Dislocation density model for the effect of grain size on the flow stress of a Ti-15.2 at.% Mo β-alloy at 4.2-650 K

摘要

Hall-Petch (H-P) plots of the effect of grain size d=4.6-22 μm on the flow stress σ at 4.2-650 K of a β-Ti—15.2 at.% Mo alloy gave that the parameter σ_i increased with strain ε and with decrease in temperature T. In contrast, the parameter K_(H-p) was relatively independent of ε and T. The corresponding dislocation density p increased with ε and with decrease in d, giving the well-known relation σ/M ≈0.5 μbρ~(1/2), where M is the Taylor factor. The magnitudes of σ and K_(H_P) calculated from ρ were in reasonable agreement with those obtained from the H-P plots. The grain size dependence of σ was in accord with Li's grain boundary ledge mechanism.