Interface bonding mechanism of AZ31 magnesium alloys during accumulative roll-bonding (ARB) was studied by scanning electron microscopy. The results indicate that a good bonding is achieved during ARB by 50% thickness reduction at 300℃ and the subsequent rolling improves the bonding of interfaces introduced in the previous cycles. The ARB specimens show a typical ductile fracture with dimples and shear zones even at the bonded interface. When bonding is insufficient, the fracture surfaces are characterized by micro-cracks. Interface bonding process during ARB consists of two opposing brittle surface layers being deformed and broken up, underlying metals being exposed and extruded under the action of normal rolling pressure through widening cracks in the surface layers and contacting with each other. Bonding quality can be improved by annealing after ARB.%采用扫描电境观察了AZ31镁合金在累积叠轧焊(ARB)过程中的界面焊合现象.结果表明:轧前预热温度为300℃和道次压下量为50％的累积叠轧焊工艺可以使AZ31板材获得良好的界面焊合,后续的累积叠轧焊变形可以有效改善界面焊合质量.ARB板材的拉伸断口呈现典型的延性断裂形貌,界面未形成良好焊合的部分呈现裂口焊合形貌.累积叠轧焊变形中的界面焊合过程包括:表面硬化脆性层减薄、断裂,氧化膜破碎,暴露出来的新鲜金属在轧制压力的作用下沿裂纹流动、相互接触,形成冶金结合.后续退火可以改善界面焊合质量.
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