奥贝球墨铸铁切削机理研究

通过切屑根部的金相照片和扫描电镜观察，提供了奥贝球铁材料生成积屑瘤的证据和机理，积屑瘤形状介于鼻形和楔形之间，成因和碳钢（４５钢）相似。通过切削试验，论述了切削变形规律。     

3Al2O3.2SiO2f／Al—Si复合材料磨损机理

本文通过复合材料磨面，磨屑及亚表层的ＳＥＭ特征分析，研究了３Ａｌ２Ｏ３．２ＳｉＯ２ｆ／Ａｌ－Ｓｉ复合材料的润滑衣干滑动磨损机理。润滑状态下复合材料的耐磨性大大优于Ａｌ－Ｓｉ合金，其磨损为纤维断裂与剥落及磨粒磨损；而复合材料在干滑动条件下的耐磨性反而稍差于Ａｌ－Ｓｉ合金，其磨损为粘着磨损，磨粒磨损和层离剥落。     

机械工件切削中积屑瘤问题的改善对策

在机械工件的切削过程中,被切金属层在切削刃和前刀面的作用下,受挤压而产生以剪切滑移变形为主的塑性变形,会有少量切屑分子粘结在车刀刀刃部位的边缘,从而产生坚硬的积屑瘤。因此,分析积屑瘤的产生机理、弊端以及影响积屑瘤产生的主要因素,提出了抑制和消除积屑瘤的对策,以提高机械工件的加工合格率。     

银白屑切削法和银白屑刀具

銀白屑切削法是利用积屑瘤对切削的积极作用,使之在鋼类的高速重切削中显著提高切削效率的一种新切削法。本文闡述了銀白屑切削法的机理,并具体介紹了三种銀白屑刀具。     

不同材料的椭圆振动切削特性研究

基于椭圆振动切削机理,利用Thirdwave-AdvantEdge软件研究了椭圆振动切削过程,分析了椭圆振动切削难加工材料的切削机理,比较了铝、黄铜、不锈钢、镍合金四种材料在椭圆振动切削时切屑形态、切削力和剪切变形区温度的变化。模拟发现,不锈钢的平均切削力和切削温度接近于有色金属铝和黄铜,而远低于镍合金的平均切削力和切削温度。研究结果表明,椭圆振动切削不仅可以降低难加工材料切削时的切削力和切削温度,还有利于其切屑的排除,抑制积屑瘤的产生,提高表面加工质量。     

利用导电加热切削抑制积屑瘤和鳞刺的研究

通过导电加热的温度补偿，导电加热切削能有效抑制金属切削表面的积屑瘤和鳞刺。刀－工接触区的温升与加热电流密切相关，存在一个与最佳切削温度相适应的最佳加热电流值范围。     

SiCp－A356铝基复合材料薄带的双辊铸造

采用双辊铸造设备，生产了厚为２～５０ｍｍ的ＳｉＣｐ－Ａ３５６铝基复合材料簿带，研究了搅拌工艺、薄带厚度等因素对ＳｉＣ颗粒分布、铸造缺陷和薄带力学性能的影响。结果表明，当浇注前进行搅拌，并保证一定的铸造速度时，可获得ＳｉＣ颗粒均匀分布、表面质量好的复合材料薄带。比较了双辊铸造和金属型铸造两种条件下的组织和性能。     

单晶金刚石刀具切削有色金属磨损机理研究

研究单晶金刚石刀具切削有色金属的磨损机理,分析切削过程影响加工工件表面粗糙度的影响因素和切削速度、进给量、背吃刀量等因素对积屑瘤生成的影响,以及积屑瘤对刀具切削力的影响。给出了切削过程中刀具与工件接触区温度和压力过高,导致金刚石刀具刃口发生石墨化、溶解、崩刃等磨损破损。前后刀面磨损、崩刃是金刚石刀具磨损主要形态。金刚石刀具磨损是微观磨损的不断积累,其磨损程度与磨损速度取决于金刚石碳原子在有色金属或在其它非金属材料原子中的溶解率。     

积屑瘤状态对微细切削表面轮廓特征的影响

研究了微细切削条件下,刀具前刀面上的积屑瘤状态对切削表面轮廓特征的影响,为合理选择和控制微细切削刀具的切削条件,以及评价微细切削的表面形貌特征提供实验依据.利用表面粗糙度仪分别提取了无积屑瘤、积屑瘤生长、稳定和脱落等4种积屑瘤状态下的切削表面轮廓,选取幅值密度函数(ADF)、自相关函数(ACF)和功率谱密度函数(PSD...     

