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

制造业正在经历一场革命性的范式转变，这主要是由添加剂制造(AM)技术的出现推动的，预计到2025年，这将代表一个1000-2500亿美元的市场。尽管添加剂制造在汽车、航空航天、电力和消费品行业前景光明，但它面临着与工艺缺陷和缺陷有关的挑战，这些缺陷和缺陷导致性能和性能低于预期。缺陷包括与凝固有关的氧化、气孔和有害的残余应力，以及缺乏熔化和/或颗粒重熔缺陷限制了产品的机械性能和性能，阻碍了它们的市场准备。这些缺陷中的许多是由于颗粒粘合所需的高熔化温度造成的。然而，冷喷涂作为一种新兴的AM，其工作温度低于熔化温度，因此不存在上述与凝固有关的问题。 冷喷涂是一种利用动能在低于熔化温度的温度下打印金属粉末的工艺。利用加热的加压气体，微米级金属粉末通过收敛-发散喷嘴加速到超音速。撞击能使颗粒和基材发生严重的局部塑性变形，产生机械互锁。因此，粘合是无氧化、无气孔、高度致密和无裂纹的。此外，高速冲击的强化效应产生了有益的压缩残余应力。冷喷涂技术作为一种涂层技术，广泛应用于汽轮机叶片腐蚀等缺陷零件的几何和结构修复。然而，最近，由于其在打印复杂几何形状的大型物体方面的灵活性，打印速度快，并且不需要控制环境，该技术被考虑用于制造零件。随着冷喷涂添加剂制造(CSAM)在金属和非金属衬底上印刷金属/陶瓷粉末的好处，冷喷涂技术将在AM市场占有相当大的份额。 这项研究的重点是了解冷喷涂技术沉积轻质金属粉末的过程物理，以发现工艺参数与冷喷涂零件的内聚和结合性能之间的联系。这项研究的结果将导致为汽车、航空航天、电力和消费品行业制造更耐用和可靠的基于性能的部件。该项目培训的研究生将培养过程建模、CSAM材料表征和产品性能优化方面的技能，这些技能在这些行业中非常受欢迎。

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.