Fretting Wear Behavior and Mechanism of Inconel 690 Alloy Related to the Displacement Amplitude

Fretting wear tests on Inconel 690 alloy were carried out at different displacement amplitudes. The results indicated that with an increase in displacement amplitude, the ratio of tangential force to normal load and wear volume increased. The fretting mode gradually transformed from mostly stick, mixed stick–slip, to full sliding, showing the competition of fretting-induced fatigue cracking and fretting-induced wear. There was a gradient plastic strain created by fretting, which resulted in the formation of a nanocrystalline tribologically transformed structure (TTS) and plastic deformation layers. The plastic strain in the plastic deformation layer gradually increased with an increase in displacement amplitude.     

Effect of Cold Rolling on the Fretting Wear Behavior and Mechanism in Inconel 690 Alloy

The influence of cold rolling on the fretting wear behavior and mechanism of Inconel 690 alloy at 320?°C in air was studied. The wear volume and worn surface were obtained and analyzed using laser scanning confocal microscopy, electron back-scattering diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The grinding surface and strain distribution were also studied by electron back-scattering diffraction to analyze the mechanism of fretting damage. The results indicated that with an increase in cold rolling reduction, the microhardness was increased. However, the friction coefficient and wear volume first increased and then decreased. The characteristics of fretting areas changed from a gross slip regime to a partial slip regime. Accordingly, the damage mechanism in the gross slip regime was a combination of oxidative wear, abrasive wear, and delamination, whereas the damage mechanism in the partial slip regime was mainly adhesive wear.     

Experimental Study of the Fretting Wear Behavior of Incoloy 800 Alloy at High Temperature

The fretting wear behavior of the nuclear power material Incoloy 800 was investigated in this study. A PLINT high-temperature fretting tester was used on an Incoloy 800 cylinder against a 304SS cylinder at vertical cross contact under different temperatures (25, 300, and 400°C). During testing, a normal load of 80 N was applied, and the displacement amplitudes ranged from 2 to 40 µm. The fretting wear mechanism at high temperatures and the kinetic character of the materials of the Incoloy 800 steam generator tube were analyzed. Results showed that the fretting running regimes varied little with ncreasing temperature, and some microcracks were observed in both the mixed fretting regime (MFR) and the partial slip regime (PSR) at high temperatures. Slight abrasive wear and microcracks were the main wear mechanisms of the Incoloy 800 alloy in PSR, whereas those in the MFR and the gross slip regime were oxidative wear, abrasive wear, and delamination.     

The Effects of Sodium Chloride Solution on Fretting Wear Behavior of Nickel Based Alloy in Partial Slip Regime

The investigations on fretting wear behaviors of nickel based alloy in NaCl solution and atmosphere indicated that wear mechanism and regional transformation from partial slip regime (PSR) to the mixed regime (MR) are significantly affected by NaCl solution. The crevice corrosion induced by synergy of chloride ion and deformed asperities caused wear mechanism changed from adhesive and oxidation wear (PSR in atmosphere) to abrasive and oxidation wear (PSR in NaCl solution) and to oxidation and delamination wear (MR in NaCl solution), meanwhile accelerated the regional transformation from PSR to MR. However, the annular fatigue crack was almost unaffected by NaCl solution, which propagated along the direction of 40-50^° to surface in the mode of transgranular and intergranular in all conditions.     

Investigation on the Fretting Wear Behavior and Mechanisms of Alloy 690TT during the Transformation from Mixed Regime to Partial Slip Regime Induced by Elevated Temperature

Fretting wear of Alloy 690TT can occur in the steam generator of a nuclear power plant, in which the interfacial conditions are changed as the temperature varies. In this study, the gradual transformation from the mixed fretting regime (MFR) to the partial slip regime (PSR) occurred with an increase in test temperature. Correspondingly, there was a competition in wear modes due to the formation of a nanostructured tribologically transformed structure (TTS), presence of delamination cracking, nucleation of fatigue cracks, and oxidation. Delamination within the TTS dominated first. As the area of TTS and the plastic deformation region was reduced, fatigue cracks began to initiate. Oxidation was accelerated by an increase in the test temperature, and that effect resulted in reduced wear volume of Alloy 690TT in the MFR.     

