Grain size-dependent Sc microalloying effect on the yield strength-pitting corrosion correlation in Al-Cu alloys

摘要: Abstract Coarse-grained (CG), fine-grained (FG), and ultrafine-grained (UFG) Al-2.5 wt% Cu (Al-Cu) alloys were respectively prepared, with without 0.3 wt% Sc addition, for comparison. The influences of minor addition on the microstructural evolution, tensile mechanical properties pitting corrosion resistance systematically studied at different grain scales. A significant microalloying effect precipitation was observed that promoted dispersion finer θ′-Al2Cu precipitates in CG alloy favored intragranular FG UFG alloys, smaller size leading to a stronger effect. induced convincing increases yield strength all three scales, improved (in Al-Cu alloys) or retained alloy) same time. This indicates inverse strength-pitting correlation as usually can be broken by addition. strengthening mechanisms discussed size-dependent mediated rationalized terms competition between positive influence derived from interfacial segregation negative come deformation-induced dislocations. present findings provide possible approach break heat-treatable Al modifying precipitate/matrix interfaces through suitable atom segregation.