Cuboidal γ' phase coherent precipitation-strengthened Cu–Ni–Al alloys with high softening temperature

Abstract Coherent precipitation of cuboidal γ' phase is an efficient strategy to improve high temperature properties in nickel-based alloys. The present work aims to introduce this strengthening mechanism into copper alloys to solve the issue of deficient heat resistance. The results shown that a series of cuboidal γ' coherent precipitation-strengthened Cu100-y(Ni3/4Al1/4)y alloys were obtained in the (Ni+Al) content range of 20 at. % to 50 at. %. These alloys are shown to exhibit excellent comprehensive mechanical properties, high melting point, and a softening temperature of 1273K or more than 1273K. Their hardness and yield strength increased with the rise of temperature, ascribing to splitting of γ′ phase. AFM surface current mode and three-dimensional reconstruction of microstructure was performed to determine that γ phases remain conductive body in Cu100-y(Ni3/4Al1/4)y alloys, and meanwhile temperature-dependent resistivity was characterized and discussed, which showed the improvement of resistivity thermal stability attributing to coherent precipitation of γ' phase. Comparing to other Cu commercial alloys, cuboidal γ' phase coherent precipitation-strengthened alloys possess a great potential under high-temperature loads and service environments. In further researches, continued efforts will be required in the multi-component design of Cu100-y(Ni3/4Al1/4)y alloys to improve the comprehensive performance.