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The effect of nano-TiO2 additions on the densification and mechanical properties of SiC-matrix composite

Khodaei, M ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ceramint.2019.11.128
  3. Publisher: Elsevier Ltd , 2020
  4. Abstract:
  5. This research studied the effect of adding TiO2 nanoparticles along with Al2O3 and Y2O3 additives on the physical and mechanical properties of a SiC-matrix composite. The samples were fabricated through a pressureless process at 1900 °C. The results showed that the addition of TiO2 nanoparticles up to 4.5 wt% inhibited the excessive growth of SiC grains. According to the investigations, the microstructure and final properties of composites were affected by density, synthesized phases as well as their distribution in the matrix, and grain size. The highest density, Young's modulus, hardness, indentation fracture resistance, and flexural strength, alongside with the lowest brittleness index were respectively, 98.7%, 401.2 GPa, 27.1 GPa, 6.1 MPa m1/2, 522.7 MPa and 292.19 × 10−6 m−1, attributed to sample containing 4.5 wt% TiO2. Microstructural observations showed that the stresses caused by the difference in the thermal expansion coefficients of SiC and TiC, the formation of micro-cracks, the occurrence of crack deflection and crack branching mechanisms, as well as grain pull-out were the main reasons for the improvements in indentation fracture resistance. © 2019 Elsevier Ltd and Techna Group S.r.l
  6. Keywords:
  7. SiC-TiC composite ; Additives ; Alumina ; Aluminum oxide ; Elastic moduli ; Fracture mechanics ; Fracture toughness ; Indentation ; Nanoparticles ; Silicon carbide ; Thermal expansion ; TiO2 nanoparticles ; Titanium carbide ; Titanium dioxide ; Crack branching ; Crack deflections ; In-situ reactions ; Indentation fracture resistances ; Micro-structural observations ; Nano-TiO2 ; Physical and mechanical properties ; Thermal expansion coefficients ; Cracks
  8. Source: Ceramics International ; Volume 46, Issue 5 , April , 2020 , Pages 6477-6483
  9. URL: https://www.sciencedirect.com/science/article/pii/S0272884219333188