Multiscale Simulation of Microstructure Evolution during Preparation and Service Processes of Physical Vapor Deposited c-TiAlN Coatings

Physical Vapor Deposited(PVD)TiAlN coatings are extensively utilized as protective layers for cutting tools,renowned for their excellent comprehensive performance.To optimize quality control of TiAlN coatings for cutting tools,a multi-scale simulation approach is proposed that encompasses the microstructure evolution of coatings considering the entire preparation and service lifecycle of PVD TiAlN coatings.This scheme employs phase-field simulation to capture the essential microstructure of the PVD-prepared TiAlN coatings.Moreover,cutting simulation is used to determine the service temperature experienced during cutting processes at varying rates.Cahn-Hilliard modeling is finally utilized to consume the microstructure and service condition data to acquaint the microstructure evolution of TiAlN coatings throughout the cutting processes.This methodology effectively establishes a correlation between service temperature and its impact on the microstructure evolution of TiAlN coatings.It is expected that the present multi-scale numerical simulation approach will provide innovative strategies for assisting property design and lifespan prediction of TiAlN coatings.

Microstructure and mechanical properties of TiN/TiAlN multilayer coatings deposited by arc ion plating with separate targets

TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. The results show that the output plasmas of titanium target without filter and aluminium target with filter reach the substrate with the same order of magnitude. Meanwhile, the number of macropartieles in TiN/TiAlN multilayer coatings deposited with separate targets is only 1/10-1/3 of that deposited with alloy target reported in literature. Al atom addition may lead to the decrease of peak at （200） lattice plane and strengthening of peak at （111） and （220） lattice planes. The measured hardness of TiN/TiAlN multilayer coatings accords with the mixture principle and the maximum hardness is HV2495. The adhesion strength reaches 75 N.

Structure and wear resistance of TiN and TiAlN coatings on AZ91 alloy deposited by multi-arc ion plating

In order to investigate the microstructure of TiN and TiAlN coatings and their effect on the wear resistance of Mg alloy, TiN and TiAlN coatings were deposited on AZ91 magnesium alloy by multi-arc ion plating technology.TiN and Ti70Al30N coatings were prepared on the substrate,respectively,which exhibited dark golden color and compact microstructure.The microstructures of TiN and Ti70Al30N coatings were investigated by X-ray diffractometry(XRD)and scanning electron microscopy(SEM).The micro-hardness and wear resistance of TiN and Ti70Al30N coatings were investigated in comparison with the uncoated AZ91 alloy. The XRD peaks assigned to TiN and TiAlN phases are found.The hardness of TiN coatings is two times as high as that of AZ91 alloy, and Ti70Al30N coating exhibits the highest hardness.The wear resistance of the hard coatings increases obviously as result of their high hardness.

Microstructures and properties of PVD TiAlN coating deposited on cermets with different Ti(C,N)grain size

In the present work,TiAlN coatings were deposited on Ti(C,N)-based cermet substrates by physical vapor deposition method.Emphasis was focused on the influence of grain size of cermet substrates on the microstructure,growth behavior,mechanical properties,adhesion strength and wear behavior of the coatings.The results show that finer Ti(C,N)grain size leads to higher nucleation density and lower growth rate of coatings,indicating the crystallite size of the TiAlN coatings decreases with decreasing Ti(C,N)grain size.Nanoindentation tests show that the coatings deposited on cermets of the finest grain size exhibit the highest hardness(H),elastic modulus(E),H/E and H3/E2 of 34.5 GPa,433.2 GPa,0.080 and 0.22,respectively.The adhesion strength between coating and substrate is also enhanced with decreasing Ti(C,N)grain size by scratch test,which corresponds to the grain size and H/E and H3/E2 of the coating.Besides,the lower surface roughness and better mechanical properties of the coating deposited on finer grained cermet contribute to the better wear resistance of the coating.

