Synergetic strengthening from grain refinement and nano-scale precipitates in non-equiatomic CoCrFeNiMo medium-entropy alloy

A strategy to improve the tensile properties of Co17.5Cr12.5Fe55Ni10Mo5 (at%) medium-entropy alloy through high-pressure torsion and subsequent annealing is presented in this work. Microstructural study revealed that the high-pressure torsion process led to the formation of fine grains (<=-1 mu m) and profuse nano-scale Mo-rich mu-phase precipitates. And resultantly, the yield strength of the alloy was tuned from -400 MPa to -1 GPa, while preserving reasonable uniform elongation over 15%. The combination of strengthening from grain refinement and precipitation contributed to the excellent strength, while the post-HPT annealing provided substantial ductility.

Automated summary

A strategy to improve the tensile properties of Co17.5Cr12.5Fe55Ni10Mo5 medium-entropy alloy through high-pressure torsion and subsequent annealing was presented. The combination of grain refinement and precipitation contributed to excellent strength, while post-HPT annealing provided substantial ductility, resulting in a yield strength of 1 GPa with over 15% uniform elongation.