Dimensional Change During Sintering of Fe–Cu–C Alloys: A Comparative Study

Abstract

In the present study, varying contents of elemental copper (1–8 wt%) and carbon (0.3–1.25 wt%) were added in iron powder to investigate the dimensional changes of Fe–Cu–C pellets during sintering. Further, two types of copper powders of different sizes (coarse and fine) were employed to determine the effect of copper particle size on the expansion behaviour of Fe–Cu–C. All pellets were compacted at 637 MPa pressure and sintered at 1120 °C under a flowing N2–10 % H2 atmosphere. The study indicated that green density of pellets, copper particle size and carbon content are the decisive parameters for the expansion behaviour of Fe–Cu–C alloys. Further, expansion increases with increasing of Cu contents and decreases by increasing carbon contents. Critical quantitative analysis indicated a larger expansion in coarse copper powder (up to 2 wt% Cu) compared to fine copper addition but beyond this expansion was marginal. Higher densification was observed between 0.3 and 0.7 wt% C pellets compared to 0.7 and 1.25 wt% C pellets in case of coarse Cu powder but no such trend was found in case of fine Cu powder. Metallography further supports the expansion behaviour and showed presence of more undissolved copper with increasing carbon content.