Effects of Sintering Temperature and Time on the Properties of Al-Cu PM Alloy

Abstract

Aluminium-based powder metallurgy (PM) alloys have a number of advantages over cast and wrought aluminium alloys. These PM alloys can be produced using either prealloyed or elemental premixes, with the latter offering a longer die life because of their softer nature compared with prealloyed powders. It is found that the use of an Al-Cu premixed PM alloy gives green density values higher than those of Al-Cu prealloyed systems reported in the literature. Most commercial aluminium PM alloys and alloy developments are based on the Al4Cu system. The amount of liquid phase has significant effects on the microstructure and the mechanical properties of sintered products. Lack of a liquid phase results in inadequate mechanical properties, while an excess of liquid phase causes distortion and shape deformation of the compacts formed by sintering. The objective of this study is to determine the properties of an Al4Cu PM alloy produced using an elemental premix. The effects of the amount of liquid phase on microstructural features and mechanical properties are assessed through thermal analyses. It is found that the optimum transverse rupture strength is obtained by sintering at 600 degrees C for 2 h.