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The effects of quench rate and pre-deformation on precipitation hardening in Al–Mg–Si alloys with different Cu amounts

Abstract

The effects of quench rate after solution heat treatment in combination with 1% pre-deformation on precipitation hardening in three Al–Mg–Si alloys have been investigated by transmission electron microscopy and hardness measurements during an isothermal heat treatment. The alloys contain different Cu amounts (up to 0.1 wt%) and the same amounts of other solute elements. While a Cu amount below 0.01 wt% does not affect precipitation hardening, an addition of 0.1 wt% Cu increases hardness due to the formation of a fine microstructure having a high number density of short precipitates. A double peak hardness evolution was observed during isothermal heat treatment. This effect was most pronounced for alloys with low quench rate, and less pronounced for alloys with 1% pre-deformation and 0.1 wt% Cu addition. The low quench rate also led to wider precipitation free zones. This effect was also less pronounced by 1% pre-deformation and addition of 0.1 wt% Cu.

Category

Academic article

Client

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

Language

English

Author(s)

Affiliation

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

Year

2014

Published in

Materials Science & Engineering: A

ISSN

0921-5093

Publisher

Elsevier

Volume

609

Page(s)

72 - 79

View this publication at Cristin