Constrained sintering: A delicate balance of scales

Sintering is a common technique for the production of ceramic, metallic and composite bodies and components. During this process it is known that internal stresses can arise from external constraint or from differential densification. These stresses can give rise to significant strain rate changes, distortions and damage in the fired parts. For quality control of sintered bodies, it is necessary to measure or predict the changes in deformation behaviour that occurs as the porous starting bodies undergo densification. Contributions of the continuum mechanical approach to this problem of constrained sintering are reviewed. Theoretical predictions as well as experimental techniques and results are detailed. Special emphasis is given to the development of anisotropy that can develop in the microstructure of a sintering body in response to the internal stresses.