Texture and Cross Slip Effects on Ultrasonic Wave Velocity Changes Under Simple and Pure Shear States.

Abstract

Although stress and strain states are same in simple and pure shear states, longitudinal wave velocity changes propagating in the plastically deformed medium under simple and pure shear states are apparently different each other according to authors' theoretical and experimental research works. The objective of this paper is to discuss the effect on ultrasonic wave velocity changes due to texture and cross slip under simple and pure shear states via finite element polycrystal analysis. In small plastic deformation range, in spite of quite different longitudinal wave velocity changes under simple and pure shear states, the texture developments and transverse wave velocity changes under both states are similar each other. That suggests dependence of transverse wave velocity on texture. Next, the multiplicative amounts of intersected slides between primary and secondary slip systems, which relates closely to the amount of cross slip, under simple and pure shear states are examined. The result, i.e., this multiplicative amount under pure shear state is larger than that under simple shear state, means the point defects induced by cross slip are much easier to introduce under pure shear state than under simple shear state and suggests that the point defects induced by cross slip may cause quite different longitudinal wave velocity changes.