TiC-High Mn Steel-Bonded Cermets with Improved Strength and Impact Toughness

TiC-high Mn steel-bonded cermets are prepared by powder metallurgy techniques. The effects of (Ti0.5W0.5)C or WC on the microstructure, hardness, transverse rupture strength (TRS), and impact toughness (IM) are investigated. The results show that regardless of the additives used, the hardness and TRS of cermets increase with the increase in W content. However, IM is not directly proportional to the W content. Peak IM value is obtained at 5% WC addition. The highest IM of 15.12 J cm(-2) is measured from the cermet with (Ti0.5W0.5)C additive with a hardness and TRS of 64.8 HRC and 2510 MPa, respectively. Liquid phase sintering occurs at vacuum sintering. Black core-gray outer rim structure is formed in cermets with WC additives and white inner rims appear in cermets with higher W content. White core-gray rim structure is formed in cermets with (Ti0.5W0.5)C additives. The impact fracture mode of the cermets is the intergranular fracture accompanied by the tearing edges of the binder. The tearing of the high Mn steel binder is the main source of IM. IM peaks are attributed to the contradictory effects of decreased fraction and refined binder microstructure.