Fundamentals of Spray Deposition Via Osprey Processing

Abstract

The fundamentals of spray deposition via the Osprey™ process have been analysed to identify critical process parameters, and to understand their effect on the integrity of the preforms produced. From the resulting knowledge base, the directly controlled process parameters may be related to the shape and structure of the preform. Our approach has involved the development of an integral model for spray casting using established theoretical principles to describe droplet-gas interactions in flight and subsequent droplet consolidation at the substrate. The model is implemented to predict the fraction of liquid in the spray upon impact, the temperature distribution in the consolidated material, and the shape/geometry of the preform produced. Five primary process parameters can be controlled to optimise two critical dependent parameters; the latter are the physical and thermal characteristics of (i) the metal spray at impact, i.e. ‘deposition condition’, and (ii) the partially liquid layer on the surface of the growing deposit. PM/0552