Dry sliding wear response of zinc-based alloy over a range of test speeds and loads: a comparative study with cast iron

This study pertains to the observations made during the sliding wear response of a zinc-based alloy in different test conditions. The effects of sliding speed and load on the wear behaviour of the alloy have been studied. The properties evaluated were wear rate, frictional heating and coefficient of friction. The wear performance of the zinc-based alloy has been compared with that of a conventional cast iron in identical test conditions. The wear rate of the samples increased with applied load and sliding speed while the seizure resistance (load) deteriorated with speed. The zinc-based alloy exhibited less wear rate and reduced frictional heating than that of the cast iron while friction coefficient followed a reverse trend. Observed wear response of the samples has been discussed in terms of specific features like lubricating, load carrying, microcracking and thermal stability of various microconstituents of the samples, and substantiated further through the features of wear surfaces, subsurface regions and debris.     

料浆中碳化硅含量对TZNT钛合金微粒磨粒磨损性能的影响

用TE66型试验机分析了TZNT钛合金的微粒磨粒磨损行为,用15JE型数显式测量显微镜测量了磨斑直径,研究了料浆中碳化硅含量(0.05～0.25 g·cm-3)对合金磨损体积的影响,并建立了磨损机制图.结果表明:在0.05～0.50 N载荷下,TZNT钛合金的磨损体积均随着料浆中碳化硅含量的增加而增大;且在相同条件下,其在Hank's模拟体液中的磨损体积小于其在蒸馏水中的磨损体积;随着料浆中碳化硅含量的增加,TZNT钛合金的磨损形式由二体磨损向混合磨损和三体磨损转变.     

The Effect of Heat Treatment on Sliding Wear Behaviour of a Zinc-Based Alloy Containing Nickel and Silicon

This investigation deals with the observations made pertaining to the sliding wear behaviour of a zinc-based alloy containing nickel and silicon in partially lubricated condition. Wear tests were conducted over a range of applied pressures and sliding speeds. The effect of microstructural changes brought about through T6 heat treatment involving solutionizing followed by artificial ageing on wear behaviour was also investigated. The wear rate increased with pressure. The slope of the wear rate versus pressure plots was low initially up to a specific pressure. This was followed by a higher slope beyond the (specific) pressure. In some cases, the rate of change in wear rate, i.e. the slope, decreased at still higher pressures. Moreover, the (specific) pressure decreased with sliding speed in general. Increasing sliding speed caused the wear rate of the as-cast zinc-based alloy to increase up to a sliding speed of 2.68m/s. The trend reversed at a still higher speed of 4.60m/s. However, increasing wear rate with speed was noted for the heat-treated alloy over the entire speed range. Heat treatment led to reduced wear rate up to a sliding speed of 2.68m/s. An opposite trend was observed at a higher speed of 4.60m/s in this case. Specimen seizure was noted at speeds above 2.68m/s in the case of the as-cast alloy whereas seizure took place only at 4.60m/s for the heat-treated alloy samples. Frictional heating increased with pressure and speed. The specific response and changing mode of distribution of various phases were thought to be responsible for the typical wear behaviour of the alloy in specific material and test conditions. The predominance of parameters like thermal stability and cracking tendency over each other is suggested to lead to the varying wear behaviour of the alloy in different (material and sliding) conditions. The wear response of the samples has been substantiated through characteristics of their wear surfaces, subsurface regions and debris.     

铜包石墨含量对铜锰铝复合材料摩擦磨损性能的影响

为改善铜锰铝合金的烧结性能,并提高其在干摩擦下的摩擦磨损性能,以铜包石墨作为自润滑相加入到铜锰铝合金中,采用等离子真空压力烧结方法制备铜锰铝/石墨复合材料,分析铜包石墨含量对复合材料的密度、硬度的影响,探讨不同复合材料在干摩擦和油润滑条件下的摩擦磨损性能.结果表明:相比真空和氢气还原气氛下的烧结方式,等离子体烧结铜锰铝...     

