On plastic relaxation of thermal stresses in reinforced metals

D. C. Dunand*, A. Mortensen

*Corresponding author for this work

Research output: Contribution to journalArticle

148 Scopus citations

Abstract

Silver chloride containing alumina fibers or glass microspheres is used as a model material to study matrix plasticity induced by thermal mismatch in metal matrix composites. Resulting matrix dislocations are decorated at room temperature in the bulk material and observed by optical microscopy. Plastic deformation of the matrix around the inclusions is found to take the form of (i) rows of prismatic dislocation loops puched into the matrix and/or (ii) a plastic zone containing tangled dislocations surrounding the inclusions. From the number of loops punched by spheres, the temperature interval over which slip of prismatic loops is operative is calculated to be 100 ± 30 K wide. The stress in the plastic zone around fibers is determined from the radius of curvature of pinned dislocations, leading to the conclusion that the matrix is locally strain-hardened. A simple model taking this fact into account is proposed to predict the radius of the plastic zone around embedded cylinders and spheres and is compared to the experimental data.

Original languageEnglish (US)
Pages (from-to)127-139
Number of pages13
JournalActa Metallurgica Et Materialia
Volume39
Issue number2
DOIs
StatePublished - Feb 1991

ASJC Scopus subject areas

  • Engineering(all)

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