Ni－SiC复合镀膜粒子与基体的高温反应

研究了Ｎｉ－ＳｉＣ复合镀膜ＳｉＣ粒子与Ｎｉ基质的高温界面反应及其对耐磨性的影响，６００℃等温，ＳｉＣ粒子只发生部分反应，首先生成过渡相Ｎｉ_５Ｓｉ_２，后为Ｎｉ_３Ｓｉ取代，形成ＳｉＣ－Ｎｉ_３Ｓｉ－ｃ膜－Ｎｉ的复合体。高温下ＳｉＣ完全分解，碳膜增厚，并生成高Ｓｉ－Ｎｉ值化合物。复合镀膜的耐磨性为高温反应所控制。     

Influence of turning parameters on the machinability of homogenized Al–Cu/TiB2 in situ metal matrix composites

The increasing demand for high-strength and lightweight materials in automobile, defense, and aerospace applications necessitates the development of new composite materials and their machinability studies with wide spectrum. In this aspect, an attempt has been made to investigate the machinability characteristics of homogenized Al–Cu/TiB₂ in situ metal matrix composites. The effect of parameters, such as cutting speed, feed, and depth of cut, on performance measures, such as cutting force and surface roughness, were investigated during turning operations. As a secondary objective, the built-up edge (BUE) and chip formation are also examined. Experimental results show that better surface finish is obtained at higher cutting speed and low feed. BUE formation is observed only at low cutting speed. The chip breakability is improved due to the presence of reinforcement.     

从材料物理冶金角度探索积屑瘤的形成

从材料物理冶金角度对机械加工中积屑瘤的形成进行探索，得出一些饶有趣味的结果，在刀／屑界面上的冷焊（粘结）是形成积屑瘤的必要而不是充分条件，积屑瘤的形成是切屑中两条主裂纹扩展的结果，而材料的第二相极大地影响主裂纹的萌生与扩展，纯金属与单相结构的合金不形成积屑瘤，机械加工中能生成积屑瘤的材料必然是有一定数量第二相结构的合金、积屑瘤内显微裂纹削弱了积屑瘤本体强度是引起周期性不稳定的重要因素。     

Slip-line modeling of built-up edge formation in machining

Extensive investigations on built-up edge (BUE) formation in machining have been conducted in the past. However, very little effort has been made to quantitatively predict the size of the BUE and its effect on chip flow and cutting forces under different machining conditions. This prediction is important because it is the key to predicting the fluctuation of cutting forces and provides better rationale for explaining various machining phenomena associated with BUE formation. A new slip-line model for machining with BUE formation and its associated hodograph are proposed in this paper. Consisting of four slip-line sub-regions, the new slip-line model meets both the stress equilibrium and velocity requirements of material flow. The new model simultaneously predicts the length and height of the BUE, cutting and thrust forces, chip up-curl radius, chip thickness, and tool–chip contact length. Dewhurst and Collins's matrix technique for numerically solving the slip-line problem is employed in the mathematical formulation of the model, with non-unique solutions being obtained. It is demonstrated that one of the four slip-line angles included in the new model directly governs the size and surface shape of the BUE. Compared with the well-known Lee and Shaffer's model, the new model predicts a much longer BUE covering a larger portion of the tool rake face. A small tool rake angle tends to generate a large BUE. The predicted trends of the variation of relevant machining parameters are consistent with experimental observations.     

