Heat treatment is well-known to be effective to improve the performance of Cu-Cr alloys.The solid solution process of Cu-Cr alloys mostly selects the lower temperature Cu-Cr two-phase region,resulting in incomplete dissolution of Cr phase and inhibiting subsequent precipitation strengthening effect.A high-temperature single-phase region solid solution process was proposed to improve the strengthening effect.The effects of different solid solution processes((950℃,4 h)in the two-phase region and(1050℃,6 h)in the single-phase region)on the microstructure and properties of Cu-Cr alloy were comparably studied.The element distribution after two solid solution processes was characterized by electron probe microanalyzer(EPMA),and the microstructure of the peak-aged alloy was characterized and analyzed by XRD and TEM.The results show that,compared with solid solution in the two-phase region,the cast Cr phase is fully dissolved after solid solution in the single-phase region,and more nano Cr phases precipitate during aging.The mechanical properties of the alloy are significantly improved compared to those of the alloy at the peak-aged state after solid solution in the two-phase region,the yield strength increases by 29.3％and tensile strength increases by 25.6％,while the electrical conductivity does not decrease significantly.Strength theory calculations results indicate that the yield strength increment contributed by precipitation strengthening is 323.4 MPa,accounting for 56.9％,which is the most significant strengthening mechanism in this study.
Cu-Cr alloysolid solution in single-phase regionprecipitation strengtheningelectrical conductivity
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