钛合金复杂薄壁件3D打印—精密切削加工集成制造基础研究

The complex titanium alloy thin-wall components are widely used in the field of aerospace. Manufacturing these components usually have heavy workload, low efficiency and serious waste of material. 3D printing is an promising method to manufacture the complex titanium alloy thin-wall components, however the components manufactured by 3D printing usually have poor surface quality and low forming precision, and they can not be directly used. In order to solve these problems, one integrative manufacturing technology of 3D printing-precision cutting is proposed. In the project, the effects of selective laser melting (SLM) technologies on the quality, precision and mechanical properties of components will be studied. The defects forming mechanisms and control measures will be obtained. Compared to the traditional titanium alloy, the effects of surface topography, microstructure, physical and mechanical properties of 3D printing titanium alloy on the cutting mechanisms and surface integrity will be studied. The special cutting mechanisms of 3D printing titanium alloy will be obtained. The machining stability control method based on self-repression vibration of components will be obtained. On the basis of the above research, the typical aeronautical titanium alloy thin-wall components with good surface quality and high forming precision will be manufactured in high-efficiency, additionally, the research results will guide the 3D printing and machining of other titanium alloy components.

钛合金复杂薄壁件在航空航天领域应用广泛，用传统的切削加工方法制造，切削量大，效率低，材料浪费严重。3D打印是制造钛合金复杂薄壁件的有效方法，但现有的钛合金3D打印件表面质量和成形精度较低，通常达不到设计要求。本项目综合3D打印和精密切削加工的优势，探索钛合金复杂薄壁件3D打印—精密切削加工集成制造技术。项目主要研究钛合金复杂薄壁件激光选区熔融（SLM）成型工艺参数对构件表面质量、尺寸精度和力学性能的影响规律，缺陷形成机理与控制方法；与传统钛合金毛坯件对比，研究3D打印钛合金件表面形貌、微观组织、物理和力学性能等的差异性对切削加工质量的影响机制，揭示3D打印钛合金切削加工机理；研究3D打印钛合金复杂薄壁件切削加工的自抑振动控制方法和工艺优化。在以上研究的基础上，实现航空航天典型钛合金复杂薄壁件的高效率、高质量3D打印—精密切削加工集成制造，并为其它钛合金构件的制造提供指导。

钛合金复杂薄壁件在航空航天领域应用广泛，传统切削加工切削量大、效率低、材料浪费严重，而3D打印钛合金复杂薄壁件表面质量和成形精度难以达到设计要求。本项目综合3D打印和精密切削加工的优势，研发了一种钛合金复杂薄壁件3D打印—精密切削加工集成制造技术。主要完成内容：（1）钛合金复杂薄壁件高质量SLM成型工艺研究。通过对TC4钛合金SLM成型过程温度场仿真，发现各工艺参数下的最高温度均高于TC4钛合金熔点；激光功率每增加20W，温度升高200K；对TC4钛合金熔池大小影响的程度：激光功率＞扫描速度。综合得到，TC4钛合金复杂薄壁件SLM成型的最佳工艺为：激光功率180W，扫描速度1200mm/s。（2）3D打印钛合金切削加工机理研究。对SLM成型TC4钛合金薄壁件进行切削加工，发现试样易发生变形、欠切。工艺参数对试件变形影响主次为：轴向切深>切削速度>每齿进给量；对残余应力影响主次为：切削速度>每齿进给量>轴向切深。（3）3D打印钛合金复杂薄壁件自抑振动控制研究。采用薄壁板Rayleigh-Ritz能量解法，提出一种新型的基于离散余量体积单元的非均匀余量分配策略，有效减少工件表面的切削振纹，提高表面质量。（4）3D打印钛合金复杂薄壁件切削工艺优化。研究了余量大小和不同余量分布策略对加工变形的影响，发现在均匀余量情况下，最大加工变形量随余量厚度的增加先增大后减小。以SLM成型TC4钛合金叶片为对象，采用非均匀余量分配策略进行加工，得到工件叶盆和叶背的最大加工误差仅为98μm与104μm，相比传统均匀余量叶片，加工精度提高50%，能够较好满足航空叶片的加工精度要求，最终实现钛合金叶片SLM成型-精密切削加工一体化集成制造。项目研究成果对于航空航天钛合金复杂薄壁结构件的高效率和高质量集成制造，促进我国航空航天制造业的发展具有重要的理论意义和实际价值。