Deciphering micro-mechanisms of plastic deformation in a novel single phase fcc-based MnFeCoNiCu high entropy alloy using crystallographic texture

摘要

Single-phase equiatomic face centre cubic based MnFeCoNiCu multi principle multi-component high entropy alloy was subjected to thermo-mechanical processing followed with state of the art micro-structural and mechanical characterization and crystal plasticity simulations to establish the complete processing-microstructure-texture-property paradigm for the newly developed alloy. A characteristic Brass type texture with strong {110} < 001 > Goss and {110} < 112> Brass component was observed in 90% cold rolled sample. Microstructure of the deformed sample was characterized by absence of twinning for different rolling reductions and micro-scale shear bands were observed in the 90% rolled sample. Annealing treatment at 1173 K for different duration showed negligible change in texture and completely recrystallized microstructure with annealing twins was observed. Hardness and tensile test indicated high strength for the rolled sample and lower strength with higher ductility was observed for the annealed samples. The unique Goss-Brass deformation texture is explained on the basis of operation of partial {111} <112> slip along with conventional {111} <110> octahedral slip by crystal plasticity simulations. The operation of partial slip is attributed to short range ordering in the solid solution alloy which contributes to planar character of slip and leads to Coss-Brass deformation texture. The deformation texture is retained on recrystallization due to insignificant driving force for formation of nuclei of particular orientation and sluggish diffusion during recrystallization.