Deformation Behavior of Superalloy Powder Compact under Hot Isostatic Pressing

Herein, the deformation behavior of a superalloy powder compact under hot isostatic pressing (HIP) is investigated by implementing an elastic-plastic constitutive model into the finite element analysis software MSC Marc. The coefficients of the constitutive model are obtained from interrupted HIP experiments. Finite element calculation results for the shape change of the powder compact under HIP agree well with the experimental results. Isothermal HIP and containerless HIP, both of which are based on finite element simulations, are conducted to study the dependence of the deformation on the container and temperature gradient. The stress state in all of the regions in the powder body deviates from the isostatic state of the compact even under isostatic pressing, due to the introduction of von Mises stress under the strong influence of the container. The temperature gradient is affected by the characteristic thermal conductivity and specific heat capacity of the porous powder body and container. Nonuniform temperature and stress distribution result in nonuniform densification, which eventually results in uneven powder compact shrinkage.