Softening by severe plastic deformation and hardening by annealing of aluminum-zinc alloy: Significance of elemental and spinodal decompositions

Ali Alhamidi, Kaveh Edalati, Zenji Horita, Shoichi Hirosawa, Kenji Matsuda, Daisuke Terada

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

An Al-30. mol% Zn supersaturated solid solution alloy was severely deformed using high-pressure torsion (HPT) at 300. K and subsequently annealed at 373-673. K. The hardness and tensile strength significantly decreased and the tensile ductility increased with straining by HPT and reached a steady-state level at large imposed strains. Despite this softening behavior, the lattice strain was increased, Zn-rich particles were precipitated and the initial coarse grains were refined significantly to a size of ~190. nm while being accompanied by decomposition to Al- and Zn-rich phases because of rapid atomic diffusion. The subsequent annealing led to a hardening, but microstructural observations showed that decrease in the lattice strain, increase in the grain size and reduction in the fraction of precipitates occurred by annealing. It was shown that the unusual softening/hardening behavior of the Al-Zn alloy was mainly due to the contribution of spinodal decomposition. The formation of nano-sized lamellae by spinodal decomposition resulted in increase in hardness after solution treatment and after post-HPT annealing, while this lamellar structure was destroyed by HPT, which resulted in softening. The softening was less significant when the hardness was evaluated at low homologous temperatures.

Original languageEnglish
Pages (from-to)17-27
Number of pages11
JournalMaterials Science and Engineering A
Volume610
DOIs
Publication statusPublished - Jul 29 2014

Fingerprint

zinc alloys
Spinodal decomposition
Zinc alloys
hardening
softening
Torsional stress
aluminum alloys
plastic deformation
torsion
Hardening
Aluminum alloys
Plastic deformation
Annealing
decomposition
annealing
hardness
Hardness
Lamellar structures
lamella
ductility

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Softening by severe plastic deformation and hardening by annealing of aluminum-zinc alloy : Significance of elemental and spinodal decompositions. / Alhamidi, Ali; Edalati, Kaveh; Horita, Zenji; Hirosawa, Shoichi; Matsuda, Kenji; Terada, Daisuke.

In: Materials Science and Engineering A, Vol. 610, 29.07.2014, p. 17-27.

Research output: Contribution to journalArticle

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AU - Hirosawa, Shoichi

AU - Matsuda, Kenji

AU - Terada, Daisuke

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