强瞬态热-力耦合作用下涂层刀具非均质传热及涂层损伤机制

High speed milling technology begins to be as an advanced technology used in such fields as automobile manufacturing, aerospace, and national defense industry, etc. High speed milling with coated tools has advantage as high material removal rate, high surface integrity, and long tool service life. Coatings technology can improve the tools’ wear resistance and heat resistance, also can improve the cutting performance and service life of tools. Coating appears breaking and then induces the tool failure in coupling effects of strong transient thermo-mechanical coupling with high frequency. In this project, cutting heat transfer mechanism and coating damage mechanism in high frequency intermittent cutting are studied to find a way to increase the tool life. The non-fourier effect in high speed milling will be investigated and the heat transfer characteristics of coating with different coating material will be researched. The cutting heat transfer mechanism will be revealed under the action of strong transient thermo-mechanical coupling. Meanwhile, the theoretical model for cutting heat transfer in the condition of cyclical load and transient heat flux will be developed. The forecasting model for coating crack initiation and extension will be developed, based on the principle of crack dynamics. The coating damage mechanism in high speed milling will be explored. This research can not only help to reduce the coated tool temperature in order to improve tools service lives, but also lay a theoretical foundation for design of coating and coated tools.

高速铣削已成为模具、汽车、航空航天制造中一项重要的先进切削加工技术，具有高材料去除率和高表面完整性等优点。涂层技术的应用明显提高刀具表面的耐磨性和耐热性，增强了刀具的综合切削性能，延长了刀具使用寿命。然而涂层的韧性较差使得在承受高速铣削产生的高频强瞬态热力冲击过程中容易出现疲劳失效。本项目基于高速铣削时的强瞬态热-力耦合作用，探讨高频断续切削条件下涂层的非傅里叶传热效应，结合涂层/基体界面特性构建周期性强瞬态热力耦合作用下的切削热传导模型，揭示高速铣削过程中涂层刀具非均质传热本质；基于裂纹动力学构建涂层裂纹萌生及扩展预测模型，阐明高速铣削刀具涂层损伤机制，从而解决具有界面结构的涂层刀具切削温度预测难题，为刀具涂层设计、优化及切削参数优选提供重要的理论依据。

本项目在高频断续切削的强瞬态热-力耦合作用条件下，开展了涂层刀具的切削热传导机理和涂层损伤机制的研究，探讨了具有薄膜特性的刀具涂层传热的非傅里叶传热效应并深入分析了涂层与基体的结合界面特性，揭示了非均质传热本质。在研究切削热传到的基础上，开展了涂层刀具失效机理研究，阐明了强瞬态热-力耦合作用下涂层的裂纹萌生及扩展机制，明晰了涂层刀具的摩擦磨损演变过程。并通过人工智能算法设计了的刀具磨损量监测模型，通过试验验证其具备较好的刀具磨损量监测的能力。此项目的开展为涂层刀具高频断续切削的工艺优化提供了理论依据，为实现主动调控涂层刀具温度、监测刀具磨损，进一步提高刀具寿命奠定了理论基础。