MODELING OF ELASTIC INTERACTION STRESSES IN 2-PHASE MATERIALS BY FEM

Recently, by considering a bicrystal of alpha and beta phases of Ti al loys with Burgers orientation relationships, it has been shown that el astic interactions play a significant role in the initiation of plasti c deformation in two-phase materials. However, it is not known how far these interactions exist away from the interfaces. Further, it is not known how these interactions vary with morphology of phases (i.e. thi ckness, orientation and distribution). To study these effects systemat ically, a three-dimensional anisotropic finite element method (FEM) ha s been employed in this investigation. It is found that the interactio n stresses decay from the interface in an exponential form in a distan ce of one-sixth to one-half of the plate thickness, that large hydrost atic stresses are found within alpha plates in beta matrix and that th e anisotropic elastic material properties are not responsible for the anisotropic sliding experimentally observed by earlier investigators. In addition, it has been found that the magnitude of the interaction s tresses varies with the morphology of phases.