Interface formation in magnesium/aluminium bimetallic castings with a nickel interlayer. (2nd September 2016)

• Record Type: Journal Article
• Authors: Zhang, Hui; Li, Lingfeng; Chen, Yiqing; Luo, Alan A.; Liu, Lihua
• Is Part Of: International journal of cast metals research. Volume 29:Number 5(2016)
• Page Start: 338
• Page End: 343
• Publication Date: 2016-09-02
• Subjects: Bimetallic casting -- Interfacial reactions -- Microstructure -- Aluminium -- Magnesium -- Interfacial strength; Metal castings -- Periodicals; Founding -- Periodicals; Foundry research -- Periodicals; Foundry chemistry -- Periodicals; 671.2
• DOI: 10.1080/13640461.2016.1164915
• Languages: English
• ISSNs: 1364-0461

Abstract

Abstract : The natural oxide layer is an inherent barrier in interfacial bonding between aluminium (Al) and magnesium (Mg) alloys in Mg/Al bimetallic casting, resulting in insufficient wettability between the molten Mg and solid Al substrate during bimetallic casting processes. In this investigation, a 'zincate + nickelling' surface treatment has been developed for Al alloy 6061 substrate, replacing the oxide layer with a nickel coating. This procedure comprises a combined pickling/redox-reaction and nickelling process, which drastically improves the substrate's wettability with molten Mg. The bimetallic experiments conducted on a self-designed high-vacuum test apparatus provide valuable understanding of the interfacial phenomena of Mg/Al bimetallic castings. The test results show that the shear strength of bimetallic castings is significantly improved due to the fact that the formation of Mg–Al intermetallic compounds is impeded by a nickel coating. The potential corrosion problem associated with nickel additions could be addressed by an organic top coating for the bimetallic system.