Formation of Al-alloyed Layer on Magnesium with Use of Casting Techniques

Abstract

Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al,

Microstructure of the Bonding Zone Between AZ91 and AlSi17 Formed by Compound Casting

“…The chemical composition of the grey phase area (analysis at point 3: 58.88 at.% Al, 40.52 at.% Mg and 0.6 at.% Si) is similar to that of the Mg2Al3 intermetallic phase, which confirms the above findings that the grey matrix in the bonding zone near the AlSi17 is this phase. [18][19][20][21], the bonding zone in the Mg/Al couples fabricated by compound casting in the vicinity of Mg was also composed of the eutectic (Mg17Al12 and a solid solution of Al in Mg). The microstructure and phase composition of the bonding zone change gradually with increasing distance from the AZ91 alloy.…”

“…In this process, a metal alloy in the liquid state is cast directly onto a solid metal alloy substrate. The literature concerning this method has discussed the joining of commercially pure Mg to AlMg1 aluminum alloy [17], pure Mg to pure Al [18][19][20][21]. A continuous transition bonding zone forms between Mg and Al as a result of diffusion processes occurring at the reactive interface.…”

Characterization of the Bonding Zone in AZ91/AlSi12 Bimetals Fabricated by Liquid-Solid Compound Casting Using Unmodified and Thermally Modified AlSi12 Alloy

“…As stated above, research on the joining of Mg alloys to Al alloys using compound casting has been conducted extensively in recent years. Some studies have investigated joining pure Mg to pure Al [14], [17] and [24]. In this case, three zones can be differentiated at the interface: a eutectic (Mg 17 Al 12 + a solid solution of Al in Mg) adjacent to the Mg, the Mg 17 Al 12 intermetallic phase in the middle and the Al 3 Mg 2 intermetallic phase close to the Al.…”

Surface alloying of magnesium and AZ91 by thermochemical treatment in a medium containing zinc chloride and potassium chloride

“…Casting is another method to produce surface layers containing intermetallic phases. For example, silicon-enriched, zinc-enriched and aluminium-enriched surface layers can be formed on AZ91 in this way [24][25][26]. The analysis results show that the silicon-enriched layer contained an Mg 2 Si intermetallic phase, the zinc-enriched layer was composed of Mg-Zn intermetallic phases, while the aluminiumenriched contained Mg 17 Al 12 intermetallic phase.…”