Effects of Material Heterogeneity on the Tensile Properties of Metal Foams
材料非均匀性对泡沫金属拉伸性能的影响

Experimental investigation of material heterogeneity effect on the tensile properties of metal foam was carried out. Firstly, the material initial heterogeneity was reviewed by analyzing the initial density of specimens of the same group. Next, the review was focused on the effect of initial density on the material failure characteristic. Analytical results show that even for specimens with approximate same initial density, their failure stress and strain still present obvious discreteness. And for the specimens with different initial density, their failure stresses increases with the increment of initial density, but failure strain does not present any obvious regular patterns. Therefore, for metal foam with highly complicated meso-structure heterogeneity, it is not enough to describe their material characteristics only using initial density. Image analysis of the foam aluminum tensile failure characteristics shows that the material failure is caused by the meso- structure's failure appeared at the tensile later stage, which indicates that the nonlinearity at the early tensile stage is mainly caused by the yield of matrix material induced due to the serious heterogeneous meso-structure.