Ni3Al基单晶合金中合金化元素行为及其对性能的作用机理

Ni3Al based alloys possess low density, high specific strength and excellent high-temperature strength. It has a broad application prospects as the materials of turbine blades and vanes for aero-engines because it can improve the thrust-weight ratio, reduce weight, improve the bearing temperature and prolong the life of engines. This work intends to demonstrate the site occupancy of Mo, partitioning behavior of elements, the forming and transformation mechanism of precipitated phase in Ni3Al based single crystal alloys. The site occupancy of Mo and its relation to portioning behavior will be demonstrated through calculation of the total energy of γ and γ′ unit cell, formation heat, cohesive energy, state density and electricity density, which can enhance the theoretical foundation of design for high performance superalloys. The effect of precipitation phase on the rupture of single crystal alloys will be revealed by in-situ observing the interaction between micro-defects and the precipitation. And the mechanical will be explained from different levels such as dislocations, phases interface and microstructure. The effect of Ru addition on alloying behavior and precipitation phase in Ni3Al based alloys will be investigated. The method of inhibiting the precipitation phase which if harmful for Ni3Al -based single crystal alloys will be explored. And this will lay a solid theoretical foundation for the engineering application of Ni3Al -based single crystal alloys.

Ni3Al金属间化合物基合金具有密度小、比强度高、高温性能好等特点，如在航空发动机涡轮叶片和导向叶片上应用，将能减轻重量、提高承温能力、延长使用寿命、提高发动机推重比，在涡轮发动机上的应用前景广阔。本申请项目拟通过SEM、TEM及同步辐射X射线原位微观观察与分析研究，结合Mo强化后γ和γ′晶胞的总能量、形成热、结合能以及态密度和电荷密度的计算，探明Mo元素在Ni3Al基单晶合金中的原子占位、元素分配行为和析出相的形成和转变机制。通过析出相与微观缺陷的交互作用的原位观察，从位错、相界面、析出相和微观组织等不同层次及其相互关系，揭示析出相对单晶合金失效断裂的影响机理。探索添加Ru元素对合金化行为的影响规律，探明Ru元素对合金中析出相的影响机理及合金失效断裂机制，探索改善合金有害析出相的合金化方法，为Ni3Al基单晶合金的工程化应用奠定坚实的理论基础。

Ni3Al 金属间化合物基合金具有密度小、比强度高、高温性能好等特点，如在航空发动机涡轮叶片和导向叶片上应用，将能减轻重量、提高承温能力、延长使用寿命、提高发动机推重比，在涡轮发动机上的应用前景广阔。本项目通过SEM、TEM 及同步辐射X 射线原位微观观察与分析研究，结合Mo 强化后γ 和γ ′晶胞的总能量、形成热、结合能以及态密度和电荷密度的计算，探明了Mo 元素在Ni3Al 基单晶合金中的原子占位、元素分配行为和析出相的形成和转变机制。通过析出相与微观缺陷的交互作用的原位观察，从位错、相界面、析出相和微观组织等不同层次及其相互关系，揭示了析出相对单晶合金失效断裂的影响机理。研究了添加Ru 元素对合金化行为的影响规律，探明了Ru 元素对合金中析出相的影响机理及合金失效断裂机制，改善了合金有害析出相的合金化方法，为Ni3Al 基单晶合金的工程化应用奠定坚实的理论基础。