Effect of Annealing Temperatures on Phase Stability, Mechanical Properties, and High-Temperature Steam Corrosion Resistance of (FeNi)67Cr15Mn10Al5Ti3 Alloy

Abstract

The effect of different annealing temperatures on the phase stability and mechanical properties of (FeNi)67Cr15Mn10Al5Ti3 high-entropy alloys (HEAs) was studied. The phase stability was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscattering diffraction (EBSD). The mechanical properties of the alloy were characterized by hardness and tensile tests. Furthermore, the heat-resistant corrosion properties of the (FeNi)67Cr15Mn10Al5Ti3 alloy after annealing at 800 °C was tested under high-temperature steam. The results indicated that HEAs exposed to different annealing temperatures always exhibited the face-centered cubic (FCC) phase. With rising annealing temperature, the dendrite structure of the alloys in the as-cast condition gradually disappeared, with recrystallization and precipitation of larger grains. The tensile strength of the alloy first increased and then decreased with the rising annealing temperature, the hardness and yield strength of the alloy decreased slightly, and the tensile elongation varied greatly. These findings can be used as a basis for improving the phase stability and mechanical properties of a Cr-Fe-Ni-Mn-HEA system with unequal atomic ratios. The heat and corrosion resistance of the alloy at 360 °C and 400 °C was better than that of Zr-4 alloy.