Study on strengthening mechanism of Ti/Cu electron beam welding

• Published in: Materials & design Vol. 121; pp. 51 - 60
• Main Authors: Guo, Shun, Zhou, Qi, Peng, Yong, Xu, Xiangfang, Diao, Chenglei, Kong, Jian, Luo, TianYuan, Wang, KeHong, Zhu, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.05.2017
• Subjects: Adjacent welding; Dissimilar welding joints; Intermetallic compounds; Welding-brazing; Welding-brazing; Adjacent welding; Intermetallic compounds; Dissimilar welding joints
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2017.02.054

Welding-brazing method is widely used for dissimilar metals welding. However, it is becoming increasingly difficult to further improve the connection strength by controlling the formation of the transition layer. In this study, an innovative welding method referred to as adjacent welding was addressed, which greatly improved the tensile strength of Ti/Cu dissimilar joint. The strength of new joint could reach up to 89% that of copper base metal, compared to the use of a traditional welding-brazing method which strength coefficient is within the limit of 70%. In order to determine the strengthening mechanism of adjacent welding, optical microscopy, SEM, EDS and XRD were applied for the analysis of microstructure and phase structure. Furthermore, tensile strength was also tested. The results show that due to the process of remelting and reverse solidification of intermetallic compounds (IMCs) layer, a less complex and thinner IMCs layer was formed and TiCu (553HV) with high embrittlement existing in the front of titanium substrate was changed into Ti2Cu (442HV). Performances of joints were optimized by these changes. An interpretation module was presented for the mechanism. [Display omitted] •An innovative welding method referred to as adjacent welding was addressed for Ti/Cu welding.•Adjacent welding could greatly improve the strength of Ti/Cu joint.•An interpretation module was presented for the strengthening mechanism.