LAUSR

The A319 alloy is based in Al-Si system, its principal characteristics are high castability to produce parts with complex forms due to Si content, good machinability, light weight and optimal combination of strength and ductility. Their major applications are in the automotive industry as a material to manufacture pistons, engine blocks and cylinder heads. The T6 heat treatment is used to improve the mechanical performance of such components due to the precipitation of θ' and θ''-Al2Cu semi-coherent and metastable phases during aging treatment. Some transition metals like Ni and Fe, and some rare earths like Ce, have been used in aluminum alloys to reduce the coefficient of thermal expansion and improve the mechanical properties at relative high temperatures [1]. For example, additions of 1 to 2% Ni to 2xxx and 3xxx series alloys improve hardness and tensile properties at elevated temperatures [2]. Hayajneh et al. [3] and others investigations [4] have been reported the effect of Ni additions in the hardness properties in Al-Cu and Al-Si-Cu alloys respectively; they reported that the formation of the Al-Ni, Al-Ni-Cu intermetallic compounds have a direct relationship with mechanical properties and a significant delay in the loss of hardness values during the over-aging stage.