Effect of cermet substrate characteristics on the microstructure and properties of TiAlN coatings

The composition and structure of substrate materials have important influences on coating performance,especially in terms of bond-ing strength and coating hardness,which determine whether the coating can be used for a given application.In this study,a TiAlN coating is deposited on Ti(C,N)-based cermet(TC)substrates with 0wt%-20wt%WC by arc ion plating.The influence of cermet substrate characterist-ics on the structure and properties of the TiAlN coating is then researched.Results show that the TiAlN coating deposited on the TC substrate has a columnar grain structure.As WC increases,the strength ratio of I(111)/I(200)and adhesive strength of TiAlN gradually increases.In the ab-sence of WC in the substrate,the preferred orientation of the TiAlN coating is(200).As WC increases,the preferred orientation of the TiAlN coating becomes(111)and(200).Notable differences in adhesive strength between the coating and substrate could be attributed to the micro-structure and composition of the latter.Scratching results show that the adhesive strengths of the TiAlN coating on the 0wt%-20wt%WC cer-met substrate are 52-65 N.Among the coatings obtained that on the TC substrate with 15wt%WC presents the highest H/E and H3/E2,which indicates that this coating also features the best wear resistance.The failure mechanisms of the coated tools include coating peeling,adhesive wear,and abrasive wear.As the cutting speed increases,the degree of flank wear increases and the durability of the coating decreases accord-ingly.Increases in WC result in an initial decrease followed by a gradual increase in the flank wear of the coated cermet inserts.

AFM Analysis of TiN, TiAlN, and TiAlSiN Coatings Prepared by Cathodic Arc Ion Plating

The TiN, TiAlN, and TiAlSiN coatings were prepared on YT14 cutting tool surface with CAIP（cathode arc ion plating）, the surface morphologies and phases were analyzed with FESEM（field emission scanning electron microscopy）, and XRD（X-ray diffraction）, respectively, and the coating parameters such as 3D surface micro-topography, grain size, surface height, hierarchy, profile height, and power spectral density, etc, were measured with AFM（atomic force microscope）. The results show that the phases of TiN, TiAlN, and TiAlSiN coatings are TiN, TiN＋TiAlN, TiN＋Si_3N_4＋TiAlN, respectively, while the surface roughness Sa of TiN, TiAlN, and TiAlSiN coatings is 75.3, 98.9, and 42.1 nm, respectively, and the roughness depth Sk is 209, 389, and 54 nm, respectively, the sequence of average grain sizes is TiAlN〉TiN〉TiAlSiN. The surface bearing index Sbi of TiN, TiAlN, and TiAlSiN coatings is 0.884, 1.01, and 0.37, respectively, and the sequence of surface bearing capability is TiAlN〉TiN〉TiAlSiN. At the lower wavelength（102-103 nm）, the power spectral densities have a certain correlation, and the sequence of TiN〉TiAlN〉TiAlSiN, while the correlation is low at the higher wavelength（〉103 nm）.

Effect of pulsed electromagnetic frequency on the microstructure, wear and solid erosion resistance of CrAlN coatings deposited by arc ion plating

In this work,the chromium aluminum nitride(CrAlN)coatings were prepared on TC11 titanium alloy by composite magnetic field cathodic arc ion plating with controllable pulse electromagnetic combined with permanent magnet.The effects of electromagnetic frequency on the morphology,microstructure,nano-hardness and elastic modulus of the coatings were investigated by scanning electron microscope(SEM),X-ray diffraction(XRD)and nano-indenter.This paper has mainly studied the influence of CrAlN coatings which are prepared at various electromagnetic frequencies on the wear and erosion resistance through a series of wear and solid particle erosion experiments.It was found that the deposition rate of CrAlN coatings increases with the increase of electromagnetic frequency.And CrAlN coatings all preferentially grew along the(111)crystal plane.At 16.7 Hz,with the increase of pulsed electromagnetic frequency,the hardness is the highest(23.6 GPa)and the adhesion is the highest(41.5 N).In addition,the coating deposition exhibited the best wear and solid erosion resistance at 16.7 Hz and 33.3 Hz,the friction coefficient is about 0.35,and the erosion rate is about 0.2μm/g at 30°and less than 1μm/g at 90°,respectively.These results indicate that the CrAlN coating formed at an appropriate pulsed electromagnetic frequency can achieve excellent mechanical properties,wear and solid erosion resistance.

Effect of bias voltage on microstructure,mechanical and tribological properties of TiAlN coatings

TiAlN multilayer coatings composed of TiAl and TiAlN layers were deposited on ZL109 alloys using filtered cathodic vacuum arc(FCVA)technology.The effect of bias voltage on the microstructure and properties of the coating was systematically studied.The results show that the coating exhibits a multi-phase structure dominated by TiAlN phase.As the bias voltage increases,the orientation of TiAlN changes from(200)plane to(111)plane due to the increase of atomic mobility and lattice distortion.The hardness,elastic modulus and adhesion of the coating show the same trend of change,that is,first increase and then decrease.When the bias voltage is 75 V,the coating exhibits the highest hardness(~30.3 GPa),elastic modulus(~229.1 GPa),adhesion(HF 2)and the lowest wear rate(~4.44×10^(−5)mm^(3)/(N·m)).Compared with bare ZL109 alloy,the mechanical and tribological properties of TiAlN coated alloy surface can effectively be improved.

