基体负偏压对TiAlN/TiN膜层组织成分及硬度的影响

采用多弧离子镀技术在40Cr基体上制备TiAlN/TiN复合膜层;利用金相显微镜、扫描电子显微镜和显微硬度仪研究基体负偏压对膜层硬度的影响.结果表明:基体负偏压对膜层性能有显著影响,过高或过低的基体偏压会使得膜层表面不平整,表面显微硬度降低.基体负偏压越高,膜层中Ti、Al原子的含量就越低.     

High temperature sliding wear behaviors of ion plating TiN composite coating with ion nitriding as interlayer on hot work die steel

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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.     

不同厚度TiN和TiAlN涂层残留应力分析

TiN和TiAlN涂层常应用于精冲模,采用XRD技术分析了不同厚度TiN和TiAlN涂层的相变化,并采用Sin2ψ法测量了TiN涂层和基体以及TiAlN基体的残留应力,应用显微硬度计测量了涂层的显微硬度。结果表明:TiN涂层(111)和(222)晶面存在明显择优取向,涂层残留应力分布在-2 347～-1 920MPa,基体残留应力分布在-154.9～-69.21 MPa,均随厚度增加而减小;TiAlN涂层主要相成分为Ti3Al3N2,且(107)晶面存在择优取向,基体残留应力分布在-123.7～469.5 MPa,主要呈拉应力状态,且随厚度增加而增大,对模具寿命有较大影响;TiN和TiAlN涂层显微硬度随厚度增加而增大。     

Tribology of nitriding layer, TiN coatings and their complex on AISI D2 steel

The sliding wear and impact wear resistances of D2 steel with nitriding layer, PVD titanium nitride coating and their duplex treatment were investigated. The experimental results suggest that the duplex treatment has the best sliding and impact wear resistances under experimental conditions. And the wear resistance of PVD titanium nitride is better than that of nitriding. The impact wear resistance and wear mechanism of all three surface layers remain unchanged under impact load of 0.2 J or 1 J. All samples end with the same symptom of flaking.     

Tribological properties of duplex treated TiN/TiCN coatings on plasma nitrided PH15-5 steel

Nitriding was carried out in low pressure plasma excited by single- or dual-frequency discharge modes, at a substrate temperature of 523 K, followed by the deposition of 3 μm thick TiCN or TiN/TiCN coatings at a PH15-5 substrate temperature of 723 K. The nitrided layer was comprised of two distinct sublayers, namely a compound layer and a diffusion layer, with a total thickness of ∼ 60 μm. The compound layer was γ′-Fe₄N and the diffusion layer was a solid solution of nitrogen in iron. The thickness of the compound layer fabricated by a single mode plasma is ∼ 5 μm, while that fabricated by dual-frequency mode plasma is ∼ 35 μm.It was found, using a ball-on-disk test, that the plasma nitrided layer fabricated by dual-frequency mode improved wear resistance by nearly one order of magnitude and improved the erosion resistance by a factor of two, compared with untreated steel. This improvement was common to the two nitriding treatments and both types of hard coatings. In particular, a thicker compound layer did not impair the wear resistance or the erosion resistance of the duplex treatment. The erosion resistance shows a linear dependence on the hardness of the uppermost nitrided or deposited layer.     

Fretting wear behavior of Ti/TiN multilayer film on uranium surface under various displacement amplitudes

Ti/TiN multilayer film was deposited on uranium surface by arc ion plating technique to improve fretting wear behavior. The morphology, structure and element distribution of the film were measured by scanning electric microscopy (SEM), X-ray diffractometry (XRD) and Auger electron spectroscopy (AES). Fretting wear tests of uranium and Ti/TiN multilayer film were carried out using pin-on-disc configuration. The fretting tests of uranium and Ti/TiN multilayer film were carried out under normal load of 20 N and various displacement amplitudes ranging from 5 to 100 μm. With the increase of the displacement amplitude, the fretting changed from partial slip regime (PSR) to slip regime (SR). The coefficient of friction (COF) increased with the increase of displacement amplitude. The results indicated that the displacement amplitude had a strong effect on fretting wear behavior of the film. The damage of the film was very slight when the displacement amplitude was below 20 μm. The observations indicated that the delamination was the main wear mechanism of Ti/TiN multilayer film in PSR. The main wear mechanism of Ti/TiN multilayer film in SR was delamination and abrasive wear.     

