The cracking behaviors (i.e. crack morphologies, crack initiation and crack propagations) of titanium (TC4) and aluminum (6061 and 2024) dissimilar alloys welded joints were investigated. The results indicated that the crack initiated in the fusion zone and propagated along the grain boundaries in the fusion zone for the TC4/6061 joint, while the crack formed in the interface and serrated crack propagated in the fusion zone and interface for the TC4/2024 joint. The crack initiation and propagation in the dissimilar joints were indicated based on the thermal cycles and crack characteristics. Owing to the high cracking susceptibility of 6061 aluminum alloy, the crack formed in the fusion zone in the TC4/6061 joint, and the crack occurred in the interface and fusion zone in the TC4/2024 joint on account of the formation of brittle intermetallic compounds. Based on the analysis, the crack formation mechanism for Ti/Al dissimilar joints was clarified and possible approaches were given to avoid the crack formation.

研究了钛（TC4）和铝（6061和2024）异种合金焊接接头的开裂行为（即，裂纹形态，裂纹萌生和裂纹扩展）。结果表明，TC4 / 6061接头的裂纹始于熔合区并沿晶界扩展，而TC4 / 2024的界面处形成的锯齿状裂纹和TC4 / 2024的熔合区及界面处的锯齿状裂纹扩展。联合。根据热循环和裂纹特征表明了异种接头的裂纹萌生和扩展。由于6061铝合金的高裂纹敏感性，在TC4 / 6061接头的熔合区形成了裂纹，由于脆性金属间化合物的形成，裂纹发生在TC4 / 2024接头的界面和熔合区。在分析的基础上，阐明了Ti / Al异种接头的裂纹形成机理，并提出了避免裂纹形成的可能方法。