Morphology evolution of La2O3 and crack characteristic in W-La2O3 alloy under transient heat loading

Thermal shock tests were performed on W-La2O3 specimens by an electron beam to investigate the morphology evolution of La2O3 and crack characteristics. Cracks appeared at power densities ranging from 0.22 to 0.88 GW/m2 and disappeared completely at 1.1 GW/m2. The specimens tested at 0.22-0.66 GW/m2 kept their original morphologies except for cracks. For the specimens loaded at 0.88 and 1.1 GW/m2, the sample surfaces were divided into four areas including no heat-loaded area, two transition areas and resolidification area. In the transition areas, the left vacancies after melting, evaporation and dissociation of La2O3 particles kept their original elongated shape and aggravated the formation of crack. In the resolidification area, the craters were partly or completely filled by tungsten and the round craters with smooth edges did not facilitate the crack initiation. Thermal fatigue tests suggested that WL10 showed worse performance than pure tungsten when exposed to thermal loads.