Toughness enhancement and thermal properties of graphene-CNTs reinforced Al2O3 ceramic hybrid nanocomposites

• Published in: Chemical physics letters 2021-10, Vol.781, p.138978, Article 138978
• Main Authors: Shah, W.A., Luo, X., Rabiu, B.I., Huang, B., Yang, Y.Q.
• Format: Article
• Language: English
• Subjects: Alumina; CNTs; Fracture toughness; Graphene; Hardness; SPS; Thermal conductivity
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2021.138978

[Display omitted] •A low concentration of graphene (less than 0.4 wt%) was well dispersed into alumina matrix by physical dispersion method.•The hardness, bending strength and fracture toughness were increased significantly by 19.2%, 84.7% and 49.5%, respectively at low graphene contents.•Different types of toughening mechanisms are observed.•With the increase of graphene contents and temperature, thermal conductivity of the nanocomposites decreases. Graphene/CNTs-reinforced alumina ceramic composites were prepared by spark plasma sintering (SPS) method at 1500 °C. The distribution behaviors of graphene/CNTs reinforcements in alumina matrix composite were studied and mechanical properties of the composite were tested. The structural integrity of the graphene after sintering was analyzed by Raman spectroscopy. The composites show inter and trans-granular fracture behaviors. Many toughening mechanisms such as graphene and CNTs necking, crack bridging, crack deflection and crack branching were observed. The experiment-based calculation of heat capacity of the composite was presented in details. The thermal diffusivity and thermal conductivity of the nanocomposites were discussed. The thermal conductivity increased with the increase of grain size. The pure alumina had the highest thermal conductivity, which was 23.9 Wm−1 K−1.