退火温度对小变形拉拔Cu-0.08Ag合金组织性能的影响

目的 在分析变形量为25%的小变形拉拔加工Cu-0.08Ag合金组织与性能的基础上，研究不同退火温度对小变形拉拔Cu-0.08Ag合金微观组织、力学性能和导电性能的影响规律，为Cu-Ag合金电磁线漆包工艺的制定提供参考。方法 利用电子背散射衍射(EBSD)技术对Cu-0.08Ag合金小变形拉拔及200~500 ℃不同温度退火1 h后的样品进行组织表征，结合显微硬度计、拉伸试验机和电阻计等手段对性能进行综合分析。结果 经变形量为25%的小变形拉拔后，Cu-0.08Ag合金等轴晶组织部分晶粒沿变形方向被拉长，<111>和<100>取向占比均增大，应力集中分布在<111>晶粒内，屈服强度提高了270%，而电导率仅下降了4.1%IACS。小变形拉拔Cu-0.08Ag合金的软化温度为350 ℃。与小变形拉拔态相比，在300 ℃及以下退火时显微组织和力学性能未发生明显变化，而电导率提升了2.9%IACS。在400 ℃及以上退火时，无畸变的等轴晶粒取代变形晶粒，并产生大量的退火孪晶，晶粒取向随机分布，力学性能和电导率与小变形拉拔前的相当。结论 在300 ℃以下退火后，小变形拉拔Cu-0.08Ag合金在保持较高屈服强度的同时，其电导率也获得了提升，可获得强度和电导率良好的匹配关系。

Effect of Annealing Temperature on Microstructure and Properties of Cu-0.08Ag Alloy with Small Deformation

The work aims to study the effects of different annealing temperature on the microstructure, mechanical and electrical properties of Cu-0.08Ag alloy based on the analysis of the microstructure and properties of Cu-0.08Ag alloy with a small deformation of 25% by drawing process, so as to provide insights for the formulation of Cu-Ag alloy electromagnetic wire coating process. The microstructure of Cu-0.08Ag alloy after small deformation drawing and annealing at different temperature ranging from 200-500 ℃ for 1 hour was characterized by electronic backscattering diffraction (EBSD) technique. The microhardness, tensile properties and resistance properties of Cu-0.08Ag alloy were analyzed by means of microhardness tester, tensile tester and resistance meter. The results showed that some grains of Cu-0.08Ag alloy were elongated along the deformation direction after a small deformation of 25%. The proportion of <111> and <100> orientation grains increased while the internal stress distribution was concentrated in <111> grains. The yield strength increased by 270%, and the conductivity decreased by 4.1% IACS. The softening temperature of Cu-0.08Ag alloy after small deformation was 350 ℃. The microstructure and mechanical properties did not change significantly when the Cu-0.08Ag alloy was annealed below 300 ℃, and its conductivity increased by 2.9% IACS compared with the small deformation drawn state. When the as-deformed Cu-0.08Ag alloy was annealed at 400 ℃ and above, the undistorted equiaxed grains replaced the deformed grains, a large number of annealing twins were produced, and the grain orientation was randomly distributed. Moreover, the mechanical properties and conductivity returned to the values before the small deformation. Therefore, annealing below 300 ℃ of the as-deformed Cu-0.08Ag alloy can improve the conductivity significantly while maintaining high yield strength. The results are in a good balance between strength and conductivity.