Characterisation and assessment of titanium alloys after linear friction welding and under cyclic loading

本项目将研究钛合金线性摩擦焊后疲劳裂纹萌生和抗疲劳裂纹扩展的基本原理。根据缺陷对随后的总疲劳寿命的影响，将特别注意定义焊接后可能出现的缺陷尺寸和分布的极限。这可能需要制定一项详细的疲劳试验实验方案，然后利用分析电子显微镜和扫描电子显微镜对疲劳和断裂的微观机制--裂纹萌生和扩展--进行深入的表征和评估。包括潜在织构在内的微观结构特征也将是研究的一个重要方面，以便可以使用微观结构-加工-行为相关性来为疲劳行为模型提供输入，从而可靠地预测部件的使用性能。

This project will address fundamentals of fatigue crack initiation and fatigue crack growth resistance in titanium alloys after linear friction welding. Particular attention will be focused on defining limits of defect sizes and distributions that can be present after welding in terms of their effect on subsequent total fatigue life. This is likely to entail a detailed experimental programme of fatigue testing followed by in-depth characterisation and assessment of fatigue and fracture micro-mechanisms of crack initiation and crack growth using analytical transmission electron microscopy and scanning electron microscopy. Microstructural characterisation including underlying texture will also be an important aspect of the study in order that microstructure-processing- behaviour correlations can be used to provide input into models of fatigue behaviour to predict the in-service performance of components with confidence.