Effects of Nb on the elements diffusion and mechanical properties of laminated Ti/Al_2O_3 composites

摘要

Laminated Ti/Al_2O_3 composites with Nb addition were fabricated by tape casting and vacuum hot pressing sintering. Effects of Nb addition on the elements diffusion (Al, O and Ti) and the mechanical properties of the laminated composites were investigated. When the amount of layers was 40, the flexural strength and the fracture toughness of the laminated composite with 1.0 vol% Nb addition in both Ti and Al_2O_3 layers reached the maximum values of 387.93 MPa and 9.56 MPa m~(1/2). Based on the results of the SEM, EDS and XRD, the improvement of the mechanical properties could be attributed to the generation of AlNb_2 which formed "barrier" between the Ti and Al_2O_3 layers. As a result, the diffusion of Al and O was hindered and the thicknesses of the reaction layers were reduced eventually. Moreover, the strengthening and toughening mechanism of Nb addition was illustrated and discussed.