TC21钛合金微弧氧化涂层微动磨损行为研究

采用球盘接触形式,在50 μm和150 μm位移振幅条件下,研究了载荷(60 N、40 N和20 N)对TC21钛合金及其表面微弧氧化(PEO)涂层切向微动磨损性能的影响。结果显示,随着位移振幅的增大和载荷的减小,TC21钛合金和PEO涂层的微动区域均由部分滑移区向滑移区转变。在部分滑移区,两种材料沿微动方向的磨痕宽度随载荷的减小而减小。虽均未出现明显的材料损失,但TC21钛合金边缘微滑区存在微裂纹的萌生和扩展,其程度随载荷的减小而加重,而微动对PEO涂层只起到了平滑作用。在滑移区,两种材料的磨痕宽度随载荷的减小而增大,且均存在局部磨损。磨损程度随振幅的增大和载荷的减小而加深。其中,PEO涂层的最大磨痕深度小于TC21钛合金,显示出更好的抗微动磨损性能。     

Incoloy800合金的高温微动磨损特性

采用PLINT高温微动磨损试验机,研究核电用管材Incoloy800合金的高温微动磨损机制和动力学特性。Incoloy800合金圆管试件与0Cr18Ni9不锈钢配副件圆柱体在水平面上垂直交叉接触,控制法向载荷为80N、位移幅值为2～20μm、循环次数为3×104次,在不同温度(25℃、300℃和400℃)下进行微动磨损试验。结果表明:当载荷、温度一定时,随着位移幅值的增大,Incoloy800合金的微动运行经历从部分滑移区向混合区和滑移区规律性的转变。温度升高并未对微动运行的区域特性以及部分滑移区的稳态摩擦系数产生显著影响,但在混合区和滑移区,稳态摩擦系数随温度的升高而明显降低。Incoloy800合金的高温微动磨损机制主要表现为摩擦氧化、磨粒磨损与剥层的共同作用。     

AlCrN涂层转动微动摩擦学行为

在新型转动微动摩擦磨损试验装置上,采用球/平面接触方式,对多弧离子镀制备的AlCrN涂层与Si3N4陶瓷球进行转动微动试验,变化转角位移幅值,研究了涂层的转动微动摩擦磨损行为。结果表明:AlCrN涂层的转动微动摩擦行为明显依赖于转角位移幅值,随着转角位移幅值的增加,摩擦界面从部分滑移向完全滑移转变,摩擦因数明显增大且曲线走势明显不同。AlCrN涂层转动微动在转角位移幅值θ=0.5°时处于部分滑移状态,损伤极其轻微,界面主要由弹性变形协调;当θ增大为1°,微动运行于完全滑移状态,但涂层的损伤仍较轻,为轻微的磨粒磨损和氧化磨损;当θ进一步增大为2°,涂层损伤明显加重,且磨痕中心处有明显的塑性隆起的痕迹,与同处于滑移区的较小转角位移幅值(θ=1°)的情况明显不同。因此,转角位移幅值对AlCrN涂层的转动微动摩擦磨损行为有重要影响。     

载荷对TC21钛合金微弧氧化涂层微动磨损性能的影响

采用球盘接触形式,在50和150μm位移振幅条件下,研究了载荷(60、40和20 N)对TC21钛合金及其表面微弧氧化(PEO)涂层切向微动磨损性能的影响。结果显示,随着位移振幅的增大和载荷的减小,TC21钛合金和PEO涂层的微动区域均由部分滑移区向滑移区转变。在部分滑移区,2种材料沿微动方向的磨痕宽度随载荷的减小而减小。虽均未出现明显的材料损失,但TC21钛合金边缘微滑区存在微裂纹的萌生和扩展,其程度随载荷的减小而加重,而微动对PEO涂层只起到了平滑作用。在滑移区,2种材料的磨痕宽度随载荷的减小而增大,且均存在局部磨损。磨损程度随振幅的增大和载荷的减小而加深。其中,PEO涂层的最大磨痕深度小于TC21钛合金,显示出更好的抗微动磨损性能。     

