Residual thermal stresses in MoSi2-Mo5Si3 in-situ composites

P. Peralta, R. Dickerson, J. R. Michael, K. J. McClellan, F. Chu, T. E. Mitchell

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Residual thermal stresses in MoSi2-Mo5Si3 in-situ composites are calculated for a dilute concentration of particles of one phase embedded in a matrix of the other, using the fields of anisotropic ellipsoidal inclusions. Additionally, the eutectic interfaces are modeled as boundaries between two anisotropic half-spaces. The misorientation between MoSi2-Mo5Si3 is obtained from the literature for Mo5Si3 precipitates in MoSi2 and by electron diffraction in the scanning electron microscope (SEM) for the opposite case. Tensile stresses of up to 3 GPa can develop after cooling from the eutectic temperature due to the thermal expansion mismatch between the phases. Electron microscopy of arc-melted Si-rich Mo5Si3 shows that stresses are relieved by intergranular fracture in Mo5Si3 and either dislocation plasticity or transgranular cracks in MoSi2, in a manner consistent with the calculations.

Original languageEnglish (US)
Pages (from-to)261-269
Number of pages9
JournalMaterials Science and Engineering A
Volume261
Issue number1-2
StatePublished - Mar 15 1999
Externally publishedYes

Keywords

  • Dislocation plasticity
  • Eutectic interfaces
  • In-situ composites
  • Molybdenum disilicide
  • Residual thermal stress

ASJC Scopus subject areas

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

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    Peralta, P., Dickerson, R., Michael, J. R., McClellan, K. J., Chu, F., & Mitchell, T. E. (1999). Residual thermal stresses in MoSi2-Mo5Si3 in-situ composites. Materials Science and Engineering A, 261(1-2), 261-269.