Effect of T6 heat treatment on the mechanical properties of gravity die cast A356 aluminium alloy

Abstract

The purpose of this investigation was to evaluate the effect of T6 heat treatment on the mechanical properties of as-cast A356 gravity die casting. The geometry of the casting is designed to be cylindrical shape according to JIS H5202. The results show that T6 heat treatment can significantly improve the mechanical properties of A356 alloy. The hardness, tensile strength and ductility of A356 were improved by 106%, 106% and 214% respectively. The fatigue test shows that the T6 heat treated A356 casting can sustain 5kg-50Hz cyclic load up to 28020 cycles before fracture, achieving an improvement of fatigue strength of 23%. The morphology of T6 heat-treated A356 was changed in which the irregular eutectic phase was converted into spheroidized Si particles as a result of precipitation of silicon particles caused by solution treatment and artificial aging. The microstructural changes result in significant improvement in A356 mechanical properties. © 2011 Asian Network For Scientific Information.