钛及其合金的扭动微动摩擦磨损特性

采用新型扭动微动试验机在法向载荷为50、80和110 N及角位移幅值为0.3°~10°的条件下进行TA2和TC4合金与ZrO2对磨球的扭动微动试验。在摩擦动力学行为研究的基础上,结合磨痕形貌微观分析,考察TA2和TC4合金的扭动微动磨损特性。结果表明:可用摩擦扭矩—角位移曲线和摩擦扭矩时变曲线表征合金的扭动微动行为,获得了TA2和TC4合金的扭动微动运行工况微动图,TA2合金的混合区较TC4合金的宽。摩擦扭矩随法向载荷和角位移幅值的增加而增加,在相同试验条件下,TA2合金的摩擦扭矩始终大于TC4合金的。在部分滑移区,损伤轻微;在混合区和滑移区,损伤加剧,扭动微动摩擦磨损机制主要为磨粒磨损、氧化磨损和剥落。     

接触载荷对TC4钛合金微动磨损行为的影响

目的在不同的载荷和位移幅值下,结合微动图研究微动接触状态、滑移状态、损伤体积三者对微动摩擦磨损的影响以及不同微动接触状态和滑移状态下材料的损伤机理,为机械构件的微动磨损防护设计提供一定的理论支持。方法在相对湿度为50%、干摩擦条件下,运用SRV-V摩擦实验机,采用球/平面接触形式研究了TC4钛合金/GCr15钢球摩擦副的微动摩擦磨损行为。实验后,用原子力显微镜、纳米压痕仪、三维光学轮廓仪、场发射扫描电子显微镜及其自带的EDS,测试TC4试样的表面形貌及粗糙度、弹性模量与硬度、磨损体积与截面形貌和显微结构及磨斑、磨屑形貌成分等。结果在较低法向载荷下,完全滑移(GSR)占主导地位。磨粒磨损、粘着磨损、氧化磨损以及疲劳脱层是主要的损伤机理。另一方面,在较高法向载荷下,混合滑移(MSR)、部分滑移(PSR)占主导地位。损伤机制是由于高的应力集中,导致疲劳裂纹。此外,不同的微动运行条件下和材料损伤区域也不相同。完全滑移条件下,损伤主要集中在磨斑中心,而部分滑移条件下,损伤主要集中在磨斑边缘。结论切向摩擦力、微动振幅是影响微动磨损的重要因素。小位移幅值下,磨屑可以减缓接触面钛合金基体材料的微动磨损;而大位移幅值下,磨屑会加剧接触面基体材料的微动磨损。     

690合金管在不同法向载荷下的切向微动磨损性能研究

目的 通过690合金管/405不锈钢块(线接触)的切向微动试验,探究690合金管在不同法向载荷作用下的切向微动磨损机制和损伤演变规律。方法 采用自制的多功能复合微动磨损试验机,研究法向载荷(10、20、40 N)对690合金传热管/405不锈钢抗振条的切向微动磨损性能的影响。通过分析摩擦系数和耗散能,获得试验过程中的动力学信息,再通过光学显微镜、扫描电镜对磨痕进行微观分析,获得其磨损机制以及损伤演变规律。结果 当位移幅值为100、200 μm,法向载荷为10、20、40 N时,690合金管/405不锈钢块的微动运行状态处于完全滑移区。随着法向载荷的增加,摩擦耗散能和摩擦力增大,690合金管的损伤加剧,产生的磨屑增加,磨痕表面的剥落坑被磨屑覆盖而减少,摩擦系数呈下降趋势。沿微动方向,690合金表面的磨损区域内O、Fe、Ni和Cr的含量呈锯齿变化;沿接触方向,690合金管的磨损深度也呈现锯齿状,这都是690合金管和405不锈钢块均为非理想平面所致。结论 总体而言,随着法向载荷的增加,690合金管和405不锈钢块的磨损体积增加,690合金管主要的磨损机制为剥层和磨粒磨损。     

35CrMo钢全滑移区微动磨损行为

采用自制微动磨损试验装置,研究了法向载荷F、位移幅值δd和循环次数N对35CrMo钢全滑移区室温微动磨损性能的影响,并对其磨损形式和损伤机理进行了探讨。结果表明,F、δd、N三参数共同影响35CrMo钢全滑移区微动磨损,磨损随一个参数的增加而加重;摩擦因数变化反应出试验初期磨损比较严重,随后磨损趋于平缓;经磨痕形貌分析,可见黏着磨损、磨粒磨损;磨损机制为剥层和第三体磨损机制。     

