Near-net-shape forming of alumina powder under hot pressing and hot isostatic pressing

Densification and deformation of alumina powder under hot pressing and hot isostatic pressing were investigated. Finite element calculations were performed by implementing constitutive equations for grain growth, power law creep and diffusional creep in the user defined subroutine CREEP of ABAQUS. An alumina compact of valve head shape was produced under hot pressing and Its forming process was predicted by the finite element calculation. Densification behavior of an alumina powder compact encapsulated by a stainless steel container was also investigated under hot isostatic pressing. Inhomogeneous deformations of an alumina powder compact due to the shield effect of a container during hot isostatic pressing were observed experimentally and predicted by the finite element analysis. (C) 1997 Elsevier Science Ltd.X118sciescopu