A novel method to examine the effect of Al addition on the microstructure of CoCrFeNiMn high-entropy alloy

A novel approach was employed to investigate the effect of Al addition on the microstructure of a CoCrFeNiMn high-entropy alloy (HEA). A two-layer structure consisting of CoCrFeNiMn with a low-melting Al interlayer was subjected to heat treatment at temperatures of 600, 700, and 800 °C for up to 48 h. The purpose was to directly examine phase formation and phase stability in Al-added alloys. As a result, the heating process at 700 and 800 °C led to the formation of a few microns multilayers, primarily composed of B2-type NiAl and σ phases at the interface and the earlier temperature showed relatively good bonding. These experimental findings were complemented by CALPHAD predictions and considered physical aspects for phase prediction. This concept holds significant benefits for alloy design as it offers a cost-effective and time-saving method to investigate phase formation and stability at different temperatures in complex multi-component alloys.