高温高压水环境下位移幅值对690合金传热管切向微动磨损的影响EI北大核心CSCD

由于试验装置的限制,在模拟工程服役环境的高温高压水环境下对三代核电用690合金管/405不锈钢抗振条(AVB)的高频微动磨损研究存在不足,影响了对核电厂蒸汽发生器传热管结构完整性评价的有效性。在模拟压水堆核电厂二回路高温高压水环境下,以690合金传热管为研究对象,开展高频切向微动磨损试验。试验研究不同位移幅值(D=20、30、40、80、120μm)对690合金管微动磨损行为的影响。试验结束后,借助扫描电子显微镜、能谱仪和三维形貌仪对磨损区域进行形貌表征、能谱分析和磨损体积计算。试验结果表明:随着位移幅值的增加,磨损接触面积增大,磨损深度和磨损体积均增加,磨损加剧。当位移幅值较小时(D=20、30、40μm),磨屑不易排出接触面,多黏着在磨痕中心,磨损机制主要是黏着磨损;当位移幅值增加至80、120μm时,磨屑分布均匀,磨损机制向剥层磨损转变。随着磨损机制的转变,磨损率呈现先增加后降低的趋势,在D=80μm时,磨损率最大。通过更符合工程实际的高温高压水环境试验,对比了不同位移幅值下的传热管微动磨损性能,给出了磨损率随位移幅值变化的趋势,初步阐明了磨损机制,有利于核电装备的摩擦学性能提升,对核电厂690传热管的结构完整性评价有较好的指导作用。     

不同温度下690合金传热管与抗振条的微动磨损特性

在卧式高温微动磨损试验机(PLINT TE77)上,采取线接触方式,研究690合金传热管/405不锈钢抗振条在干态不同温度下的切向微动磨损特性。在试验参数为法向载荷40 N、位移幅值100μ、频率5 Hz和循环次数1次的条件下,分别在25、90、200和285℃这4种不同温度下进行切向微动磨损试验。结果表明:微动工况均处于滑移区,90℃时稳态摩擦因数最高;当温度升高到200和285℃时,摩擦因数经过下降期后出现一个更加明显的下降阶段,这与界面的高温氧化有关。磨损机制是磨粒磨损、氧化磨损和剥层,磨痕表面在低温(25和90℃时的氧化程度比高温(200和285℃时的严重。90℃时的磨损量比其他温度时的都高,这可能与界面水蒸气蒸发和表面摩擦氧化有关。     

Ti6Al4V 合金在Saline溶液中的扭动微动磨损

在球/面接触中存在四种微动模式,即切向、径向、转动和扭动微动,在生理介质中扭动微动是人工关节失效的主要原因之一。本文成功建立了一种可在恒温液体介质中实现球/面接触扭动微动的新的试验系统。利用该系统,在37℃的Saline溶液中进行了钛合金/二氧化锆陶瓷球的扭动微动试验,详细讨论了扭动微动的运行行为和损伤机理。结果表明,扭动微动动力学行为在很大程度上取决于扭动角位移振幅和周期数。研究建立了扭动微动运行工况图（RCFM）,包括3个区域,即：部分滑移区（PSR）,混合区（MFR）和完全滑移区（SR）。在部分滑移区,接触中心没有发现任何损伤,接触边缘上只观察到轻微的擦伤和磨损。在混合区,损坏区域从接触边缘向中心扩展,接触中心无损伤,接触边缘区域出现氧化磨损和损伤。在滑移区,整个接触区域均发生损伤,损伤机理主要是磨蚀磨损、氧化磨损、和粘着磨损。     

Torsional fretting corrosion behaviours of Ti6Al4V alloys in Hank’s simulated body fluid

