Ion-irradiation induced clustering in W-Re-Ta, W-Re and W-Ta alloys: An atom probe tomography and nanoindentation study

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• 作者：Alan Xu^a ; ^b ; David E.J. Armstrong^a ; ^{david.armstrong@materials.ox.ac.uk} ; Christian Beck^a ; Michael P. Moody^a ; George D.W. Smith^a ; Paul A.J. Bagot^a ; Steve G. Roberts^a ; ^c
• 关键词：Tungsten rhenium tantalum alloys ; Nuclear fusion ; Atom probe tomography ; Ion-irradiation ; Nanoindentation
• 刊名：Acta Materialia
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：124
• 期：Complete
• 页码：71-78
• 全文大小：2264 K
• 卷排序：124

文摘

In tungsten plasma-facing fusion reactor components, Ta is the third most abundant element formed by transmutation (after Re and Os), yet little is known about the behaviour of W-Ta alloys under irradiation and any effects Ta might have on Re clustering in W-Re-Ta alloys. In this study, W−4.5 at.%Ta, W−2 at.%Re−1 at.%Ta and W−2 at.%Re alloys were exposed to 2 MeV W+ ions to a fluence of 2.64 × 1015 ions cm−2 at temperatures of 573 and 773 K. Atom probe tomography and nanoindentation were used to characterise the chemical and physical properties of the irradiation-induced clusters and the mechanical properties of the irradiated layer. In the W-Ta alloy, no evidence of irradiation-induced clustering was found. In the W−Re−Ta alloy, at both irradiation temperatures studied the presence of Ta reduced the W-Re cluster number density and volume fraction compared to that in the W-Re alloy; however it did not alter cluster composition as the Ta was rejected from the clusters. The reduced cluster density in the W-Re-Ta alloys was associated with a smaller degree of irradiation hardening than in the W-Re alloys. Possible mechanisms by which Ta hinders cluster development are discussed.