Microwave synthesis and properties of fine-grained oxides dispersion strengthened tungsten

Dense W, W–1 wt%La2O3 and W–1 wt%Y2O3 samples with fine microstructure were fabricated by microwave sintering method using nano-scaled powders. The FESEM and TEM analysis, thermal conductivity and Vickers micro-hardness measurements were exploited to characterize these samples. It is found that the addition of Y2O3 and La2O3 nano-particles could significantly hinder the grain growth of tungsten in the consolidation process, decreasing the average grain size from 3.2 μm in pure W down to 0.7 μm in W–1%Y2O3 sample. The thermal conductivity and relative density of these samples are higher than 120 W/m K and in the range of 95–97%, respectively. The Vickers hardness of W–1%Y2O3 sample reaches as high as 6.91 GPa, 30% higher than that of pure W (5.04 GPa).