A. Morales-Rodríguez

High Temperature Mechanical Properties of Ti(C,N)-Co-Mo2C Cermets

The creep behavior of a TiCxN1-x-Co-Mo2C cermet has been investigated at temperatures between 1100-1200°C in an inert atmosphere to assess the one step mechanically induced self-sustaining reaction synthesis and pressureless sintering process, and the influence of the Mo2C additive in the high temperature mechanical properties of this cermet. The samples deform plastically at the chosen temperatures, and values of the stress exponent (n=1.70.6) and activation energy (Q= 4.30.5 eV) have been estimated from uniaxial compression tests. No significant grain growth has been detected after deformation. The reproducibility of the creep tests compared to other compositions indicates that the Mo2C addition contributes to increase notably the resistance to high temperature oxidation of the samples, so that the plastic behavior is not affected by oxidation when deformation experiments are performed in an inert atmosphere.

Influence of oxidation on high-temperature mechanical properties of zirconia/nickel cermets

The influence of an oxidizing atmosphere on the high-temperature plasticity of zirconia/nickel cermets has been studied by conducting creep tests in air. The resulting microstructure has been characterized by scanning, conventional and high-resolution electron microscopy. Despite the large microstructural changes, the composites do not exhibit mechanical degradation.

High Temperature Deformation of Laminated Ceramic Composites Obtained from the Al2O3-ZrO2 System

Symmetric structures of laminated ceramic composites were produced by super imposing alternating layers of Al2O3 and Al2O3/ZrO2 (60/40 vol%) composite prepared by tape casting. The laminated structure was designed in order to have alumina layers at the surface. The high temperature plastic deformation of the layered composites was examined in uniaxial compression testing. Compressive tests at constant strain rate and constant load were carried out in air at temperature between 1350 °C and 1500°C with the stress axis parallel to the layer interfaces. The stress exponent n and the activation energy Q were obtained. Damage was observed during creep, however more than 50% of deformation can be achieved in this configuration without macroscopic failure of these layered composites.