Effect of Inter-Metallic Phases on the Bonding Strength and Forming Properties of Al/Mg Sandwiched Composite

Abstract

Composite sheet of Twin Roll Cast (TRC) AZ31-Mg alloy and industrial pure Al-1050 was fabricated as Al/Mg/Al with a hot roll bonding process. As the diffusion zone at the interface between the layers plays a crucial role in the formation of bonding strength and formability of clad sheets. It is important to describe the processes of inter-diffusion layer generation in order to assess the abilities of the laminate composites for further processing. Thus, the aim of this study was to investigate the development of the bonding strength, microstructure and mechanical properties of the bonding interface directly after roll bonding and additionally post-annealing processes. Microstructure characterization techniques such as optical and scanning electron microscopy including energy dispersive X-ray analysis (EDX) were applied to investigate the bonding area. No inter-metallic phases were present directly after the roll bonding process. The creation and growth of Al2Mg3 and Al12Mg17 phases were apparent after annealing at temperatures of 250 to 400 °C at different times ranging from five to 120 minutes. The results prove that the growth rate of inter-metallic phases increases considerably with an increase in the annealing temperature. The micro-hardness of the interface-area was also investigated. It was observed that the two inter-metallic phases were significantly harder than the substrate Mg and Al. In order to examine the influence of the inter-metallic phases on the resulting bonding strength after the annealing process, the shear bonding strength test has been conducted for different samples that were annealed at different heat treatment conditions. The results indicate that the optimum annealing temperature is 200 °C leading to a maximum bonding strength. Moreover, the mechanical properties of the composite after roll bonding and post annealing were determined by means of room temperature tensile test. The fracture mechanism after tensile test was also discussed.Keywords:Rollbonding,Al/Mghotrollbonding,TwinrollcastAZ31,bondingstrength

Joint properties of friction welded joint between pure magnesium and pure aluminium with post-weld heat treatment

“…The growth of IMC interlayer was observed in other heating temperatures, although those results were not shown here. In this connection, the growth of IMC interlayer was also reported of other welding technique [38,39], although those were not in situ observation results. Fig.…”

The Effect of Interlayer Materials on the Joint Properties of Diffusion-Bonded Aluminium and Magnesium

“…However, the joining process and weldability are highly influenced by the tendency to form oxide layers, e.g., for aluminium and magnesium [1,2]. To improve the limited weldability of aluminium and magnesium, surface treatment is necessary to remove the stable and tenacious oxide layer and limit the formation of brittle intermetallic Al-Mg compounds [3,4].…”

“…Diffusion bonding of aluminium and magnesium with interlayer materials has been extensively investigated to improve the joint properties and promote atomic diffusion processes across the bond line [1,[3][4][5][6][7][8][9][10]. For this purpose, a large group of interlayer metals is available to influence the properties of the diffusion zone.…”