Microstructure and mechanical properties of ultrafine Ti(CN)-based cermets fabricated from nano/submicron starting powders

Starting from commercial nano/submicron raw powders, ultrafine grade (mean grain size less than 500 nm) titanium carbonitride (Ti(CN))-WC-Mo-Ni/Ni + Co-C cennets systems were fabricated and their microstructures as well as mechanical properties were characterized, tested and compared with coarse (micron-sized) cermets. Study shows that different raw materials and initial powder particle size play a critical role in determining cermets' microstructure and mechanical properties. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) in combination with energy dispersive X-ray analysis (EDX) reveal that various cermets systems present quite different morphological and structural characteristics. The reasons why these differences come about were discussed and the formation mechanism of a new type core/rim structure (white core and grey rim) was proposed too. Mechanical property testing was conducted and was related to the microstructural features. (c) 2004 Elsevier Ltd and Techna Group S.r.l. All rights reserved.