Cold Spray Solid-State Additive Manufacturing:Process-Structure-Performance Link

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Manufacturing is undergoing a revolutionary paradigm shift, driven primarily by the emergence of additive manufacturing (AM) techniques which is expected to represent a $100-250 billion market by 2025. Despite its promising future in automotive, aerospace, power and consumer product industries, additive manufacturing is facing challenges related to process defects and shortfalls that result in lower-than-expected properties and performances. Defects include solidification-related oxidation, porosity, and detrimental residual stresses, as well as lack of fusion and/or particle re-melt defects limit the mechanical properties and performance of products, hindering their market readiness. Many of these defects emanate from the high melting temperature required for particles bonding. Cold spray, as an emerging AM, however, is operating and lower-than-melting temperature and therefore is free of mentioned solidification-related issues. Cold spray is a process that uses kinetic energy to print metal powders at lower-than-melting temperatures. Micro-sized metal powders are accelerated through a convergent-divergent nozzle to supersonic velocities using a heated pressurized gas. Upon collision with substrate the impact energy makes severe local plastic deformation in particle and substrate, resulting in mechanical interlocking. The bonding is therefore free of oxidation, pore-free and highly dense, and crack-free. Moreover, the peening effect of high velocity impact creates beneficial compressive residual stresses. The cold spray technology has widely been used as a coating technology in the geometrical and structural restoration of defected parts such as corroded turbine blades. However, more recently because of its flexibility in printing large objects with complex geometries, fast rate of printing, and no need for controlled environment the technology is considered for manufacturing parts. With the benefits of cold spray additive manufacturing (CSAM) in printing metal/ceramic powders on metal and non-metallic substrates, cold spray technology will have a sizable share in AM market. The proposed research is focused on understanding the process physics of lightweight metal powder deposition by cold spray technology to discover the link between the process parameters with the cohesion and adhesion properties of cold sprayed parts. The outcomes of this research will result in manufacturing of more durable and reliable performance-based component for the automotive, aerospace, power and consumer product industries. Graduate students trained in this program will develop skills in process modeling, CSAM material characterisation, and product performance optimization which are highly sought after in these industries.