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

本计画将探讨线性摩擦焊后钛合金之疲劳裂纹起始与疲劳裂纹成长阻力之基本原理。特别注意将集中在定义的缺陷尺寸和分布的限制，可以在焊接后，在随后的总疲劳寿命的影响。这可能需要一个详细的疲劳测试实验方案，然后使用分析透射电子显微镜和扫描电子显微镜对裂纹萌生和裂纹扩展的疲劳和断裂微观机制进行深入表征和评估。微观结构表征，包括底层纹理也将是一个重要的方面的研究，以便微观结构加工行为的相关性可以用来提供输入到模型的疲劳行为预测的组件在服务中的性能与信心。

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.