ELASTOPLASTIC OPTIMUM DESIGN OF Ni/TiC FUNCTIONAL GRADIENT MATERIAL

The thermal residual stresses developed in a disk-shaped.Ni/TiC functionally gradient material (FGM) during its fabricationare investigated by an elastic-plastic finite element numerical ap-proach.Constitutive relations for the graded Ni-TiC composite interlayers between pure metal Ni and ceramic TiC are estimated by usingan effectiv-medium approach,and effective plastic strain and stressdistributions are computed for simulated cooling from an assumed fab-rication temperature.Analyses are performed for a fixed specimen ge-ometry and the graded region is treated as a series of perfectly bondedequal-thick layers.The restults are compared with those obtained by on-ly considering elastic material response to assess the effect of plasticityon the optimum fabrication design of the Ni/TiC FGM.It is demon-strated that the consideration of plasticity is of critical importance foroptimization of the metal/ceramic gradient materials.

ELASTOPLASTIC OPTIMUM DESIGN OF Ni/TiC FUNCTIONAL GRADIENT MATERIAL

The thermal residual stresses developed in a disk-shaped, Ni/TiC functionally gradient material (FGM) during its fabrication are investigated by an elastic-plastic finite element numerical ap-proach. Constitutive relations for the graded Ni-TiC composite inter-layers between pure metal Ni and ceramic TiC are estimated by using an effectiv-medium approach, and effective plastic strain and stress distributions are computed for simulated cooling from an assumed fab-rication temperature. Analyses are performed for a fixed specimen ge-ometry and the graded region is treated as a series of perfectly bonded equal-thick layers. The results are compared with those obtained by on-ly considering elastic material response to assess the effect of plasticity on the optimum fabrication design of the Ni/TiC FGM. It is demon-strated that the consideration of plasticity is of critical importance for optimization of the metal/ceramic gradient materials.