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为了更清楚地认识颗粒增强铝塑性差的细微观机制 ,进行了 (Al2 O3) P/6 0 6 1Al的拉伸和三点弯曲变形实验 ,并用扫描电镜观察了变形与断裂的细微观特征。发现 :(1)在加载过程中 ,总是基体先发生变形局部化 ,形成变形带 ;变形带内较大的 Al2 O3颗粒优先开裂 ,形成颗粒尺度的微裂纹 ;变形带内的集中变形和 Al2 O3颗粒的继续开裂交互作用 ,导致微裂纹沿着变形带连接与扩展进而发生宏观低塑性断裂 ;(2 )加载方式、材料状态和变形温度对上述过程没有本质影响。根据以上观察结果和颗粒增强铝的强化机理 ,讨论了塑性差的细微观机制以及材料状态和变形温度对 (Al2 O3) P/6 0 6 1Al塑性的影响
In order to understand the microscopic mechanism of poor ductility and poor ductility, a (Al 2 O 3) P / 6 0 6 1Al tensile and three point bending deformation test was carried out. The microscopic characteristics of deformation and fracture were observed by SEM. It is found that: (1) In the process of loading, the deformation and localization of the Al 2 O 3 particles in the deformation zone are preferentially caused by the deformation and localized deformation of the matrix, and the formation of grain-scale micro-cracks; the concentrated deformation in the deformation zone and Al 2 O3 particles continue to crack interaction, resulting in micro-cracks along the deformation zone connection and expansion and then macro-low plasticity fracture; (2) loading mode, material state and deformation temperature of the above process has no essential effect. Based on the above observations and the enhanced mechanism of particle reinforced aluminum, the microscopic mechanism of poor ductility and the effect of material state and deformation temperature on the (Al 2 O 3) P / 6 0 6 1Al plasticity