Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5436427 | Acta Materialia | 2017 | 8 Pages |
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, Wâ4.5Â at.%Ta, Wâ2Â at.%Reâ1Â at.%Ta and Wâ2Â at.%Re alloys were exposed to 2Â MeVÂ W+ ions to a fluence of 2.64Â ÃÂ 1015 ions cmâ2 at temperatures of 573 and 773Â 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 WâReâTa 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.
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