Structural relaxation and rejuvenation in a metallic glass induced by shot-peening

A. Concustell, F. O. Méar, S. Suriñach, M. D. Baró, A. L. Greer

Research output: Contribution to journalArticleResearchpeer-review

57 Citations (Scopus)

Abstract

The metallic glass Pd40Cu30Ni10P20 in as-cast or pre-annealed states was shot-peened successively at room temperature or at 77 K. The structural state of the glass was characterized by the relaxation spectrum measured in a differential scanning calorimeter. Mechanically induced relaxation of the as-cast glass and mechanically induced rejuvenation of pre-annealed samples are both more evident at 77 K than at 298 K, enabling deductions about the underlying mechanisms. The relaxation spectrum of the glass as a function of temperature displays two broad maxima, which occurring at the higher temperature is attributed to the part of the free-volume distribution associated with flow defects. In samples shot-peened at 77 K, the stored energy after deformation can be as high as 20% of the cold work. Shot-peening simultaneously generates flow defects within shear bands and destroys them in the matrix between bands: whose effect dominates is principally dependent on the initial state of relaxation of the glass. Shot-peening of partially crystallized samples appears capable of breaking up and dispersing crystallites without inducing any further significant crystallization.
Original languageEnglish
Pages (from-to)831-840
JournalPhilosophical Magazine Letters
Volume89
DOIs
Publication statusPublished - 1 Dec 2009

Keywords

  • Differential scanning calorimetry
  • Metallic glass
  • Plastic deformation
  • Structural relaxation

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