形变热处理对Cu-6.5Ni-1Al-1Si-0.15Mg-0.15Ce合金微观组织及性能的影响

摘要

The Cu-6.5Ni-1Al-1Si-0.15Mg-0.15Ce alloy was designed and prepared. The evolution of microstructure and properties during thermo-mechanical treatment were studied using optical microscopy, scanning electron microscopy, energy dispersive spectrum and transmission electron microscopy. The results show that, the microstructure of as-casting alloy is typical dendritic structure;the dendritic structure disappears after hot rolled at 920℃;the optimal solid-solution treatment for the alloy is solution treated at 960℃for 4 h. Cold deformation after solid-solution treatment has obviously effect on the properties of the alloy. Increasing the cold deformation rate, the time to approach the peak of hardness decreases, and the peak of hardness and conductivity increase;the higher the solution treatment temperature is, the faster the precipitate precipitates. After solid solution treated at 960℃for 4 h and cold rolled by 50%, then aged at 450℃for 120 min, its hardness reaches 300.8 HV, electrical conductivity is 20.6%IACS, tensile strength is 963.9 MPa and yield strength is 950.1 MPa. The nano-scale precipitates in the matrix areδ-Ni2Si. The relationships between the precipitate and matrix is:Cuδ[001] [001] , Cuδ(110) (010) , Cuδ(1 10) (100) .%设计并制备 Cu-6.5Ni-1Al-1Si-0.15Mg-0.15Ce(wt.%)合金。采用光学显微镜(OM)、扫描电镜(SEM)、能谱分析和透射电镜(TEM)等测试手段研究合金形变热处理过程中微观组织及性能的变化。合金铸态组织为典型的枝晶组织，铸锭经过920℃热轧后，枝晶组织显著消除。合金的适宜固溶处理制度为960℃/4 h。该合金固溶处理后的冷变形对合金最终性能有很大影响。冷变形程度越大，合金达到硬度峰值的时间越短，硬度峰值和电导率越高。时效温度越高，时效析出过程越快。960℃固溶4 h后冷轧50%，450℃时效2 h硬度峰值可达300.8 HV，电导率20.6%IACS，抗拉强度963.9 MPa，屈服强度950.1 MPa。合金在时效过程中析出纳米级粒子为δ-Ni2Si，其与基体的位相关系为：Cuδ[001][001], Cuδ(110)(010), Cuδ(110)(100)。