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研究Cu-2.7%Al2O3弥散强化铜合金的微观组织及其高温力学行为。结果表明:细小的Al2O3粒子均匀分布在铜基体当中,部分粗大的Al2O3粒子分布在晶界上。拉伸试验表明Hall-Petch机制是影响氧化铝弥散强化铜合金室温屈服强度的主要因素,其高温强度主要由于Al2O3粒子对晶界和亚晶界与位错的强烈钉扎作用。合金在700°C下的抗拉强度和屈服强度分别达到237 MPa和226 MPa。拉伸断口表明弥散强化铜合金显示出高温脆性。蠕变测试表明400°C下的稳态蠕变速率比700°C下的稳态蠕变速率小很多,其400°C和700°C的蠕变应力指数分别为7和5,蠕变机制为位错核心扩散型和晶格扩散型蠕变。
Study on Microstructure and High Temperature Mechanical Behavior of Cu-2.7% Al2O3 Dispersion Strengthened Copper Alloy. The results show that the fine Al2O3 particles are uniformly distributed in the copper matrix and some coarse Al2O3 particles are distributed on the grain boundaries. Tensile tests show that the Hall-Petch mechanism is the main factor affecting the yield strength of alumina dispersion-strengthened copper alloys at room temperature. The high temperature strength is mainly due to the strong pinning effect of Al2O3 particles on grain boundaries and subgrain boundaries and dislocations. Tensile strength and yield strength of the alloy reached 237 MPa and 226 MPa respectively at 700 ° C. Tensile fracture shows that dispersion strengthened copper alloys exhibit high temperature brittleness. Creep tests show that steady-state creep rates at 400 ° C are much smaller than steady-state creep rates at 700 ° C with creep stress indices of 7 and 5 at 400 ° C and 700 ° C respectively. Creep mechanisms Dislocation of the core and diffusion lattice creep.