Mechanical properties of SiC-AlN-Y2O3 composites (SiC 50%wt-AlN 50%wt), pressureless-sintered with an innovative and cost-effective method, were determined before and after oxidation performed at 1300°C for 1h. As a consequence of the oxidative treatment, fracture toughness increased from 4.6 MPa m1/2 to 6.6 MPa m1/2, flexural strength from 420 MPa to 488 MPa, Weibull modulus from 4.5 to 5.3 and thermal shock resistance (expressed as critical temperature difference) from 310°C to 380°C. First of all, these results demonstrated that a pre-oxidation treatment is needed to increase the mechanical resistance and reliability of SiC-AlN-Y 2O3 components. Secondarily, the beneficial effects of the oxidation on the mechanical properties could be explained in terms of compressive residual stresses and crack healing ability.
Effects of Oxidation on the Mechanical Properties of Pressureless-Sintered SiC-AlN-Y2O3 Composites obtained without Powder Bed
Magnani, G.
2009-01-01
Abstract
Mechanical properties of SiC-AlN-Y2O3 composites (SiC 50%wt-AlN 50%wt), pressureless-sintered with an innovative and cost-effective method, were determined before and after oxidation performed at 1300°C for 1h. As a consequence of the oxidative treatment, fracture toughness increased from 4.6 MPa m1/2 to 6.6 MPa m1/2, flexural strength from 420 MPa to 488 MPa, Weibull modulus from 4.5 to 5.3 and thermal shock resistance (expressed as critical temperature difference) from 310°C to 380°C. First of all, these results demonstrated that a pre-oxidation treatment is needed to increase the mechanical resistance and reliability of SiC-AlN-Y 2O3 components. Secondarily, the beneficial effects of the oxidation on the mechanical properties could be explained in terms of compressive residual stresses and crack healing ability.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
