The influence of post-sintering HIP on the microstructure, hardness, and indentation fracture toughness of polymer-derived Al2O3–SiC nanocomposites

摘要: Al2O3–SiC nanocomposites containing 3–8 vol.% SiC were prepared from fine α-alumina powder and a poly(allyl)carbosilane precursor of by polymer infiltration porous alumina matrix (composites IP), or warm pressing polymer-coated CW). The was converted to careful heating green specimens in inert atmosphere (Ar). residual porosity eliminated less than 10% pressureless sintering (PS) at temperatures between 1700 1850 °C. post-sintering hot isostatic (HIP) °C the 1%, but also resulted coarsening grains, inter- intragranular inclusions. Vickers hardness IP sintered T < increased 1–10%, which is attributed elimination porosity. indentation fracture toughness decreased after HIP 6 15%, respectively. CW composites their approximately 10%. maximum 5.2 ± 0.2 MPa m1/2 measured for materials 8 SiC. A correlation found toughness, mean size volume fraction intergranular inclusions CW.