Al含量对Ti1-xAlxN涂层组织结构、力学性能和铣削性能的影响

目的研究不同Al含量对Ti_(1-x)Al_xN涂层的影响,以获得铣削铸铁材料性能最佳的Ti AlN涂层。方法采用阴极电弧蒸发沉积法在WC-Co硬质合金表面制备两种不同Al含量的Ti_(0.5)Al_(0.5)N和Ti_(0.33)Al_(0.67)N涂层,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电子探针微区分析仪(EPMA)分析合金的微观组织和成分组成,通过CSM纳米硬度计和纳米划痕仪测定涂层的纳米硬度、弹性模量、抗塑性变形因子、显微硬度耗散系数MDP和划痕裂纹扩展阻力CPRs等性能指标,同时比较不同Al含量涂层刀片在铣削灰口铸铁HT250和球墨铸铁QT450时的性能和磨损机理。结果 Ti_(0.5)Al_(0.5)N和Ti_(0.33)Al_(0.67)N涂层主要物相均呈NaCl型面心立方结构,以(200)方向为择优取向,且高铝涂层的XRD衍射峰向高角度偏移量大于中铝涂层,说明高铝涂层具有更高的铝固溶量。与Ti_(0.5)Al_(0.5)N涂层相比,Ti_(0.33)Al_(0.67)N涂层的抗塑性变形因子较小,MDP和CPRs较大,表现出更优的塑性、韧性和膜基结合力。在铣削HT250和QT450时,Ti_(0.33)Al_(0.67)N涂层刀片的平均寿命分别为30、60 min,相比Ti_(0.5)Al_(0.5)N涂层,切削性能更好。结论对于Ti AlN涂层来说,提高Al的质量分数至67%可以获得更优的塑性、韧性和膜基结合力,在铣削HT250和QT450时,Ti_(0.33)Al_(0.67)N涂层刀片的切削性能较优。     

Effect of WC and group IV carbides on the cutting performance of Ti(C,N) cermet tools

The effect of carbides and nitrides from group IV (ZrC, ZrN and HfC) in the periodic table on the microstructure and cutting performance of Ti(C,N)–xWC–Ni systems was examined. The WC content was varied from 5 to 20 wt.% and additive carbides or nitrides were added individually at a level of 1 wt.%. In general, inserts containing 15 wt.% WC exhibited the longest tool life for turning while those containing 20 wt.% WC showed the longest tool life for milling. When 1 wt.% ZrC, ZrN, or HfC were added to Ti(C,N)–14WC–Ni (wt.%), these cermets showed the best cutting performance among the various cermet compositions investigated in this study. The improved performance can be attributed to the low strain energy developed between the core and rim interfaces.     

Influence of substrate properties on the impact resistance of WC cermet coatings

This research delivers a generic understanding of the design and integrated performance of the coating-substrate systems under impact loading, and comprehends the understanding of underpinning failure mechanisms. Repeated severe impacts to the coatings often result in poor performance by cracking and delamination from the coating-substrate interface. The durability of coatings thus depends on the choice of coating and substrate materials, coating deposition process, and service conditions. The design of thermal spray coatings thus requires an optimization of these parameters. This investigation provides insight into the role of coating and substrate properties on the impact resistance of coated materials, and maps the relationship between the impact resistance of WC cermet coatings on a variety of substrates. Results indicate that the delamination resistance of the coating during impact loading not only depends upon the hardness and roughness of the substrate material, but, more importantly, substrates with a higher work-hardening coefficient indicate a higher delamination resistance. The original version of this paper was published as part of the DVS Proceedings: “Thermal Spray Solutions: Advances in Technology and Application,” International Thermal Spray Conference, Osaka, Japan, 10–12 May 2004, CD-Rom, DVS-Verlag GmbH, Düsseldorf, Germany.     

Machining performance of Ti-Al-Si-N coated inserts

Ti-Al-Si-N quaternary coating has recently been developed for industrial applications due to its excellent machining performance. Here, we present a comparative research on Ti-Al-N single layer, Ti-Al-Si-N single layer, TiAlN-TiAlSiN bilayer and TiAlN/TiAlSiN multilayer coatings deposited onto cemented carbide substrates by cathodic arc evaporation. The incorporation of Si into the Ti-Al-N coating results in an increase in hardness and thermal stability due to the formation of nanocomposite nc-TiAlN/a-Si₃N₄, and thereby causes an improved performance during continuous cutting. However, the lower toughness and adhesive strength with a substrate reduce its cutting-life during milling. Further optimization of Ti-Al-Si-N coated inserts during milling can be obtained by a structure adjustment from the nanocomposite into TiAlN-TiAlSiN bilayer and TiAlN/TiAlSiN multilayer coatings, which causes an increase to 156% and 172% for the life-time of Ti-Al-Si-N coated inserts, respectively. Our results indicate that the machining performance of coatings containing Si in both continuous cutting and milling can be optimized by the structure design of the TiAlN/TiAlSiN multilayer, where the coating sustains a high hardness of the Ti-Al-Si-N coating combined with a good cohesive strength with the substrate similar to the Ti-Al-N coating.     

