Effect of gravity on dimensional change during sintering - II. Shape distortion

Phenomena of shape distortion caused by gravity under solid- and liquid-phase sintering are described numerically using the finite-element method based upon a continuum theory of sintering. Finite-element analysis is performed for the solid-phase sintering of a copper powder cylindrical specimen to replicate earlier experiments reported by Lenel et al (Trans. Am. Inst. Min. Engrs, 1963, 227, 640). The results of the finite-element calculations are also compared with experimental data on liquid-phase sintering of a W-Ni-Fe powder system using a quantitative criterion of shape distortion. It is demonstrated that shape distortion accumulated during solid-phase sintering should be taken into account when considering gravity-induced configuration-dimensional changes under liquid-phase sintering. The finite-element analysis of shape distortion under liquid-phase sintering reproduces an elephant foot shape-a final shape observed in sintering practice. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.