Microstructural analysis of W irradiated at different temperatures

Pure W was neutron irradiated at 600 degrees C, 900 degrees C, 1000 degrees C, 1100 degrees C, and 1200 degrees C with a dose of similar to 1 dpa, and its microstructure was subsequently analyzed using transmission electron microscopy (TEM). Three types of defects were observed and analyzed in detail: (i) voids, (ii) dislocation loops with a diameter of up to 20 nm and (iii) W-Re-Os containing precipitates. The TEM study includes a detailed examination of the defect structure, e.g., determination of the size and spatial distribution of voids, precipitates and dislocation loops. Application of g-imaging shows the formation of the interstitial loops with both 1/2 < 111 > and < 100 > Burgers vectors. In addition, local chemical and structural analysis revealed the formation of chi-type precipitates, which are attached to the voids at 1100 degrees C. It was also found that voids, loops and precipitates are surrounded by a solid solution cloud enriched with Re and Os. The use of highly sensitive nanoscale chemical analysis allows the identification of differences in Re/Os segregation at and in the vicinity of the three defect types. A precise analysis of the chemical composition of the precipitates and clouds around the voids was achieved by a special preparation of their replicates. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Pure W material was neutron irradiated at temperatures ranging from 600°C to 1200°C, resulting in the formation of voids, dislocation loops, and W-Re-Os containing precipitates. The microstructure analysis revealed the detailed structure of these defects, including the size and distribution of voids, precipitates, and loops. Additionally, chemical and structural analysis showed that the defects were surrounded by a solid solution cloud enriched with Re and Os, and nanoscale chemical analysis identified differences in Re/Os segregation at and near the defects.