TiAlN/CrAlN纳米结构多层膜的结构与性能

采用射频磁控溅射方法制备了单层TiAlN、CrAlN复合薄膜以及不同调制周期和不同层厚比(lTiAlN/lCrAlN)的TiAlN/CrAlN纳米结构多层膜。薄膜采用X射线衍射仪、扫描电子显微镜、显微硬度仪进行表征。结果表明:TiAlN、CrAlN复合薄膜和TiAlN/CrAlN多层膜均为面心立方结构,呈(111)面择优取向。TiAlN/CrAlN多层膜的择优取向与调制周期和层厚比无关。层厚比为1的TiAlN/CrAlN多层膜的硬度依赖于调制周期,在调制周期为8nm时,达到最大;固定TiAlN的厚度为4nm,改变CrAlN层的厚度,在研究范围内,多层膜的硬度随着CrAlN层厚度的增加而增加。探讨了多层膜的致硬机制。TiAlN/CrAlN多层膜抗氧化温度比其组成单层膜高了近200℃,并讨论了其抗氧化机制。

H13表面TiAlN/CrAlN复合涂层的摩擦磨损性能研究

采用真空电弧离子镀工艺在H13钢表面制备Ti Al N/Cr Al N复合涂层,利用划痕试验仪、盘式摩擦磨损试验机、金相显微镜和努氏硬度计分析Ti Al N/Cr Al N膜层的结合力和摩擦学性能,金相组织形貌和试样表面的显微硬度。结果表明,Ti Al N/Cr Al N复合薄膜表面组织分布均匀,结合致密,涂层与基体间的结合力是影响涂层承载能力的主要因素之一,Ti Al N复合涂层的摩擦性能优于H13基体和Cr Al N复合涂层的摩擦性能,Ti Al N/Cr Al N复合涂层的结合力分别为35 N和24 N,沉积有Ti Al N涂层试样表面摩擦系数最小,减摩效果最好,耐磨性能优越,并能有效地抵抗摩擦磨损。

Effect of 10% Si addition on cathodic arc evaporated TiAlSiN coatings

The effect of 10% Si （mole fraction） addition on TiAlSiN coatings was studied. Ti0.5Al0.5N, Ti0.5Al0.4Si0.1N and Ti0.55Al0.35Si0.1N coatings were deposited on WC？Co substrates by cathodic arc evaporation. The microstructure and mechanical properties were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, nano-indentation measurement and scratch test. The mechanisms of how Si affects the properties and failure modes of TiAlSiN coatings were also discussed. The results show that the addition of 10% Si results in the formation of nc-（Ti,Al,Si）N/a-Si3N4 nano-composite structure. The hardness and toughness of TiAlSiN coatings increase, whereas the coating adhesion strength decreases. Compared with Ti0.55Al0.35Si0.1N coating, Ti0.5Al0.4Si0.1N coating has higher hardness but lower toughness. The dominant failure mode of TiAlN coating is wedging spallation due to low toughness and strong interfacial adhesion. The dominant failure mode of TiAlSiN coatings is buckling spallation due to improved toughness and weakened interfacial adhesion.

TiAlN,CrAlN和TiCrN涂层的制备及摩擦学性能研究

运用直流和射频磁控共溅射的方法制备TiAlN、CrAlN和TiCrN3种涂层,研究涂层的力学性能及在空气和水基切削液中的摩擦学性能,揭示其磨损机制。研究发现,Al元素主要以固溶体形式存在于TiAlN和CrAlN涂层内;3种涂层的显微硬度分别为HV719.3、HV1022.5和HV973.5。在空气中TiAlN、CrAlN和TiCrN涂层与SUS440C钢球对摩的稳态摩擦因数分别为1.25、1.14和1.31,TiAlN和CrAlN涂层的磨损机制主要是氧化磨损,而CrTiN涂层以磨粒磨损为主;而在水基切削液中3种涂层与SUS440C钢球对摩的摩擦因数明显降低,其对应的稳态摩擦因数分别为0.44、0.47和0.77,但磨痕上的划痕加剧,其磨损机制以磨粒磨损为主。

