Latent hardening in high‐density polyethylene

摘要

When a parallelopiped specimen is compressed in the x direction (primary deformation) while holding the y dimension unchanged by a vise, the specimen is anisotropically hardened as follows: When the y direction is subsequently compressed while holding the x dimension unchanged the flow stress is higher than the case without the primary deformation. This is similar to the latent hardening in single crystals. On the other hand, if the second compression is in the z direction instead of the y direction, a softening results. Since this second compression reverses the primary deformation, it is similar to the Bauschinger effect. Both effects are reported here together with the results of two successive compressions in two mutually perpendicular directions without any constraints in either compression.