The effect of ball milling on the mechanical properties of TiN consolidated by pulsed current activated sintering

Commercial TiN powders were high-energy ball milled for various durations and consolidated without a binder using the pulsed current activated sintering method (PCAS). The effect of milling on the sintering behavior, crystallite size and mechanical properties of TiN compacts were evaluated. A dense TiN compact with a relative density of up to 99% could be readily obtained within 4 min. The ball milling effectively refined the crystallite structure of TiN powders and facilitated the subsequent densification. The sinter-onset temperature was reduced appreciably by the prior milling for 40 h from 1200 °C to 800 °C. Accordingly, the relative density of TiN compact increased as the milling time increases. The microhardness of sintered TiN was linearly proportional to the density. It is clearly demonstrated that a quick densification of TiN bulk materials to near the theoretical density could be obtained by the combination of PCAS and the preparatory high-energy ball milling process.