ABSTRACT

Torsional fretting corrosion in a physiological medium is one of the main reasons that artificial joints fail. In this study, we carried out experiments on torsional fretting corrosion in Titanium alloys (Ti6Al4V) against Zirconium dioxide (ZrO₂) ceramic balls under 37°C in a Hank’s simulated body fluid. During the tests, we recorded electrochemical corrosion parameters using an electrochemical analysis system in real-time. We analysed the torsional fretting dynamics behaviours, damage mechanisms, and electrochemical corrosion behaviours in detail using the micro-examinations of a scanning electron microscope (SEM), an energy-dispersive X-ray (EDX), a profilometer, and an X-ray photoelectron spectrometer (XPS). The results showed that the dynamics behaviours strongly depended upon the torsional angular displacement amplitude and the number of cycles. The friction torque increased with increases in the torsional angular displacement amplitude and normal load. We established a running condition fretting map (RCFM), which included three fretting running regimes: a partial slip regime (PSR), a mixed fretting regime (MFR), and a slip regime (SR). We determined that the influences of torsional fretting on electrochemical corrosion behaviours were strongly correlated to the angular displacement amplitude. Under large angular displacement amplitudes, the corrosion of the Ti6Al4V alloys in Hank’s simulated body fluids were accelerated by torsional fretting, especially during the initial stage of the test. However, when the angular displacement amplitude was smaller than 1°, the corrosion potentials and corrosion currents were almost invariable during the entire duration of the test. The damage to the Ti6Al4V alloy was the result of wear and corrosion. The wear mechanisms were attributable to delamination and abrasive wear in the three fretting regimes. We observed almost no damage on the contact centre and only slight scratches and wear on the contact edge in the PSR. In MFR testing, the damage zone extended to the contact centre and the sticking zone (which exhibited no damage) contracted to the contact centre with increases in the number of cycles. Ultimately, in MFR and SR testing, the damage mechanisms were primarily the result of abrasive wear, oxidation wear, tribochemical reactions, adhesion wear, and electrochemical corrosion.     

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.     

Fretting wear of micro-arc oxidation coating prepared on Ti6Al4V alloy

Micro-arc oxidation(MAO)coating was prepared on Ti6Al4V alloy surface and its characterizations were detected by Vickers hardness tester,profilometer,scanning electric microscope(SEM),energy dispersive X-ray spectrometer(EDX)and X-ray diffractometer(XRD).Fretting wear behaviors of the coating and its substrate were comparatively tested without lubrication under varied displacement amplitudes(D)in a range of 3-40μm,constant normal load(Fn)of 300 N and frequency of 5 Hz.The results showed that the MAO coating,presenting rough and porous surface and high hardness,mainly consisted of rutile and anatase TiO2 phases.Compared with the substrate,the MAO coating could shift the mixed fretting regime(MFR)and slip regime(SR)to a direction of smaller displacement amplitude.In the partial slip regime(PSR),lower friction coefficients and slight damage appeared due to the coordination of elastic deformation of contact zones.In the MFR,the friction coefficient of the coating was lower than that of the substrate as a result of the prevention of plastic deformation by the hard ceramic surface.With the increase of the displacement amplitude,the degradation of the MAO coating and the substrate increased extremely.The fretting wear mechanisms of the coating were abrasive wear and delamination with some material transfer of specimen.In addition,the coating presented a better property for alleviating fretting wear.     

Deformation of Si(100) in spherical contacts — Comparison of nano-fretting and nano-scratch tests with nano-indentation

Nano-indentation, nano-scratch and nano-fretting tests were performed on highly polished Si(100) using a commercial ultra-low drift nano-mechanical test system (NanoTest, Micro Materials Ltd.) fitted with a 4.6 μm sphero-conical diamond indenter. In addition to plastic deformation, the contact deformation of Silicon is strongly affected by phase transformation and micro-/nano-fracture at room temperature. The objective of this work was to investigate the influence of tangential loading by comparison of deformation in the idealised loading in the nano-indentation test with the more complex tribo-contact situations. A novel method is introduced allowing quantitative comparison of deformation during loading in the nano-indentation, nano-scratch and nano-fretting tests. The loading curves in all three tests were almost identical at very low load. Tangential loading in the nano-scratch and nano-fretting tests promotes yield resulting in greater penetration depths at higher load than in nano-indentation. Contact damage assessment by in situ measurements of probe displacement during nano-fretting was supported by post-test SEM imaging and wear scar measurement by confocal microscopy. The nano-fretting crack morphology was related to the normal load applied and resulting track length. A brittle/ductile response of the material was observed, characterised by brittle micro-chips around wear track and ductile wear debris observed in the centre of the contact. The critical loads in the nano-scratch test show a subtle dependence on scan speed and loading rate. Pronounced lateral cracking observed in high load nano-scratch and nano-indentation tests is absent in the nano-fretting tests, which is consistent with the fretting wear process minimising the accumulation of strain.     

