保温时间对铝/铜钎焊接头界面化合物和力学性能的影响

Influence of dwelling time on interfacial compounds and mechanical properties of aluminum/copper brazing joints

采用Zn-22Al钎料配合KAlF4-CsAlF_4无腐蚀钎剂,在不同保温时间下对铝/铜进行炉中钎焊,研究了保温时间对钎焊接头、微观组织形貌,铜侧界面元素分布以及接头力学性能的影响.结果表明,随着保温时间的延长,Al/Cu接头Cu/钎缝界面CuAl_2化合物由层片状逐渐转变为树枝状并向钎缝内部生长;钎缝中的CuAl_2相由粗大块状转变为长条状或薄片状;Cu/钎缝界面处Zn元素含量峰值在保温时间为2 min时出现在铜母材与AlCu化合物之间,随着保温时间延长,Zn元素峰值逐渐向钎缝内部迁移.同时,铝/铜钎焊接头的抗剪强度随保温时间延长先提高后降低.

Aluminum and Copper was brazed using Zn-22 Al solder with KAlF4-CsAlF4 non-corrosive flux at different dwelling time.The influence of dwelling time on the interfacial microstructure,interfacial elements distribution and mechanical properties of the brazing joints was studied.Results showed that the CuAl_2 interfacial compounds transformed from Lamellar structure to dendritic structure gradually and grew into the brazing seam;CuAl_2 phase transformed from massive structure to strip or foliated structure in the solder layer;the peak of Zn content on the interface of Cu/Solder layer appeared between the AlCu compounds and Cu substrates when dwelling time came to 2 mins,it moved toward the inside of the solder layer if dwelling time extended.Meanwhile,shear strength of Al/Cu brazing joints increased before reducing with the extending of dwelling time.