厚板铜/铝搅拌摩擦焊接头的组织分析

Microstructure of friction stir welded joint of Cu/Al dissimilar metals thick plate

用搅拌摩擦焊方法焊接板厚为10 mm的铜/铝对接接头,观察了接头的横截面形貌、显微组织,测试了接头的拉伸性能、显微硬度和电阻率。结果表明,在合适的工艺参数下采用双面焊工艺可能获得无缺陷的对接接头。金相分析结果表明,接头的铜/铝界面上形成了"钩子"形貌且铜和铝在该处形成的一种迭状交互结构,产生了一种灰色物质,焊核区中分布着铜颗粒。在接近铜铝界面区域内显微硬度值急剧升高,可能是产生了金属间化合物。接头拉伸式样的断裂都发生在铝侧热影响区,接头的拉伸强度是铝母材的125%。电阻率试验结果表明铜/铝接头的电阻率是纯铝母材的电阻率的92.6%,能够满足电力行业的要求。

Friction stir welded 10 mm Cu/A1 butt joints was conducted, and the cross-sectional morphology, microstructures, tensile strength, microhardness and electrical resistivity were investigated. The results showed that the butt joint without defects was obtained by double-sided welding process with appropriate welding parameters. The Cu was exhibited in the form of hook at the Cu/A1 interface at the joint, and some gray lamellar organization was formed near the Cu/A1 interface, and some Cu particles were found in the welding nugget. A sharp increase in the microhardness was shown near to the Cu/AI interface, which was due to the formation of intermetallics. The butt joints were all fractured at the base metal of aluminum and had good strength,which was 125% of the pure AI. The electrical resistivity of the Cu/A1 joint was 92.6% of the pure A1, which could well meet the requirements of power industry.