A356铝合金微弧氧化膜微动磨损行为的研究

采用微弧氧化（MAO）在A356铝合金表面制备MAO膜,利用球-平面接触在SRV-V微动摩擦磨损机上探究变载荷和位移下微弧氧化对A356微动磨损机理的影响。结果表明：MAO膜由疏松层和致密层构成,其均匀性、致密性和结合力良好。MAO膜的摩擦系数、磨损率均低于A356,MAO膜减摩耐磨性较好。随位移增加MAO膜的摩擦耗散能系数低于A356,MAO膜能提升A356微动磨损过程的稳定性。载荷增加时A356磨损机制为磨粒磨损-粘着磨损,伴随犁削和疲劳剥层; MAO膜磨损机制为磨粒磨损-粘着磨损和疲劳剥落。位移增加时A356磨损机制为粘着磨损和疲劳剥落,伴随微犁削;MAO膜磨损机制为粘着磨损和疲劳剥层-粘着磨损和磨粒磨损。A356的磨痕内聚集Fe、O元素,存在材料转移和氧化磨损;MAO膜磨痕内聚集Fe元素,存在材料转移。     

Inconel690在联氨溶液中的磨损行为(英文)

在控制法向载荷分别为20、50和80 N,位移幅值分别为80、150和200μm的两种不同环境下,以Si3N4陶瓷球/Inconel690平面接触的方式,在PLINT高温微动试验机上进行微动腐蚀试验,循环次数为2×104。结果表明:在滑移区,当载荷、位移幅值一定时,相同温度联氨溶液中的稳态摩擦因数比其在蒸馏水中高;稳态摩擦因数随溶液的温度增加而增加;磨损体积随溶液温度增加而增加。Inconel 690在联氨溶液摩擦过程中,磨损程度除受到位移幅值、荷载影响以外,温度对磨损体积有显著影响。温度的增加即降低溶液的溶解氧又促进联胺与溶解氧的吸收反应,起到降低氧化腐蚀的作用。在蒸馏水中Inconel 690合金材料的磨损机制主要为磨粒磨损和剥层,而在联氨溶液中其磨损机制主要为裂纹伴随磨粒磨损和剥层。     

双粗糙表面的微动磨损行为研究

目的 建立符合实际情况的粗糙表面微动磨损模型,准确揭示连接结构的磨损机理.方法 利用ABAQUS有限元软件中的UMESHMOTION子程序和能量耗散模型,建立粗糙表面的微动磨损模型,并探究不同表面粗糙度、材料和振动频率对粗糙表面微动磨损的影响.结果 在外部载荷、振动频率和材料相同的情况下,下试件表面粗糙度为0.2μm的...     

微动接触中分形粗糙表面的温升分布研究

目的 研究不同分形参数下表面粗糙度对微动接触表面温升的影响。方法 通过创建Python脚本,将MATLAB中利用Weierstrass-Mandelbrot函数构造的分形表面轮廓坐标导入ABAQUS中,使用样条曲线拟合轮廓坐标,构建包含粗糙表面的二维柱面-平面接触模型,研究表面粗糙度、法向载荷、切向载荷以及材料属性对接触表面温升的影响规律。结果 微动接触状态下,温升在接触宽度方向上呈先增后减的趋势,且沿深度方向温升幅值逐渐减小。不同粗糙度的表面节点具有相似的温升分布历程,热影响区主要分布于接触区表层附近,并在此表层产生高的温度场。粗糙接触模型会出现局部温升峰值,同时剪切摩擦应力和接触压力分布具有离散性,与文献中已有结论一致。结论 接触表面温升幅值随着粗糙度的增大而增大。当表面粗糙度和法向载荷一定时,随着切向载荷幅值的增大,上试件的相对滑移距离和摩擦热产生率增加,引起温升幅值增大。考虑材料属性时,发现温升幅值大小与材料导热性密切相关,材料导热性能越好,接触表面温升幅值越小。