Metal injection moulding of aluminium alloy 6061 with tin

Abstract

A metal injection moulding technique for the production of aluminium alloy components is described. A part is formed by injection moulding a mixture of alloy 6061 and 2 wt-%Sn with a resin consisting of stearic acid, palm oil wax and high density polyethylene. The resin is removed by a combination of solvent and thermal processing. The parts are then sintered in a nitrogen atmosphere to a density of 97%. Sacrificial magnesium blocks which act as an oxygen and moisture getter are placed in the vicinity of the parts during sintering. This ensures surface integrity. Aluminium nitride forms throughout the part, which provides structural rigidity and dimensional stability and limits grain growth. After artificial aging, the tensile strength is 300 MPa. The technique allows the production of small complicated shapes and provides an additional means to manufacture aluminium components for a wide variety of applications.