Finite Element Simulation of Pyroplastic Deformation for Ceramic Bodies During Liquid Phase Sintering Process

Increasing the amount of vitreous phase formed in the ceramic body during the liquid phase sintering process, with decreasing in its viscosity leads to the pyroplastic deformation. It sometime causes to crack, failure or rejection of ceramic parts, so the prediction and modification of these deformation is the key factor for ceramic manufacturing process. Physical and mechanical behavior of the ceramic body during sintering process including the viscose flow deformation, anisotropic shrinkage, heterogeneous densification, as well as sintering stress, have significant influence on the both final body dimensional precision and densification process. In this paper, the finite element method has been developed to study pyroplastic deformation, physical, and mechanical behavior of hard porcelain ceramic body during liquid phase sintering process. After raw materials analysis, the standard hard porcelain mixture as a ceramic body was designed and prepared. The finite element method for the ceramic specimens during the liquid phase sintering process are implemented in the CREEP user subroutine code in ABAQUS. Densification results confirmed that the bulk viscosity was well-defined with relative density. Dilatometry, SEM, XRD investigations as well as bulk viscosity simulation results confirmed that the “mullitisation plateau” was presented as a very little expansion at the final sintering stage, because of the highly amount of mullite formation.