Understanding Microstructure Evolution and Control During Hot Deformation: Application to Solid State Joining of High Strength Alloys

本项目的目的是获得更好的理解的管理机制控制微观结构的演变过程中固态连接，特别是线性摩擦焊。后者是一种很有前途的制造技术，它允许生产近净形部件和连接不同的材料。这两个主题都是非常重要的制造业，因为它们的广泛应用将导致更低的报废材料，更短的“上市时间”和更低的产品生命周期成本。然而，主要的问题之间的关系的工艺参数（包括在过程中的严重变形阶段）和微观结构的演变和它们的联合影响的疲劳寿命的接头，仍然有待解决。同时，从实验室研究结果到工业尺寸组件的成功过渡需要更逼真的模拟工具，这些工具还可以考虑作为工艺参数的函数的微观结构演变。该项目在此背景下进行，旨在开发一种包括微观结构演变的材料模型。超高强度钢，用于飞机起落架的应用，和一种新的高温合金，开发的飞机盘和叶片的应用将在本调查中使用。将使用光学显微镜和扫描电子显微镜研究微观结构的演变。将进行焊后热处理，并检查其对接头机械性能（包括疲劳寿命）的影响。这项工作的好处将从航空航天工业扩展到加拿大的其他工业，如汽车、铁路、石油和天然气，这些工业使用这些合金，许多部件都采用固态连接。此外，两名博士生和两名硕士生将在项目期间接受培训。

The aim of the present project is to gain a better understanding of the governing mechanisms controlling microstructure evolution during solid state joining, specifically, linear friction welding. The latter is a promising manufacturing technology, which allows the production of near net shape components and joining of dissimilar materials. Both topics are of high importance to manufacturing industry as their widespread applications will result in lower scrapped material, shorter 'time-to-market' and lower life cycle cost of products.However, major questions regarding the relationships between process parameters (including the severe deformation phase during the process) and microstructure evolution and their combined influence on fatigue life of the joint, remain to be addressed. In parallel, successful transition from laboratory findings to industrial size components requires more realistic simulation tools, that can also take into account microstructure evolution as a function of process parameters. The project inscribes in this context and is aimed to develop a material model that will include microstructure evolution. An Ultra High Strength Steel, used for aircraft landing gear applications, and a new superalloy, developed for aircraft disk and blade applications will be used in the present investigation. The evolution of the microstructure will be studied using optical and scanning electron microscopies. Post weld heat treatments will be applied and their influences on mechanical properties of the joint, including its fatigue life, will be examined. The benefits of the work will extend beyond the aerospace industry to other Canadian industries, such as automotive, rail and oil and gas where these alloys are used and solid state joining is applied for many components. Moreover, two PhD and two Masters students will be trained during the course of the project.