Analysis and understanding of the permeability-porosity relationship of powder materials by cold compaction and solid-state hot sintering is very important for material design and optimization. This work presents a pore-scale numerical framework, including a discrete element method for powder cold compaction, a cellular automata algorithm with curvature-driving redistribution for solid-state hot sintering and a lattice Boltzmann method for fluid flow simulation, to study the permeability-porosity relationship of materials by cold compaction and solid-state hot sintering processes. The results show that the cubic scaling law always holds for the porous materials by cold compaction, while the hot sintering process decreases the permeability dramatically at low porosity. An exponential decay function has been proposed as a correction factor to the permeability-porosity relationship of materials by compaction & sintering processes, which predicts the permeability asymptotically approaching to the cubic scaling law at high porosity while agreeing well with both numerical and experimental data at low porosity. The microstructure evolution analysis shows that the small pores that connect large pores may vanish by sintering, which causes the remarkable permeability decrease at low porosity. The excellent agreements between the numerical predictions and the experimental measurements suggest that the proposed numerical framework provides a powerful tool for analysis and optimization of material designs.

分析和理解冷压和固态热烧结粉末材料的渗透率-孔隙率关系对于材料设计和优化非常重要。这项工作提出了一个孔隙尺度的数值框架，包括用于粉末冷压的离散元方法、用于固态热烧结的具有曲率驱动再分布的元胞自动机算法和用于流体流动模拟的格子玻尔兹曼方法，以研究渗透率-冷压和固态热烧结过程中材料的孔隙率关系。结果表明，冷压多孔材料的立方比例定律始终成立，而热烧结过程在低孔隙率下显着降低了渗透率。已提出指数衰减函数作为压实和烧结过程中材料渗透率-孔隙率关系的校正因子，它预测渗透率在高孔隙率下渐近地接近立方比例定律，同时与低孔隙率下的数值和实验数据吻合得很好孔隙率。微观结构演化分析表明，连接大孔隙的小孔隙可能因烧结而消失，导致低孔隙率下渗透率显着下降。数值预测与实验测量之间的良好一致性表明，所提出的数值框架为材料设计的分析和优化提供了强大的工具。它预测渗透率在高孔隙率下渐近地接近立方比例定律，同时与低孔隙率下的数值和实验数据吻合得很好。微观结构演化分析表明，连接大孔隙的小孔隙可能因烧结而消失，导致低孔隙率下渗透率显着下降。数值预测与实验测量之间的良好一致性表明，所提出的数值框架为材料设计的分析和优化提供了强大的工具。它预测渗透率在高孔隙率下渐近地接近立方比例定律，同时与低孔隙率下的数值和实验数据吻合得很好。微观结构演化分析表明，连接大孔隙的小孔隙可能因烧结而消失，导致低孔隙率下渗透率显着下降。数值预测与实验测量之间的良好一致性表明，所提出的数值框架为材料设计的分析和优化提供了强大的工具。这导致在低孔隙率下渗透率显着下降。数值预测与实验测量之间的良好一致性表明，所提出的数值框架为材料设计的分析和优化提供了强大的工具。这导致在低孔隙率下渗透率显着下降。数值预测与实验测量之间的良好一致性表明，所提出的数值框架为材料设计的分析和优化提供了强大的工具。