Wetting behaviour of Cu–Ga alloys on 304L steel. (5th February 2016)

• Record Type: Journal Article
• Authors: Silze, F.; Wiehl, G.; Kaban, I.; Wendrock, H.; Gemming, T.; Kühn, U.; Eckert, J.; Pauly, S.
• Is Part Of: Materials & design. Volume 91(2016)
• Page Start: 11
• Page End: 18
• Publication Date: 2016-02-05
• Subjects: Brazing -- Reactive wetting -- Gallium -- Copper -- Steel -- Phase transformation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2015.11.034
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: In the present work, the wetting behaviour of the Cu–GaX (X = 10–30 wt.%) liquid alloys on 304L steel was investigated in vacuum at temperatures between 1123 and 1373 K. Contact angle and surface tension measurements were performed using the sessile drop setup. In general, the Cu–GaX (X = 10–30 wt.%) alloys show good or even excellent wetting on 304L steel. However, the wetting mechanism strongly depends on the Ga content. While for Ga-poor alloys secondary wetting occurs, there is a partial dissolution of steel grains combined with an austenite-to-ferrite transformation for larger Ga contents. Cu penetrates along the grain boundaries of the substrate and provides a path for Ga diffusion into the steel. The dissolution of steel grains at the interface is suggested to be responsible for slowing down of the spreading at elevated temperatures. Understanding these interrelations between microscopic and macroscopic effects is important for the development of new Cu-based liquid alloys containing Ga, especially for applications involving steels. Graphical abstract: Highlights: Cu–GaX (X = 10–30 wt.%) alloys exhibit complete wetting on 304L steel under vacuum conditions. Ga diffuses into steel grains at the interface and replaces the steel alloying element Ni. Locally changed steel composition causes a phase transformation of austenite into ferrite. Transformed steel grains flow into the liquid Cu–Ga alloys. The former steel surface including the oxide layers is destroyed.