高性能超细晶高锡磷青铜合金组织及性能研究

Microstructure and Properties of High-Performance Ultrafine Grain High-Tin Phosphorus Bronze Alloy

锡磷青铜兼具优异的强度和弹性性能,可以作为精密仪器仪表和航空航天等技术领域连接器和接插件的关键基础材料。以高性能超细晶粒组织Cu-Sn-P合金带材为研究对象,采用大变形加工率轧制和在线连续光亮退火组合的工艺技术,研究高锡Cu-Sn-P合金冷加工过程硬化规律、再结晶过程组织演变规律与动力学方程,以及不同晶粒尺寸合金带材的折弯特性。结果表明,加工硬化对Cu-Sn-P合金力学性能影响显著,合金的强度和硬度随着加工率的增加而增大。当加工率达到65%时,合金抗拉强度可达980 MPa;同时Sn含量越高,加工硬化效果越明显。当加工率为60%时,Cu-Sn-P合金再结晶初始温度为350℃,再结晶温度升高和保温时间延长均会导致再结晶晶粒尺寸的长大。保温时间到达临界值后晶粒尺寸不再随着时间的延长而继续长大。结合大加工率和在线光亮退火的组合工艺,高锡Cu-Sn-P合金的晶粒尺寸可以达到4~6μm。Cu-Sn-P合金在450~550℃保温时再结晶过程的晶界迁移热激活能Q=18.56 kJ/mol,晶粒长大的动力学方程为D=D_(0)^(2+)5960.4te-2232/T。当抗拉强度≥900 MPa时,超细晶粒Cu-Sn-P合金折弯性能可以达到R/t≤3,表面光滑无裂纹。

Cu-Sn-P alloy has excellent strength and elastic properties,and can be used as the key basic material of connectors and connectors for precision instruments,aerospace and other high-tech fields.The hardening regulation,recrystallization structure evolution,and dynamic equation of high-performance ultra-fine grain structure Cu-Sn-P alloy strip during the preparation process were investigated,combing high deformation rate rolling,online continuous bright annealing technology and bending characteristics of different grain sizes alloy strip.The results showed that work hardening had a significant effect on the mechanical properties of Cu-Sn-P alloy and the higher the processing rate,the higher the strength and hardness of the alloy.The tensile strength of the alloy could reach 980 MPa,when the working rate reached 65%.The initial recrystallization temperature of Cu-Sn-P alloy was 350℃,and the higher the Sn content,the more obvious the work hardening effect.When the processing rate was 60%,both an increase in recrystallization temperature and an extension of holding time might result the growth of recrystallized grain size.However,after the holding time reached the critical value,the grain size no longer continued to grow with the extension of time.By combining high processing rate and online bright annealing,the grain size of high-tin Cu-Sn-P alloy could refine to 4~6μm.The grain boundary migration thermal activation energy could be expressed as Q=18.56 kJ/mol during the recrystallization process of Cu-Sn-P alloy at 450~550℃insulation,and the kinetic equation for grain growth could be expressed as D=D_(0)^(2+)5960.4te-2232/T.R/t of ultrafine grain Cu-Sn-P alloy could be equal or lesser than 3,with no crack free on the surface,when the tensile strength was more than 900 MPa.