Effects of aluminum metal flux heat treatments on titanium–tungsten mixed carbide powders

This work describes the effects of aluminum metal flux heat treatments on titanium-tungsten mixed carbide powders. Titanium, tungsten, and carbon-bearing reagents were immersed in a liquid aluminum metal flux at 1500 °C for 24 h. Upon cooling, (Ti1-xWx)C powders were recovered from the solidified metallic matrix via chemical treatments. The WC content of the mixed carbide solid solution was determined by correlation of powder density and unit cell volume with composition. Analysis of lattice parameter ranges determined from peak broadening of X-ray diffraction patterns indicates that metal flux heat treatment enhances the chemical homogeneity of the powders. Particle size measurements show product powders exhibit log-normal distributions with volume mean diameters ranging from 4-15 μm depending on composition. Electron microscopy indicates powders are composed of equiaxed faceted particles. Observed trends in average elemental composition of recovered particles relative to batch charges are rationalized based on phase equilibria data. An aluminum metal flux heat treatment enhances the chemical homogeneity and crystallinity of titanium-tungsten mixed carbide powders. [Display omitted] •Aluminum metal flux heat treatment enhances the chemical homogeneity and crystallinity of titanium-tungsten mixed carbide powders.•After heat treatment in liquid aluminum at 1500 °C for 24 h, recovered mixed carbide powders are primarily 4–15 μm faceted monocrystals with log-normal particle size distributions.•Trends in average elemental composition of recovered mixed carbide powders can be rationalized based on phase equilibria data.