脉冲偏压占空比对TiN/TiAlN多层薄膜微观结构和硬度的影响

目的研究脉冲偏压占空比对TiN/TiAlN多层薄膜微观结构和硬度的影响规律。方法利用脉冲偏压电弧离子镀的方法,改变脉冲偏压占空比,在M2高速钢表面制备5种TiN/TiAlN多层薄膜,对比研究了薄膜的微观结构、元素成分、相结构和硬度的变化规律。结果 TiN/TiAlN多层薄膜表面出现了电弧离子镀制备薄膜的典型生长形貌,随着脉冲偏压占空比的增加,薄膜表面的大颗粒数目明显减少。此外,脉冲偏压占空比的增加还引起多层薄膜中Al/Ti原子比的降低。结论 TiN/TiAlN多层薄膜主要以(111)晶面择优取向生长,此外还含有(311),(222)和(200)晶相结构。5种多层薄膜的纳米硬度均在33GPa以上,当脉冲偏压占空比为20%时,可实现超硬薄膜的制备。     

High temperature wear and friction properties of duplex surface treated bearing steels

Duplex treatments by thermo reactive diffusion (TRD) chromizing and puls plasma nitriding were carried out on AISI 52100 and 8620 bearing steels. Tribological behaviors of TRD chromized and duplex treated bearing steels were investigated against Al₂O₃ ball in ball-on-disc system at room temperature and 500 °C. The samples were pack chromized in a furnace at temperature of 1000 °C for 5 h. After chromizing, the samples were puls plasma nitrided for 5 h at 500 °C. The coated steels were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scratch and microhardness testing. Plasma nitriding of chromized steels increased the total thickness of the compound layer. The subsequent plasma nitriding increased the surface hardness to 2135 HK_0.025 due to the formation of CrN and Cr₂N. The surface hardness and scratch resistance of coating can be increased with duplex treatment of chromizing followed by plasma nitriding, resulting in high wear resistance. Tribological tests indicated that puls plasma nitriding process decreased the coefficient of friction values and wear rate of the chromized steels at room temperature and 500 °C. Also, examination of the worn surface of the samples showed that particularly at high temperature, the oxidized compact layer occurs and tribo-oxidation played an important role in oxidation behaviour of the steels after the duplex treatment.     

TiN/TiSiN多层膜高温微动磨损特性

采用高精度PLINT高温微动磨损试验机研究了690合金及其表面等离子体化学气相沉积(PCVD)制备TiN/TiSiN多层膜的高温微动磨损特性。结果表明,试验温度（25、200、300 ℃）下TiN/TiSiN多层膜XRD未检测出氧化物,TiN/TiSiN多层膜的硬度和临界载荷分别为2318 HV0.05、57 N。690合金在200 ℃时的摩擦系数、磨损体积均高于室温和300 ℃下的值。TiN/TiSiN多层膜的摩擦系数在200 ℃时最大,在室温时最低;TiN/TiSiN多层膜磨损体积受温度影响较小。相同试验条件下,TiN/TiSiN多层膜摩擦系数和磨损体积均低于690合金,TiN/TiSiN多层膜能有效减低基材的微动损伤。室温时,690合金磨损机制为磨粒磨损和剥层;200 ℃时为磨粒磨损、剥层和氧化磨损;300 ℃时为磨粒磨损和氧化磨损。试验温度下,TiN/TiSiN多层膜的磨损机制均为剥层。     

TiN/TiAlN涂层Ti(C,N)基金属陶瓷刀具的切削性能

采用多弧离子镀技术在Ti(C,N)基金属陶瓷基体上沉积了TiN/TiAlN多层涂层,通过扫描电镜、涂层附着力自动划痕仪对其显微组织形貌和涂层的结合强度进行了分析,并对涂层和未涂层金属陶瓷铣刀以及硬质合金铣刀进行了切削0Cr18Ni9钢的试验.结果表明,多弧离子镀TiN/TiAlN涂层均匀,TiN/TiAlN多层涂层与金属陶瓷之间的结合强度高达57.52 N.TiN/TiAlN涂层金属陶瓷的切削性能明显优于未涂层金属陶瓷和硬质合会YW2,其平均寿命为硬质合金刀具的2倍.TiN/TiAlN涂层金属陶瓷刀具的失效形式主要是磨损和崩刃,没有涂层剥落现象,TiN/TiAlN涂层与基体的结合强度很好.未涂层金属陶瓷刀具的磨损形式主要是磨损和粘着.     

