Effect of particle shape on microstructure and compressive response of 316L SS foam by space holder technique

Abstract

316 L stainless steel (SS) foams with varying porosities have been developed through PM route using irregular and spherical particles shaped SS powder using urea as space holder. The effect of SS particle shape on microstructure and compressive deformation behaviour of SS foams with varied relative density were studied. The cell size and the cell wall thickness in the foam produced by both types of shapes are comparable. The yield stress, elastic modulus, plateau stress, plastic modulus, micro-hardness and energy absorption values are higher in the foam made through irregular particle shape as compared to spherical one inspite of slightly lesser relative densities. This is due to presence of higher micro-porosities in the cell wall in the foam produced by spherical particles. Therefore, the densification strain is slightly higher in SS foam made with spherical particles. The presence of fewer contacts between spherical powders led to lesser densification in the cell wall region and thus higher micro-porosity evolved. The yield stress, elastic modulus, plateau stress (σpl), plastic modulus and energy absorption (Eab) follow power-law relationship irrespective of SS powder particle shapes. However densification strain follows linear relationship.