Preparation of high‐strength (Ta,W)C solid‐solutions by spark plasma sintering

Abstract

Abstract(Ta,W)C bulks were prepared by spark plasma sintering. Densification kinetics and solid‐solution formation kinetics were performed on the powder mixtures using TaC and W powders. The as‐received tungsten powder had a spherical shape and rather coarse size. By using the crushed and as‐received powder, it can be suggested that sintering at 2000°C limits the reaction volume to 3–6 μm and hence allows forming a complete solid‐solution using finer powders. The lattice parameter, hardness, toughness, and strength were investigated as a function of the TaC content. The flexural strength of the (Ta,W)C ceramic bulks was investigated up to 2000°C and it was found that the maximum strength was for the 60 mol.% TaC composition. Strength as a function of the temperature tended to increase up to 1200°C followed by a gradual decrease to 2000°C. When the TaC was reinformed by coarse W spheres, the flexural strength monotonically decreased from 570 MPa at room temperature to 220 MPa at 2000°C.