Heating and structural disordering effects of the nonlinear viscous flow in a Zr55Al10Ni5Cu30 bulk metallic glass

Hidemi Kato, Akihisa Inoue, H. S. Chen

Research output: Contribution to journalConference article

Abstract

Heat evolution of stress-induced structural disorder, ΔH s(ε), of a Zr55Al10Ni5Cu 30 bulk metallic glass (BMG) during constant ram-velocity deformation at the glass transition region (Tg= 680 K) was deduced from in-situ measurements of temperature change of the deforming sample. At the transition from the linear to nonlinear viscoelasticity, the behavior of viscosity change with strain, η(ε), is qualitatively consistent with the enthalpy evolution of the structural disordering, ΔHs(ε), but not with the temperature change, ΔT(ε). It is concluded that the initial softening deformation is due to the stress-induced structural disordering. The change in the nonlinearity, -logη̃ -logη/ηN, is found to be proportional to the ΔHs and the slope of ΔHs(-logη̃) can be estimated to ∼ 400 J/mol, where ηN is the Newtonian viscosity. On the other hand, the temperature raise, ΔT(ε), is pronouncedly delayed as compared with the η(ε) and ΔHs(ε) at the transition, but is determined by the product of stress and plastic strain-rate, σ· ε̇p, and is nearly proportional to it at the steady-state. The slope of ΔT(σ· ε̇p) can be estimated to 5.2×10-2 K mol/W.

Original languageEnglish
Pages (from-to)251-256
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume806
Publication statusPublished - 2003 Dec 1
EventAmorphous and Nanocrystalline Metals - Boston, MA., United States
Duration: 2003 Dec 12003 Dec 4

ASJC Scopus subject areas

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

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