Al-Cu-Mg合金的断裂韧性与拉伸延性模拟

基于铝合金中的脆性结晶相在外力作用下发生断裂而形成微裂纹的过程服从Weibun分布，建立了Al-Cu-Mg合金断裂韧性与拉伸延性的细观力学模型。模型的解析表明，在外力作用下由结晶相断裂而形成的微裂纹的体积分数随着外加应力的增加而增加：在相同的外加应力作用下，结晶相含量较高时微裂纹的体积分数也较高。同时模型的计算表明，Al-Cu-Mg合金的拉伸延性及断裂韧性与结晶相的含量及尺寸有很大关系；拉伸延性与断裂韧性随着结晶相体积分数与尺寸的增加而减小；因此通过对铝基体的纯化，减少Fe与Si元素的含量或者通过强化固溶处理可以降低结晶相的体积分数与尺寸，从而提高Al-Cu-Mg合金的拉伸延性与断裂韧性。

Modeling on fracture toughness and tensile ductility of Al-Cu-Mg alloy

A meso-scaled model was developed for the fracture toughness and tensile ductility of Al-Cu-Mg alloy based on the fact that the volume fraction of microcracks caused by the constituents cracking satisfies Weibull distribution under externally applied stress. Model analysis indicates that the volume fraction of microcracks caused by the constituents cracking increases with the externally applied stress. Under the same externally applied stress, the volume fraction of the microcracks increases with that of the constituents. The model calculation indicates that the fracture toughness and tensile ductility of Al-Cu-Mg alloy decrease as the size and volume fraction of the constituents increase. Thus, both purification and enhanced solution treatment can improve the tensile ductility and fracture toughness of Al-Cu-Mg alloy by decreasing the volume fraction and size of the constituents.