Crater wear mechanisms of TiCN–Ni–WC cermets during dry machining

TiCN–Ni-based cermets are attractive cutting tools because of the combination of high hardness and wear resistance with improved toughness and thermal shock resistance. The present work reports the effect of WC addition (0–15 wt.%) on the machining performance of TiCN–20 wt.% Ni cermets against boiler steel. The cutting force was measured on-line using dynamometer, with respect to varying cutting speed and feed rate, in dry and orthogonal cutting conditions. The principal aim of the present investigation is to evaluate the dominant mechanisms, responsible for material removal on the rake face of cermets, using SEM–EDS. The cutting performance of TiCN–Ni cermet is observed to improve with the addition of WC content upto 10 wt.%. While, the adhesion of tribochemical layer is dominant with limited WC content, the presence of abrasive grooves and pull-outs are observed for TiCN–20Ni cermets containing higher amount of WC (>10 wt.%).     

Adherent coating on gradient cemented carbide with ultrafine Ti(C_(0.5),N_(0.5))

Gradient cemented carbide is usually employed as the substrate for coated carbide insert. In this work,gradient cemented carbide with ultrafine Ti(C_0.5,N_0.5) was prepared and its microstructure and properties were researched. Moreover, this novel substrate was coated to investigate cutting performance. It is found that the average WC grain size in the gradient zone is larger than that in the bulk. Owing to ultrafine Ti(C_0.5,N_0.5) introduction, gradient cemented carbide prepared by vacuum sintering exhibits full densification. By contrast, the gradient cemented carbide with ultrafine Ti(C_0.5,N_0.5) shows higher transverse rupture strength(TRS) and hardness than the homogenous one. Gradient cemented carbide suffers small TRS reduction after coating, and the bonding between coatings and gradient substrate is tidy and compact. The coated gradient cemented carbide shows much better endurance and impact resistance than the coated homogenous one. It confirms the superiority of gradient cemented carbide when used as the substrate for coating inserts.     

Investigation on wear behaviour of cryogenically treated TiAlN coated tungsten carbide inserts in turning

Cryogenic treatment has been ascribed as a way of improving the cutting life of tungsten carbide turning inserts. Most of the research conducted till date has not reported any effort to excavate the effect of cryogenic treatment on the performance of coated tungsten carbide inserts in terms of adhesion strength of coatings deposited on tungsten carbide substrate. In order to understand the effect of cryogenic treatment on the adhesion strength of coatings, a comparative investigation of the wear behaviour and machining performance of cryogenically treated coated tungsten carbide inserts in orthogonal turning has been carried out in this study. The commercially available TiAlN coated square shaped tungsten carbide inserts (P25) were procured and subjected to cryogenic treatment at two levels −110 °C (shallow treatment) and −196 °C (deep treatment) of temperature independently. The criterion selected for determining the turning performance was based on the maximum flank wear (0.6 mm) as recommended in ISO 3685-1993. The results showed that shallow cryogenically treated coated tungsten carbide inserts performed significantly better as compared with deep cryogenically treated and untreated inserts. Major outcome of the present study includes a substantial decrease in tool life of deep cryogenically treated inserts as compared to untreated inserts indicating the destructive effect of deep cryogenic temperature (−196 °C) on TiAlN coated inserts which is further supported by VDI-3198 indentation test.     

Micro-blasting of PVD Films, an Effective Way to Increase the Cutting Performance of Coated Cemented Carbide Tools

This paper investigates the feasibility of increasing the wear resistance of cemented carbide tools through micro-blasting of their PVD-coatings. The enhanced and graded film strength properties before and after micro-blasting are determined by means of a FEM-based evaluation of nanoindentation results. The coating topomorphy, induced by micro-blasting, was monitored and correlated to the substrate roughness and film adhesion. The cutting performance of inserts, coated with micro-blasted films, was investigated in milling and explained with the aid of a cutting process FEM simulation. The obtained results reveal a tool life growth through micro-blasting of coatings, deposited on substrates with appropriate roughness characteristics.     

Investigation on the corrosion process of carbon steel coated by HVOF WC/Co cermets in neutral solution

The corrosion protection afforded to a carbon steel substrate by two cermet coatings (WC/12 wt.% Co and WC/17 wt.% Co; 0.05, 0.01 and 0.2 mm coating thickness), applied by high velocity oxygen fuel (HVOF) technique, has been studied in 3.5% NaCl solutions. Potentiodynamic polarization curves of cermet constituents, substrate and coated samples, iron and cobalt dissolution kinetics under potentiostatic conditions and galvanic coupling tests have been carried out.Cermet layer hinders the anodic process and WC/17%Co is more protective than WC/12%Co, particularly at high coating thickness. It is likely that the increase in the matrix cobalt content changes the pore morphology, from interconnected to isolated pores, with enhanced protective efficiency.     