A study on the wear behavior of hardened medium carbon steel

It is well known that the mechanical properties such as strength and hardness of structural steel are usually enhanced by the martensite-phase transformation method. In many industrial applications, hardness has always been used as an index to reflect the wear-resistance performance. As a result, steel is quenched to a large extent in order to increase the hardness and wear-resistance performance. In general, from the wear mechanism, no exact relationship between the hardness and wear resistance of materials can be formulated. Also there are few conclusive studies on the effects of running procedures on wear-resistance performance. Therefore, the friction behavior of S45C carbon steel with and without a quenching process was evaluated by a rotating tribometer under various test conditions. The experimental results show that the running conditions cause a great influence on the wear-resistance performance of the materials. Under low speed and light apparent pressure conditions, the quenched specimens have high wear-resistance performance. Contrarily, at high speed and heavy loading, the wear-resistance performance of hardened specimens decreases due to tempering effects at the rubbing surface when the contact temperature becomes increased. Therefore, this causes more severe wear to the hardened specimens than to the unhardened specimens.     

Influence of porosity on the sliding wear behavior of sintered Fe-1.5Mo-0.7C steels

Fe-1.5Mo-0.7C steels with different porosity can successfully be prepared by using traditional compacting, vacuum sintering, and in part Hot Isostatically Pressing (HIPing). Their dry sliding wear behavior in both as-sintered and heat treated states were investigated. When porosity is lower than 6.2%, further decreases of porosity have less influence on the wear coefficient of both as-sintered and heat treated steels. Pores in the sintered steels collect the debris during the rubbing process, and therefore the disadvantage in wear process due to the poor hardness and mechanical strength caused by high porosity is partly compensated for. During dry sliding the as-sintered steels have three types of wear mechanisms (i.e., oxidational wear, abrasive wear, and delamination wear), while oxidational wear and delamination wear are the main regimes in heat treated steels. Oxidation leads to the wear of sintered steels and in the meantime the oxides attached to the rubbing surface further lower intense wear of the rubbing system. Abrasive wear and delamination wear, which result in flake debris, are responsible for high wear coefficients.     

H13钢表面镀铬和气体渗氮复合处理的组织及性能

对调质后的H13钢进行镀铬+540 ℃气体渗氮处理,获得氮化铬表层,然后将其进行耐磨试验,并与同温度经常规气体渗氮及离子渗氮后的H13钢试样进行组织及耐磨性对比。结果表明:3种工艺处理后试样的主要磨损机制为粘着磨损和磨粒磨损,镀铬/渗氮试样表面摩擦因数最低,为0.44,耐磨性最好,但镀铬+渗氮层与基体的结合力最差。     

Fatigue behavior of duplex treated TiCxN1−x- and Ti1−xAlxN-hard coating steel compounds

Recently, modified surface treatment methods for cutting tools were developed combining a heat treatment and a subsequent hard coating (duplex treatment). As a consequence, the wear resistance has been improved considerably. As fatigue is an important failure mechanism during application, the present paper focuses on the improvement of the fatigue behavior by an optimization of heat treatment and hard coating. The problem is approached in two steps: first, the fatigue behavior of high-speed tool steel S6-5-2 is investigated, surface-treated with different plasma heat treatments (plasma nitriding and -carbonitriding). The results on bending fatigue testing indicate the superiority of plasma nitriding compared with both plasma carbonitriding and untreated substrate. Hence, in a second step the plasma nitrided tool steel is coated with PACVD hard coatings of the system Ti-Al-C-N and the fatigue behavior of these hard coating steel compounds is investigated. Obviously, the type and stoichiometry of the hard coating influence the fatigue behavior of the compound. For TiC_xN_1−x films, the fatigue strength increases with increasing carbon content, whereas for Ti_1−xAl_xN-films, the fatigue strength decreases with increasing Al content. While for an optimized hard coating the fatigue behavior of the compound is superior to hardened non-nitrided steel, no significant improvement was found as compared with plasma nitrided steel.     

调制结构对TiN/TaN多层膜的生长行为及力学性能的影响

利用反应磁控溅射方法,制备了调制周期相同而调制比不同的TiN／TaN多层膜．利用XRD,HRTEM和纳米压痕仪分别对多层膜的结构、微观状态和力学性能进行了系统研究．结果表明：调制结构不仅改变多层膜的生长速率,而且能导致多层膜择优生长取向的变化;界面应力的存在使得薄膜生长速率随沉积层厚度的增加而下降;在TiN／TaN多层膜中存在着各自独立外延生长的[111]和[100]两种取向的调制结构,且具有不同的调制周期;调制周期为6nm左右的TiN／TaN多层膜的硬度与弹性模量分别提高约50％与30％;在调制比为3：1时,硬度最大值为34．2GPa,弹性模量为344．9GPa;根据结构和力学性能的分析结果,讨论了TiN／TaN多层膜的硬化机制．     

