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Reactive friction-stir processing of nanocomposites: effects of thermal history on microstructure–mechanical property relationships

Khodabakhshi, F ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1080/02670836.2017.1318244
  3. Abstract:
  4. The effects of thermal history on the microstructure and mechanical properties of a friction-stir-processed Al–Mg–TiO2 (3 vol.-%, 20 nm) nanocomposite were studied. It is shown that, with increases in peak temperature, a more uniform distribution of nanoparticles in the metal matrix, and a refined grain structure, are attained. Transmission electron microscopy indicated that the mechanism of grain refinement is influenced by the hard inclusions, changing from discontinuous to continuous dynamic recrystallisation. A fine-grained nanocomposite (average grain size of 3 µm) with a uniform distribution of nanoparticles is obtained after four fully-overlapping passes at 1200 rev min−1 and 100 mm min−1. Under these circumstances the mechanical properties, including yield stress (95%), tensile strength (36%) and hardness (72%) are significantly enhanced relative to the untreated alloy. © 2017 Institute of Materials, Minerals and Mining
  5. Keywords:
  6. Friction-stir processing ; Mechanical property ; Nanocomposite ; Aluminum ; Friction ; Friction stir welding ; Grain refinement ; Grain size and shape ; High resolution transmission electron microscopy ; Mechanical properties ; Metal nanoparticles ; Microstructure ; Nanocomposites ; Nanoparticles ; Tensile strength ; Transmission electron microscopy ; Tribology ; Average grain size ; Continuous dynamics ; Friction stir processing ; Hard inclusions ; Microstructure and mechanical properties ; Peak temperatures ; Thermal history ; Uniform distribution ; Yield stress
  7. Source: Materials Science and Technology (United Kingdom) ; Volume 33, Issue 15 , 2017 , Pages 1776-1789 ; 02670836 (ISSN)
  8. URL: https://www.tandfonline.com/doi/abs/10.1080/02670836.2017.1318244