高压冷却下PCBN刀具切削高温合金表面残余应力分析及变质层成形机理  

Analysis of Surface Residual Stress and Formation Mechanism of Metamorphic Layer in PCBN Tool Cutting Superalloy under High-pressure Cooling

作　　者：吴明阳[1] 张亚利 程耀楠[1] 张剑宇 褚维旭 WU Mingyang;ZHANG Yali;CHENG Yaonan;ZHANG Jianyu;CHU Weixu(School of Mechanical Engineering,Harbin University of Science and Technology,Harbin 150080)

机构地区：[1]哈尔滨理工大学机械动力工程学院,哈尔滨150080

出　　处：《机械工程学报》2022年第1期231-243,共13页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51475128);黑龙江省自然科学基金(Ε2016043)资助项目。

摘　　要：镍基高温合金是一种典型的难加工材料,在高温下具有优良的机械性能,广泛应用于航空航天、能源等领域。切削过程中,在切削力和切削热的共同作用下,工件材料发生严重的塑性变形,导致已加工表面残余应力和变质层分布不均匀,从而降低工件的疲劳强度,高压冷却润滑辅助加工技术可有效改善此问题。因此,研究高压冷却下GH4169切削表面残余应力和变质层具有重要的理论意义和实用价值。首先,对不同冷却压力下的温度、应力和残余应力进行仿真分析,采用X射线衍射法对不同冷却压力下的切削表面残余应力进行测量,分析冷却压力对切削表面残余应力的影响规律,并与仿真结果进行比较;其次,在残余应力结果分析的基础上,利用EDS和XRD观测GH4169已加工表面变质层与基体的微观组织结构并进行对比分析;最后,分析切削速度、进给量和冷却压力对已加工表面变质层厚度的影响。结果表明:已加工表面变质层的XRD衍射峰比基体的XRD衍射峰宽而低,说明GH4169已加工表面变质层出现了晶粒细化现象;在给定的参数范围内,随着切削速度、进给量的增大,变质层厚度也随之增加,但随着冷却压力的增大,减弱了由热-力耦合和塑性变形综合作用下而引起残余应力分布不均匀的情况,进而使变质层厚度呈减小趋势。Nickel-based superalloy is one of the typical difficult-to-cut materials. It is used widely in aerospace, energy, and other fields, because of its excellent mechanical properties at high temperatures. During the cutting process, severe plastic deformation of the workpiece occurs because of the combined action of cutting force and cutting heat. It leads to an uneven distribution of residual stress and metamorphic layers on the machined surface, thereby reducing the fatigue strength of the workpiece. High-pressure cooling and lubrication-assisted machining technology can effectively improve this problem. Therefore, it has important theoretical significance and practical value to study the residual stress and metamorphic layer of GH4169 under high-pressure cooling. Firstly,the temperature, mises stress, and residual stress are simulated and analysed under different cooling pressures. The residual stress under different cooling pressures by using X-ray. The influence of cooling pressure on the residual stress is analysed and compared with the simulation results. Secondly, based on the analysis of residual stress results, EDS and XRD are used to observe the microstructure of the machined surface metamorphic layer and the matrix of GH4169 for comparative analysis. Finally, the effects of cutting speed, feed rate, and cooling pressure on the thickness of the machined surface metamorphic layer are analysed. The results show that the XRD diffraction peak of the metamorphic layer on the machined surface is wider and lower than that of the matrix,indicating that the grain refinement occurs in the metamorphic layer. For the given range of parameters, the thickness of the metamorphic layer increases with the increasing cutting speed and feed rate. However, with the increase of cooling pressure, the uneven distribution of residual stress caused by thermo-mechanical coupling and plastic deformation is weakened, and the thickness of the metamorphic layer decreases.

关 键 词：高压冷却 残余应力 变质层 晶粒细化 微观组织 

分 类 号：TG506[金属学及工艺—金属切削加工及机床] V263[航空宇航科学与技术—航空宇航制造工程]