极薄壁微构件的微加工损伤机理及对使役性能的影响

In order to solve the high and special demand on the material, size and performance, the research on surface integrity in the micro machining and its influence mechanism on mechanical property of micro structured component will be carried out. Considering the micro texture and structure of Elgiloy alloy, analyzing the micro mechanism character, and by means of the thermodynamic model of micro-cutting Elgiloy in the condition of multi-field coupling, considering the size effect in the meso-scale in the micro cutting, the finite element analysis method is used to set up the micro-cutting model in the condition of multi-field coupling, and combine with the micro-cutting experiments, the material removal mechanism and the surface generation mechanism of ultra-precision micro-cutting Elgiloy are proclaimed. Through the research on the regularity of surface roughness and the surface damaged layer in the micro-cutting Elgiloy under the meso-scale, the micro-cutting surface quality prediction model based on the micro diamond cutting tool is established with the vibration frequency character of the micro thin-wall structured component. The research results will meet the strict requirement on the surface roughness and surface damaged layer of super thin-walled micro structure, and increase the system precision and its stability of new micro inertial instruments for aviation.

针对新一代航空微型惯性传感器极薄壁微挠性结构件的微加工过程中微薄壁结构断裂、加工表面完整性差等瓶颈问题，围绕微加工过程中遇到的材料特殊性、尺寸特殊性和性能特殊性的难题，本项目拟运用理论分析、仿真模拟与实验研究相结合的研究手段，开展极薄壁微构件微加工的表面完整性、损伤机理及对其使役性能的影响机制等关键科学问题的研究。通过建立基于微观组织结构及其微观力学特性的微细切削仿真模型，考虑塑性应变梯度和多重耦合尺度效应，采用有限元仿真分析与微切削实验相结合的研究方法，揭示极薄壁微构件的微加工过程中尺寸效应对于表面生成机理、表面损伤层的形成机理和演变规律、以及表面完整性对于极薄壁微构件使役性能的影响机制，为微构件的精密加工提供理论指导和技术支持，满足极薄壁微构件的加工表面形貌、表面完整性和使役性能的苛刻要求，提高航空微型惯性传感器的系统级精度及其稳定性。

面向新一代航空微型惯性传感器极薄壁微挠性结构件的微加工过程中微薄壁结构断裂、加工表面完整性差等瓶颈问题，针对微加工过程中遇到的材料特殊性、尺寸特殊性和性能特殊性的难题，本项目采用理论分析、仿真模拟与实验研究相结合的研究手段，开展了多重尺寸效应作用的极薄壁微构件微切削加工表面生成机理、极薄壁微构件微切削加工损伤层的形成机制与演变规律、微切削表面完整性对极薄壁微构件力学特性的影响机制的研究工作。建立了考虑微铣刀弱刚度特性的微铣削力模型，揭示了刀具直径、刀齿间历史轨迹相互作用和刀具跳动对切入角、切出角和瞬时未变形切屑厚度的影响规律；建立了考虑刀具跳动的切出侧边毛刺和切出底边毛刺特征尺寸的预测模型，揭示了切出位置毛刺特征的变化规律，提出了抑制切出位置毛刺的方法；建立了基于微铣削加工表面特征降维分析的力学性能组合预测模型，实现了对薄壁微构件力学性能的无损获取，为薄壁微构件使役性能的评价提供了理论支撑。本项目的研究成果，为微构件的精密微细铣削加工提供了理论指导和技术支持，满足极薄壁微构件的加工表面完整性和使役性能的苛刻要求，应用于微惯性传感器零件的加工，提高了航空用微型惯性传感器的系统级精度、可靠性及稳定性。