TY - JOUR
T1 - Surface damage in ultrafine and multimodal grained tungsten materials induced by low energy helium irradiation
AU - El-Atwani, Osman
AU - Efe, Mert
AU - Heim, Bryan
AU - Allain, Jean Paul
N1 - Funding Information:
This work was supported in part by the US Department of Energy’s 2010 Early Career Award DE-SC0004032. We would like to thank Prof. Anter El-Azab for the valuable discussion regarding the irradiation damage of tungsten materials, Prof. Joanna Groza and Dr. Dat Quach for the spark plasma sintering of the tungsten powders, and Bradley Schultz for the assistance with the metallography.
PY - 2013
Y1 - 2013
N2 - Although tungsten is considered the best candidate as a plasma facing component (PFC) in the divertor region in the International Thermonuclear Experimental Reactor (ITER), severe morphology changes such as cavities, blisters, bubbles and nanostructure formation are expected. Increasing defect sinks in the tungsten microstructure is one of the possible solutions to mitigate the irradiation damage. In this work, helium irradiation at low energy (50 and 200 eV) and temperatures of 600 (threshold of vacancy migration) and 950 °C were performed on multimodal and ultrafine grained tungsten prepared by spark plasma sintering and severe plastic deformation (SPD), respectively. The multimodal samples consisted of small grains (300-700 nm size) juxtaposed to larger grains (1-3 μm size). Detachment of the small grains was observed in the multimodal grained tungsten irradiated at 600 °C and a fluence of 1 × 1022 m-2 due to grain boundary grooving. On the same sample but at 950 °C, detachment and nanostructuring of the small grains were observed together with recrystallization of the large grains. Irradiation of the SPD samples at 200 eV and 950 °C to a fluence of about 2 × 1022 m-2, resulted in nanostructuring of the ultrafine grained shear bands in the microstructure.
AB - Although tungsten is considered the best candidate as a plasma facing component (PFC) in the divertor region in the International Thermonuclear Experimental Reactor (ITER), severe morphology changes such as cavities, blisters, bubbles and nanostructure formation are expected. Increasing defect sinks in the tungsten microstructure is one of the possible solutions to mitigate the irradiation damage. In this work, helium irradiation at low energy (50 and 200 eV) and temperatures of 600 (threshold of vacancy migration) and 950 °C were performed on multimodal and ultrafine grained tungsten prepared by spark plasma sintering and severe plastic deformation (SPD), respectively. The multimodal samples consisted of small grains (300-700 nm size) juxtaposed to larger grains (1-3 μm size). Detachment of the small grains was observed in the multimodal grained tungsten irradiated at 600 °C and a fluence of 1 × 1022 m-2 due to grain boundary grooving. On the same sample but at 950 °C, detachment and nanostructuring of the small grains were observed together with recrystallization of the large grains. Irradiation of the SPD samples at 200 eV and 950 °C to a fluence of about 2 × 1022 m-2, resulted in nanostructuring of the ultrafine grained shear bands in the microstructure.
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U2 - 10.1016/j.jnucmat.2012.11.012
DO - 10.1016/j.jnucmat.2012.11.012
M3 - Article
AN - SCOPUS:84871785437
SN - 0022-3115
VL - 434
SP - 170
EP - 177
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
IS - 1-3
ER -