Effects of Loading and Sliding Speed on the Dry Sliding Wear Behavior of Mg-3Al-0.4Si Magnesium Alloy

The friction and wear properties of Mg-3Al-0.4Si alloy were investigated using a pin-on-disc tester. Morphologies and compositions of worn surfaces were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) for identification of the wear mechanisms. Microstructural evolution and hardness change in subsurfaces were analyzed by confocal scanning laser microscopy and hardness testing. The results revealed that the wear behavior of Mg-3Al-0.4Si alloy was classified into two types of wear regimes; that is, mild and severe. In the mild wear regime, wear rates increased at a low slope with increasing load; the corresponding wear mechanisms were oxidation, abrasion, and delamination. In the severe wear regime, wear rates increased rapidly at a high slope with load; the wear mechanisms were severe plastic deformation and surface melting. Analysis of microstructural evolution on the subsurface identified the reason for the transition from mild to severe wear; that is, the realization of dynamic recrystallization (DRX) in the surface layer material. A contact surface DRX temperature criterion for the mild to severe wear transition was proposed, and the critical DRX temperatures for the mild to severe wear transition were calculated using DRX kinetics.     

蜂窝状铝合金高速加工刀具粘附行为及其作用机理研究

通过高速铣削试验方法对蜂窝状铝合金高速铣削刀具的粘附行为及粘附机理进行了研究。结果表明,由于初期铝屑粘附在刀具表面上,致使后期切削加工中的铝切屑与刀具表面的化学活性近似,使得铝屑进一步强化粘附在刀具表面,且由于高速加工中产生的高温和高压作用,使得粘附层材料发生变形。后续切屑划擦初期的粘附层,使粘附层出现变形和犁沟现象,加剧刀具与工件间的摩擦状态。同时,铝合金高速加工中高的塑性变形特征是发生粘附磨损的另一重要作用机制。此外,切屑表层材料受到剧烈剪切变形引起表面积增加,使切削形成的金属表面膜破裂,在与刀具表面紧密接触的近乎为真空环境下刀具不断切削新的表面,活性非常高,极易发生摩擦化学反应,较高摩擦化学反应形成的表面厚度达到临界值时将发生磨损,导致刀具粘附磨损加剧。     

Effects of Contact Pressure and Sliding Speed on the Unlubricated Friction and Wear Properties of Zn-15Al-3Cu-1Si Alloy

The unlubricated friction and wear properties of Zn-15Al-3Cu-1Si alloy were studied over a range of contact pressure (1–5 MPa) and sliding speed (0.5–2.5 ms^?1) for a sliding distance of 2,500 m using a block-on-disc type test machine. It was observed that as the contact pressure increased, the friction coefficient of the alloy decreased but its working temperature, surface roughness, and wear volume increased. Sliding speed had no significant effect on the friction coefficient of the alloy but increased its working temperature, surface roughness, and wear volume. It was also observed that the formation of a hard and brittle surface layer had a great influence on the wear behavior of the experimental alloy. The hardness and thickness of this layer increased with increasing contact pressure and sliding speed. However, contact pressure was found to be much more effective on the hardness of the surface layer of this alloy. Both adhesion and abrasion were observed to be the dominant wear mechanisms for the alloy under the given sliding conditions. The results obtained from the friction and wear tests are discussed in terms of the test conditions and microstructural changes that take place during sliding.     

陶瓷粉末种类对聚氨酯复合材料冲蚀磨损性能的影响

用聚四氢呋喃醚二醇(PTMG)、甲苯二异氰酸酯(TD I)反应,与不同种类的陶瓷粉末进行共混,制得耐磨蚀聚氨酯复合材料。评价了聚氨酯陶瓷复合材料的耐磨性,通过扫描电镜观察了聚氨酯陶瓷复合材料的磨损形貌,探讨了陶瓷粉末增强聚氨酯弹性体的磨损机制。结果表明:当—NCO含量为6.35%,Si3N4粉末、TiN粉末质量分数为10%时,耐磨性能最好,分别提高纯聚氨酯弹性体抗冲蚀磨损性能1.88倍和2.81倍。     

