A study on carbon concentration distribution and microstructure of P/M materials prepared by carbusintering

Carbusintering (CBS) process was used to produce powder metallurgy (P/M) parts (Fe–2Ni–1.5Cu–xC). Influence of sintering parameters such as temperature on diffusion coefficient of carbon was investigated. The specimen with the porosity of 6–13% got the carbon content of the surface ranged from 1.23 to 1.32 wt.%. After heat treatment, the hardness and impact energy were enhanced to 48 HRC (484 HV) and 13 J, respectively. The change in carbon concentration along the case depth was determined quantitatively by means of chemical analysis. The carbon concentration profile was satisfactorily modeled by classical solution derived from Fick’s second law. An undesired acicular structure was observed in the specimen with low green compact density due to the high carbon content. CBS process can provide outstanding performance in surface hardening of P/M materials. The use of CBS process was able to make process simple by taking sintering and carburizing as one step. The higher carbon content of the surface in P/M parts can be easily achieved compared to conventional carburizing.