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Muon kinetics in heat treated Al (–Mg)(–Si) alloys

Abstract

Al–Mg–Si alloys are heat-treatable and rely on precipitation hardening for their mechanical strength. We have employed the technique of muon spin relaxation to further our understanding of the complex precipitation sequence in this system. The muon trapping kinetics in a material reveals a presence of atom-sized defects, such as solute atoms (Mg and Si) and vacancies. By comparing the muon kinetics in pure Al, Al–Mg, Al–Si and Al–Mg–Si when held at different temperatures, we establish an interpretation of muon trapping peaks based on different types of defects. Al–Mg–Si samples have a unique muon trapping peak at temperatures around 200 K. This peak is highest for samples that have been annealed at 70–150 °C, which have microstructures dominated by a high density of clusters/Guinier–Preston zones. The muon trapping is explained by the presence in vacancies inside these structures. The vacancies disappear from the material when the clusters transform into more developed precipitates during aging.

Category

Academic article

Client

  • Research Council of Norway (RCN) / 193619

Language

English

Author(s)

Affiliation

  • Norwegian University of Science and Technology
  • Toyama University
  • Riken
  • CCLRC Rutherford Appleton Laboratory
  • SINTEF Industry / Materials and Nanotechnology

Year

2013

Published in

Acta Materialia

ISSN

1359-6454

Publisher

Pergamon Press

Volume

61

Issue

16

Page(s)

6082 - 6092

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