Effects of Alloy Chemistry and Solidification Rate on the Mechanical Properties of an Al-9Si-1Cu Alloy for Powertrain Applications

Abstract

The potential use of an Al-9Si-1Cu alloy (W328 alloy) as a replacement for W319 alloy in engine blocks was investigated.. The ambient mechanical properties (tensile, hardness and fatigue) of sand and permanent mould cast test bars along with bars machined from a sand cast automotive component were studied. The tensile properties were evaluated in as-cast and T6 heat-treated conditions. The effects of Fe and Mn on properties were also investigated. The castings in W328 alloy exhibit lower porosity than W319 alloy, which is attributed to the smaller solidification range and feeding distance and larger volume fraction of the eutectic phase. Higher iron levels increased the level of intermetallics and reduced properties. The addition of Mn did not offset the effect of higher iron levels. The W328 alloy offers some advantages over the 319 alloy and is a potential candidate for production of automotive components such as engine blocks and cylinder heads.