Mechanical properties and microstructures of W–TiC and W–Y2O3 alloys fabricated by hot-pressing sintering

Abstract

Bulk pure tungsten (W), W-0.5 wt%TiC (WTC05) and W-1 wt%Y2O3 (WY10) materials were prepared by a developed two-step hot-pressing (HP) sintering method. Metallographic observation, SEM and TEM characterization were conducted to obtain the information of material microstructures. The results indicate that a small amount of TiC or Y2O3 addition could effectively improve the sinterability and reduce the grain size of the HP sintered WTC05 and WY10 alloys. The relative density of WTC05 and WY10 reaches as high as 99%, and the average grain size of WTC05 and WY10 are 2.61 μm and 3.57 μm, respectively, which are several times smaller than that of pure W. Among the three W materials, pure W has the poor tensile performance with insufficient strength and ductility, WTC05 has the highest tensile strength with the ultimate tensile strength of 1082 MPa at 300 °C, and WY10 has the best ductility and moderate strength. The relationship between the microstructures and the tensile properties has been investigated, and suggestions on microstructure parameters have been proposed for preparing high performance W-based materials.