Synthesis of AlN-TiN nanostructured composite powder by reactive ball milling and subsequent thermal treatment

▶ A part of AlN was found to be gradually reduced by Ti during MA and Ti(Al,N) solid solution formed after early stages of milling. ▶ The particle size of supersaturated Ti(Al,N) solid solution and AlN reduced to submicron size and nanocrystalline structure as evident from XRD and SEM results. ▶ The lattice parameter and interplanar distance of Ti shows that all of the decomposed Al dissolved in the Ti lattice by MA and causes its contraction, while only 1 at.% of N dissolves to form Ti(Al,N) solid solution and leads to its dilation and the remaining N reacts with Ti to form TiN. ▶ Annealing of 360 ks MA powder leads to phase transformation as a result of increased thermal diffusivity, the formation of more TiN phase with more under-stoichiometric characteristic, as well as stress releasing and grain growth.