Author/Authors :
Tokunaga، نويسنده , , K. M. Baldwin، نويسنده , , M.J and Doerner، نويسنده , , R.P. and Nishijima، نويسنده , , D. and Kurishita، نويسنده , , H. and Fujiwara، نويسنده , , T. and Araki، نويسنده , , K. and Miyamoto، نويسنده , , Y. and Ohno، نويسنده , , N. and Ueda، نويسنده , , Y.، نويسنده ,
Abstract :
Ultra-fine grain W-(0.5, 1.5)wt%TiC alloys and stress relieved powder metallurgy W have been exposed to D-He mixed plasmas, some with added Be. The fixed exposure conditions are ion energy 60 eV and flux 3 to 6 × 1022/m2 s. Sample temperature is 1123 K and exposure times scanned 1000–11,000 s. Typical He/D ion is 0.2 and Be is 0.2% of the plasma. A remarkable change of the tungsten surfaces results from the plasma exposures. Formation of a nano-structured layer on the exposure surfaces is observed and believed to be related to He bubble formation. In addition, the growth rate of the nano-structured layer depends on the microstructure of the samples. In the case of a D-He plasma with Be, at 60 eV, plasma sputters away most of Be deposits with little effect on the He induced nano-structured layer formation.