载荷对径向微动磨损的影响

为了研究在实际工况中较为常见的圆柱/平面接触副的径向微动磨损特性,分析载荷对径向微动磨损影响,本文通过ANSYS建立圆柱/平面的径向微动磨损模型,分析施加载荷过程,不同时间点的载荷对径向微动磨损的影响,并通过接触切应力和X方向应力的分析,提出径向微动磨损在粘滑过渡点以及X方向应力为零的点为裂纹萌生点.     

Mo离子注入提高TC4合金微动磨损抗力的研究

对TC4合金进行了Mo离子注入表面改性处理,利用摩擦磨损试验机进行了点接触微动磨损试验,借助读数显微镜和表面粗糙度仪测量出有关参数,计算出试样的微动磨损体积。结果表明,Mo离子注入使试样表面硬度提高,微动磨损体积明显降低。在微动磨损初期,Mo离子注入具有较好的减摩效果。Mo离子注入带来的表面强化效应是基体合金的微动磨损抗力得以提高的主要原因。     

ZM5镁合金微动磨损特性研究

采用高精度微动试验台研究了ZM5镁合金的微动磨损行为,法向载荷变化范围为50～200N、位移幅位为5～40μm。通过摩擦力-位移-循环次数变化分析,结合显微观测,结果表明:ZM5镁合金的微动磨损行为与微动区城特性密切相关。它的微动损伤形貌主要是磨损,在初期阶段的磨损机制主要是粘着和氧化,中后期是粘着、氧化和磨粒磨损共同作用的结果。     

钛合金球与骨水泥界面之间的微动磨损机制研究

采用钛合金球与自制骨水泥试样以球/平面接触方式,在自制的微动摩擦磨损试验机上开展干摩擦和25%小牛血清介质中切向微动磨损试验研究,考察钛合金球与骨水泥界面之间的微动运行特性,并采用S-3000N型扫描电镜观察磨痕形貌来分析其微动磨损机制。结果表明:随着微动振幅的增加,微动运行由部分滑移区向混合区转变。随着接触载荷的增加,试样接触面之间更容易发生黏着。与干摩擦相比,在小牛血清溶液中部分滑移区向较大振幅区扩展。部分滑移区摩擦因数值较低且保持稳定,混合区的摩擦因数先增大后保持不变。稳定摩擦因数随着接触载荷的增加而减小,随微动振幅增大而增大。骨水泥试样的磨损量在小牛血清介质中比在空气中大,并且随接触载荷增大而增大。骨水泥在小牛血清介质中微动磨损的损伤机制主要为黏着磨损和疲劳磨损,溶液分子在应力作用下对骨水泥基体有削弱作用。     

AZ91D镁合金微动磨损特性研究

采用液压高精度材料试验机考察了平面一球面接触的AZ91D镁合金摩擦副的微动磨损行为，分析了位移幅值、法向载荷和频率等参数对摩擦因数和磨损体积的影响，考察了不同实验条件下的磨斑形貌，并探讨了其磨损机理。结果表明：AZ91D镁合金的微动区域可分为部分滑移区、混合区和滑移区3个区域，粘着磨损、疲劳磨损和磨粒磨损分别是3个区域的主要磨损机制；磨损体积随着位移幅值和法向载荷的增加而增大，但却随着频率的增大而减小。在微动部分滑移区和混合区，摩擦因数随着位移增大迅速增加；在微动滑移区，摩擦因数随法向载荷的增大而减小，而位移幅值和频率对摩擦因数的影响较小。     

