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Fabrication of Al Based Nanocomposite with Al2O3 and Al3Ti Reinforcements by Mechanical Milling and Press and Sintering (In situ method) and Investigation of Its Wear Behavior

Shabani Nezhad, Parisa | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45623 (07)
  4. University: Sharif University of Technology
  5. Department: Material Science and Engineering
  6. Advisor(s): Seyed Reihani, M
  7. Abstract:
  8. In this study, Aluminium based nanocomposite with Al3Ti and Al2O3 nanoparticles have been elaborated by mechanical alloying. For this purpose, Al and TiO2 powders have been blended with weight ratios of 10, 20 and 30 percents and were milled using a planetary mill. Morphological variations in different timing periods of mechanical milling process was investigated by Scaning Electron Microscopy (SEM) and The optimal times for alloying were determined for each combination. The pure Aluminium and the powder with 10, 20 and 30%wt reinforcement had coax morphology after respectively for 44, 30, 24 and 14 hours. after studing phase transformations by XRD analysis, the final powders were cold pressed and sintered. Micrstructure investigations were studied using optical microscopy, and samples were characterized by brinel hardness, density measurement and XRD analysis on compacted samples. The result shows that increasing the weight percentage of reinforcement increases the hardnesses from 24.31 for pure Aluminium to 45.16, 61.85 and 83.76 for the nanocomposites with respectively 10, 20 and 30% wt reinforcement. Sample densities were decreased by increasing weight percent. Wear tests, using pin-on-disk apparatus, were evaluated on disk samples with constant linear velocity 0.1 m/s in constant sliding distance 250m and under applied load 10, 20, 30 and 40N. Samples containing 10% wt reinforcement, relative to the samples containing 20 %wt reinforcement, showed lower friction coefficient and higher wear resistance. For samples containing 10%wt reinforcement, the force that transition occured from mild wear to severe wear, was between 30 and 40N while this force for the sample containing 20%wt, was between 20 and 30N. The samples containing 30%wt reinforcement, were failed during sintering process
  9. Keywords:
  10. Mechanical Alloying ; Aluminum Matrix Nanocomposite ; Pin-On-Disk ; Wear ; In-Situ Reaction ; In-Situ Reinforcement Particles ; Reinforcement Percentage

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