镍基超合金表面空蚀诱导纳米沉淀相的形成及演变机制

空蚀表面新组织结构的形成可能会使材料空蚀损伤机制发生根本变化，对这类微观结构进行深入研究是理解材料空蚀磨损行为的关键所在。本项目旨在系统研究镍基超合金在空蚀磨损过程中磨损表面空蚀诱导纳米沉淀相析出、组成、结构、分布及形状，阐明镍基超合金表面空蚀诱导纳米结构沉淀相的形成及演变机制；揭示空蚀诱导纳米沉淀相的形成与镍基超合金成分、微观组织结构之间的关联；研究空蚀诱导纳米沉淀相在空蚀表面和亚表面层对材料塑变、裂纹形成与扩展、位错的形成、变形方式和加工硬化特性等方面的影响，阐明纳米沉淀相的形成对镍基超合金空蚀磨损性能的影响；建立空蚀诱导纳米沉淀相的形成与空蚀磨损行为之间的关系。本项目的开展将为新型长寿命耐空蚀镍基超合金材料的设计及其在特殊工况环境下的应用提供理论依据和技术支撑。

The formation of new structures on the eroded surface can cause an essential change in mechanism of cavitation erosion of a material. The deep research on these new microstructures plays a key role to understand the cavitation erosion behavior of material. In this project, we will make a systematic study on the precipitation, composition, microstructure, distribution and shape of cavitation-induced nanoprecipitates on the eroded surface of nickel-based superalloy in cavitation erosion process. Formation and evolution mechanism of cavitation-induced nanoprecipitates on the nickel-based superalloy surface in cavitation erosion process will be calrified. The correlation will be revealed between the formation of cavitation-induced nanoprecipitates and the composition and microstructure of nickel-based superalloy. We will systematically study the effect of precipitation of cavitation-induced nanostructured phases on the plastic deformation, formation and propagation of crack, dislocation formation, dislocation deformation and work-hardening characteristic on the eroded surface and sub-surface of nickel-based superalloy. The effect of the formation of nanoprecipitates on cavitaion erosion performance of the nickel-based superalloy will be calrified. The correlation will be founded between the formation of nanoprecipitates induced by cavitation and the cavitation erosion behavior of nickel-based superalloy. The project will give theoretical basis and technical support for the designing of new nickel-based superalloy with long life and the application of nickel-based superalloy in special environmental conditions.