Comparison of the behavior of Zr(41.2%)Ti(13.8%)Cu(12.5%)Ni(10%)Be(22.5%) amorphous and crystallized mirrors under deuterium ion bombardment

Experiments have been performed to determine the effect of deuterium plasma exposure on mirrors fabricated from Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy (Vitraloy 1, V1) in both the amorphous and crystallized state. It was found that for deuterium ion above ∼ 2.6×1024 ions/m2, cracks and chips appeared on the surface of the crystallized mirrors. At a factor of two higher fluence, 5.2×1024 ions/m2 of 60 eV ions, one specimen disintegrated into many fragments. The mirror specimens kept in the amorphous state, however, were not observed to have experienced any visual changes even after exposure to ion fluences as high as 1.5×1025 ions/m2. The difference in behaviour is explained as being due to hydrogen embrittlement, and differences in hydrogen transport between the two alloy states.