Advanced peening processes for the fatigue life improvement of aerospace components

喷丸强化是用高速喷丸冲击金属零件。冲击塑性拉伸表面，并诱发一层压残余应力和冷加工。在适当的条件下，该工艺提供的部件可以承受比未经处理的部件多20倍的疲劳循环。飞机的几乎每一个金属部件都经过喷丸处理。高温喷丸强化（HTSP）是在高温下进行常规喷丸强化。作者已经证明，与喷丸强化相比，HTSP可以进一步提高疲劳寿命。振动强化（VP）是一种改进的精加工工艺，其效果与喷丸强化相似，但表面光洁度要高得多。这两种方法在工业环境中的适用性还有待证明。**本研究将深入研究HTSP和VP对航空航天材料（钢、钛和铝）疲劳寿命的影响。该研究将涉及HTSP和VP装置的制造研究，并深入研究它们在表面特性、残余应力、硬度、显微组织变化和疲劳寿命方面的影响。这项工作将由10名工程学士、1名硕士和4名博士在4年内完成。这项工作将与蒙特卡罗理工大学、蒙特卡罗宇航技术中心和赛峰集团（在加拿大和法国）合作进行。该项目有可能引发加拿大航空航天工业的重大创新。首先，与喷丸强化相比，HTSP有可能提高疲劳寿命，这将使加拿大飞机更轻、更耐用。VP也有可能产生比喷丸强化更好的疲劳寿命改善，并且还可以将两种制造工艺合并为一个：喷丸和表面精加工。因此，这些工艺有可能通过生产更轻、更耐用的零件，以及产生更便宜、更快的后制造工艺，提高我们航空航天工业的竞争力。此外，更轻和更耐用的部件减少了航空旅行的环境印记，这对环境是有益的********

Shot peening consists in impacting a metal part with high velocity shots. The impacts plastically stretch the surface and induce a layer of compressive residual stresses and cold working. Under the right conditions, the process delivers components that can withstand 20 times more fatigue cycles than untreated parts. Nearly every metallic part of an aircraft is shot peened. High Temperature Shot Peening (HTSP) consists in carrying out conventional shot peening at elevated temperature. Authors have demonstrated that HTSP can deliver even further fatigue life improvement than shot peening. Vibratory Peening (VP) is a modified finishing process that induces similar benefits as shot peening but for a much better surface finish. The applicability of these two processes within an industrial context have yet to be demonstrated.** This research will thoroughly investigate the effects of HTSP and VP on the fatigue lives of aerospace materials, namely: steel, titanium and aluminum. The research will involve manufacturing research HTSP and VP setups and thoroughly investigate their effects in terms of surface characteristics, residual stresses, hardness, microstructural changes and fatigue life. The work will be carried out by 10 B.Eng, 1 MSc and 4 PhD students over 4 years. The work will be carried out in collaboration with Polytechnique Montréal, Centre Technologique en Aérospatiale and Safran S.A. (in Canada and in France). This project has the potential to trigger significant innovation for the Canadian aerospace industry. First, HTSP has the potential to yield better fatigue life improvement than shot peening, which will yield to lighter and more durable Canadian aircraft. VP has the potential to also yield better fatigue life improvement than shot peening and also to combine two manufacturing processes into one: peening and surface finishing. These processes have therefore the potential to increase the competitiveness of our aerospace industry by producing lighter and more durable parts, as well as yielding cheaper and faster post-manufacturing processes. Moreover, lighter and more durable parts reduce the environmental imprint of air travel, which is beneficial for the environment.********