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以电解加钛6009变形铝合金为研究对象,利用扫描电镜研究了电解加钛6009变形铝合金在单向拉伸载荷下的断裂机理,观察了裂纹的萌生与扩展过程。研究结果表明,电解加钛6009变形铝合金的断裂过程与一般塑性材料基本相同,局部应力集中和应变造成粗大的分散相和基体分离及缺陷是裂纹优先萌生的部位。裂纹的扩展主要是平行于滑移条纹扩展和沿晶扩展,当裂纹尖端有较大Mg2 Si颗粒存在时,微裂纹会在Mg2 Si/基体界面再形核而扩展,最终导致合金断裂。
Taking electrolytic titanium 6009 deformed aluminum alloy as the research object, the fracture mechanism of electrolytic titanium alloy 6009 under uniaxial tensile load was studied by scanning electron microscope, and the initiation and propagation of cracks were observed. The results show that the fracture process of electrolytic titanium alloy 6009 is basically the same as that of the general plastic materials. The localized stress concentration and strain cause the coarse dispersed phase and the matrix separation and the defect is the preponderant crack initiation site. The crack propagates mainly parallel to the slippage fringes and along the grain growth. When larger Mg2 Si particles exist at the tip of the crack, the micro-cracks will expand and nucleate again at the interface of Mg2 Si / matrix, finally resulting in the fracture of the alloy.