Effect of Zr addition on the AlCoCrFeNiZrx high-entropy alloy

Adding alloying elements is a common way to regulate the microstructure in the high entropy alloys (HEAs). In this study, the effect of Zr addition on the crystal structure and mechanical properties of high entropy alloys was explored by XRD, molecular dynamics simulation and nanoindentation test. The results show that with the increase of the Zr element ratio, the crystal structure of the alloy changes from BCC to a mixed crystal structure including FCC and amorphous structure. The nanoindentation test shows that the hardness of the alloy increases first and then decreases with the increase of Zr element ratio, among which the hardness of Zr0.8 alloy is the highest, while the elastic modulus decreases with the increase of Zr ratio. In addition, molecular dynamics simulation also found that stacking faults exist in Zr0.8 alloy, forming Lomer-Cottrell (L-C) locks, which significantly improved the performance of the material.