刀具前角对超声复合加工成形切屑组织与性能的影响  

Effect of Tool Rake Angle on Microstructure and Properties of UltrasonicCompound Machining Formed Chip

作　　者：孙海猛 牛赢[1,2] 焦锋 王壮飞[1] SUN Haimeng;NIU Ying;JIAO Feng;WANG Zhuangfei(School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China;Xixia County Internal Combustion Engine Intake and Exhaust Pipe Limited Liability Company,Nanyang 474500,Henan,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454003 [2]西峡县内燃机进排气管有限责任公司,河南南阳474500

出　　处：《材料导报》2023年第17期225-231,共7页Materials Reports

基　　金：河南省自然科学基金(202300410172);国家自然科学基金(52175399);河南省重点研发与推广专项(212102210056)。

摘　　要：超细晶纯铜作为重要的基础材料和功能材料成为当前金属材料的研究热点,本工作在大应变挤压-切削法(Large strain extrusion machining,LSEM)的基础上提出超声复合切削法(Ultrasonic compound cutting,UCC)来制备超细晶纯铜。超声复合切削中刀具前角是影响切屑应变、晶粒尺寸、位错密度及性能的关键要素,为了研究刀具前角对纯铜切屑组织和性能的影响,基于ABAQUS软件建立超声复合切削三维有限元模型,分析切削变形区等效应变、等效应变率和切削温度的变化;设计单因素试验,分析刀具前角和超声振动对切屑微观组织、位错密度和显微硬度的影响。结果表明:随着刀具前角的增加,等效应变和切削温度逐渐减小,等效应变率会先增大后减小。与LSEM切屑相比,加入超声振动后切屑晶粒细化程度和位错密度均提高,硬度增加5%。当刀具前角为30°时,切屑晶粒由粗晶细化至亚微米级拉长晶,宏观硬度从基体的92.5HV提高至131.8HV;当刀具前角为15°时,晶粒进一步细化为等轴细晶,位错密度为1.14×10^(13)m^(-2),硬度提高至184.3HV,此时纯铜切屑的硬度符合Hall-Petch关系。Ultrafine grained pure copper as an important basic material and functional material has become the current research hotspot of metal mate-rials.In this work,ultrasonic compound cutting was proposed to prepare ultrafine grained pure copper based on large strain extrusion machining.In UCC,the tool rake angle is the key factor affecting chip strain,grain size,dislocation density and properties.In order to study the effect of tool rake angles on the microstructure and properties of pure copper chip.A 3D Finite element analysis(FEM)model of ultrasonic compound cutting was established based on ABAQUS analysis software,and the change of equivalent strain,equivalent strain rate and cutting temperature in the shear deformation zone were analyzed.Single-factor tests were designed to analyze the effects of tool rake angle and ultrasonic vibration on chip microstructure,dislocation density and micro-hardness.The results show that:With the increase of tool rake angle,the equal strain and the cutting temperature gradually decrease,the equal strain rate first increases and then decreases.Compared with LSEM chip,the grain refinement degree and dislocation density of chip has be improved after adding ultrasonic vibration,and the hardness also increase by 5%.When the tool rake angle is 30°,the chip grain is refined from coarse grain to submicron elongated grain,and the macro-hardness is increased from 92.5HV to 131.8HV;when the tool rake angle is 15°,the grain is further refined into equiaxed fine grain,the dislocation density is 1.14×10^(13)m^(-2)and the hardness is also increased to 184.3HV.At this time,the hardness of pure copper chips conforms to the Hall-Petch relationship.

关 键 词：刀具前角 超声复合切削法 微观组织 位错密度 硬度 

分 类 号：TG506.5[金属学及工艺—金属切削加工及机床]