车轮钢摩擦副滚动摩擦磨损特性研究

在NENE-2型磨损试验机上利用往复滚动试验装置研究了不同制动状态下车轮钢的滚动摩擦磨损特性。结果表明:不同滚滑状态下的切向摩擦力是变化的,随制动力的增加,滚动摩擦副对应的摩擦因数和摩擦阻力相应增大;平面试样的表面磨痕形貌由于切向摩擦力的变化而明显不同;随切向摩擦力的增大滚动磨损机制亦发生改变,从磨粒磨损逐渐转变为粘着磨损,磨损加剧且磨痕深度变大。     

TiAlZr合金微动磨损性能研究

采用高精度液压式微动磨损试验机研究了TiA lZr合金在不同微动运行区域的微动磨损行为,建立了其运行工况微动图。试验结果表明:滑移区、混合区和部分滑移区的摩擦因数随循环次数变化呈现不同的规律,其中部分滑移区摩擦因数较低,磨损体积随着位移幅值的增大而增大;滑移区、混合区磨损体积随着法向载荷的增加而增大,而部分滑移区磨损体积随着法向载荷的增加而减小;滑移区磨屑堆积于中心区域,磨损以磨粒磨损和剥层机制为主;混合区磨损机制主要表现为粘着磨损与磨粒磨损并存;部分滑移区磨损轻微。     

钛合金在水介质中的微动磨损特性研究

在SRV实验机上对TC11钛合金在水中进行微动磨损研究，研究了载荷大小、振幅等对摩擦因数和磨损量的影响。结果表明，钛合金在水中微动的摩擦因数虽然随载荷或振幅的变化无规律可循，但随着振幅的减小却越来越稳定；其磨损量均随着载荷或振幅的增加而增加；小振幅时的磨损机制符合疲劳脱层理论，而大振幅时则主要是磨粒磨损机制。     

冷轧高锰钢耐磨性及磨损机制研究

通过对高锰钢进行冷轧变形,考察了不同变形量下冷轧高锰钢的硬度变化,利用自制三体磨料磨损试验机测试了不同磨料磨损工况下,固溶态及其冷轧态的磨损特性。结果表明,冷轧变形可以大幅提高高锰钢的硬度。在软磨料的磨损条件下,冷轧变形可以有效提高高锰钢的耐磨性;在硬磨料的磨损条件下,冷轧变形对耐磨性没有贡献。利用M M Khruschov的磨损区域理论和E Rabinnowicz的磨损模型解释了在软磨料磨损条件下,冷轧变形提高高锰钢耐磨性的机制;同时利用K H ZumGahr的磨损模型解释了在硬磨料磨损条件下,冷轧变形对高锰钢耐磨性没有贡献的机制。     

TC4合金冲击磨损性能与机制的研究

固定冲击频率,在3组大小不同的冲击力下,在自制的小载荷冲击磨损实验机上对TC4合金进行了系列周次的冲击试验,研究了TC4合金的冲击磨损性能与磨损机制.结果表明:试样的整个冲击磨损过程可分为3个阶段,即无磨损阶段、微量磨损阶段和严重磨损阶段,增加冲击力将缩小前2个阶段的进程,加速材料的磨损;在各冲击力下磨痕轮廓及形貌的变化规律基本一致.TC4合金的磨损过程是接触表面硬化、启裂、疲劳剥落的过程,其磨损机制主要表现为塑性变形和疲劳剥落.     

