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Effect of low Cu addition and thermo-mechanical history on precipitation in Al-Mg-Si alloys

Abstract

The effect of cooling rate after solution heat treatment and its combination with 1% pre-deformation on precipitation hardening in two Al-Mg-Si alloys is investigated by transmission electron microscopy (TEM), and related to material hardness. Two alloys have been used, one Cu-free and the other with low Cu additions (~0.1 wt%), both having the same amounts of other solutes. A double peak hardness evolution during an isothermal heat treatment was observed with slow cooling after solution heat treatment. This effect was less pronounced in the Cu-added alloy. The 1% pre-deformation also made this effect less pronounced, but it led to faster initial hardness evolution and delayed over-aging. Maximum hardness was not influenced by cooling rate and the pre-deformation. Hardness was directly related to precipitate number densities.

Category

Academic article

Client

  • NORTEM / 197405
  • Research Council of Norway (RCN) / 193619

Language

English

Author(s)

Affiliation

  • Norwegian University of Science and Technology
  • SINTEF Industry / Materials and Nanotechnology

Year

2014

Published in

Materials Science Forum

ISSN

0255-5476

Publisher

Trans Tech Publications

Volume

794-796

Page(s)

1014 - 1019

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