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以粒度为38~150μm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。
The porous metal materials with different porosity were prepared from two kinds of stainless steel powders (irregular shape and spherical shape) with particle size of 38-150μm. The porous metal materials were sintered in a vacuum furnace at 1250 ℃ for 2 h. The porosity and compressive strength of sintered samples were measured by Archimedes’ law and computerized universal mechanical testing machine respectively. The microstructure of sintered samples was observed by optical microscope. Finally, the fractal dimension of pore structure was calculated by fractal theory. The relationship between porosity, compressive strength and fractal dimension was analyzed. The results show that the fractal dimension increases with the increase of porosity. In addition, the Boltzmann model satisfies the fractal dimension and the porosity, while the compressive strength and the fractal dimension satisfy the exponential model.