银铜复合带在低过载电流下沿界面分断的失效机理研究  

Failure Mechanism of Ag/Cu Composite Strips Break Along the Interface Under Low Overload Current

作　　者：张陕南 侯江涛 沈元勋 钟素娟 秦建 龙伟民 ZHANG Shannan;HOU Jiangtao;SHEN Yuanxun;ZHONG Sujuan;QIN Jian;LONG Weimin(State Key Laboratory of High Performance&Advanced Welding Materials,China Academy of Machinery Zhengzhou Research Institute of Mechanical Engineering Co.,Ltd.,Zhengzhou 450001,China)

机构地区：[1]中国机械总院集团郑州机械研究所有限公司,高性能新型焊接材料全国重点实验室,郑州450001

出　　处：《材料导报》2025年第9期132-136,共5页Materials Reports

基　　金：国家自然科学基金(U22A20191)。

摘　　要：银铜复合带以铜代银,相较于纯银熔体材料节银降本,且满足大功率、高低压电路的熔断保护需求,是新一代熔断器用熔体材料,具有广阔的市场应用前景。针对复合带材低过载电流下沿Ag/Cu界面分断,而非纯银狭径处分断的非正常失效现象,通过研究不同折弯工艺下,折弯前后及低过载电流测试前后的界面组织演变、元素分布及电性能变化规律,揭示了银铜复合带异常分断失效模式及机理。结果表明,折弯工艺会影响复合带分断失效模式,折痕位于Ag/Cu界面时,局部应力会使Ag/Cu界面处产生微裂纹。当低过载电流通过带材时,在界面表层集肤效应的作用下,微裂纹的存在使得局部电阻升高而引起热量快速积聚,铜原子沿着界面向银侧大量扩散,并形成了大尺寸的低熔点银铜共晶组织区,具有较低分断条件,另外由于银、铜原子扩散速率的差异,极易形成大量Kirkendall空洞,并进一步扩展形成大的“陨坑”状结构,贯穿带材造成破坏,从而引起带材沿着Ag/Cu界面分断非正常失效。The Ag/Cu composite strip,replacing Ag with Cu,represents a new generation of fuse material with a wide market application prospect compared with pure Ag fuse material due to its advantages such as saving Ag and reducing cost,meeting the needs of high power,high and low voltage circuit fuse protection.There is an abnormal failure phenomenon that the composite strip breaks along the Ag/Cu interface under low times of overload current instead of breaking at the narrow diameter of pure Ag.For this phenomenon,the abnormal break failure mode and mechanism of Ag/Cu composite strips were revealed by studying the interfacial microstructure evolution,element distribution and electrical properties before and after bending and before and after the low overload current test in different bending processes.The results show that the bending process changes the break failure mode of the composite strips,and when the fold is at the Ag/Cu interface,the local stress causes microcracks around the Ag/Cu interface.When the low-fold overload current passes through the strip,under the role of skin effect in the interface surface layer,the existence of microcracks makes the local resistance increase,causing rapid heat accumulation.A significant number of Cu atoms diffused through the interface to the Ag strip,resulting in the formation of large-sized low-melting point Ag/Cu eutectic zones with lower breaking conditions.Due to the difference in the diffusion rate of Ag and Cu atoms,it easily forms a large number of Kirkendall voids at the interface,which can subsequently expand to create a large crater-like structure through the strip to cause damage,resulting in the strip along the Ag/Cu interface breaking abnormal failure.

关 键 词：银铜复合带 熔体材料 组织演变 银铜共晶 分断机理 

分 类 号：TG454[金属学及工艺—焊接] TM241[一般工业技术—材料科学与工程]