Development of a super ductile diecast Al–Mg–Si alloy

Abstract

a b s t r a c tThe super ductile diecast aluminium alloys have been developed particularly for application in automotive body structure. On the basis of the reviewing aluminium alloys currently available, the requirement of diecast aluminium alloys is summarized and the Al-Mg-Si system is focused in the development. The effect of various alloying elements on the microstructure and the mechanical properties, such as yield strength, ultimate tensile strength and elongation is assessed. The optimized composition of the super ductile Al-Mg-Si alloy has been found to be at 5.0-5.5 wt% Mg, 1.5-2.0 wt% Si, 0.5-0.7 wt% Mn, 0.15-0.2 wt% Ti with Fe o 0.25 wt% for the best combination of strength and ductility, which shows 150 MPa of yield strength, 300 MPa of ultimate tensile strength, and 15% of elongation under as-cast condition. The paint baking hardenability of the optimized alloy is found to be insignificant. Less than a 10% increase in the yield strength was achieved, with a slight decrease in the elongation after aging at 180 1C for 30 min, which is a simulated process of paint baking. Cu is found to slightly increase the yield strength under the as-cast condition and after the heat treatment, but with a significant reduction in the ductility. Therefore, Cu should be limited in the super ductile aluminium alloy. The microstructure of diecast aluminium alloys at the optimized composition consists of the primary a-Al phase, the a-AlFeMnSi intermetallics and the Al-Mg 2 Si eutectics. There are two types of primary a-Al phase: dendritic or fragmented dendritic a-Al phase solidified in the shot sleeve and globular a-Al particles solidified in the die cavity. The a-AlFeMnSi intermetallics is in the form of compact morphology and with a size of less than 3 mm. The eutectic cells are at size of 10 mm with a typical lamellar morphology of a-Al phase and Mg 2 Si phase.Crown

Microstructure and Mechanical Properties of Ductile Aluminium Alloy Manufactured by Recycled Materials

“…The main requirements for the alloy include the yield strength over 140MPa, ultimate tensile strength (UTS) over 280MPa and elongation over 15% [1]. These have been achieved through the optimised control of alloy composition, casting parameters and solidification process in high pressure die casting (HPDC) [2].…”

Phase Diagram of Al-Ca-Mg-Si System and Its Application for the Design of Aluminum Alloys with High Magnesium Content

“…It is advisable to alloy aluminum-magnesium alloys with silicon, which is included in a number of branded alloys (for example, 512) with a content of 1.5-2% [1,[5][6][7]. Silicon (Si) maintains a low density (it forms, with magnesium (Mg), the Mg 2 Si phase, the density of which is only 1.88 g/cm 3 [2]) and high corrosion resistance, while also increasing the hardness and casting properties of the alloy.…”

Repeatability of tensile properties in high pressure die-castings of an Al-Mg-Si-Mn alloy

“…This lightweighting is driven by the need to reduce CO 2 emissions in the use stage of vehicles [1,2], reducing tailpipe emissions by increasing fuel efficiency through effective weight reduction of the vehicle [3,4]. The application of Al-Mg-Si-Mn alloys [5,6] is one of the most recent developments for body structural castings.…”