Research on additive manufacturing has been focused mainly on how process parameters can be varied to produce desired microstructures. In this talk, our focus is expanded to include the role that the composition of the alloy plays on microstructural development. Heat transport, melting, and fluid flow are modeled at the macroscale via a thermal Lattice Boltzmann model (or other continuum-level models), accounting for laser absorption and Marangoni flow in the melt pool. At the microscale, solidification is modeled using a coupled thermal/fluid/solute flow/solidification cellular automata model with temperature and fluid flow boundary conditions passed from the macroscale, enabling the linking of process parameters, melt pool conditions, alloy thermodynamics, and microstructure. We will compare model results to experimental results for solidification morphology as a function of the melt pool conditions for Ti-xCu, Ti-xTa, Ti-xFe, Ti-xMo, Ti-xAl, and Ti-xAl-yMo.