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

Alan Xu, David E.J. Armstrong, Christian Beck, Michael P. Moody, George D.W. Smith, Paul A.J. Bagot, Steve G. Roberts
2017 Acta Materialia  
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, WÀ4.5 at.%Ta, WÀ2 at.% ReÀ1 at.%Ta and WÀ2 at.%Re alloys were exposed to 2 MeV Wþ ions to a fluence of 2.64 Â 10 15 ions cm À2 at temperatures of 573 and 773 K. Atom probe tomography and nanoindentation were
more » ... 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 WÀReÀTa 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.
doi:10.1016/j.actamat.2016.10.050 fatcat:qiqaraldoja3lk2re3yptedagi