Effect of adding a type of binder phase on the microstructure, properties and heat treatment of steel bonded TiC cermets

Particulate TiC reinforced 465 maraging stainless steel matrix Cermets were processed by conventional P/M. The binder phase was added in the form of elemental powders and master alloy powders. The microstructures, binder phase variation with TiC content and mechanical properties were evaluated. The addition of a type of binder phase largely effects the microstructure and mechanical properties. When a master alloy binder phase was used the microstructure showed interphase debondings, microcracks and large growths of TiC particles. Where as, elemental powders in the composition of binder phases showed defect free microstructure of steel bonded cermets. The binder phase variation from starting composition was observed with increase in wt% TiC content and this variation was higher when the master alloy powders were used as a binder. After heat treatment and aging, an increase in hardness was observed. The increase in hardness was attributed to the aging reaction in maraging stainless steel. The response to heat treatment was decreased with an increase in TiC content due to the shift of binder phase from the starting composition.