Abstract
The tensile deformation behavior by {11\bar22}⟨\bar1\bar123⟩ slip of zinc thin sheet crystals was investigated at the temperature range from 168 to 423 K. It became clear by the observations of slip lines and etch pits that the deformation mode in yielding at temperatures lower than room temperature was inhomogeneous, while that at temperatures higher than r.t. was homogeneous. The mean free path of edge dislocations decreased with increasing temperature. A yield stress-temperature curve showed a negative slope at the low temperatures and a positive slope at the high temperatures. The former dependence was explained by the Peierls mechanism, and the latter dependence by the thermally activated conversion from glissile edge dislocation to sessile one. The work hardening ratio increased rapidly with increasing temperature. It was found that m=1.43 and n=0.57 at 207 K and m=0.48 and n=0.19 at r.t. in the relationships of ρ∝σm and ρ∝εn, where ρ is the dislocation density, σ the flow stress and ε the strain. The unload hardening in the work hardening stage at 207 K increased with increasing unloading time. It was concluded that the work hardening at 207 K was controlled by prismatic loops.
