Development and homogeneity of microstructure and texture in a lamellar AlCoCrFeNi2.1 eutectic high-entropy alloy severely strained in the warm-deformation regime

Artikel i vetenskaplig tidskrift, 2019

The effect of severe warm rolling on microstructure and texture homogeneities was investigated in a lamellar (L12 + B2) AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA). The EHEA 90% warm-rolled at 400 °C showed disordering of the L12 phase and a remarkable increase in hardness. A much finer microstructure was observed on ND-RD (Normal Direction-Rolling Direction) plane as compared with that on the RD-TD (Rolling Direction-Transverse Direction) plane. The L12/Face Centered Cubic (FCC) phase developed α-fiber texture ND//(110) with a particularly strong brass ({110}(112)) component, while the B2 phase developed the usual RD (//(110) and ND (//(111)) fibers. Nevertheless, inhomogeneities in texture were noticed. Upon annealing at 800 °C, the ND-RD showed an ultrafine microduplex structure, while the RD-TD showed a retained lamellar structure. A rather uniform microduplex structure evolved after annealing at 1200 °C due to the accelerated kinetics of transformation at higher temperatures. The L12/FCC phase showed the retention of the α-fiber components, while the B2 phase showed stronger ND-fiber after annealing, although inhomogeneities in texture existed.