Relationship between Compressive Strength and Fractal Dimension of Pore Structure

摘要:

以粒度为38~150 μm的两种不锈钢粉末（不规则形状和球形）为原料制备了不同孔隙度的金属多孔材料，将其在真空炉中于1250℃进行烧结，保温时间为2 h。然后利用阿基米德定律和计算机控制万能力学试验机分别测试烧结试样的孔隙度与压缩强度，采用金相显微镜观察烧结试样的微观组织，最后利用分形理论计算孔结构分形维数，并分析了孔隙度、压缩强度与分形维数的关系。结果表明：分形维数随着孔隙度的增加而逐渐增大。另外，分形维数与孔隙度之间满足玻耳兹曼模型，而压缩强度与分形维数满足指数模型

Abstract:

Two kinds of stainless steel powders, having spherical shape and irregular one with the particle sizes from 38 μm to 150 μm were used to produce porous metal materials, the specimens were sintered at 1250 °C for 2 h in vacuum. Their porosities and compressive strength were tested using Archimedes’ principle and a computer controlled universal testing machine, respectively. Furthermore, the microstructures were observed by an optical microscope. In addition, the fractal theory was used to investigate the fractal dimension of the pore structure and analyze the relation ship between the compressive strength, the porosity and the fractal dimension. The results show that the fractal dimension increases gradually with increasing of the porosity. The relation ship between the fractal dimension and the porosity can be expressed using the Boltzmann model. The compressive strength and the fractal dimension can be presented by the exponential model