【作者】 周俊；

【导师】 韩荣第；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 GH4169是以Ni-Cr固溶体为基体，Ni3Nb和Ni3(Al,Ti,Nb)为强化相组成的，属Ni基变形高温合金，其组织稳定、激活能大、有害相少，故其强度高、塑性与韧性好、抗高温、抗氧化、抗热腐蚀性好，能在高温、高频应力应变及腐蚀性气氛下长期稳定工作，已经成为航天、航空、能源等行业关键零部件不可或缺的重要结构材料。GH4169是最难加工的高温合金之一，切削加工性只有0.1左右，表现在切削力大、切削温度高、加工硬化严重、刀具使用寿命低，其常规切削速度只有10~15m/min，严重影响GH4169的切削加工效率，航空、航天、能源等行业的迅猛发展迫切要求解决GH4169难加工、切削速度低的问题。故GH4169的高速切削相关技术与机理的研究，具有重要的理论意义和广阔的应用价值。首先，在综述高速切削GH4169相关技术及机理的国内外研究现状的基础上，为达到高效切削的目的，进行了高效切削GH4169相关技术的的高速车削与铣削试验，研究了高速切削GH4169时，切削用量对切削力、切削温度、表面质量（粗糙度、加工硬化、残余应力）的影响规律与特点；对Salomon的高速切削时切削温度降低的假说进行了探讨；并用过热水蒸汽和磁化乳化液进行了切削时冷却润滑作用效果的研究；还进行了适合GH4169高速切削的TiAlN涂层硬质合金、细晶粒硬质合金、Si3N4+Al2O3+TiC复合陶瓷三种刀具材料的刀具磨损试验，研究了刀具磨损过程、使用寿命及刀具性能价格比。然后，对高速切削GH4169时形成的力-热耦合强应力场作用下的变形特点与本构关系建模进行了研究，以期获得材料力学性能实验法无法实现的符合高速切削力学特点的本构方程，提高高速切削GH4169有限元仿真的精度。在此用直角切削快速落刀试验法获取了切屑根，以直角切削绝热剪切力学模型为基础，研究了高速切削GH4169时的高温、大应变、高应变率的材料变形特点，探讨了基于切削试验法的材料本构关系模型的建模方法，构建了能较真实反映GH4169的高速切削力学特点的本构方程；并将其作为材料模型对GH4169高速切削进行了有限元仿真，切削试验证明基于切削试验法构建本构关系模型是准确的。再后，对高速切削GH4169中产生的强韧螺卷形切屑的卷曲过程进行了力学解析及有限元仿真，研究了从单一卷曲到复杂卷曲条件下切屑卷曲过程中的弹塑性力学行为，通过对切屑横截面上应力状态的分析，找出了单一及复杂卷曲条件下应力的分布规律。最后，研究了高速切削GH4169时切屑的锯齿和毛边的特征及毛边的生成机理。对车削试验获得的切屑及快速落刀试验获得的切屑根标本进行了显微观测，研究了第一变形区材料的变形与损伤的特点及规律，并基于微孔洞聚合与裂纹扩展理论，研究了高速切削GH4169的绝热剪切带微损伤的产生与两次演化的断裂力学行为与演化过程的规律特点，揭示了切屑毛边的生成机理。更多还原

【Abstract】 GH4169is a kind of Ni-base superalloy which has Ni-Cr solid solution as matrix,Ni3Nb and Ni3(Al,Ti,Nb) as strengthening phase. Its stable tissue, great activationenergy and low detrimental phase contribute to its property of high strength, goodplasticity, antioxidation and good corrosion resistance. So it can work for a long timeunder high temperature and corrosive circumstances even the stress and strain changefrequently. It has been the indispensable material in aerospace, aviation and energyindustry etc. GH4169is one of the most difficult-to-cut materials, whose depth of cut isonly about0.1. The strong cutting force, high cutting temperature, severe phenomenonof work hardening, short life span of cutting tool and common cutting speed of10~15m/min greatly lower the processing efficiency. The low cutting speed is an urgentproblem to be solved in aerospace, aviation and energy industry which are enjoying fastdevelopment. So reserch on the correlation technique and mechanism of the high-speedcutting GH4169is of great significance both in theory and in practice.Firstly, after the summary of high speed cutting theories and techniques at homeand abroad, to reach the goal of high speed cutting, a test based on Salomon hypothesisis to be carried on. The cutting force, cutting temperature and the influencing factorsand regulations of surface quality (surface roughness, work hardening, residual stress)are to be researched through turning test, milling test and simulation on the system. Andthe method to improve the cooling lubrication effect during high speed cutting ofGH4169will also be studied.Secondly, the deformation feature and constitutive modeling of high speed cuttingGH4169under the influence of mechanical-thermo coupled strong stress field were tobe studied. In order to get the dynamical constitutive equation conformed to high-speedcutting GH4169, which is beyond mechanical testing. Meanwhile, improve the accuracyof FEM simulation of GH4169high speed cutting.Through the test of rapid tooldisengage during right angle cutting to obtain chip root on the basis of physical modelof two dimensions cutting. And during the research of high speed cutting, metal elasticand plastic deformation with high temperature, strong strain and great strain rate arenoticed. To probe the modeling method of material constitutive modeling on the basis ofright angle cutting test and build constitutive equation that can rightly explain themechanics feature of cutting difficult-to-cut materials with high speed. Then throughcomparing the result of FEM simulation of GH4169high speed cutting based on theequation with the test result to verify whether the modeling method is accurate orreliable.Thirdly, tough curl chips will be produced during most cuttings of GH4169. Through dynamical analysis and FEM simulation method, the elastic and plasticdynamic phenomenon under complicated conditions is studied while the chips arecurled. And through analyzing the force condition on the cross section of the chips, lawsof stress distribution are to be discovered.Lastly, mechanism of chips formation will be discussed via probing the chipfeature of cutting GH4169with high speed. Through micro-observing the chips fromturning test and chip roots from rapid tool disengage test, observing the features andlaws of the deformation and damage of materials in the first deforming zone with CCDobserving system and SEM，analyzing difficult-to-cut GH4169material with goodhardness, high strength and high toughness, showing the twice deformation(first in thefirst deforming zone and the second in the second deforming zone) and damage processon the influence of high temperature, great stress and high stress rate of high speedcutting, the mechanism of how chips are formed is revealed.更多还原