ULTRASONIC ANALYSIS OF ELASTIC PROPERTIES OF TWO LEAN POWDER METAL (PM) ALLOYS

摘要

Young's modulus, shear modulus, bulk modulus, and Poisson's ratio were calculated from ultrasonic velocity measurements on tensile bars of two, as-sintered PM alloys that were prepared at varying green densities: (i) Astaloy CrA + 0.7 C, a pre-alloyed material containing 1.8 Cr and 0.1 Mn; and (ii) D.AQ + 0.6 C, a diffusion alloy containing 0.5 Ni and 0.5Mo. For both alloys, linear increases were observed between sintered density and the following: S-wave (shear-wave) velocity, P-wave (tension-compression wave) velocity, and each modulus above. Poisson's ratio was relatively constant with respect to sintered density and alloy composition. Averaged over all specimens was a Poisson's ratio of 0.272. Tensile tests were used to independently investigate the role of composition and sintered density on Young's moduli; results are in good agreement with Young's moduli derived from sound velocity measurements.