Power-law creep model for densification of powder compacts

Densification behaviour of powder compacts by power-law creep during pressure-assisted compaction at an elevated temperature was investigated. A constitutive model was proposed for the densification behavior of powder compacts under a power-law creep situation based on the plastic deformation theory for porous materials which satisfies the uniaxial stress condition. The proposed power-law creep model is compared with Shima and Oyane’s model (Int. J. Mech. Sci. 18 (1976) 285) and Kim and Jeon’s model (Mater. Sci. Eng. A245 (1998) 64). Experimental data generated by hot isostatic pressing of 316L stainless steel powder compacts at a temperature of 1125°C under different pressures from reference were compared with calculated results using the proposed constitutive model. The difference between the calculated results and the experimental values was discussed in conjunction with Ashby’s densification mechanism map or HIP diagram.