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
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