He Ziquan, Liu Fei, Gao Ping, Pang Lihui, Su Yong
School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China.
Materials (Basel). 2024 Nov 22;17(23):5726. doi: 10.3390/ma17235726.
Dissimilar welding between aluminum and copper poses significant challenges, primarily due to differences in their thermal and mechanical properties, resulting in brittle intermetallic compounds, limited joint strength, and high electrical resistivity. This study aims to overcome these issues by employing Ag-18Cu-10Zn filler material and optimizing laser power with a focus on improving joint strength and electrical conductivity. The results indicate that the incorporation of silver and zinc enhances the phase composition and microstructure of the weld. By forming solid solution phases such as AgAl and CuZn, the brittle AlCu phase commonly found in traditional Al/Cu welding is replaced. This not only promotes the heterogeneous nucleation of fine silver-rich grains but also restricts the excessive growth of silver-poor grains, resulting in a uniform distribution of fine grains throughout the weld. These modifications contribute to both fine-grain strengthening and dispersion strengthening. At an optimal laser power of 750 W, joint strength reaches 109 MPa, while joint resistivity decreases to 3.19 μΩ·cm, 12.6% lower than that of the aluminum alloy base material. This study proposes a process for achieving highly conductive, reliable Al/Cu dissimilar metal joints, potentially impacting the aluminum-copper connections in battery modules for new energy vehicles.
铝与铜的异种焊接带来了重大挑战，主要是由于它们在热性能和机械性能方面存在差异，从而导致脆性金属间化合物、接头强度有限以及高电阻率。本研究旨在通过采用Ag-18Cu-10Zn填充材料并优化激光功率来克服这些问题，重点是提高接头强度和电导率。结果表明，银和锌的加入改善了焊缝的相组成和微观结构。通过形成诸如AgAl和CuZn等固溶体相，取代了传统铝/铜焊接中常见的脆性AlCu相。这不仅促进了富银细晶粒的异质形核，还限制了贫银晶粒的过度生长，从而使细晶粒在整个焊缝中均匀分布。这些改进有助于细晶强化和弥散强化。在750W的最佳激光功率下，接头强度达到109MPa，而接头电阻率降至3.19μΩ·cm，比铝合金母材低12.6%。本研究提出了一种实现高导电性、可靠的铝/铜异种金属接头的工艺，可能会对新能源汽车电池模块中的铝铜连接产生影响。