电弧离子镀和高功率脉冲磁控溅射AlTiN涂层及其切削性能研究

目的 比较两种沉积方法制备的AlTiN涂层的切削性能.方法 利用高功率脉冲磁控溅射技术(HiPIMS)和电弧离子镀技术(AIP),在硬质合金车刀片上沉积AlTiN涂层,比较和研究两种AlTiN涂层的组织形貌特性及综合性能.利用扫描电子显微镜和X射线能量色散谱仪,观察和检测涂层的生长形貌和元素含量.采用激光共聚焦扫描显微...     

The effect of the multi-layer surface coating of carbide inserts on the cutting forces in turning operations

In this paper, the effects of the multi-layer hard surface coating of cutting tools on the cutting forces in steel turning are presented and discussed, based on an experimental investigation with different commercially available carbide inserts and tool geometries over a range of cutting conditions. The cutting forces when turning with surface coated carbide inserts are assessed and compared qualitatively and quantitatively with those for uncoated tools. It is shown that hard surface coatings reduce the cutting forces, although the reduction is marginal under lighter cutting conditions. The cutting force characteristics for surface coated tools are also discussed and shown to have similar trends to those of uncoated tools.     

PVD涂层刀具高速铣削CoCrMo合金的性能研究

目的为了提高涂层硬质合金刀具的切削性能,研究了物理气相沉积PVD法制备的涂层硬质合金铣刀在高速干式环境下的铣削性能。方法采用阴极电弧技术制备了TiN、TiAlN以及TiAlSiN涂层硬质合金铣刀刀头,通过一同沉积涂层的硬质合金圆片,间接测量得出涂层的显微硬度、厚度和平均摩擦系数,并以CoCrMo合金为切削对象,进行了PVD涂层与无涂层刀具高速铣削下的对比试验。结果TiAlSiN显微硬度最高达3800HV,摩擦系数达0.3,TiAlN涂层平均膜厚为2μm,间接测得TiN、TiAlN以及TiAlSiN涂层的结合力依次为60、58、42N。在三者的切削性能中,TiAlSiN涂层的切削性能比TiAlN和TiN涂层的好,同等切削参数时,TiN刀具的高速铣削时间最短,TiAlSiN涂层的平均磨损值为0.1895,TiN的平均磨损值为0.3047。结论涂层中添加Al、Si,极大地提高了刀具的使用性能,改善了刀具切削过程中的耐磨性、红硬性,极大地延长了刀具的使用寿命。TiAlSiN涂层的硬度高,耐磨损性好,切削性能好,适合高速铣削加工。     

Effect of the crystallinity of diamond coatings on cemented carbide inserts on their cutting performance in milling

Micro-crystalline diamond (MCD) coatings were deposited on cemented carbide inserts at different temperatures using hot filament chemical vapor deposition technique. For investigating the effect of the developed diamond crystallinity on the fatigue strength and wear behaviour of the prepared MCD coated inserts, inclined impact tests and milling investigations were conducted correspondingly. Raman spectra were recorded for capturing the crystalline phases after the film deposition and their potential changes after the impact and milling experiments induced by the mechanical and thermal loads. Thus, the explanation of the cutting performance of the employed diamond coated inserts with various crystalline phases was enabled.     

Wear behavior of adaptive nano-multilayered TiAlCrN/NbN coatings under dry high performance machining conditions

Application of quaternary nitride nano-multilayered coatings results in significant improvements in tool life as well as wear behavior of ball nose end mills under severe conditions of dry high speed machining of hardened H13 steel (HRC 55-57). Tool life of different nano-multilayered TiAlCrN-based coatings with addition of transitional metals based (of V and VI groups) nitride layers has been compared. Tool life of TiAlCrN/NbN coating was found to be higher than compared to the other nano-multilayered coatings. Investigation of surface structure characteristics of the TiAlCrN/NbN coating using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and High Resolution Electron Energy Loss Spectroscopy (HREELS) has been performed. The properties of the coatings such as microhardness, modulus of elasticity, coefficient of friction and oxidation stability at elevated temperatures were also studied. Cutting forces at the tool/workpiece interface have been measured in-situ. Temperatures on the surface of cutting tools were evaluated. The features of friction and wear behavior as well as mechanisms of tribo-adaptation of TiAlCrN/NbN nano-multilayered coatings were outlined.     

