Spark plasma sintering of TixTa1−xC0.5N0.5-based cermets: Effects of processing conditions on chemistry, microstructure and mechanical properties

• Powdered cermets based on (Ti,Ta)(C,N) have been synthesized by reactive milling.
• Ceramic composition was tailored by the initial Ti/Ta atomic ratio.
• Powdered cermets were highly densified by spark plasma sintering at low temperature (1150 °C).
• Cermets microstructure was highly dependent of the synthesis procedure.
• Grain growth was limited without adversely impacting high densification by using SPS procedure.

Nanometric powdered TixTa1−xC0.5N0.5-based cermets were fabricated using a mechanically induced self-sustaining reaction and consolidated by spark plasma sintering. Highly dense cermets were obtained, and their chemistry, microstructure and mechanical properties were characterised by X-ray diffraction, scanning electron microscopy, image analysis, microindentation and nanoindentation. The microhardness was found to depend directly on the contiguity and size of the ceramic hard particles. The samples synthesised at the lowest temperature (1150 °C) exhibited more homogeneous microstructures and smaller ceramic particles and the best combination of microhardness and fracture toughness.