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The effects of nano Mgo on physical and mechanical properties of Al 2O3-SiC composites

Nemati, A ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.4416/JCST2012-00034
  3. Publisher: 2012
  4. Abstract:
  5. In this research, the effects of nano-sized MgO in Al2O 3-SiC composites were investigated. The overall changes in the density and mechanical properties of sintered samples (hardness, bending strength and toughness) were evaluated. After mixing, drying and uniaxial compaction of the powders, they were first heat-treated at low temperature in an electric furnace to remove any residuals. They were then heat-treated at high temperature (1700 °C) inside a graphite furnace in argon atmosphere for sintering (at normal and high pressure). The content of MgO in the Al 2O3-10 vol% SiC composite was 0, 500, 1000, and 1500 ppm. Thefracture toughness(KIC)of sintered composite with 10 vol%SiC(nano-sized)anddifferentamountsofMgOwas investigated by means of the Vickers indentation method. Microstructural analysis was performed using a scanning electron microscope. The data showed that the mechanical properties were increased up to 1000 ppm MgO and then decreased above that. Microstructural observations revealed that in Al2O3-10 vol% SiC nanocomposites, nano-scale SiC particles were normally distributed all over the Al2O3 matrix and inhibited the abnormal grain growth of Al2O3. In addition, transgranularly fractured alumina grains were observed on the fracture surface of the samples. The results also showed that the fracture toughness of the composites withMgOwas improved and better than that of Al2O3-10 vol% SiC samples
  6. Keywords:
  7. Additive ; Nanocomposite ; Abnormal grain growth ; Alumina grains ; Argon atmospheres ; Fracture surfaces ; Graphite furnaces ; High pressure ; High temperature ; Low temperatures ; MgO ; Microstructural analysis ; Microstructural observations ; Nano-scale SiC ; Physical and mechanical properties ; Sintered samples ; Strength and toughness ; Uniaxial compaction ; Vickers indentation method ; Additives ; Alumina ; Aluminum ; Density (specific gravity) ; Electric furnaces ; Grain growth ; Mechanical properties ; Microstructure ; Nanocomposites ; Normal distribution ; Scanning electron microscopy ; Sintering ; Toughness ; Silicon carbide
  8. Source: Journal of Ceramic Science and Technology ; Volume 3, Issue 1 , 2012 , Pages 29-34 ; 21909385 (ISSN)
  9. URL: http://www.ceramic-science.com/articles/all-articles.html?article_id=100140&doi=10.4416/JCST2012-00034