含有金属黏结相的热喷涂WC涂层在盐雾中的腐蚀行为

研究黏结相化学成分对涂层材料的耐盐雾腐蚀性能的影响,对采用超音速火焰喷涂制得的WC?17Co和WC?10Co?4Cr涂层进行电化学试验和长时间的盐雾腐蚀实验(浓度为5%的NaCl溶液,温度35°C)。结果表明：WC?10Co?4Cr涂层的耐盐雾腐蚀性能优于WC?17Co涂层。对于WC?17Co涂层,主要腐蚀行为除了粘结金属的腐蚀外还包括WC颗粒与粘结相金属之间发生的微点偶腐蚀;对于WC?10Co?4Cr涂层,形成的氧化物有利于抑制金属相与粘结相的腐蚀。说明金属材料成分是影响超音速火焰喷涂WC基涂层耐盐雾腐蚀性能的重要因素之一。     

粉末结构对超音速火焰喷涂WC系金属陶瓷涂层结合强度的影响

采用４种典型的ＷＣ系硬质合金粉末与Ｗ－Ｎｉ复合粉末,研究了粉末结构、粘结相的成分与含量,以及超音速火焰喷涂（ＨＶＯＦ）条件对涂层结合强度的影响。结果表明：对于具有高熔点的ＷＣ及Ｗ颗粒构成的复合粉末,ＨＶＯＦ涂层的结合强度大于结胶的强度,几乎不受粉末结构和粘结相成分的影响。试验表明：喷涂料子具备液固两个相结构是ＨＶＯＦ涂层获得高结合强度的必要条件,而ＷＣ与Ｗ的高密度是保证ＨＶＯＦ涂层高结合强度的充分     

Cutting performance of coated tools with various adhesion strength quantified by inclined impact tests

Coated tools with PVD-films of almost the same mechanical properties may perform differently. This effect can be attributed to the film adhesion. For highlighting this phenomenon, the adhesion of coatings with practically identical mechanical properties deposited on cemented carbide and powder metallurgical high speed steel inserts was quantified by FEM-based evaluations of inclined impact test and nano-indentation results. Moreover, the films’ mechanical properties were assessed by repetitive nano-impacts. Based on these data and on FEM calculations of the cutting process, the coated tools cutting performance was explained in all investigated material and interrupted cutting process cases.     

SiC晶须增韧WC陶瓷刀具材料的研究

通过正交试验法对WC/SiCw陶瓷复合材料进行了成分和热压工艺参数优化,经优化制备的该类复合材料与纯WC材料相比,弯曲强度提高了约50%,断裂韧性提高了30%￣40%,维氏硬度提高了10%￣15%。切削试验表明,本试验制得的WC/SiCw复合陶瓷刀具材料的车削性能优于同类型硬质合金材料,表明通过SiCw替代金属粘结相来增韧补强WC陶瓷刀具材料的方法是可行的。     

Applications of Cr-Based Metal Nitride Hard Coatings Using Multi-Magnetron Sputtering Sources and Elemental Metal Targets

METAL NITRIDE or carbide coatings on cutting toolsare effective ways of improving tool performance.Thedriving force for high productivity and precision inmetal machining has led to the requirement of acontinual improvement of conventional hard coatings.It is necessary that those attractive properties of hardcoatings could be simultaneously retained.Highhardness resists abrasive wear.High chemical orthermal stability reduces dissolution wear andmaintains physical properties at a high tempe…     

Properties of TiAlCrN coatings prepared by vacuum cathodic arc ion plating

TiAlCrN coatings were deposited by means of vacuum cathodic arc ion plating technique on TC11 (Ti-6.5 Al-3.5 Mo-1.5 Zr-0.3Si) titanium alloy substrates. The composition, phase structure, mechanical performance, and oxidation-resistance of the nitride coatings were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), auger electron spectroscopy (AES), and X-ray photoelectron microscopy (XPS). A new process for preparing protective coatings of the titanium alloy is successfully acquired. The experimental results indicate that the added element chromium in the TiAlN coatings make a contribution to form the (220) preferred direction. The phases of the coatings are composed of (Ti, Al)N and (Ti, Cr)N. After 700℃ and 800℃ oxidation, AES analysis shows that the diffusion distribution of the TiAlCrN coatings emerges a step shape. From the outside to the inner, the concentrations of O, Al, and Cr reduce, but those of Ti and N increase. The Al-rich oxide is formed on the surface of the coatings, and the mixed structure of Ti-rich and Cr-rich oxides is formed in the internal layer. The oxidation resistance of the TiAlCrN coatings is excellent at the range of 700 to 800℃. Adhesion wear is the dominant mechanical characteristic for the titanium alloy at room temperature, and the protective coatings with high hardness can improve the mechanical properties of the titanium alloy. The wear resistance of the TC11 alloy is considerably improved by the TiAlCrN coatings.