitude. The modeling used a standard model of an elastoplastic body with hardening. References 1. Troshchenko V.T., Sosnovskii L.A. Soprotivlenie ustalosti metallov i splavov [Fatigue resistance of metals and alloys]. Kiev, Naukova Dumka Publ., 1987. 1302 p. 2. Ivanova V.S. Strukturno-energeticheskaya teoriya ustalosti metallov [Structural-energy theory of fatigue of metals]. Tsiklicheskaya prochnost’metallov [Cyclic strength of metals]. Moscow, Academy of Sciences of the Soviet Union Publ., 1962, pp. 11–23. 3. Cof fi n L.F. Low-cycle fatigue: a review. Applied Material Research , 1962, vol. 1, no. 3, pp. 129–141. 4. BathiasC. Gigacycle fatigue inmechanical practice .Vergal,Marcel Dekker, 2005. 304 p. ISBN9780203020609. DOI: 10.1201/9780203020609. 5. Naito T., Ueda H., Kihushi M. Fatigue behavior of carburized steel with internal oxides and non-martensitic microstructure near the surface. Metallurgical Transactions A, Physical Metallurgy and Materials Science , 1984, vol. 15, no. 7, pp. 1431–1436. 6. Kanazawa K., Nishijima S. Fatigue fracture of low alloy steel at ultra-high cycle regime under elevated temperature conditions. Journal of the Society of Materials Science , 1997, vol. 46, no. 12, pp. 1396–1400. DOI: 10.2472/jsms.46.1396. 7. Murakami Y., Nomoto T., Ueda T. Factors in fl uencing the mechanism of superlong fatigue in steels. Fatigue and Fracture of Engineering Materials and Structures , 1999, vol. 22, no. 7, pp. 581–590. DOI: 10.1046/j.1460- 2695.1999.00187.x.