High-temperature deformation behavior of a novel high strength and high elasticity Cu–20Ni–20Mn–0.3Nb–0.3Cr–0.1Zr alloy

Abstract The elongation of high-strength copper alloy with tensile strength over 1300 MPa is generally less than 3%. In this paper, a novel Cu–20Ni–20Mn-0.3Nb-0.3Cr-0.1Zr(wt.%) alloy was prepared, of which the tensile strength, elastic modulus and elongation is 1445 MPa, 147 GPa and 6.8%, respectively. The flow stress strain and microstructure evolution during high temperature deformation at different strain temperatures and strain rates are studied to obtain the high temperature deformation law and dynamic recrystallization mechanism of the alloy. The research shows that the flow stress of the design alloy increases rapidly with the increase of the strain during the initial stage of thermal deformation. When the strain rate is higher and the strain temperature is lower, the peak value of flow stress is larger. The thermal activation energy of the designed alloy is 353.31 kJ/mol. When the strain temperature is 650°C–720 °C and the strain rate is 0.1s−1-5s−1, the alloy is in the hot deformation instability zone. The optimal deformation temperature of the alloy is 750°C–850 °C. When the deformation temperature reaches 800 °C, dynamic recrystallization occurs in the alloy structure. When the design alloy is deformed at a temperature of 850 °C, the recrystallization power of the alloy is mainly the deformation stress energy, and the degree of recrystallization mainly depends on the strain rate. At this time, the faster the strain rate is, the more obvious the recrystallization effect is, and even the recrystallization grain growth will occur.