纵扭超声辅助磨削氮化硅亚表面损伤及其试验研究  

Subsurface Damage and Experiment of Silicon Nitride by Longitudinal Torsional Ultrasonic Assisted Grinding

作　　者：闫艳燕[1] 马千里 张亚飞 秦飞跃 赵波[1] YAN Yan-yan;MA Qian-li;ZHANG Ya-fei;QIN Fei-yue;ZHAO Bo(School of Mechanical and Power Engineering,Henan Polytechnic University,Henan Jiaozuo 454000,China)

机构地区：[1]河南理工大学机械与动力工程学院,河南焦作454000

出　　处：《表面技术》2023年第2期55-66,共12页Surface Technology

基　　金：国家自然科学基金(51575163)。

摘　　要：目的探究纵扭超声辅助磨削工艺参数对氮化硅陶瓷亚表面损伤的影响规律。方法首先,建立纵扭超声振动下单颗磨粒的切削轨迹及其切削弧长模型,分析纵扭超声辅助磨削独特的加工机理。其次,考虑砂轮表面磨粒的随机分布特性,并基于硬脆材料脆塑转变特性及其临界转角界定,给出纵扭超声辅助磨削单颗磨粒未变形切屑厚度的概率学模型,进而建立纵扭超声辅助磨削过程中单颗磨粒的平均法向磨削力模型。最后,建立纵扭超声辅助磨削氮化硅亚表面损伤深度模型,并进行试验验证。结果纵扭超声振动的引入增大了纵扭超声辅助磨削过程中单颗磨粒的切削弧长,减小了单颗磨粒平均未变形切屑厚度,降低了单颗磨粒的法向磨削力,最终降低了氮化硅陶瓷亚表面损伤的深度,获得了较好的氮化硅陶瓷表面加工质量。氮化硅亚表面损伤深度随着超声振幅的增大而降低,当超声振幅为6μm时,亚表面损伤深度为5.65μm,相较于普通磨削亚表面损伤深度降低了33.6%。理论模型预测结果与试验结果趋势一致,预测结果与试验结果的最大误差为13.38%,平均误差为8.34%,因此该模型能够为氮化硅实际加工中亚表面损伤深度的预测提供一定参考。结论纵扭超声辅助磨削能够有效降低氮化硅陶瓷加工表面的亚表面损伤深度,进而提高氮化硅陶瓷工件的使用性能。Silicon nitride ceramics is widely used in aerospace,automotive industry and other fields because it has some advantages,such as high strength,high temperature oxidation resistance and simple to preparation.However,silicon nitride ceramics is one of the typical hard and brittle materials,and its high hardness and brittleness lead to serious subsurface damage in the ordinary grinding process,which seriously reduces the workpiece performance.Ultrasonic assisted grinding is considered as state of the art machining process for brittle and hard to machining materials such as ceramics and optical glasses.The work aims to grasp the influence of the process parameters during longitudinal torsional ultrasonic assisted grinding on the subsurface damage of silicon nitride ceramics.In this study,a theoretical subsurface damage model was proposed with the consideration of the ductile-to-brittle transition removal mechanism and random distribution of wear particles in ultrasonic assisted grinding of ceramics.Firstly,the cutting trajectory and cutting arc length model of a single abrasive particle during longitudinal torsional ultrasonic vibration were established.The unique machining mechanism of longitudinal-torsional ultrasonic assisted grinding was analyzed.Secondly,based on the brittle-plastic transition characteristics of brittle materials and the definition of its critical angle,the probabilistic model of the undeformed chip thickness of a single abrasive particle in longitudinal-torsional ultrasonic assisted grinding was given with considering the stochastic distribution nature of the grits on the surface of the grinding wheel.Then the average normal grinding force model of a single abrasive particle in the process of longitudinal-torsional ultrasonic assisted grinding was established by combination of grinding force in plastic removal stage and brittle removal stage.The parameter k was introduced to represent the influence of overlapping and intersection between different diamond grits.Finally,a model of subsurface dam

关 键 词：纵扭超声磨削 氮化硅 亚表面损伤 平均未变形切屑厚度 磨削加工 脆塑性转变 

分 类 号：TG580.1[金属学及工艺—金属切削加工及机床]