2009 Volume 49 Issue 4 Pages 582-586
The austenite of the Hadfield type manganese steels (1.0–1.4% C; 12–14% Mn), even though able to be hardened by impact, explosion, etc., is very ductile, tough and deformable, so that the industrial parts made with this material often suffer important geometric deformations during service. To minimize this problem, it is necessary to reinforce the austenitic matrix with hard, microscopic and dispersed ceramic particles, such as TiC, in order to increase the austenite stiffness while maintaining its toughness. Indeed, the development of a liquid metallurgy process enabling the reinforcement by means of the addition of the ceramic material to the molten metal in the melting furnace would become an important advance in this field. Nevertheless, these ceramic products are prone to the coalescence and have poor wettability by the molten bath, so that, their yield and the subsequent property improvement is very low.
These disadvantages are solved if the ceramic particle is a complex carbide (TiMo)C bonded by metallic Fe, having a masteralloy of the Fe(TiMo)C type made by self-propagated high temperature synthesis (SHS). After that, its addition to the liquid austenitic manganese steel, the pouring of the mix (steel+carbides), its solidification, for example in sand molds, and the subsequent heat treatment (solution annealing and rapid quenching) produces composite castings or parts composed by an austenitic matrix and discrete carbide (TiMo)C particles inserted in it.
This paper describes the process required to fabricate such a material and its characteristics.