Design of stable and ultra-hard mixed carbides for increased productivity in machining

Purpose and goal

The project aimed to optimize materials and processes for the newly developed mixed carbide TZrC for increased productivity in machining. It has been demonstrated that TiZrC powder can be prepared, the sintering of WC-Co TiZrC proved to be poor free, but the properties are not significantly better than our reference material (WC-Co TiC-ZrC).

Expected results and effects

The microstructure after sintering of WC-Co TiZrC and WC-Co-TiC-ZrC was similar and their hardness were essentially the same. The decomposition of TiZrC to TiC and ZrC during sintering proved to be very fast and the fine lamellar structure of the gamma phase coarsened during sintering. This result is due to the special mechanism of the decomposition, which was difficult to predict at the start of the project. In spite of the somewhat disappointing results the work to optimise the sintering of the mixed carbide will continue within other closely related projects.

Planned approach and implementation

A large part of the project was devoted to the characterization of the synthesized powder of TiZrC but also to the optimization of the sintering process and characterization of sintered materials, including interrupted sintering experiments.