Optimization of Heat Treatment of CuNiSiCrRE Alloy

By means of Brinell hardness tester and eddy-current conductometer as well as SEM, the effects of solid solution temperature, aging and cold deforming before aging on microstructure and properties of the CuNiSiCrRE alloy were studied, then the optimum heat treatment was determined. The results show that the optimized heat treatment process was solution at 900 ℃ for 1.5 h with cooling in water, 40% cold-working and aging at 480 ℃ for 2 h with cooling in air. The hardness was 229 HB, electrical conductivity was 45.6%IACS, tensile strength reached 674 MPa, yield strength was 641 MPa, elongation was 16% and softening temperature was 540 ℃. Tensile fracture was ductile fracture.