Microstructural characteristics of commercial purity W and W-1% La2O3 alloy

The microstructures of four kinds of commercial tungsten materials have been investigated. The W-1% La2O3 alloys with the rolling or forging state have a much better microstructure than pure tungsten as sintered or rolled state because the dispersion of lanthanum oxide particles can effectively inhibit pores and cracks, and greatly refine compactness. The La2O3 particles with a large size up to 5 μm existed in the W-1% La2O3 alloys tend to be the most unfavorable factors in the mechanical performance of the alloys. Several kinds of other submicrometer-sized phases including WO3, WO2, W3O8 and La2(WO4)3 were confirmed to exist in the W-La2O3 alloy, which suggests that an inadequate hydrogen reduction occurred seriously during the alloy preparation procedure.