难变形金属热强旋成形机理及形/性一体化控制研究

Plastic forming of difficult-to-deform metal at room temperature is very difficult due to the the large deformation resistance and the poor plasticity. Ni-based high-temperature alloy is regarded as the heart of the engine, while the cylindrical parts of Ni-based high-temperature alloy are usually manufactured by welding after rolling. This project proposed to manufacture the whole thin-walled cylindrical part of Ni-based high-temperature alloy with high-precision based on the hot power spinning method, and to study the forming mechanism and precision/property integrated control of the difficult-to-deform metal during hot power spinning. It mainly focues on the research of the mothod of precision/property integrated control of the macro dimensional accuracy and micro organization structure to obtain the high precision cylindrical part with the high temperature service performance; establishment of the high temperature constitutive model and deformation-heat transmission-microstructure coupling simulation model to realize the macro plastic deformation and micro structure evolution coupling simulation, to reveal the essence of plastic deformation of hot power spinning of difficult-to-deform high-temperature alloy metal. The corresponding spinning equipment will be developed, the thin-walled Ni-based high-temperature alloy cylindrical parts (Haynes230) will be manufactured and the forming process design specification of hot power spinning will then be established. It will lay the solid theoretical foundation and provide the reliable practice base of the hot power spinning both in the high-level technique field of air jet engine and traditional industrial field of gas turbin.

难变形金属在室温下变形抗力大、塑性差，常温下进行塑性成形极为困难。镍基高温合金被称为发动机的心脏，现有的镍基高温合金筒形件多采用板料卷制后焊接的方法生产。项目首次提出采用热强旋方法来实现具有高尺寸精度要求的薄壁镍基高温合金筒形件的完整制造，并对其热强旋成形机理及形/性一体化控制方法展开研究。重点研究能对制件的宏观尺寸精度及微观组织结构进行形/性一体化控制的方法、以达到在获得高精度薄壁筒形件的同时能满足其高温服役性能的要求；建立起难变形金属高温本构模型及变形-传热-微观组织耦合的有限元模型，以实现热强旋过程宏观塑性变形和微观组织演变的耦合模拟，揭示其塑性变形的本质；研制出相应的工艺装备、旋制出难变形镍基高温合金（Haynes230）薄壁筒形件，并形成相应的热强旋工艺设计规范，为热强旋技术在航空喷气发动机等高端技术领域及各种工业燃气轮机等传统技术领域的推广应用奠定夯实的理论基础及实践依据。

难变形金属在室温下变形抗力大、塑性差，常温下进行塑性成形极为困难。镍基高温合金被称为发动机的心脏，现有的镍基高温合金筒形件多采用板料卷制后焊接的方法生产。项目采用热强旋方法实现了具有高尺寸精度及性能要求的薄壁镍基高温合金（Haynes230）筒形件的完整制造，并对其热强旋成形机理及形/性一体化控制方法展开了研究。项目提出采用高温平面应变压缩试验作为筒形件热反旋时的物理模拟试验，构建出了可准确预测Haynes230合金高温流变行为的本构模型。建立了动态再结晶动力学模型、动态再结晶晶粒尺寸模型，实现了热强旋过程的变形-传热-组织演变有限元数值模拟。构建了微观组织演变元胞自动机模拟模型，解决了基体晶粒及再结晶晶粒识别、晶界可视化等建模关键技术问题，实现了热强旋过程中微观组织演变的动态观测。提出基于热加工图来研究热强旋过程中材料的微观组织演变机制、流变失稳机制及成形工艺条件。研制出了相应的热强旋工艺装备，在基于热加工图获得的有利于动态再结晶及塑性成形条件的基础上，进行了Haynes230合金筒形件热强旋成形实验研究。获得了旋压工艺参数对热强旋筒形件宏观成形质量及微观组织演变的影响规律，并揭示出热强旋过程筒形件内壁裂纹等典型缺陷的成因。采用灰色关联度法进行了宏观成形质量及组织性能协同研究的多目标优化，实现了难变形金属筒形件的热强旋过程形/性一体化控制。高温（800℃）力学性能测试结果表明，与原始管坯相比，Haynes230筒形旋压件的屈服强度及抗拉强度分别最大提高了65.1%和46.5%。本项目的完成，实现了难变形金属筒形件的高精度、高性能、低成本制造，对推动高端核心装备先进成形技术的发展和完善具有重大的科学意义和应用价值。