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通过对开孔泡沫铝进行拉伸实验,考察了泡沫金属材料的非均匀性对其拉伸性能的影响。首先,通过分析同一批试件的初始密度,考察了材料的初始非均匀性;其次,重点考察了初始密度对材料破坏特性的影响。分析表明,即使初始密度比较接近的试件,它们的破坏应力和应变也有较大的离散性;对于不同初始密度的试件,破坏强度有随初始密度的增加而变大的趋势,但破坏应变则无明显的变化规律。因此,对于泡沫金属这种细观结构非均匀性比较严重的材料,仅仅使用初始密度尚不足以刻画其材料特征。对泡沫铝的拉伸破坏特性进行了图像分析,结果表明,材料的拉伸破坏主要是由拉伸后期才出现的细观结构破坏引起的。这说明,早期的拉伸非线性特征主要是由材料的强非均匀性导致基体材料屈服而引起的。
Through the tensile test of open-cell aluminum foam, the influence of the non-uniformity of the foam metal material on the tensile properties was investigated. First of all, by analyzing the initial density of the same batch of samples, the initial non-uniformity of the material was investigated. Secondly, the influence of the initial density on the failure characteristics of the material was investigated emphatically. The analysis shows that the specimens with different initial densities have greater dispersion stress and strain. For the specimens with different initial densities, the fracture strength tends to increase with the initial density, but the strain There is no obvious change rule. Therefore, for the foam metal, a kind of material with more inhomogeneous microstructure, just using the initial density is not enough to characterize the material. The tensile failure characteristics of aluminum foam were analyzed by image analysis. The results show that the tensile failure of the material is mainly caused by the destruction of meso-structure which occurs only in the late stage of drawing. This shows that the early tensile non-linear features are mainly caused by the material’s strong non-uniform yield caused by the matrix material.