Mechanical properties of nanostructured TiN–AlN composites rapidly consolidated by pulsed current activated sintering

Commercial TiN and AlN powders were high-energy ball milled for various durations and consolidated without a binder using the pulsed current activated sintering method (PCAS). The effects of milling on the sintering behavior, crystallite size and mechanical properties of the TiN–AlN composites were evaluated. A dense nanostructured TiN–AlN composite with a relative density of up to 99% could be readily obtained within 3 min. The ball milling effectively refined the crystallite structure of the TiN and AlN powders and facilitated subsequent densification. The sintering-onset temperature was appreciably reduced by milling for 40 h from 1200 °C to 1000 °C. Accordingly, the relative density of the TiN–AlN composite increased as the milling time was increased. This clearly demonstrates that the quick densification of nanostructured TiN–AlN bulk materials to near the theoretical density could be obtained by the combination of PCAS and the preparatory high-energy ball milling process.