Research On High Temperature Mechanical Behavior Of Copper Alloy Materials With Aerospace Power Systems

In this paper, high temperature tensile, high temperature fatigue and high temperature creep behavior of Cu-0.2%Zr and Cu-3%Ag-0.5%Zr alloy have been studied. Test by test, obtained different factors on two alloys'mechanical properties of high-temperature law. Methods of metallographic and SEM have been used,analysis the microstructure and failure fracture of CuZr and CuAgZr alloy systematically,discussion the fracture mechanism of two alloys under different microstructures at high temperature。CuZr and CuAgZr alloy high temperature tensile test results at the same temperature and stretch rate show that, the yield strength, tensile strength of smaller grain size material are batter than the bigger grain size. Results consistent with Hall-Petch relationship. The fracture morphology of SEM results show that, two alloys tensile fracture mechanism of high-temperature ductile fracture along the grain, the fracture of plastic materials, the better the smaller, share of the fracture zone and a larger proportion of fiber.Two alloys in the same stress ratio of high temperature and high cycle fatigue test results show that, under the same stress level, with increasing temperature, fatigue life of the two alloys decreased, smaller grain size materials high temperature and high cycle fatigue life are longer, obtained the fatigue limit at different temperatures of two alloys. At the stage of high-cycle fatigue, comparison with the test stress, temperature impact greater on the fatigue life of two alloys. Intergranular fracture of two alloys are ductile fracture, but fracture characteristics are no significant than temperature tensile fracture.CuZr and CuAgZr alloy at the same strain under high temperature low cycle fatigue test results show that, with increasing temperature, the fatigue performance of the two alloys is improved. CuAgZr alloy in fatigue process showed cyclic softening feature. Fracture surface of the two alloys are more holes, the fracture is mainly intergranular ductile fracture, fracture characteristics of the porous aggregate. Universal slope method using data obtained from the calculated equation are more practical and reliable, the method can be used to predict low cycle fatigue properties of two alloys as an effective criterion. Analysis shows that under the general slope, high temperature low cycle fatigue of CuZr alloy show better performance resistance.High temperature creep test results of two alloys show that, the microstructure of CuZr and CuAgZr alloy have significant changes after creep, and the larger grain size materials have better high temperature creep resistance. In intermediate temperature creep zone, viscous dislocation slip is CuZr and CuAgZr creep process control mechanisms. In high temperature creep zone, the creep process of CuZr and CuAgZr alloy are mainly controlled by grain boundary diffusion mechanism. High temperature creep fracture of CuZr and CuAgZr alloy showed ductile intergranular fracture, and exists secondary cracks. Creep rupture data of two alloys are found Monkman-Grant relationships.