Anomalous wetting of Ti–48 at.% Al–2 at.% Cr–2 at.% Nb substrates by liquid copper

Abstract

Conventionally, the wetting of metallic substrates by liquid metals involves undermining of the substrate–oxide layer by the liquid. Evidence is presented here for an alternative wetting process involving spreading of liquid copper along the exterior of the oxide layer on Ti–48 at.% Al–2 at.% Cr–2 at.% Nb substrates. A mechanism is presented that involves compositional changes in the liquid, which in turn allow a wetting-promoting reaction between the (initially unreactive) liquid and the exterior layer of the substrate oxide.