The effect of corrosive environment on the crack growth behaviour of nickel based superalloys

镍基高温合金在燃气轮机发动机中的运行使部件暴露在温度、应力、时间和环境等各种条件下。此外，气体环境与操作的高温相结合，可能会导致腐蚀性物质的形成，这些腐蚀性物质可能会在使用过程中侵蚀部件并导致降解。构件材料性能的一个关键方面是了解疲劳裂纹在材料中的扩展速率，这通常是在空气中进行的。然而，腐蚀性物质对裂纹扩展速率的影响还远未得到很好的了解。利用斯旺西大学结构材料研究所现有的专家测试室，这项研究将试图调查腐蚀环境对现代镍基高温合金裂纹扩展速率的影响。这项研究将试图了解不同加载波形和循环的影响，以确定腐蚀损伤对疲劳裂纹扩展速率的影响。在测试之后，有必要对测试过程中形成的断裂面和腐蚀性物种进行详细的表征，以了解运行机制并深入了解腐蚀裂纹扩展行为的关键方面。

The operation of nickel-base superalloys in gas turbine engines exposes the components to a broad range of conditions ranging across temperature, stress, time and environment. Furthermore, the gaseous environment, in combination with the high temperatures of operation, can lead to the formation of corrosive species, which can attack the component and lead to degradation during service. One key aspect of component material behaviour is the understanding of the propagation rates of fatigue cracks in the material, which is conventionally conducted in air. However, the impact of corrosive species on crack propagation rates is far less well understood. Utilising the specialist testing chambers available at the Institute of Structural Materials, Swansea University, this study will seek to investigate the role of corrosive environments on the crack propagation rates of a modern nickel-base superalloy. The study will seek to understand the effect of different loading waveforms and cycles in order to determine the impact of corrosion damage on fatigue crack propagation rates. Following testing, detailed characterisation of the fracture surfaces and corrosive species formed during testing will be necessary to inform the operative mechanisms and provide insights into the critical aspects of corrosion crack growth behaviour.