65Mn钢表面溅射TiAlN和CrAlN复合膜制备及性能研究

采用磁控溅射在65Mn钢基体表面分别制备了不同Al含量（臆40at%）的TiAlN和CrAlN复合膜,研究了Al含量对TiAlN和CrAlN复合膜性能的影响,并对溅射前后摩擦磨损性能进行了对比。采用X射线衍射、扫描电镜、能谱仪（EDS）、纳米硬度仪和高温摩擦磨损试验机,系统分析了Al含量对TiAlN和CrAlN复合膜微结构、力学性能和高温摩擦磨损性能的影响。结果表明,复合膜均为面心立方结构,且呈（111）择优取向生长。随Al含量增加,晶格常数逐渐减小,而硬度逐渐增大。室温下材料的摩擦因数为0.6~0.7,300℃条件下摩擦因数为0.6~0.8,600℃条件下摩擦因数为0.4~0.9;表面溅射Ti0.6Al0.4N和Cr0.62Al0.38N后,其室温耐磨性分别是65Mn钢的1.7倍和2.0倍,300℃下耐磨性分别为65Mn钢的2.7倍和3.0倍,600℃下耐磨性分别为65Mn钢的3.5倍和4.0倍。

基于X射线反射研究溅射工艺对CrAlN/TiAlN周期膜界面结构的影响

为研究X射线反射技术在纳米多层膜界面微结构表征中的应用,采用反应磁控溅射技术在单晶硅基片上制备CrAlN/TiAlN纳米周期膜,利用X射线反射技术系统研究溅射工艺参数对CrAlN/TiAlN纳米周期膜界面微结构的影响规律。结果表明:增加铝靶功率可提高膜层的溅射速率和降低膜层的界面粗糙度,然而较高的铝靶功率会使膜层界面出现严重的弥散;较大和较小的负偏压都不利于形成完整的周期膜调制结构和光滑的界面;提高Ti/Cr靶电流可有效改善周期膜的调制界面结构,但太大的靶电流会导致膜层间扩散加重,形成弥散界面。N2流量与Ar流量对膜层界面粗糙度具有相反的影响作用。试验得到的优化工艺参数为:铝靶功率80W,溅射负偏压-200 V,Ti/Cr靶电流0.2A,N2流量30cm^3/min,Ar流量10cm^3/min。

CrAlN/TiAlN纳米多层膜界面结构的中子与X射线反射研究

采用反应磁控溅射技术在单晶硅基片上制备了CrN纳米单层膜和CrAlN/TiAlN纳米周期膜,利用非极化中子和X射线反射对膜层厚度、膜层界面粗糙度、界面扩散等表面、界面结构和性质进行了系统研究。中子反射测得的CrN纳米单层膜和CrAlN/TiAlN纳米周期膜的厚度与设计厚度的差别为3.8%~4.2%。散射长度密度（SLD）分析结果表明,膜层间和膜层与基底间界面较为清晰,扩散较少。X射线反射测得的膜层厚度较中子反射测得的膜层厚度偏高,对于较小调制周期的多层膜,界面弥散会对X射线反射结果产生较大误差。

MICROSTRUCTURAL CHARACTERISTICSAND OXIDATION BEHAVIOR OFTi_(1-x)Al_xN PVD-COATINGS

Recent research on microstructural characteristics and oxidation behavior of Ti(1-x)AlxN thin film were surveyed. The Ti(1-x)AlxN coatings have three different phase regions, Bl structure for lower x value, wurtzite structure for higher x value and unidentified structure for medium x value. Based upon the selective oxidation mechanism the oxidation results of Ti(1-x)AlxN thin film with different Ti/Al ratio were predicated.

