CAJ | 학술논문

对高速铣削的切屑进行了微观组织研究，建立了切削要素、切屑形态、切削力、表面粗糙度等因素之间的关系。研究发现，切削速度越高，热量向外扩散的时间越少，聚集在剪切带内的热量越多，剪切带内发生动态再结晶的可能性也就越高，大量的热量促进了剪切带内的热塑性失稳，进而使绝热剪切带产生的频率大幅度提高，切屑的锯齿化程度也就随之加大；计算了不同切削条件下绝热剪切带中心的温度、热量扩散速度等，发现热量扩散速度远低于其变形速度，进而证明了高速切削钛合金Ti-6Al-4V时，绝热剪切带内发生了动态再结晶现象。考虑到再结晶软化效应对材料本构的影响情况，建立了改进J-C本构模型，该模型用两个表达式表述不同临界应变值区间范围的材料本构特征，理论计算证明了改进J-C本构比J-C本构更准确。
대고속선삭적절설진행료미관조직연구，건립료절삭요소、절설형태、절삭력、표면조조도등인소지간적관계。연구발현，절삭속도월고，열량향외확산적시간월소，취집재전절대내적열량월다，전절대내발생동태재결정적가능성야취월고，대량적열량촉진료전절대내적열소성실은，진이사절열전절대산생적빈솔대폭도제고，절설적거치화정도야취수지가대；계산료불동절삭조건하절열전절대중심적온도、열량확산속도등，발현열량확산속도원저우기변형속도，진이증명료고속절삭태합금Ti-6Al-4V시，절열전절대내발생료동태재결정현상。고필도재결정연화효응대재료본구적영향정황，건립료개진J-C본구모형，해모형용량개표체식표술불동림계응변치구간범위적재료본구특정，이론계산증명료개진J-C본구비J-C본구경준학。
The microstructure of chips in high-speed milling is analyzed, and the relationship between the cutting factors, chip formation, cutting force and surface roughness is established. It is found that the higher cutting speed is the less time heat spreads, the more heat in the shear zone gathers, the higher the possibility of occurrence of dynamic recrystallization in shear zone gets. A large amount of heat promotes the thermoplastic instability within the shear zone, the frequencies of the adiabatic shear band and the degree of serrated chip increase. The temperature and the cooling rate in adiabatic shear band are calculated, and it is found that deformation time is much lower than the cooling time. It is proved that dynamic recrystallization phenomenon occurs in high speed milling. The modeling of new developed J-C constitutive model which considers recrystallization softening effect is built; it has two expressions according to the different characteristics of material constitutive during critical strain values. Theoretical calculations proved that the developed J-C constitutive is more suitable than J-C constitutive.