前驱体浸渍法制备泡沫镍屈服强度与孔结构的关系

Relationship between yield strength and pore structure of nickel foam prepared by impregnation method

采用有限元模拟技术计算不同孔结构泡沫镍的屈服强度,并以气雾化Ni-20Cr合金粉末为原料,以不同孔径的聚氨酯泡沫为模板,控制浸渍工艺制备出不同孔径与不同密度的泡沫镍铬合金,研究合金屈服强度随密度与孔径尺寸的变化关系。有限元模拟计算结果表明,开孔泡沫金属材料的屈服强度符合Gibson-Ashby方程,在开孔泡沫金属材料密度一定的情况下,材料的屈服强度不随孔径的变化而变化。实验结果表明,对于相同孔径的泡沫金属材料,其屈服强度和相对密度的关系为σ/σs与相对密对(即ρ/ρs)的1.5次方呈线性关系(σ和σs分别为泡沫材料与致密材料的屈服强度;ρ和ρs分别为泡沫材料与致密材料的密度);而具有相同密度和不同孔径的泡沫镍铬合金,其屈服强度很接近,验证了开孔泡沫金属材料屈服强度随密度的变化规律符合Gibson-Ashby方程。

The yield strength of nickel foam with different pore structure were calculated by using finite element simulation. Nickel alloy foams with different density were prepared using polyurethane foam as precursor through controlling impregnation process. Relationship between pore size and yield strength of nickel chromium alloy foam was then studied. The simulation results show that the yield strength of open cell metal foam is in accordance with the Gibson-Ashby equation. That is, the yield strength of metal foam does not change with the pore size while the density of the foam material is constant. The experimental results show that for the metal foam with the same pore structure, the relationship between the yield strength and the relative density accords with Gibson-Ashby equation. And for nickel chromium alloy foam with same density and different pore size, the yield strength are very close to each other, which further verifies Gibson-Ashby equation.