THE EFFECT OF THE CUTTING FLUID ON SURFACE ROUGHNESS IN BORING OF LOW CARBON STEEL-TECHNICAL COMMUNICATION

In spite of their environmental and human health problems, the cutting fluids still have been used widely in industry due to cutting fluid application can increase cutting performance in metal cutting. In this article, the effect of the cutting fluid on surface roughness in boring of AISI 1030 low carbon steel was investigated depending on BUE and chip formations and other cutting parameters, such as cutting speed, feed rate and tool nose radius. In most of boring experiments, the wet cutting did not show more preferable results than dry cutting. However, cutting fluid application with big nose radius and small feed rate improved the surface roughness up to 80%. This progress was attributed to a favorable chip formation as much as effective cooling.     

Dry machining of aluminum for proper selection of cutting tool: tool performance and tool wear

Machining of aluminum and its alloy is very difficult due to the adhesion and diffusion of aluminum, thus the formation of built-up edge (BUE) on the surface. The BUE, which affects the surface integrity and tool life significantly, affects the service and performance of the workpiece. The minimization of BUE was carried out by selection of proper cutting speed, feed, depth of cut, and cutting tool material. This paper presents machining of rolled aluminum at cutting speeds of 336, 426, and 540 m/min, the feeds of 0.045, 0.06, and 0.09 mm/rev, and a constant depth of cut of 0.2 mm in dry condition. Five cutting tools WC SPUN grade, WC SPGN grade, WC + PVD (physical vapor deposition) TiN coating, WC + Ti (C, N) + Al₂O₃ PVD multilayer coatings, and PCD (polycrystalline diamond) were utilized for the experiments. The surface roughness produced, total flank wear, and cut chip thicknesses were measured. The characterization of the tool was carried out by a scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) pattern. The chip underface was analyzed for the study of chip deformation produced after machining. The results indicated that the PCD tool provides better results in terms of roughness, tool wear, and smoother chip underface. It provides promising results in all aspects.     

Simulation study on chip formation mechanism in grinding particle reinforced Cu-matrix composites

Based on the coupling method of finite element method and smoothed particle hydrodynamics method, the process of single abrasive grain cutting particles reinforced Cu-matrix composites with small volume fraction of particle phase is simulated, and the chip formation mechanism of particle reinforced Cu-matrix composites was analyzed. It can be concluded that the plastic removal of the Cu-matrix is still the main removal form of the composite, but the existence of the reinforced particle phase affects the cutting deformation behavior and the chip morphology. During the cutting process, the interfaces between part of reinforced particles and the Cu-matrix are broken, and resulting in the particles falling off into chips, but most of the particles will form continuous mixed chips with copper alloy, with the plastic deformation of the Cu-matrix. The extrusion of abrasive particles leads to pile-up of dislocation producing in Cu-matrix around the reinforced particle, which interferes with the continuous plastic deformation of Cu-matrix, thus affects the cutting force and cutting temperature of the abrasive grain. The simulation results show that with the increase of cutting speed, the cutting force decreases, but the cutting temperature increases. As the cutting depth increases, the cutting force and cutting temperature increase. The increase of reinforced particle content will lead to the increase of cutting force and cutting temperature.     

碳化硅增强铝基复合材料切削加工研究进展

针对近年来Si Cp/Al复合材料的切削加工研究状况,对Si Cp/Al复合材料在切削加工中的切削力、刀具磨损、表面完整性、切屑与缺陷形成机理、加工温度、仿真模拟及特种与复合加工技术等方面进行分析与总结,以便更全面地了解碳化硅增强铝基复合材料的切削加工研究进展。     

PCD刀具超声振动切削金属基复合材料SiCp/Al的特性研究

试验研究了普通和超声切削新型颗粒增强金属基复合材料SiCp/Al的切削特性 ,得到超声振动切削该材料的切屑形态、切削力变化规律     

基于MATLAB的积屑瘤图像处理与分析

在金属切削中,积屑瘤对刀具使用寿命和工件表面质量有很大的影响,应用MATLAB对由机器视觉系统获得的刀具二维图像进行边缘检测,并采用图像相减法来计算积屑瘤的面积,获得了清晰的刀具轮廓图像和积屑瘤大小随时间的变化曲线,实现了刀具积屑瘤变化的在机监测。