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The role of microstructural features on the electrical resistivity and mechanical properties of powder metallurgy Al-SiC-Al2O3 nanocomposites

Khodabakhshi, F ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.matdes.2017.05.047
  3. Abstract:
  4. There are many engineering applications in which composite materials are required to satisfy two or more criteria regarding physical and mechanical properties. In this article, Al-matrix nanocomposites reinforced with different volume fractions of SiC nanoparticles (~ 50 nm; up to 6%) were processed by powder metallurgy (P/M) routes through mechanical milling and hot consolidation techniques. Microstructural studies showed that nano-metric Al2O3 particles with a size of ~ 20 nm and volume fraction of ~ 2% were formed and distributed in the metal matrix, owing to the surface oxides breaking. Microstructural analysis also revealed that the size of cellular structure and the density of dislocations increased with the concentration of hard inclusions. However, the limit of deformability of the nanocomposite materials containing a high amount of nanoparticles (> 4 vol%) led to less densification upon hot consolidation stages deteriorating mechanical strength. It was shown that the formation of non-equilibrium grain boundaries with high residual stresses as well as scattering around nano-metric inclusions and dislocations influenced the electrical resistivity of the nanocompsites. A linear relationship between the concentration of hard inclusions, electrical resistivity and yield strength was found. This observation demonstrates the importance of substructure and microstructures on the physico-mechanical properties of metal matrix nanocomposites. © 2017 Elsevier Ltd
  5. Keywords:
  6. Aluminum matrix nanocomposite ; Electrical resistivity ; Aluminum ; Aluminum powder metallurgy ; Composite materials ; Electric conductivity ; Grain boundaries ; Mechanical alloying ; Mechanical properties ; Metallurgy ; Metals ; Microstructural evolution ; Microstructure ; Milling (machining) ; Nanocomposites ; Nanoparticles ; Powder metallurgy ; Powder metals ; Silicon carbide ; Volume fraction ; Aluminum matrix ; Consolidation techniques ; Engineering applications ; Metal matrix nano composites ; Microstructural analysis ; Non-equilibrium grain boundaries ; Physical and mechanical properties ; Physicomechanical properties ; Metallic matrix composites
  7. Source: Materials and Design ; Volume 130 , 2017 , Pages 26-36 ; 02641275 (ISSN)
  8. URL: https://www.sciencedirect.com/science/article/pii/S0264127517305282