The Osprey spray deposition process is an attractive alternative technology to manufacture net or near net shape components. The process entails atomization of a liquid stream of metal into a spray of molten droplets which subsequently impinge and consolidate on a substrate to produce a homogeneous deposit. The overall objective of this research proposal is to predict and control the evolution of microstructure during solidification in the spray deposition process. The study will develop a model for the microstructure formation during solidification in spray, the integrating the interaction of micro- and macroscopic solidification events. Initially, experimental and analytical studies will be performed in order to quantify the size, number and spatial distribution of the generated nuclei. Concomitantly, the solidification of the spray deposit will be modeled, taking into account the growth kinetics of dendrite tips and solute balance at the scale of the grain size. Evaluation of the microstructure will also be analyzed as particle coarsening during liquid phase sintering. Utilizing the overall model for evolution of microstructure from the first phase of the program, the study will be extended to design and tailor alloy compositions to produce the required microstructures and properties in components for specific applications.
