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 HV0.2) 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. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

By using novel freeze-drying and low temperature sintering techniques, high-performance carbide dispersion strengthened tungsten alloys were successfully synthesized with outstanding hardness and uniform distribution of TiC particles. The new technology can be applied to prepare other alloys with ultrafine grains and second phase particles.