Al 2 O 3 has a high Young's modulus (380 GPa), a low density (3.98 g• cm-3), good high-temperature mechanical properties, biocompatibility and excellent oxidation resistance. Al 2 O 3 has been used for automotive, aerospace, bio-materials and various industrial applications. Despite its various merits, the low fracture toughness of the material below the brittle-ductile transition temperature has limited its use for wide application. To enhance its fracture toughness, the method commonly utilized has been to make a composite by the addition of a second phase to fabricate nanostructured materials. In the study, nano-powders of Al 2 O 3 and Nb were synthesized during the ball milling according to the reaction(Nb 2 O 5 + 10/3 Al → 2Nb + 5/3 Al 2 O 3). The nanostructured Nb-Al 2 O 3 composite was consolidated within a short time from the milled powders using high-frequency induction heated sintering. The average grain sizes of Al 2 O 3 and Nb in composite sintered at 1400°C were 63 and 250 nm, respectively. The relative density of the Nb-Al 2 O 3 composite was about 99% under the simultaneous induced current and application of 80 Mpa pressure. The fracture toughness and hardness of the composite were about 8.7 MPa• m 1/2 and 1460 kg/mm 2 , respectively. The fracture toughness of the nanostructured Nb-Al 2 O 3 composite was higher than that of monolithic Al 2 O 3 .

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