Alloying of TiC-FeCr cermet in manganese vapor

Abstract

Conventional vacuum sintering is not suitable for producing manganese containing cermets because of the physical-chemical properties of manganese, high vapor pressure, combined with high sintering temperature of cermets (1400-1600 °C). Sintering in Mn-rich microatmosphere does not only prevent Mn loss, but also enables additional in-situ alloying of the binder phase during sintering. We studied alloying of TiC-based cermet bonded with high chromium steel during sintering in Mn-rich atmosphere. Sintering in manganese vapor was found to increase sinterability of the TiC-FeCr cermet, resulting in the formation of ∼1 mm thick Mn-rich surface layer with homogeneous microstructure while the core region of the material remained unaffected. This core region exhibited highly increased Mn content and competitive mechanical properties – hardness of ∼1200 HV30 and indentation fracture toughness of ∼13 MPa*m^1/2. In addition, an unusual ε-type martensitic phase was observed in the surface layer.