Critical strain for the initiation of dynamic recrystallization in a Ni-Fe base alloy

Abstract

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 × 10-4 s-1 - 5 s -1 with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ" (matrix-hardening phase) and δ (grain boundary phase) on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.