Expansion During Liquid Phase Sintering of Iron–Copper Compacts

Abstract

An attempt has been made to develop a quantitative approach to the swelling during isothermal liquid phase sintering of Fe–Cu compacts. The time dependent expansion was followed during sintering at 1150°C by measuring anisotropic changes in dimensions using photography and micrometry. Cylindrical compacts containing up to 20%Cu, pressed at 200, 250, and 300 MPa, were examined. Differences were observed in the extent of swelling, sintering behaviour, and sintered structure between compacts containing ≤5%Cu and ≥10%Cu; these differences can be reasonably attributed to differences in the quantity of the fused melt. The extent of swelling can be assessed satisfactorily on the basis of the bulk density of green compacts, which reflects both powder characteristics and compaction conditions. Such an assessment enables quantitative comparison of results obtained under different sintering conditions. PM/0501