航空轻合金高速切削动态力学性能基础数据研究

Facing the pressing demand of intelligent manufacturing for building cutting foundation database of typical materials, high-speed cutting dynamic mechanical property data acquisition and characterization are studied on aviation light alloys. Considering the susceptibility of light alloy texture features to properties, a constitutive model for materials that under high-speed cutting process is established by means of theoretical analysis, material/cutting experiment and finite element simulation. Based on the fact of material embrittlementat high strain rate, high pressure fracture test method is applied to simulate the high stress condition during high-speed cutting. A material failure model conformed to the high-speed cutting process is built, while the mechanisms of aviation light alloy embrittlement under high strain rate and chip morphology transformation are revealed. The micro-constitutive model of dislocation density, strain and stress is established based on dislocation glide-twin crystal deformation mechanism; the microstructure evolution rule of processed material surface is analyzed. High speed cutting simulation and testing are used to obtain the surface integrity parameters, while a mapping relationship between cutting process parameters, surface integrity is established. Fundamental data on dynamic mechanical properties of aviation light alloys for high-speed cutting is validated by simulation and experiment. This project has important theoretical significance and application value for providing the research methods and basic data for building the foundation database of aviation alloys during high speed cutting process.

面向智能制造对典型材料切削基础数据库的迫切需求，针对航空轻合金在高速切削下动态力学性能数据获取和表征展开研究，借助理论分析、试验和模拟仿真等手段，考虑轻合金织构特征对性能影响的敏感方向，建立高速切削条件下材料本构模型；针对材料高应变率脆化现象，应用高压断裂试验方法创造高速切削的高应力状态，获取符合高速切削条件的材料断裂失效模型，揭示航空轻合金高应变率脆化对切屑形态转化的影响规律；基于材料位错滑移-孪晶变形机制，建立位错密度与切削应变、应力的微观本构模型，通过数值模拟分析加工表面微观组织演化及其对表面完整性的影响规律，进行高速切削试验验证，检测加工表面完整性，建立高速切削工艺参数与表面完整性的映射关系，获得航空轻合金高速切削动态力学性能物理基础数据。项目的研究将为航空高速切削工艺基础数据库的构建提供研究方法和基础数据支持，具有重要的理论意义和应用价值。

航空轻合金动态力学性能研究中存在的各向同性假设、应变率不满足高速切削工况等局限性问题，项目考虑轧制-预拉伸等成形处理后材料微观织构特征导致宏观力学性能各向异性，重点完成了高速切削条件下材料动态力学性能的获取和表征方法的研究工作。. 借助霍普金森动态拉压实验获取材料的动/静态力学性能数据，引入角度函数、应变率敏感性、各向异性系数、塑脆转换函数以表征各向异性和应变率对材料动态力学性能的影响，依次建立了动态冲击拉伸、压缩及剪切条件下钛合金、铝合金等航空轻合金的J-C本构模型和J-C损伤模型；基于KME位错密度模型，引入空间角度函数表征性能影响的敏感方向，构建了材料微观位错-应变本构模型，揭示了材料微观组织演化与宏观动态力学性能的内在关联机制，并完成了模拟仿真验证。. 综合考虑高速切削加工过程高应变率、高温、高应变及材料脆化等特征，基于Oxley正交切削理论和切削反求法，融合J-C本构模型参数和切削变形区关键数据，分别构建了考虑平面成形角度和应变率敏感性的切削本构模型、基于应力转换的空间本构模型以及考虑高应变率脆化效应的 J-C 断裂损伤模型，准确描述了高速切削条件下材料变形、断裂失效及加工硬化行为；将上述构建的考虑各向异性特征和高应变率脆化效应的宏/微观本构模型、断裂失效模型应用于高速切削过程的模拟分析，结合对动态冲击试样断口形貌、剪切角、切屑形态等宏微观分析，引入切削能比、绝热剪切能量判据、锯齿化程度/频率、塑脆转化临界速度等表征参数，阐明了钛合金、铝合金等航空轻合金的切屑形成机制、绝热剪切行为、塑脆断裂转换规律，获取了理想切屑形态和表面完整性的宏微观性能的基础数据和工艺条件，项目为航空航天领域典型材料切削工艺数据库构建提供了研究方法和基础数据支持，对航空合金材料高性能制造具有重要的工程意义和应用价值。