GH4169合金Delta工艺中片层状δ相的球化机理及控制方法

The engine is one of the key components of aerospace equipment. The turbine disks and engine shafts in the engines are GH4169 alloy forgings with large size and complex shape, and the defects such as coarse grain and duplex grain always appear in the large and complex forgings. The Delta Process is an effective method to control the grain size of the alloy, but the full spheroidization of plate-like δ phase pre-precipitated during hot deformation is the key for the success of Delta Process. The GH4169 alloy with plate-like δ phase pre-precipitated is the research object in this project. The three-dimensional map of the spheroidal volume fraction of plate-like δ phase during the hot working will be obtained by numerical simulation and experiments, and the spheroidal critical condition of plate-like δ phase will be determined. The thermodynamics and dynamics models for the dissolution of plate-like δ phase in GH4169 alloy without deformation will be established by the theoretical calculation and experiments. The influence of hot deformation parameters and recrystallization on the dissolution rate will be studied to explore the spheroidal mechanism of plate-like δ phase during the hot working. The spheroidal theory model of plate-like δ phase during the hot working will be established by the theoretical modeling analysis. Based on these researches, the purpose to precisely control the microstructure and mechanical properties of GH4169 alloy can be achieved. This project will enrich the theoretical basis of Delta Process of GH4169 alloy, and provide important academic and application value to improve the manufacture of large and complex GH4169 alloy forgings.

发动机是航空航天装备所需的关键零部件之一，其涡轮盘和转动轴多为大型复杂GH4169合金锻件，但该合金的大型复杂锻件在热锻成形中极易出现粗晶、混晶等缺陷，Delta工艺是有效调控晶粒的一种手段，该工艺成功的关键在于预析出的片层状δ相在热变形中能否充分球化。项目以预析出片层状δ相的GH4169合金为研究对象，通过数值模拟和实验，建立热变形中片层状δ相的球化体积分数三维图，明确其球化临界条件；通过理论计算和实验，建立未变形时片层状δ相的溶解热力学和动力学模型；通过对热变形参数和再结晶影响溶解速率的研究，探索热变形中片层状δ相的球化机理；通过理论建模分析，构建热变形中片层状δ相的球化理论模型。最终达到精确调控GH4169合金组织和性能的目的。本研究将进一步充实GH4169合金Delta工艺的理论基础，对于提高我国大型复杂GH4169合金锻件制造技术水平具有重要的学术和应用价值。

GH4169合金的Delta工艺是有效调控晶粒的一种手段，该工艺成功的关键在于预析出的片层状δ相在热变形中能否充分球化。本研究以预析出片层状δ相的 GH4169合金为研究对象，通过热处理和等温热模拟压缩实验，结合有限元模拟分析以及组织观测和分析技术，系统地研究了热变形中合金的高温变形机制和片层状δ相的球化机理。建立了热变形中片层状δ相的球化体积分数三维图，明确了热变形中片层状δ相的球化临界应变。建立了热变形中片层状δ相的球化理论模型，并在有限元软件中进行了用户子程序开发，对热模拟压缩过程中片层状δ相的球化体积分数进行了数值模拟，模拟结果与实际基本吻合。本项目的研究可以进一步充实GH4169 合金 Delta 工艺的理论基础，对提高我国大型复杂 GH4169合金锻件制造技术水平具有重要的学术和应用价值。