Microstructure and Mechanical Properties of an Al-Mg-Si-Cu Alloy for High Temperature Applications

The high specific properties of aluminium based nanostructured alloys have attracted significant attention due to their promise for structural applications especially at elevated temperatures such as pistons for internal combustion engines. Several types of aluminium-based nanostructured alloys have been developed with microstructures of nanometre-sized particles embedded in the aluminium matrix. In this work a newly developed aluminium based nanostructured alloy is studied to understand its microstructure formation, stability and mechanical properties at elevated temperatures. The microstructure was characterised by means of X-ray diffraction, light and scanning electron microscopies. Heat treatments were carried out to determine the T6 condition properties and the microstructural stability at elevated temperatures for long periods of exposure. The hardness of the new alloy at T6 was 30% higher than the corresponding to Al-4032 which is the commonly used alloy for piston application. The work also compared the mechanical properties of the new alloy with two conventional aluminium alloys used in piston applications. The new alloy has 1.3–4.7 times higher strengths than Al-4032.