Fabrication and mechanical properties of tungsten alloys reinforced with c-ZrO2 particles

The tungsten alloys reinforced by ZrO2 were prepared using azeotropic distillation method combined with powder metallurgy method, and then the sintered tungsten alloys were swaged to obtain compact bars. The microstructures of W-xZrO2 (x = 0, 0.25, 1.0 and 1.5 wt%) alloys were investigated by means of SEM, XRD and TEM. The results show that ZrO2 exist as a stable cubic phase in tungsten alloys by adding Y2O3. Fine ZrO2 particles (500-800 nm) are dispersed in the tungsten matrix, and thus refine the grain size and improve the physical properties and strength of tungsten alloys. With the increase of the ZrO2 content, the relative density, hardness and compressive strength of tungsten alloys were all increased. The swaged W-1.5 wt%ZrO2 alloy shows the finest microstructure with an average grain size of 47.18 μm, reducing 34.76% compared with that of pure tungsten. And thus, the swaged W-1.5 wt%ZrO2 alloy achieves the highest compressive strength (1941.3 MPa) and failure strain (23.1%) at the same time, increasing 23.27% and 22.37%, respectively, compared with that of pure tungsten.