Roles of alloying elements in wetting of SiC by Al

• Published in: Journal of alloys and compounds Vol. 784; pp. 1212 - 1220
• Main Authors: An, Qin, Cong, Xiao-shuang, Shen, Ping, Jiang, Qi-chuan
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05.05.2019; Elsevier BV
• Subjects: Alloying effects; Alloying elements; Aluminum base alloys; Aluminum carbide; Aluminum matrix composites; Contact angle; Copper; Disruption; Evaporation; Interface; Magnesium; Metal matrix composites; North American Industry Classification System; Oxide coatings; Sessile drop method; Silicon carbide; Silicon dioxide; Titanium; Wettability; Wetting; Wetting; Interface; Contact angle
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.01.138

Wetting of SiC by Al alloys is a key issue in the preparation of SiC-reinforced Al matrix composites. The wettability could be improved by alloying of Al, yet controversial results widely exist in the literature. We investigated the effects of four important alloying elements (Si, Cu, Ti and Mg) and their concentrations on the wettability in the Al/SiC system using a dispensed sessile-drop method. The results demonstrate that Si could weaken or even inhibit the formation of Al4C3 and substantially improve the wettability via an adsorption effect; Cu slightly deteriorates the wettability, but alleviates the formation of Al4C3 by decreasing the activity of Al; Ti strongly adsorbs at the solid−liquid interface, forming TiCx instead of Al4C3, and thus significantly improves the wettability; Mg may also favor the wettability due to its help in the disruption of the oxide film covering the Al surface via evaporation and its strong affinity for the silica film on the SiC surface; but for a clean Al/SiC system, the effect of Mg is essentially limited. In addition, the evaporation of Mg always leads to a reduction in the drop volume, which causes a decrease in the apparent contact angle, but this effect is usually neglected. •A dispensed sessile drop method was used to evaluate the wettability.•Si weakens the Al4C3 formation and improves the wettability via adsorption.•Cu slightly deteriorates the wettability, but alleviates the formation of Al4C3.•Ti improves the wettability via adsorption and formation of TiCx at the interface.•Mg has a limited improving effect except for a pre-oxidized SiC surface.