Aging Behavior of Al 6061 Alloy Processed by High-Pressure Torsion and Subsequent Aging

Intan Fadhlina Binti Mohamed, Seungwon Lee, Kaveh Edalati, Zenji Horita, Shoichi Hirosawa, Kenji Matsuda, Daisuke Terada

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

A process to achieve strengthening in an Al 6061 alloy by grain refinement to ~200 nm using high-pressure torsion (HPT) and fine precipitation using aging treatment is studied. It is shown that although aging of the HPT-processed sample is effective for extra strengthening of the alloy, the imposed shear strain and the aging temperature should be selected carefully. The HPT processing after 5 turns leads high saturation hardness and tensile strength of 163 Hv and 470 MPa, respectively. The hardness at the saturation level remains the same during aging at 373 K (100 °C), while the hardness decreases by aging at 423 K (150 °C). When the disks are processed for 0.75 turns (lower shear strains) and aged at 373 K (100 °C), the hardness increases above the hardness level at the saturation because of the formation of B′ and β′ precipitates. Quantitative analyses indicate that three major hardening mechanisms contribute to the total hardening: grain boundary hardening through the Hall–Petch relationship, dislocation hardening through the Bailey–Hirsch relationship and precipitation hardening through the Orowan relationship. This study shows that the contribution of different strengthening mechanisms can be estimated using a linear additive relationship in ultrafine-grained aluminum alloys.

Original languageEnglish
Pages (from-to)2664-2673
Number of pages10
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume46
Issue number6
DOIs
Publication statusPublished - Jun 1 2015

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

Cite this