亜鉛における{11\bar22}⟨\bar1\bar123⟩すべりの温度依存性

Abstract

The tensile deformation behavior of zinc thin sheet crystals was investigated at the temperature range from 207 to 333 K. The tensile axis of specimens is parallel to 〈11\bar20〉, and the surface is parallel to {0001} (A specimens) or {00\bar10} (B specimens). B specimens showed such anomalous dependence that the yield stress increased from 11 to 13 MPa with increasing temperature, in contrast with the yield stress of A specimens decreasing from 13 to 9 MPa. The length of slip bands which appeared just after yielding decreased from 3 to 0.3 mm, and the mean free path of edge dislocations evaluated by the etch pit technique decreased from 300 to 10 μm with increasing temperature. The stress-strain curves of both A and B specimens exhibited stage I having the small work hardening ratio and then stage II having the large ratio. Stage II began just after the bundle of slip bands widening with strain filled up the whole of specimen. With increasing temperature, the strain of stage I decreased and the work hardening ratio at stage II increased rapidly.From the standpoint of propagation of dislocation multiplication, the above results were explained by structural peculiarity of edge dislocation core, prismatic loops as barriers and dislocation reaction.