(1. 中南大学 材料科学与工程学院，长沙 410083； 2. 粉末冶金国家重点实验室，长沙 410083)
摘 要: 利用硬度计、双臂电桥、金相显微镜、透射电镜和背散射电子衍射观察等技术研究Cu-0.3Mg-0.16Ca(质量分数，%)合金在加工过程中组织结构的演变规律及性能变化。结果表明：设计合金经780 ℃、1 h固溶处理后冷轧变形状80%时，硬度为167HV，抗拉强度为545 MPa，电导率70.24%IACS；当变形量达到90%时，硬度为174HV，抗拉强度为600 MPa，电导率为68.68%IACS，均高于同状态下的高铁接触线用CTMH型Cu-0.4Mg合金的性能。设计合金固溶态组织为以大角度晶界为主的等轴晶，所占比例最高的是60°的大角度晶界；随着冷变形的进行，合金组织中开始出现分布不均匀的小角度晶界，随着变形量的进一步增加，小角度晶界先增多后减少。当变形量达到80%时，合金轧面的变形织构以S剪切织构和Copper织构为主，此时合金显微组织中的变形条带发生弯曲，向胞状组织过渡。
关键字: Cu-Mg-Ca合金；高强度；高电导率；显微组织
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. State Key Laboratory of Powder Metallurgy, Changsha 410083, China）
Abstract:The microstructure evolution of the designed Cu-0.3Mg-0.16Ca (mass fraction, %) alloy was studied by metallographic microscopy, transmission electron microscopy and electron backscattered diffractometry. The result shows that, after being homogenized at 780 ℃ for 1 h, followed by cold rolling with a reduction of 80%, the designed alloy shows prospective comprehensive properties with tensile strength of 545 MPa and electrical conductivity of 70.24%IACS. When being cold-rolled to 90% reduction, the tensile strength and electrical conductivity of Cu-0.3Mg-0.16Ca (mass fraction, %) alloy approach 600 MPa and 68.68%IACS, respectively, which are both higher than those of CTMH Cu-0.4Mg alloy that is commonly used in high-speed railway contact wires. The fraction of low-angle grain boundaries of the alloy increases and then decreases with the increase of deformation. After a cold rolling reduction of 80%, the textures of S and Copper are predominatant.
Key words: Cu-Mg-Ca alloy; high strength; high electrical conductivity; microstructure
