Effects of sintering schedule on the characteristics of fe-based powder compacts formed through warm compaction route

Abstract

This paper presents the sintering characteristics of Fe-based powder compacts formed through the warm compaction method. Iron powder ASC100.29 (73 wt%), chromium powder (22 wt%), and aluminium powder (5 wt%) were mixed mechanically for 60 mins in preparing the feedstock. The powder mixture was subsequently compacted at 200°C through simultaneous loading of 325 MPa from upper and lower punches. The defectfree green compacts were then sintered in an argon gas fired furnace at a rate of 10°C/min by varying the sintering time (30, 60, and 90 mins) and temperature (600, 750, and 900°C), respectively. The sintered samples were characterized through physical and mechanical properties and their microstructures were analysed through scanning electron microscopy. The results revealed that sintering at 900°C for 90 mins contributed to the highest volumetric expansion and relative density change, which are not expected in the powder metallurgy industries. A moderate sintering temperature of 750°C for a holding time of 60 mins was found to produce a sintered sample with higher bending strength. In these sintering conditions, better dispersion of the alloyed elements is also observed. © Universiti Malaysia Pahang Publishing.