TRANSACTION PAPER

The influence of Mn on the tensile properties of SSM-HPDC Al-Cu-Mg-Ag alloy A201

H. Möller^I; E.P. Masuku^I; U.A. Curle^I; P.C. Pistorius^II; R.D. Knutsen^III; G. Govender^I

^IMaterials Science and Manufacturing, CSIR, Pretoria, South Africa
^IIDepartment of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, USA
^IIIUCT Centre for Materials Engineering, Cape Town, South Africa

SYNOPSIS

A201 aluminium alloy is a high strength casting alloy with a nominal composition of Al-4.6Cu-0.3Mg-0.6Ag. It is strengthened by the Ù(Al₂Cu) phase and the è'(Al₂Cu) phase during heat treatment. Further strengthening of this alloy system can be obtained through the addition of transition elements, but care must be taken as other elements might have adverse effects on the mechanical properties. The objective of this study is to determine the influence of Mn on the tensile properties of rheo-processed Al-Cu-Mg-Ag alloy A201. ThermoCalc software was used to predict the different phases that can be expected in the alloys, and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) was used to investigate the actual phases that formed. The influence of these phases on tensile properties is quantified. SEM and ThermoCalc revealed that there is an increased amount of the Al₂₀Cu₂Mn₃ with increasing Mn. The tensile properties showed that high amounts of Mn do have adverse effects on the tensile properties of alloy A201, especially the ductility.

Keywords: Semi-solid metal (SSM) forming, alloy A201, intermetallics, Al₂₀Cu₂Mn₃

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