Low-temperature annealing behavior and tensile properties of the rapidly solidified Cu3Ag0.5Zr0.4Cr0.35Nb alloy reinforced by cold rolling

Abstract

To obtain a uniform microstructure with fine second-phase particles, the Cu3Ag0.5Zr0.4Cr0.35Nb alloy is fabricated through gas atomization and hot isostatic pressing, followed by cold rolling. The microstructural evolution and tensile properties of the alloy after isothermal annealing at low temperature are investigated. The results show that the low-temperature annealing leads to an obvious increase in elongation but a mild decrease in strength, and the desirable combinations of strength and elongation after annealing for different times are achieved. When annealed at 350 °C for 1 h, the alloy exhibits a high strength of 665 MPa and an acceptable elongation of 10%. Prolonging the duration to 8 h, a decreased strength (610 MPa) and high elongation (15%) are obtained. The stable nano-sized Cr2Nb and micro-sized Cu4AgZr particles provide a strong pinning effect on boundary migration and significantly slow the subgrain growth during recovery, which contributes to the retention of good strength. The improved ductility results from the recovered ability to accumulate dislocations after annealing.