Fundamental Studies of Strengthening Mechanisms in Metals Using Dislocation Dynamics

摘要

A distributed dislocation method has been developed to quantify the elastic fields of inclusion eigenstrain problems in 2D and 3D (Lerma et al. 2003). The inclusions can be of any shape or size and the eigertstrains can be arbitrarily assigned, i.e. constant or non-constant within the inclusion. The method works well for material or field points inside or outside the inclusion domain, and is straightforward to apply. The method is based on discretizing the inclusion-matrix interface into a mesh of small regions of misfit represented in the method by dislocation loops with appropriately assigned Burgers vectors. The method works well for relatively far points from the inclusion although it also works for relatively close points at the expense of increasing the mesh density, i.e. the computational time involved. It was shown that, with increasing mesh density, the method converges into known analytical solutions for some specialized geometry and misfits. Recently, we have developed a new distributed-dislocation method for modeling eigenstrain problems such as gamma prime inclusions/particles in nickel-base superalloys. Here the dislocation loops representing the misfit are distributed throughout the volume of the inclusion with the dislocation lines themselves lying on the inclusion-matrix interface.