Different Lattice Distortion Effects on the Tensile Properties of Ni-W Dilute Solutions and CrFeNi and CoCrFeMnNi Concentrated Solutions

Abstract

The lattice distortion from a solute is mainly due to atomic size and chemical bonding differences with neighboring atoms. The lattice distortion effects in conventional alloys and high-entropy alloys are known to be different but lack of clarification. In this study, FCC-structured dilute solid solutions of Ni, Ni–2at.%W, and Ni–4at.%W and concentrated solutions of equiatomic CrFeNi and CoCrFeMnNi metals were designed to compare their tensile properties. The lattice distortion of both W-containing alloys was only around the large and strong W atoms but that of the two concentrated solutions with similar inter-element atomic size and shear modulus prevailed at all lattice sites. Results showed that the trends in both types of lattice distortion were significantly different on tensile properties. The combination with strength and ductility from high concentration of distorted lattice points was superior over that from low concentration ones even the latter had larger nominal atomic size difference and shear modulus difference. The evolution mechanisms on different mechanical properties from dilute alloys to concentrated alloys were elucidated and clarified under the large contrast of lattice distortion. The universal solid solution strengthening mechanism had been established.