Hydrogen blister formation and cracking behavior for various tungsten materials

In order to study hydrogen blistering and subsequent cracking behavior of pure W, K-doped W, and La2O3-doped W, 1 keV H 3 + (main ion components) ion beams were irradiated at 653 K to fluences up to 1 × 1025 H/m2. Two pre-irradiation heat treatments were done for stress relief (900 °C) and recrystallization (1300 °C for pure W and 1500 °C for K-doped and La2O3-doped W). It was found that blister characteristics and cracking behavior strongly depended on microstructures and dopant materials. For W materials with layered microstructure, blister shapes were mostly spherical-like, while for W materials with recrystallized (or disordered) microstructures, blisters had complicated plateau-like shapes with many cracks. Addition of K or La2O3 dopants increased the number of blisters and exfoliations for both stress relieved and recrystallized W.