【作者】 徐凯；

【导师】 卢晓红； 牛金波；

【作者基本信息】 大连理工大学 ， 机械工程， 2024， 硕士

【摘要】 镍基高温合金Inconel 718微小零部件以其优良的高温强度、热稳定性和抗热疲劳性能备受航空航天、轨道交通、能源动力和生物医疗等领域的青睐。但镍基高温合金Inconel 718强度高、导热率低、粘性大、硬质点多,是一种典型的难加工材料。激光辅助微铣削技术是加工镍基高温合金微小零部件的潜在有效手段。然而,激光辅助微铣削是复杂的热力耦合过程,相关研究处于探索阶段。因此,本文以实现镍基高温合金Inconel718激光辅助微铣削过程仿真和高质、高效、低耗加工为目标展开研究,具体研究内容如下:（1）激光辅助微铣削实验平台的搭建与激光预热温度场仿真。基于课题组前期自主搭建的微铣削平台,完成激光光源的选型和配置,结合微铣削力和温度测量系统,完成激光辅助微铣削实验平台的搭建,为激光辅助微铣削实验提供平台基础。通过ABAQUS有限元仿真软件建立了基于高斯激光移动热源的激光预热温度场仿真模型,将仿真输出的温度场与实验测量得到的温度进行对比,验证仿真模型的有效性。通过对仿真输出的温度场进行分析,确定合理的激光参数范围,为后续仿真与实验奠定基础。（2）考虑尺度效应及应变软化效应的材料本构模型构建及Inconel 718激光辅助微铣削过程仿真。综合考虑激光辅助微铣削过程中的应变软化效应与尺度效应,对经典Johnson-Cook材料本构模型进行修正,建立适用于激光辅助微铣削过程的材料本构模型。通过VDFLUX子程序与VUMAT子程序分别完成高斯移动热源与修正后材料本构模型的添加,基于ABAQUS实现完全热力耦合的多子程序有限元仿真,并通过实验验证仿真模型的有效性。（3）镍基高温合金Inconel 718激光辅助微铣削正交试验与参数优化。以主轴转速n、每齿进给量f_z、轴向切深a_p和激光功率P为影响因素,进行了四因素四水平L₁₆（4⁴）正交试验。分别对微铣削力、工件表面粗糙度、刀具直径减少率以及材料去除率进行极差分析。基于正交试验结果建立了表面粗糙度和刀具直径减少率预测模型,并对模型进行可靠性及显著性检验;最后,以低表面粗糙度、高材料去除率以及低刀具直径减少率为优化目标,基于遗传算法实现了工艺参数多目标优化,获得了Pareto最优解集。本文探索了镍基高温合金Inconel 718激光辅助微铣削的过程仿真,可为探究激光辅助微铣削机理提供参考。本文面向多目标的工艺参数优化研究成果为实现激光辅助微铣削高质、高效、低耗加工提供参考。更多还原

【Abstract】 Micro-parts of nickel-based superalloy Inconel 718 with its excellent high-temperature strength,thermal stability and thermal fatigue resistance are highly favored by the aerospace,rail transportation,energy power and biomedical and other fields.However,due to its high strength,low thermal conductivity,high viscosity,and hard spots,the nickel-based superalloy Inconel 718 is considered a typical difficult-to-machine material.Laser-assisted micro-milling technology is a potentially effective method of machining micro-parts of nickel-based superalloys.Nevertheless,laser-assisted micro-milling is a complex thermal-mechanical coupling process,and the related research is in the exploratory stage.Therefore,this paper aims to realize the simulation of laser-assisted micro-milling process and high quality,high efficiency and low consumption machining of nickel-based superalloy Inconel 718,the main research contents are as follows:（1）Construction of laser-assisted micro-milling experimental platform and simulation of laser preheating temperature fields Based on the micro-milling platform built independently by the group in the early stage,the selection and configuration of the laser light source is completed.Combined with the cutting force and temperature measurement system,the construction of the laser-assisted micro-milling experimental platform is completed,providing a platform basis for laser-assisted micro-milling experiments.A simulation model of laser preheating temperature fields based on Gaussian heat source is established by ABAQUS,and the temperature fields output from the simulation is compared with the experimental results to verify the validity of the simulation model.By analyzing the simulation temperature fields,a reasonable range of laser parameters is determined,which lays the foundation for the subsequent simulation and experiments.（2）Construction of material constitutive model considering scale effect and stress softening effect and process simulation of laser-assisted micro-milling Inconel 718.Considering the stress softening effect and scale effect in the laser-assisted micro-milling process,the Johnson-Cook material constitutive model is modified to make it applicable to the laser-assisted micro-milling process.The addition of Gaussian moving heat source and modified material constitutive model is accomplished by VDFLUX subroutine and VUMAT subroutine,respectively,and the fully thermal-mechanical coupling multi-subroutine finite element simulation is realized based on ABAQUS,and the validity of the simulation model is verified through experiments.（3）Orthogonal tests and parameter optimization for laser-assisted micro-milling Inconel718.A four-factor,four-level L₁₆（4⁴）orthogonal test was conducted with spindle speed n,feed per tooth f_z,axial depth of cut a_p and laser power P as the influencing factors.The cutting force,workpiece surface roughness,reduction ratio of tool diameter,and material removal rate were analyzed by range analysis,respectively.Based on the results of orthogonal tests,a prediction model for surface roughness and reduction ratio of tool diameter was established,and the model was tested for reliability and significance;finally,with the optimization objectives of low surface roughness,high material removal rate,and low reduction ratio of tool diameter,a multi-objective optimization of the process parameters based on the Genetic Algorithm was realized,and the Pareto optimal solution set was obtained.This paper explores the process simulation of laser-assisted micro-milling nickel-based superalloy Inconel 718,which can provide a reference for exploring the mechanism of laser-assisted micro-milling.The multi-objective oriented process parameter optimization research results in this paper provide reference for realizing high quality,high efficiency and low consumption processing of laser-assisted micro-milling.更多还原