Combination of metal and ceramic is well known and has many industrial applications. Metal/ceramic joints become more and more important in modern technology. The fracture at or near such interfaces often limits the reliability of these joints. Knowledge of the stress and deformation fields at the crack tip at a metal/ceramic interface is needed in order to develop a fundamental understanding of this fracture process. In many situations, cracks initiate at interfaces and advance along, towards or away from the interfaces. Despite their widespread use, a basic understanding of these interfaces has been vague.In most of the cases, improvements in interface properties proceed via a costly and time consuming trial-and-error process in which numerous materials are evaluated until suitable performance is obtained. Computational methods provide a wide range of possibilities to study the fracture behavior of such metal/ceramic interfaces. Various groups postulated that the fracture energy of interfaces depends not only on work of adhesion (W adh ), but also on the amount of plasticity that occurs in the metal during the fracture process. The orientation of crystals in components of a joint can vary the amount of plasticity in them; but these orientations need to be optimized. To the author’s knowledge there is not that much work in this field in the literature. In this thesis, at first a crystalline solid was studied. Different groups of crystalline lattices, slip systems, kinematics of single crystals, constitutive equations and hardening relations were studied. For simulation of single crystals, Abaqus software and a UMAT subroutine was used. This UMAT was written by Y. Huang at 1991. In the next step of thesis, this UMAT was reviewed. Implementation of single crystal’s formulation and updating state variables including calculation of shear strain increments were studied. In addition, the effect of crystal orientation on fracture behavior in metal component of a metal/ceramic composite was studied. According to available experimental works, a four point bending simulation model was prepared.The simulation results were compared with experimental observations qualitatively. To obtain the orientation with maximum fracture energy, a bicrystal model under tension load was also studied. This model had a crack at the interface. The ceramic part of model was Alumina. To examine FCC and BCC lattice, the metal part of model was Copper and Niobium respectively. In order to investigate effects of different metal orientations in a single crystalline metal, Taguchi’s design of experiments (DOF) method was used. Using this method, the orientation that gives the highest energy release rate was determined. Keywords: Metal-Ceramiv Materials, Single Crystals Metals, Fracture Mechanics,Simulation in Abaqus Taguchi's Optimazation.
