ABSTRACT An aluminium/steel CMT-welded joint is mainly composed of fusion zone (FZ), interfacial intermetallic compound (IMC) zone, and heat-affected zone (HAZ). IMC and FZ are the weakest link in the welded joint. The fatigue fracture indicates that the lattice distortion caused by the lattice mismatch of Fe2Al5 and Fe is more likely to engender dislocation slipping and cracks easily nucleate during the fatigue testing. The hysteresis loop is shifted to the right, which indicating that the specimen experiences a ratcheting effect. In the high-stress condition, the cyclic hardening induced by the ratcheting strain is much stronger than that in the lower stress condition, which improves the fatigue life of the materials.

中文翻译：

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冷金属过渡熔融钎焊铝/钢异种接头疲劳损伤研究

摘要 铝/钢 CMT 焊接接头主要由熔合区 (FZ)、界面金属间化合物 (IMC) 区和热影响区 (HAZ) 组成。IMC和FZ是焊接接头中最薄弱的环节。疲劳断裂表明Fe2Al5和Fe晶格失配引起的晶格畸变更容易引起位错滑移，疲劳试验中裂纹容易形核。滞后回线向右移动，这表明样品经历了棘轮效应。在高应力条件下，棘轮应变引起的循环硬化比低应力条件下强得多，从而提高了材料的疲劳寿命。