Effects of grain boundary and chemical short-range order on mechanical properties of NiCoCr multi-principal element alloys: A molecular dynamics simulations

Abstract

Due to their outstanding mechanical properties, multi-principal element alloys (MPEAs) are attracting exceptional interest. In this work, we used molecular dynamics (MD) simulations to investigate the effects of grain boundaries (GBs) and chemical short-range order (CSRO) on the mechanical properties of NiCoCr MPEAs. We demonstrated that the presence of various grain boundaries and CSRO affects these characteristics by analyzing lattice distortion, elastic constants, elastic moduli, the Kleinman parameter, the machinability index, and the Vickers hardness of NiCoCr MPEAs. Elastic moduli show a rising trend with grain boundaries and CSRO, indicating that NiCoCr becomes more rigid. Our studied MPEAs are ductile according to Cauchy pressure, Pugh’s ratio, and Poisson’s ratio. According to the results of the anisotropy factor analysis, NiCoCr MPEAs are inherently anisotropic, and the addition of CSRO exacerbates this property. The presence of CSRO and GBs has an important effect on the mechanical features of MPEAs including as stability, fracture toughness, and ductility. The findings suggest that a better understanding of these effects can contribute to the design and development of MPEAs with enhanced mechanical characteristics for a variety of applications.