Microstructure and micro-texture evolution during the dynamic recrystallisation of a Ni-30Fe-Nb-C model alloy

摘要

The evolution of microstructure and micro-texture during discontinuous dynamic recrystallisation of an austenitic Ni-30Fe-Nb-C model alloy subjected to interrupted plane strain compression at strains (ε) of 0.23, 0.35, 0.68, 0.85 and 1.2 was investigated using electron backscattering diffraction and transmission electron microscopy. Throughout the strain range, the majority of dynamic recrystallisation events comprised nucleation in necklace-like arrangements located at and along grain boundaries via bulging. At ε ≥ 0.68, discrete nucleation events were also observed within grain interiors. Grain growth during dynamic recrystallisation is characteristic of strain induced boundary migration. The initial texture comprised Cube-RD ({013}〈100〉), Cube-ND ({001}〈310〉) and Cube ({001}〈100〉) orientations. Up to ε ≤ 0.35, the unrecrystallised grain fractions comprised the Brass ({110}〈112〉) or Copper ({112}〈111〉) orientations and an intensity spread near Rotated Goss ({011}〈011〉). Between 0.68 ≤ ε ≤ 1.2, the texture of the unrecrystallised grain fractions was similar to that of the recrystallised grains throughout the strain range; both of which are dominated by the Cube orientation. The dominance of the Cube orientation in the secondary deformed and recrystallised grains can be ascribed to its low stored energy and orientation stability.