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Intermetallic phase identification on the cast and heat treated 6082 aluminium alloy

Andrzej S. Nowotnik 1Grazyna E. Mrowka-Nowotnik 

1. Rzeszow University of Technology, Rzeszów, Poland

Abstract

In the technical aluminium alloys besides the intentional additions, transition metals such as Fe and Mn are always present. Even not large amount of these impurities causes the formation a new phase components. The exact composition of the alloy and casting condition will directly influence the selection and volume fraction of intermetallic phases. During casting of 6xxx alloys, a wide variety of Fe-containing intermetallics such as Al-Fe, Al-Fe-Si and Al-Fe-Mn-Si phases are formed among the aluminium dendrites. The type of these phases depends mainly on the cooling rate and Fe to Si ratio of the alloy. These intermetallics have different unit cell structures, morphologies, stabilities and physical and mechanical properties. As cas billets require require a homogenization treatment to make the material suitable for hot extrusion. During this homogenization several processes take place such as the transformation of interconnected plate like beta-Al5FeSi intermetallics into more rounded discrete alpha-Al12(FeMn)3Si particles and the dissolution of beta-Mg2Si particles. Transformation of beta-Al5FeSi to alphac-Al12(FeMn)3Si intermetallics is important because it improves the ductility of the material. Dissolution of Mg2Si is also important since it will give maximum age hardening potential for the extruded product. In this study, several methods was used such as: optical microscopy, transmission (TEM) and scanning (SEM) electron microscopy in combination with electron dispersive X-ray (EDX) using polished sample, and X-ray diffraction (XRD) to identification intermetallics compounds in 6082 aluminium alloy.

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2006, Symposium I, by Andrzej S. Nowotnik
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-20 14:07
Revised:   2009-06-07 00:44