(1. 河南科技大学 材料科学与工程学院，洛阳 471023；
2. 河南科技大学 有色金属共性技术河南省协同创新中心，洛阳 471023)
摘 要: 采用SEM、EDS、XRD等对苛刻热循环下Sn2.5Ag0.7Cu0.1RExNi/Cu钎焊界面IMC及接头性能进行研究。结果表明：苛刻热循环下Sn2.5Ag0.7Cu0.1RExNi/Cu钎焊界面IMC由(Cu,Ni)6Sn5和Cu3Sn相组成；随热循环周期的增加，钎焊接头的界面IMC (Cu,Ni)6Sn5形态由波浪状转变为局部较大尺寸的“笋状”，IMC平均厚度和粗糙度增大，相应接头剪切强度降低。添加适量Ni 0.05%(质量分数)的钎焊接头界面IMC平均厚度和粗糙度最低，接头剪切强度最高。在100热循环周期内，随热循环周期增加，Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu钎焊接头剪切断口由呈现钎缝处的韧性断裂向由钎缝和IMC层组成以韧性为主的韧-脆混合断裂转变。
关键字: 无铅钎料；苛刻热循环；接头；金属间化合物；性能
（1. College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China;
2. Collaborative Innovation Center of Nonferrous Metals, Henan University of Science and Technology, Luoyang 471023, China）
Abstract:The effect of severe thermal cycling on the IMC and mechanical property of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joint was analyzed by SEM, XRD and EDS. The results show that the Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under severe thermal cycling exhibit duplex intermetallic compounds (IMCs) structure; i.e., a layer of (Cu, Ni)6Sn5 close to the solder and a layer of Cu3Sn adjacent to the Cu substrate. The morphology of the IMC in soldered joints transfers from wavy-shape into larger bamboo shoots with the increasing of thermal cycling, which causes increase of roughness and thickness, as well as decrease of the shear strength. When the Ni adding content of solder alloy is 0.05% (mass fraction), the roughness and average thickness of IMC are the lowest, the shear strength is the highest. Within 100 thermal cycling, the fracture mechanism of the joints exhibits from plastic fracture occured in the solder seam of Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu to ductile-brittle mixed fracture of plastic fracture oriented in the interfacial of IMC and solder seam.
Key words: lead-free solder alloy; severe thermal cycling; solder joints; intermetallic compound(IMC); property
