Synthesis and characterization of nano TiC dispersed strengthening W alloys via freeze-drying

In order to synthesize carbide dispersion strengthened tungsten (CDS-W) with high performance, the W-(0, 0.2, 0.5, 1.0 wt%)TiC alloys were synthesized by novel freeze-drying and low temperature sintering . When adding the optimum amount of 0.5 wt%TiC, the W–TiC composite powders possess finest grain size (about 30 nm). Afterwards, a prominent balance between the high density (98.3%) and ultrafine grain (680 nm) was achieved in the sintered W-0.5 wt%TiC alloys. Furthermore, the TiC particles (<50 nm) keep their original size and are uniformly distributed within W matrix. The ultrafine size of W grain and TiC particles are mainly attributed to the uniform doping of powder precursors and their stable phase interface . As a result, the sintered W-0.5 wt%TiC alloys possess the highest hardness (625 ± 38 HV 0.2 ) among all the sintered samples. Based on above analysis, the new technology of freeze-drying can be employed to prepare W–ZrC alloys or other alloys with ultrafine grains and second phase particles.