Vibratory peening for the fatigue life improvement of aerospace parts

大多数航空航天金属零件都经过表面处理以提高其疲劳寿命。传统的喷丸处理包括将硬颗粒高速投射到韧性金属表面上。该工艺引起压缩表面残余应力，这有利于提高疲劳寿命，但也引起粗糙度，这降低了疲劳寿命。喷丸零件通常进行表面处理，以提高其表面光洁度。振动喷丸是一种振动精加工工艺，其引起的压缩残余应力与喷丸引起的压缩残余应力相当，但表面光洁度要好得多。因此，该过程可能是一个有趣的替代喷丸，因为它结合了两个步骤在一个。这项工作的目的是了解振动喷丸处理效果的加拿大公司，VibraFinish，对材料的气体涡轮机发动机制造的赛峰。这项科学研究将调查振动喷丸对高强度钢和钛合金的粗糙度、硬度、残余应力以及微观结构变化的影响，以评估其在提高疲劳寿命方面的潜力。这项工作将由一名理学硕士学生在一名研究助理和来自该行业的工程师的支持下进行。如果该工艺在提高疲劳寿命方面的潜力得到科学证明，该项目将成为VibraFinish、蒙特利尔理工学院和赛峰集团之间更重要的合作研发项目的基础。该项目旨在更好地了解该流程的效果，以优化该流程。因此，该拟议项目可以帮助一家加拿大公司在竞争激烈的市场中确立其领导地位，并为加拿大赛峰公司提供一种改进性能的新流程。

Most metallic aerospace parts are surface treated to improve their fatigue lives. Conventional shot peening consists of projecting hard particles at high velocity onto a ductile metallic surface. The process induces compressive surface residual stresses, which is beneficial for improving fatigue life, but also roughness, which decreases fatigue life. Shot peened parts are often surface treated for improving their surface finish. Vibratory peening is a vibratory finishing process that induces compressive residual stresses comparable to those induced by shot peening, but for a much better surface finish. The process could therefore be an interesting alternative to shot peening since it combines two steps in one. The objective of this work is to understand the vibratory peening treatment effects of a Canadian company, VibraFinish, on materials used in gas turbine engines manufactured by Safran. This scientific study will investigate the effects of vibratory peening on roughness, hardness, residual stresses as well as microstructural changes for high strength steel and titanium alloys so as to assess its potential at improving fatigue life. The work will be carried out by a MSc student supported by a research associate and engineers from the industry. If the process' potential at improving fatigue life is scientifically demonstrated, this project will be the grounds for a more important collaborative research and development project between VibraFinish, Polytechnique Montréal and Safran. This project would aim at better understanding the process' effects in a view of optimizing it. As such, this proposed project could help a Canadian company to establish its leadership in a competitive market as well as providing Canada-based Safran companies with a new process of improved performance.