含过渡层TiAlN和CrAlN硬质膜的制备及其抗氧化性能研究

采用磁控溅射技术制备TiAlN、CrAlN及含Ti、Cr过渡层的TiAlN、CrAlN四种薄膜,并对其进行850℃大气热处理实验,通过激光共聚焦显微镜、纳米压痕仪对热处理后的试样进行测试。表征结果显示:热处理后的TiAlN薄膜及含有Ti过渡层的TiAlN薄膜硬度及弹性模量都大幅降低,前者比后者的表面粗糙度小、抗氧化性能更优;热处理后CrAlN薄膜的硬度和弹性模量大幅下降,而含Cr过渡层的CrAlN薄膜热处理后的硬度、模量相对较高,表面粗糙度也相对较小。

CrN/TiAlN多层涂层的微观结构和摩擦磨损性能

特种装备车辆往往在高速、高冲击等复杂环境下运行,底盘选装密封件表面容易被磨损造成密封失效,在密封工作面制备硬质涂层是提高服役寿命、延长维修周期的重要方法。采用物理气相沉积法在45#钢表面制备单层CrN涂层和不同过渡层厚度的多层CrN/TiAlN涂层,用X射线衍射仪、扫描电子显微镜、表面轮廓仪、纳米压痕仪和往复式摩擦磨损试验机,研究涂层的微观结构、机械性能和摩擦磨损性能。结果表明单层CrN涂层厚度为0.87μm,其硬度和模量最小为19.49 GPa和160.53 GPa。CrN/TiAlN多层涂层的硬度和模量明显提高,且随过渡层厚度增加而增大,4CrN/TiAlN涂层的硬度和模量可达到39.86 GPa和386.72 GPa。在空气环境下的摩擦磨损试验中,单层CrN涂层被快速破坏;CrN/TiAlN多层涂层的平均摩擦因数随着过渡层厚度的增加先增大后减小,最大磨损深度和磨痕截面积不断下降。4CrN/TiAlN涂层具有最优摩擦磨损性能,其平均摩擦因数为0.792 5,磨痕截面积为315.09μm^(2),磨损机理为磨粒磨损和少量粘着磨损。提高过渡层厚度能够降低基体的塑性变形,降低涂层与基体的物理性能差异,减少涂层开裂并提高涂层摩擦磨损性能。通过调控过渡层厚度获得性能优异的CrN/TiAlN多层涂层,研究成果可应用于车辆旋转密封件上,显著提高密封工作面耐磨损性能。

表面等离子渗氮对TiAlN涂层TiCN基金属陶瓷性能的影响

针对TiCN基金属陶瓷,调节不同N_(2)/Ar流量比对其进行等离子渗氮,并在渗氮样品表面沉积TiAlN涂层。采用GIXRD、EDS、SEM、HR-TEM、划痕测试、纳米压痕测试和光学图像测试仪等研究了渗氮过程N_(2)/Ar流量比对涂层组织结构、膜基界面状态、力学性能和涂层金属陶瓷刀片切削性能的影响。结果表明,随着N_(2)/Ar流量比的提高,TiAlN涂层晶粒逐渐细化,涂层厚度不断降低,基体表面仍有黏结相残留,进而影响表面涂层的生长和性能。当N_(2)/Ar流量比为1时,膜基界面处存在硬质相生长区和富黏结相生长区两种涂层生长区域,涂层在硬质相表面为共格外延生长,富黏结相区域存在原子排列紊乱的过渡区,涂层为半共格外延生长;涂层(200)晶面取向最强,织构系数为1.91;涂层硬模比(H/E)最高,为0.094。当N_(2)/Ar流量比为2时,TiAlN涂层的硬度和弹性模量均最高,分别为34.15GPa和416.64GPa。在切削加工过程中,切削接触区域主要发生磨粒磨损和粘着磨损。当N_(2)/Ar流量比为1时,涂层TiCN基金属陶瓷刀片切削性能最佳。

TiAlN/Cr、TiAlN/CrN和TiAlN/CrAlN多层涂层的热盐腐蚀行为

钛合金的热盐腐蚀问题已引起人们的广泛关注,金属氮化物防护涂层是延长钛合金服役寿命的有效途径.采用多弧离子镀技术在钛合金表面沉积了TiAlN/Cr涂层、TiAlN/CrN涂层、TiAlN/CrAlN-5涂层和TiAlN/CrAlN-10涂层.通过扫描电子显微镜(SEM)、能量色散谱仪(EDS)、X射线衍射仪(XRD)、划痕测试仪、3D激光显微镜等测试手段对比研究了4种多层涂层的热盐腐蚀行为,分析了涂层热盐腐蚀前后的微观形貌和物相成分.结果表明:Al元素的添加和调制周期的优化可以提高涂层的致密性,改善涂层表面质量.其中TiAlN/CrAlN-10多层涂层由于界面密度高,表现出优异的耐热盐腐蚀性能.