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

Abstract The microstructures of four kinds of commercial tungsten materials have been investigated. The W–1% La 2 O 3 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 La 2 O 3 particles with a large size up to 5 μm existed in the W–1% La 2 O 3 alloys tend to be the most unfavorable factors in the mechanical performance of the alloys. Several kinds of other submicrometer-sized phases including WO 3 , WO 2 , W 3 O 8 and La 2 (WO 4 ) 3 were confirmed to exist in the W–La 2 O 3 alloy, which suggests that an inadequate hydrogen reduction occurred seriously during the alloy preparation procedure.