复杂应变路径下难变形金属材料室温可旋性研究

The complicated structure has become the development trend of components widely used in modern industry. The composite spinning, a kind of typical forming technology under the complex strain paths, is an effective process for manufacturing of thin-walled axisymmetric part with complicated shape. However, there is still no corresponding spinnability characterization method of the composite spinning. Focusing on the difficulty to characterize the spinnability under complex strain paths, the spinnability characteristic curve and the spinning forming limit diagram is put forward to characterize the spinnability base on the spin-forming characteristics under the complex strain paths in this project. The instability wrinkling and the ductile fracture criterion under complex strain paths and the whole process numerical simulation model are established; the formation mechanisms of instability wrinkling and ductile fracture defects during the complex strain paths are emphatically studied, to realize the prediction of wrinkling and fracture. The spinnability characteristic curve and the forming limit diagram of spinning under complex strain paths are established by means of numerical simulation and experiment. Based on the above research, the composite spinning method is put forward to manufacture the conical-cylindrical parts of the nickel base superalloy with high efficiency, high precision and low cost at room temperature, which is widely used in the engine and gas turbine combustor. After the implementation of this project, not only the spinning forming theory can be improved, but also the key scientific problems of spinnability characterization under the complex strain path can be solved. It will provide theoretical basis for the development of the advanced manufacturing technology for core equipment, and has important scientific significance and remarkable practical value.

结构复杂化已成为现代工业所需零件的发展趋势，复合旋压作为一种典型复杂应变路径下的成形技术，是制备复杂薄壁构件最有效的方法，其可旋性还未有相应的表征方法。项目拟针对复杂应变路径下可旋性表征困难的问题，基于复杂应变路径下旋压成形特征，提出采用可旋性表征曲线及成形极限图对其进行表征，并构建出复杂应变路径下的失稳起皱准则、韧性断裂准则及全流程数值模拟模型；着重研究复杂应变路径下失稳起皱、损伤破裂等典型缺陷形成机理，实现对起皱及破裂等缺陷的预测；通过数值模拟与试验相结合，构建出复杂应变路径下可旋性表征曲线及成形极限图；在此基础上，以发动机及燃气轮机燃烧室内常用的锥筒形构件为例，提出采用室温复合旋压的方法实现其高效、高精度、低成本制造。项目的实施不仅完善了旋压成形理论、解决了复杂应变路径下可旋性表征这一关键科学问题，还为推动现代装备先进制造技术的发展奠定理论基础，具有重要的科学意义和广阔的应用前景。

结构复杂化已成为现代工业所需零件的发展趋势，复合旋压作为一种典型复杂应变路径下的成形技术，是制备复杂薄壁构件最有效的方法，但其可旋性还未有相应的表征方法。项目针对在复杂应变路径下可旋性表征困难的问题，采用可旋性表征曲线对其进行定量表征，并对复杂应变路径下的应变路径变化规律、失稳起皱及损伤破裂等典型缺陷形成机理展开了研究。项目提出构建复合旋压全流程有限元模型，探索出成形参数对应变路径的影响规律，建立了复合旋压时的应变路径变化曲线。提出基于平面屈曲理论和德鲁克公设，构建了复杂应变路径下的失稳起皱判据，采用Fortan语言，通过二次开发将其与有限元模型进行耦合，实现了对失稳起皱的预测，提出了基于凸缘扇形压应力区的失稳起皱形成机制。根据剪切旋压及拉深旋压时的塑性变形及损伤形成特征，通过断口扫描分析了复合旋压时裂纹形成机制，分别构建修正的Oyane韧性断裂准则与修正的Lou韧性断裂准则，实现了对剪切-拉深复合旋压分阶段损伤断裂的精确模拟。提出以各工序的变形程度为横纵坐标，构建出了复杂应变路径下镍基高温合金可旋性表征曲线，实现了对复杂应变路径下难变形金属可旋性的准确表征。研制出了相应的复合旋压工艺装备，进行了可旋性实验，获得了工艺参数对可旋性的影响规律，并验证了可旋性表征曲线的准确性。在此基础上，提出采用室温复合旋压成形的方法，实现了航空发动机及燃气轮机镍基合金锥筒形件高效、高精度、低成本制造。本项目的完成为镍基高温合金复合旋压成形方法及工艺的确定提供了理论依据，推动了现代装备制造技术的发展与完善。