高超声速飞行器异型超高温密封结构三维柔性滚压成形机理与电辅助形性调控

The special ultrahigh-temperature sealing rings are the key structures to ensure the operable hatch doors of hypersonic vehicles being strictly sealed. The shape characteristics of the sealing rings, such as spatial heterotype, thin wall, large scale, complex-shaped section, et al., and the high-strength and hard-to-deform characteristics of supperalloy make the forming of the sealing rings extremely hard. Aiming at the problems lying in the current technology of rolling and compression molding, such as the low rate of finished products, the low flexibility, the out-of-control performance, a new technology of the 3D flexible rolling accompanied by electric-assisted shape and performance control is proposed in this project. To solve the problem of the coupling responses of the non-uniform deformation and microstructure evolution under the coupling action of electric, thermal and force fields, the multiscale simulation based on the fully-coupling modeling of crystal plasticity and cellular automata will be adopted, and the research works will then be carried out on the non-uniform deformation mechanism during the electric-assisted rolling process and the control of forming precision, the microstructure evolution mechanism and performance control, the rules of electric treatment and the whole-process integrated control. These works are to reveal the relations among the non-uniform deformation of the rings, the parameters of rollers and processing, and forming defects and microstructures. Accordingly, a new approach for shape and performance control of the sealing rings should be developed as that the electric-assisted forming and electric online treatment by considering the forming and the microstructure evolution within one pass and the inheritance of forming defects and microstructures between passes simultaneously. The study in this project is to provide a basis for the high-performance precise forming and manufacturing of the special ultrahigh-temperature sealing rings for hypersonic vehicles.

异型超高温密封结构是保证高超声速飞行器活动舱门密封的关键构件。其空间异型、薄壁、大尺寸、截面形状复杂，采用高温合金材料，高强度、难变形，使得成形极其困难。针对现有滚压+模压方法成品率极低、柔性差、性能难控制的问题，本项目提出了三维柔性滚压成形+电辅助形性调控的新方法。针对其中复杂未知的电热力多能场耦合作用下构件不均匀变形与组织演化耦合响应问题，提出了采用基于晶体塑性与元胞机全耦合的多尺度建模仿真方法，并开展异型超高温密封结构电辅助滚压不均匀变形机理与精度调控、组织演化机理与性能调控、电脉冲热处理规律与全过程综合调控等研究。以揭示该过程中不均匀变形、模具/工艺参数、成形缺陷/组织之间的关联关系。进而考虑全过程道次内成形与组织演化和道次间缺陷与组织的遗传，发展通过电辅助成形和电脉冲在线热处理进行形性协同调控的新方法。该研究可为高超声速飞行器异型超高温密封结构高性能精确成形制造提供依据。

本项目提出了三维柔性滚压成形+电辅助形性调控的新方法，解决了异型超高温密封结构成形过程中存在的成品率极低、柔性差、性能难控制等问题。在此过程中，围绕“电热力多能场对高温合金变形的细微观作用机理与规律”、“异型超高温密封结构滚压不均匀变形机理”、“异型密封结构电脉冲处理规律与全过程综合调控”三方面科学问题，完成了镍基高温合金脉冲电流多尺度作用机理及建模、脉冲电流对密封结构组织性能影响规律、异型超高温密封结构柔性滚压变形机理与成形精度控制、异型超高温密封结构电辅助柔性滚压+电脉冲处理全过程综合调控四方面研究内容。研究取得的进展包括：（1）揭示了脉冲电流作用下镍基高温合金的宏观力学响应、细微观组织演变规律，阐明了脉冲电流作用的多尺度机理，并实现了定量表征；（2）提出了脉冲电流作用的局部焦耳热效应，揭示了脉冲电流对异型超高温密封结构滚压成形微观组织及力学性能的影响规律；（3）发明了四种多道次柔性滚压成形新方法，模拟揭示了其成形机理及缺陷演变规律；（4）研制了具有自主知识产权的异型超高温密封结构脉冲电流辅助柔性滚压成形专用装备，批量研制了4种类型十几种规格的镍基高温合金异型截面密封件，并在无人机、巡航弹等领域开展了装机应用。项目成果在热加工顶级期刊J Mater Process Tech、材料领域顶级期刊J Alloy Compd等国内外重要学术期刊发表论文11篇，授权发明专利4项，在国内外重要学术会议做邀请报告5次。以本项目成果为重要支撑，获2020年度陕西省自然科学一等奖，项目负责人入选青年长江学者，获批陕西省杰青和陕西高校青年创新团队，培养博士生6人、硕士生7人。