Statistical experimental design of Al–Cu–Mg–Si P/M alloys

Abstract

The principle that alloys are designed to accommodate the manufacture of goods made from them as much as the properties required of them in service has not been widely applied to pressed and sintered P/M aluminium alloys. Most commercial alloys made from mixed elemental blends are identical to standard wrought alloys. Here we use a statistical design of experiment approach to re-evaluate the composition spectrum of the 2xxx alloys. Copper has the major influence on the tensile properties. Magnesium and silicon do effect some properties, but to a lesser extent. The major value of magnesium is breaking up the surface oxide layer. Conversely, an extensive secondary pore network develops from excess magnesium and this severely limits the ductility. Hard intermetallic particles, which are a residue of the sintering liquid, also reduce the tensile ductility. The tensile strength is limited by the low ductility, which is related to the equilibrium liquid volume at the sintering temperature, as well as the sintered density.