含硫化铜纳米粒子润滑脂的微动磨损性能研究

在微动磨损试验机上考察了含有硫化铜纳米粒子脲基脂的微动磨损性能。结果表明:硫化铜纳米粒子能显著降低微动磨损体积,随着纳米粒子含量增加,微动磨损量降低;在微动磨损后期纳米粒子的存在还能降低摩擦因数。低负荷下,润滑脂中硫化铜纳米粒子有利于降低微动磨损量;但在高负荷条件下,磨损量迅速增大,说明高负荷下微动磨损方式发生了变化。XPS分析表明,微动磨斑表面膜含有Cu、FeS等物质,说明硫化铜纳米粒子能显著降低微动磨损的原因在于纳米粒子化学性质非常活泼,在微动过程中容易与摩擦表面发生化学反应,形成具有保护性的沉积物膜和化学反应膜。     

硬度对钢蜗轮副用材料微动磨损特性的影响

通过调整40CrNiMoA钢的热处理工艺参数获得了4种不同硬度的试样,在无润滑、室温条件下,在SRV Ⅳ微动磨损试验机上研究了硬度对40CrNiMoA钢-18Cr2Ni4WA钢摩擦副微动磨损量和摩擦因数的影响.结果表明:试验条件下,随着40CrNiMoA钢硬度的增加,其微动磨损体积减小,而较硬的18Cr2Ni4WA钢的微动磨损量变化趋势则与试样的位置等有关,但总存在一个硬度配对使得两摩擦副微动磨损体积相等;摩擦因数在40CrNiMoA钢为上试样时,随时间变化较平稳,波动较小;当40CrNiMoA钢为上试样时,其微动磨损机制主要为黏着磨损,而18Cr2Ni4WA钢的磨损机制以磨粒磨损和黏着磨损为主.     

Torsional Fretting Wear Behavior of Bonded MoS2 Solid Lubricant Coatings

The effects of applying a bonded MoS₂ solid lubricant to a 1050 steel substrate were investigated using a torsional fretting wear apparatus. Tests were conducted under a normal load of 50 N with angular displacement amplitudes ranging from 0.1 to 5°. Wear scars were examined using scanning electron microscopy, energy-dispersive X-ray spectrometry, optical microscopy, and surface profilometry. The MoS₂ coating exhibited different torsional fretting regimes than those of the substrate. Fretting regimes of the coating were primarily in the partial slip regime (PSR) and the slip regime (SR) with no mixed fretting regime. The width of the PSR narrowed. Due to the lubricating effects of the coating, the friction torque was consistently lower than that of the substrate. The damage to the coating in the PSR was very slight, and its granular structure remained even after 1,000 cycles. The damage mechanism to the SR coating was a combination of abrasive wear, oxidative wear, and delamination. The MoS₂ coating had potential to alleviate torsional fretting wear.     

有机钼复合润滑剂在高温微动和滑动条件下的摩擦磨损行为

以矿物基650SN油作为基础油,采用复配技术制备了有机钼复合润滑剂。利用SRV微动磨损试验机和T-11滑动磨损试验机考察了该复合剂的高温摩擦学行为,采用扫描电子显微镜和X射线光电子能谱仪对其润滑下的磨痕表面形貌和表面膜的元素组成进行了分析,探讨了复合剂的减摩润滑机制。结果表明:有机钼复合剂具有良好的高温微动和滑动摩擦学行为,与基础油相比,复合剂能够使钢-钢摩擦副在高温微动和滑动过程中的摩擦因数降低28%和43%,抵抗微动和滑动磨损的能力分别提高53%和54%。这是由于有机钼复合剂通过分解、吸附和摩擦化学反应,在摩擦副金属表面形成了含磷酸盐的沉积膜和含FeS、MoS2的化学反应膜共同组成的复合边界润滑膜,从而表现出优良的减摩润滑效果。     

ZnOw填充铸型尼龙复合材料滚动摩擦磨损行为

研究ZnOw填充铸型尼龙(MC)复合材料的滚动摩擦学性能.结果表明,ZnOw/MC复合材料的拉伸强度随氧化锌晶须含量增加而升高,而断裂伸长率随氧化锌晶须含量的增加而降低;ZnOw/MC复合材料的摩擦因数和磨损率均随氧化锌晶须含量增加而降低;随着氧化锌晶须填充量的增加,磨损.ZnOw/MC复合材料的磨损机制由黏着磨损变为疲劳