The Alstruc homogenization model for industrial aluminum alloys

Abstract

Wrought aluminum alloys are often given a homogenization heat treatment before extrusion or rolling. Foundry alloys are sometimes given a solution heat treatment before age hardening. The purpose is

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  to remove particles and segregation gradients that will give films or areas with low melting temperatures, in order to avoid tearing during extrusion and rolling;

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  to round off hard particles with sharp edges, which give poor ductility and holes in thin walled products;

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  to form secondary particles (dispersoids) for grain size control during extrusion and rolling;

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  to obtain a uniform distribution of alloying elements in solid solution before rolling, extrusion or age hardening.

The Alstruc homogenization program gives semi-quantitative estimates of the changes in the microstructure during the later part of the heating stage and during the holding stage. The program has separate subroutines for AA3xxx (AlMnFe with Mg and Si), AA5xxx (AlMg with Fe, Si and Mn) and AA6xxx (AlMgSi with Fe, Mn and Cu) wrought alloys and for AlSi foundry alloys with Fe, Mg and Cu. The estimates of the changes in the microstructure during cooling are qualitative.

This paper is compiled of three parts: 1 Industrial homogenization process for aluminum alloys, 2 The homogenization process – structural perspective, 3 The homogenization process – modeling needs, 4 Homogenization model development, 5 Experimental comparison and verification of Alstruc for AA6xxx-alloys present the program concept, 6 Experimental Comparison and verification of Alstruc for AA3xxx-alloys, 7 Experimental comparison and verification of Alstruc for AlSi foundry alloys, 8 Industrial alloys: aluminum corner of the solid-state AlMgMnFeSiCu phase diagram present the results of the curve fitting and verification process for industrial alloys, and Section 9 presents interesting phase diagrams.

Solidification	Homogenization
AA1xxx
AA3xxx	AA3xxx
AA5xxx	(AA5xxx)
AA6xxx	AA6xxx
AA7xxx
$\text{AlSi}$+++	$\text{AlSi}$+++