The Constitutive Creep Equation for a Eutectic Sn-Ag Alloy Using the Modified Theta-Projection Concept

Yoshiharu Kariya, Masahisa Otsuka, William J. Plumbridge

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Creep data for a eutectic tin-silver alloy at temperatures between 298 K and 398 K have been analyzed using the modified theta-projection concept, instead of the steady-state creep constitutive equation in the following formula: εcr = A (1 - exp(-αt)} + B (exp(αt) - 1}, where A, B, and a are constants to be experimentally determined. The equation describes well the creep curves of the eutectic tin-silver alloy up to the tertiary stage. All constants exhibited power law relationships with the applied stress. The rate constant, α, has a high stress exponent, which is attributed to dispersion strengthening. The rate constant a and the strain factor B only showed temperature dependence, while the strain factor A was independent of temperature. The activation energy for α was 65 kJ/mol at high stresses and 90 kJ/mol at low stresses. The energies suggest that the dislocation pipe diffusion and the lattice diffusion are predominant at high stresses and low stresses, respectively.

Original languageEnglish
Pages (from-to)1398-1402
Number of pages5
JournalJournal of Electronic Materials
Volume32
Issue number12
Publication statusPublished - 2003 Dec
Externally publishedYes

Fingerprint

eutectics
Eutectics
Creep
projection
Silver alloys
tin alloys
Tin alloys
silver alloys
Rate constants
dispersion strengthening
steady state creep
constitutive equations
Constitutive equations
Temperature
Activation energy
Pipe
exponents
activation energy
temperature dependence
temperature

Keywords

  • θ projection
  • Constitutive equation
  • Creep
  • Lead-free solder
  • Nonsteady state
  • Sn-3.5Ag

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

Cite this

The Constitutive Creep Equation for a Eutectic Sn-Ag Alloy Using the Modified Theta-Projection Concept. / Kariya, Yoshiharu; Otsuka, Masahisa; Plumbridge, William J.

In: Journal of Electronic Materials, Vol. 32, No. 12, 12.2003, p. 1398-1402.

Research output: Contribution to journalArticle

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