Thermo mechanical effects on Ti deformation mechanisms in cold dwell

循环载荷是航空发动机中部件的特征，在这种情况下，它们同时暴露在低频(例如起飞和着陆)和高频(例如振动)载荷下。因此，了解是什么赋予了钛合金的疲劳强度，特别是它是如何受到载荷频率和其他环境参数(如温度)的影响的，这是非常重要的。通过广泛的测试，工程师们已经建立了不同钛合金的疲劳强度和微观结构之间的良好经验关系。然而，控制这种行为的实际物理机制并不完全清楚。我们在知识上的这种差距使得我们很难考虑到以前经验以外的材料和/或操作条件。这也让人很难理解如何改进合金，从而减少合金的使用量，这将有助于制造更轻、更高效的航空发动机。这个项目的目的是提高我们对这些重要合金在低频循环加载和不同温度下如何在微观结构尺度上变形的理解。与劳斯莱斯合作，你将使用曼彻斯特大学开发的新实验技术，以亚微米的空间分辨率测量这些合金的变形，帮助揭示导致疲劳失效和损伤的物理过程，并了解如何避免这些过程。这项工作将利用曼彻斯特罗伊斯研究所(www.royce.ac.uk)提供的独特的最先进设施，包括具有现场测试能力的高分辨率电子显微镜、三维晶体取向测绘机器和高分辨率透射电子显微镜。成功的候选人将加入曼彻斯特研究钛合金的大型研究团队(10+)，并与劳斯莱斯和其他英国及国际大学的科学家和工程师合作。该项目提供关于目前可用的一些最先进的表征方法的机会和培训，并提供使用开放源码包进行高级数据分析的健全培训。此外，还将有机会参观劳斯莱斯和其他合作机构。

Cyclic loading is characteristic of components in an aero-engines, where they are exposed to both low frequency (e.g. take off and landing), and high frequency (e.g vibration) loading. Therefore it is very important to understand what gives Ti alloys their fatigue strength, and in particular how it is affected by the load frequency and by other environmental parameters like temperature. Through extensive testing, engineers have developed sound empirical relationships between fatigue strength and the microstructure of different Ti alloys. However, the actual physical mechanisms controlling this behaviour are not fully understood. This gap in our knowledge makes it difficult to account for material and/or operating conditions outside previous experience. It also makes it difficult to understand how the alloy could be improved, so that less of it can be used, which would help build lighter, more efficient aero-engines. The aim of this project is to improve our understanding of how these important alloys deform at the micro-structural scale during low frequency cyclic loading, and at different temperatures. Working in collaboration with Rolls-Royce, you will use new experimental techniques developed at the University of Manchester to measure the deformation of these alloys with sub-micron spatial resolution, helping to unravel the physical process that lead to fatigue failure and damage and understand how they can be avoided. This work will make use of unique state-of-the-art facilities available at the Royce Institute at Manchester (www.royce.ac.uk), including high-resolution electron microscopes with in-situ testing capability, machines for 3-dimensional crystal orientation mapping, and high resolution transmission electron microscopes. The successful candidate will join a large team of researchers (10+) working on titanium alloys at Manchester, and collaborate with scientists and engineers at Rolls-Royce and other UK and international universities. The project provides access and training on some of the most advanced characterisations methods currently available and sound training in advanced data analysis using open source packages. There will also be opportunities to visit Rolls-Royce and other partner organisations.