Effects of thermal residual stresses and thermal-induced geometrically necessary dislocations on size-dependent strengthening of particle-reinforced MMCs

Dongfeng Cao, Qingfeng Duan, Shuxin Li*, Yucheng Zhong, Haixiao Hu

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)

Abstract

The thermal residual stresses (TRSes) can noticeably increase the yield strength and flow stresses of particle-reinforced metal-matrix composites (PR-MMCs) and show size-dependence due to thermal geometrically necessary dislocations (GNDs) when the size of particles is on the order of micron. This TRSes strengthening is attributed to the conventional thermal-elasto-plastic constituent mismatch (regardless of particles’ size) and the presence of GNDs (size-dependent). A modified Taylor-based nonlocal theory (TNT) of plasticity is proposed to quantify the individual contributions of size-dependent GND strengthening. An axisymmetric unit-cell model of uniform and aligned particle distribution with various particle sizes is built to study thermal-induced non-uniformly distributed GNDs, their evolution and contributions to the stress strengthening under combined thermal and mechanical loading. The results show that the proposed methodology can effectively capture the size dependence of thermal-induced GNDs which keeps a sharp gradient variation in the zone near the matrix-inclusion interface and gradually flattens out in the zone far away from the interface. It is demonstrated that TRSes significantly improve the yield strength and flow stresses. It also revealed that the contribution of thermal-induced GNDs increased as the particle size in the PR-MMCs decreased. The simulation results were validated by experimental results reported in the literature.

Original languageEnglish
Pages (from-to)290-297
Number of pages8
JournalComposite Structures
Volume200
Early online date30 May 2018
DOIs
Publication statusPublished - 15 Sep 2018

Keywords

  • Geometrically necessary dislocation (GND)
  • Metal matrix composites (MMCs)
  • Strain gradient theory
  • Thermal residual stresses

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