Effects of oxide particles on the microstructural and mechanical properties of W-Ni-WB composites

Abstract

This study reports the effect of La2O3 addition on the microstructural and some mechanical properties of the W-Ni-WB composites. Composites having the compositions of W - 1 wt% Ni - 2 wt% WB and W - 1 wt% Ni - 2 wt% WB - x wt% La2O3 (x = 0.5 and 1) were fabricated by mechanical alloying (MA) and activated sintering methods. Phase and microstructural characterizations of the mechanical alloyed powders and sintered samples were carried out using X-ray diffractometer, scanning electron microscope (SEM), particle size analyzer and electron probe microanalyzer. Archimedes density and microhardness measurements, and sliding wear tests were also conducted on the sintered samples. The results showed that 1 wt% addition of La2O3 particles yields the lowest average particle size (290 nm) with a homogeneous particle size distribution of the composite powders. The sinterability and wear resistance of the composites, and the distribution of the particles throughout the sintered microstructure were also improved by adding oxide dispersoids into the W-Ni-WB composites. MA'd and sintered W - 1 wt% Ni - 2 wt% WB, - 1 wt% La2O3 composite had the relative density, average microhardness, and wear volume loss values of 96.97%, 6.02 GPa, and 115.8 mu m(3), respectively.