铝基复合材料/低碳钢异种材料过渡液相扩散焊

Transient liquid phase bonding of dissimilar materials of aluminium metal matrix composites/low carbon steel

用市售厚约50μm的纯铜箔作中间层在590℃分别保温30 min及2h进行了铝基复合材料/低碳钢异种金属过渡液相扩散焊试验。结果表明,薄弱界面并非钢/中间层界面,而在于Al MMC/残留中间层一侧界面;液相优先溶解铝基复合材料的棱边而形成明显的环状缺口将导致应力集中;被挤出的多余液相全部流布于铝基复合材料的外表面,而未曾流向钢一侧。断口分析表明,接头沿残留中间层内部(压力较低时)及AlMMC的表层区断裂(压力较高时);Fe向残留中间层内发生了过渡的溶解,足以形成金属间化合物,由此导致接头强度均很低。

Transient liquid phase bonding of dissimilar materials of aluminium metal matrix composite(MMC)/low carbon steel was carried out using 50 μm thick commercial copper foil at 590℃ for 30 min and 2h,respectively.The results show that the weak interface is not interlayer/steel interface,but the residual interlayer/MMC interface;the edge of MMC preferentially dissolved by extruded liquid phase leads to a circular notch around faying surface;and the extruded liquid phase spread towards MMC side,but not towards steel side.From the fracture surface, it is known that the joint fracture occurs within the residual interlayer(under lower pressure) or the surface region of MMC(under higher pressure);iron atoms can be remarkably dissolved into interlayer to form intermetallic compounds in metal matrix.Therefore,the joint strengths were low.