Despite having many attractive properties, ZrO2 ceramic has a low fracture toughness which limits its wide application. One of the most obvious tactics to improve its mechanical properties has been to add a reinforcing agent to formulate a nanostructured composite material. Nanopowders of ZrO2 and Cr were synthesized from CrO3 and Zr powder by high energy ball milling for 10 h. Dense nanocrystalline 2/3Cr-ZrO2 composite was consolidated by a high-frequency induction heated sintering method within 5 min at 600˚C from mechanically synthesized powder. The method was found to enable not only rapid densification but also the inhibition of grain growth, preserving the nano-scale microstructure. Highly dense 2/3Cr-ZrO2 composite with relative density of up to 99.5% was produced under simultaneous application of a 1 GPa pressure and the induced current. The hardness and fracture toughness of the composite were 534 kg/mm2 and 7MPa·m1/2, respectively. The composite was determined to have good biocompatibility.

The current concern about these materials (MoSi2 and NbSi2) focuses on their low fracture toughness below theductile-brittle transition temperature. To improve the mechanical properties of these materials, the fabrication of nanostructuredand composite materials has been found to be effective. Nanomaterials frequently possess high strength, high hardness, excellentductility and toughness, and more attention is being paid to their potential application. In this study, nanopowders of Mo, Nb,and Si were fabricated by high-energy ball milling. A dense nanostructured MoSi2-NbSi2 composite was simultaneouslysynthesized and sintered within two minutes by high-frequency induction heating method using mechanically activated powdersof Mo, Nb, and Si. The high-density MoSi2-NbSi2 composite was produced under simultaneous application of 80MPa pressureand an induced current. The sintering behavior, mechanical properties, and microstructure of the composite were investigated.The average hardness and fracture toughness values obtained were 1180kg/mm2 and 3MPa·m1/2, respectively. These fracturetoughness and hardness values of the nanostructured MoSi2-NbSi2 composite are higher than those of monolithic MoSi2 orNbSi2.

Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties, including high strength, high hardness, excellent ductility and toughness. In this study, nanopowders of Al2O3, MgO and TiO2 were prepared as starting materials by high energy ball milling for the simultaneous synthesis and sintering of the nanostructured compound Mg4Al2Ti9O25 by high-frequency induction heating process. The highly dense nanostructured Mg4Al2Ti9O25 compound was produced within one minute by the simultaneous application of 80MPa pressure and induced current. The sintering behavior, grain size and mechanical properties of the Mg4Al2Ti9O25 compound were evaluated.