Effect of minor addition of silicon on deformation behaviour and texture evolution in CrFeNi medium entropy alloy

The present investigation systematically explores the effect of a minor addition of silicon on the microstructure, texture, and mechanical properties of FCC CrFeNi medium entropy alloy during rolling at room temperature. The addition of 2 at% Si in CrFeNi alloy results in the reduction of stacking fault energy from 22.4 mJ/m2 for CrFeNi to 18.6 mJ/m2 for (CrFeNi)98Si2 alloy. Bulk texture analysis reveals the presence of Brass and Goss texture components in the 90 % rolled samples. Microtextural study reveals that in CrFeNi and (CrFeNi)98Si2 alloy, Goss-orientated grains exhibit greater stability throughout the deformation compared to Cu-oriented grains. In addition to twinning, profuse shear banding was observed in both alloys at 90 % rolling reduction. The mechanical properties of homogenised (CrFeNi)98Si2 alloy demonstrate the enhanced combination of yield strength and hardness due to improved solid solution strengthening and dislocation strengthening accompanied by a marginal decrease in ductility due to twinning-induced strain hardening. While in 90 % rolled CrFeNi and (CrFeNi)98Si2 alloy, both yield strength and ultimate tensile strength increase drastically due to enhanced solid solution and dislocation strengthening though with a significant decrease in ductility.