"Microstructural Evolution of Aeroengine Materials Under Repeated Impact" 

Nikita Chari, MSE PhD Candidate 

Advisor: Professor Martinez-Guo

ABSTRACT

Aeroengines are often subject to repeated impact due to sand, gravel, and foreign object damage (FOD). The ingestion of these particulates can result in significant damage to aeroengine components. Over time, these impacts can change the internal microstructure through grain refinement, dislocation accumulation, phase transformations, and the initiations of microcracks. The microstructure of a material governs its performance, determining properties like strength and fatigue resistance. The mechanical properties of aeroengine materials under repeated impact have been well studied and documented, however, the microstructural evolution under impact has not been studied. Each component in an aeroengine has a service life limit expressed as flight hours/cycles after which, withstanding severe damage, the component is retired from service. Developing a quantitative understanding of microstructural evolution under impact and erosion conditions can improve service life prediction models, possibly allowing for inspection intervals and retirement criteria based on material degradation rather than fixed operational limits.