分离靶电弧离子镀制备TiN/TiAlN多层薄膜的微观结构和力学性能(英文)

采用分离靶电弧离子镀制备TiN/TiAlN多层薄膜。为了减少大颗粒的不利影响,利用直线型磁过滤方法来减少低熔点铝靶产生的大颗粒。结果表明,没有过滤的钛靶和磁过滤的铝靶等离子体到达基体的输出量在相同的数量级,同时,采用该方法制备的薄膜中的大颗粒数目是文献中报道的合金靶制备的薄膜大颗粒数目的1/10～1/3。Al元素的添加引起薄膜在(200)晶面的峰值降低,而在(111)和(220)晶面的峰值增强。TiN/TiAlN多层薄膜的最大硬度为HV2495,薄膜的硬度增强符合混合法则,结合力达75 N。     

W-Mo-V改进型H13模具钢的力学性能与磨损行为

研究了自主研发的W-Mo-V系改进型H13模具钢(HBJ3钢)经500、550和600 ℃回火后的显微组织、力学性能和磨损行为,并与H13钢进行了对比。结果表明,与H13钢相比,HBJ3钢经600 ℃回火后的硬度和抗拉强度均有明显提高。在回火温度为500、550和600 ℃时,HBJ3钢的摩擦因数和磨损率均低于H13钢,磨损率分别低38%、58%和64%。HBJ3钢的磨损机理主要是氧化磨损和磨料磨损,而H13钢还有剥层磨损机制。     

Tool wear and machining performance of cBN–TiN coated carbide inserts and PCBN compact inserts in turning AISI 4340 hardened steel

PCBN is the dominant tool material for hard turning applications due to its high hardness, high wear resistance, and high thermal stability. However, the inflexibility of fabricating PCBN inserts with complex tool geometries and the prohibitive cost of PCBN inserts are some of the concerns in furthering the implementation of CBN based materials for hard turning. In this paper, we present the results of a thorough investigation of cBN plus TiN (cBN–TiN) composite-coated, commercial grade, carbide inserts (CNMA 432, WC–Co (6% Co)) for hard turning applications in an effort to address these concerns. The effect of cutting speed and feed rate on tool wear (tool life), surface roughness, and cutting forces of the cBN–TiN coated carbide inserts was experimented and analyzed using analysis of variance (ANOVA) technique, and the cutting conditions for their maximum tool life were evaluated. The tool wear, surface roughness, and cutting forces of the cBN–TiN coated and commercially available PCBN tipped inserts were compared under similar cutting conditions. Both flank wear and crater wear were observed. The flank wear is mainly due to abrasive actions of the martensite present in the hardened AISI 4340 alloy. The crater wear of the cBN–TiN coated inserts is less than that of the PCBN inserts because of the lubricity of TiN capping layer on the cBN–TiN coating. The coated CNMA 432 inserts produce a good surface finish (<1.6 μm) and yield a tool life of about 18 min per cutting edge. In addition, cost analysis based on total machining cost per part was performed for the comparison of the economic viability between the cBN–TiN coated and PCBN inserts.     

Influence of bilayer period and thickness ratio on the mechanical and tribological properties of CrSiN/TiAlN multilayer coatings

Nanostructured CrSiN/TiAlN multilayer coatings were deposited by a bipolar asymmetric reactive pulsed DC magnetron sputtering system. The thickness ratio of CrSiN to TiAlN layers was fixed at 1:1. The bilayer periods of the coatings were controlled to be from 6 to 40 nm. Furthermore, two CrSiN/TiAlN multilayer coatings with the same bilayer period (20 nm) but different CrSiN/TiAlN thickness ratios (2:8 and 8:2) were also deposited to explore the influence of thickness ratio on the mechanical properties of the multilayer coatings. The crystalline structures of the coatings were determined by a glancing angle X-ray diffractometer. The microstructures of thin films were examined by a scanning electron microscopy and a transmission electron microscopy, respectively. A nanoindenter, a micro Vickers hardness tester, and a pin-on-disk wear tester were used to evaluate the hardness, the toughness and the tribological properties of the thin films, respectively. The maximum hardness of the multilayers was obtained when the bilayer period was at 10 nm for the coating with the same thickness ratio of CrSiN to TiAlN layers (1:1). Meanwhile, the thickness ratio of CrSiN to TiAlN layer had great influence on the hardness and the toughness properties of the multilayer coatings. The hardness and the toughness of the CrSiN/TiAlN multilayer coatings increased as the individual TiAlN layer thickness increased.