| Abstract: | Pure tungsten(W) and chromium doped W(W-5%Cr) are prepared by powder metallurgy. The microstructure,blistering and helium retention are investigated by x-ray diffraction,scanning electron microscopy,transmission electron microscopy and thermal desorption spectroscopy(TDS). These results show that the average size and density of helium blisters on the surface of pure W are much larger than those on the W-5%Cr alloy. Vacancyimpurity pairs can reduce the migration coefficients of vacancy and vacancy-helium complexes, and Cr may play a role of such an impurity. Moreover, the TDS result shows that the highest desorption peak moves to higher temperature, which is attributed to the He_mCr_kV_n complexes in the W-Cr alloy. In addition,the helium retention is found to be higher in W than in W-5%Cr. |
