Microstructure of a commercial W–1% La2O3 alloy

Abstract W–1% La 2 O 3 alloy is considered as the most promising material for plasma-facing components of fusion reactors. The microstructure of a commercial W–1% La 2 O 3 alloy was investigated using optical and transmission electron microscopes. The microstructure of pure tungsten can be improved significantly by fabrication of W–1% La 2 O 3 alloys. W–1% La 2 O 3 alloys can be produced with no porosities and cracks, and with various oxide phases dispersed in alloy matrix. La 2 O 3 with different crystal structures, La 6 W 2 O 15 , WO 2 , WO 3 and W 3 O 8 phases were identified in as-forged W–1% La 2 O 3 alloy. Long strip-like La 2 O 3 has a very large size, whereas spherical La 6 W 2 O 15 , navicular WO 3 , hexagonal W 3 O 8 and short rod-like La 2 O 3 are smaller particles. Most identified phases have a heterogeneous distribution. Forging leads to a more dispersive distribution of large-sized La 2 O 3 particles but not of fine WO 3 particles compared with rolling. The mechanical properties of the alloys are also discussed.