-NCO含量对聚氨酯/陶瓷复合材料冲蚀磨损性能的影响

用聚四氢呋喃醚二醇（PTMG）与甲苯二异氰酸酯（TDI）反应,再与陶瓷粉末进行共混,制得耐磨蚀聚氨酯复合材料.用相对抗冲蚀磨损性法评价了聚氨酯陶瓷复合材料的耐磨性,通过扫描电镜观察了聚氨酯复合材料的磨损形貌,尝试解释了陶瓷颗粒增强聚氨酯弹性体的抗冲蚀磨损机制.试验表明：当-NCO含量为6.35%、Si3N4粉末质量分数为10%时,耐磨性能最好,可提高纯聚氨酯弹性体抗冲蚀磨损性能近2倍.     

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.     

PCD刀具高速铣削GH4169合金的刀具磨损规律研究

为研究PCD刀具高速铣削GH4169合金时刀具的磨损规律,采用单因素试验法分别对不同铣削参数下后刀面磨损程度随切削路程的变化进行对比。结果显示主轴转速对高速铣削GH4169合金时刀具磨损的影响不大,采用顺铣、切削液冷却的方式,并适当降低每齿进给量有助于减小刀具磨损。使用BP神经网络对试验数据进行训练,建立了刀具磨损预测的模型,预测结果与实际结果误差在5%以内。     

油润滑条件下镍基纳米Al2O3复合刷镀层磨粒的铁谱分析及其磨损机制研究

为研究纳米颗粒复合电刷镀层在含沙粒油润滑条件下的磨损机制,首先制备了镍基纳米Al2O3复合电刷镀层,采用T-11球盘式磨损试验机进行复合刷镀层在含沙粒油润滑条件下的磨损试验,采用FTP-X2型分析式铁谱仪对复合镀层磨损试验后的润滑油中的磨粒形貌进行了研究。结果表明,含磨粒油润滑条件下,复合镀层的磨屑表现出以下3种形貌特征：切削状磨粒、蠕虫状磨粒和岩石状磨粒。这说明,在本实验条件下,复合刷镀层的磨损失效机制主要有磨粒磨损、粘着磨损和疲劳剥层。     

导卫辊用WC-Co基合金微细晶粒的生成及其磨损机理

采用一种自制的WC-Co基合金作轧钢导卫辊材料，在轧制2000t45钢后用SEM和洛氏硬度计等对其表面形貌及硬度进行了分析和研究。结果表明：合金的主要磨损机制是体积塑性变形、犁沟效应和疲劳磨损。硬度由使用前的56HRC下降到49HRC，硬度下降的主要原因是合金表面部分晶粒在(受到冲击滑动摩擦作用)高速剪切变形条件下发生了动态再结晶，形成了200nm左右的细小晶粒。微细晶粒形成符合一种渐进式位相向差亚晶合并再结晶机制。     

载荷和转速对HDPE多元复合材料摩擦学性能的影响

为改善高密度聚乙烯(HDPE)的力学性能、自润滑性和耐磨性,以HDPE为基体,通过填充六钛酸钾晶须(PTW)、聚四氟乙烯(PTFE)和滑石粉制备一种HDPE复合材料.在MMW-1型摩擦磨损试验机上测试复合材料在不同载荷和转速下的摩擦因数、磨损率,采用扫描电镜(SEM)分析磨痕形貌,探讨HDPE复合材料的摩擦磨损规律.结...     

SiC颗粒对镁基复合材料摩擦磨损性能的影响

采用粉末冶金法制备了AZ91镁合金和SiC颗粒增强的镁基复合材料,SiC的粒度分别为18 μm和8μm,经热压烧结后制得试样.通过扫描电子显微镜观察分析基体和增强体的微观组织形貌,并将制备出的材料分别放入MMW-1型摩擦磨损试验机上,研究SiC的粒度对镁基复合材料摩擦磨损性能的影响.实验结果表明:SiC颗粒的加入能有效...     

无污染切削介质下钛合金铣削刀具磨损机理研究

绿色制造和可持续发展的难加工材料的高速切削技术是21世纪重要的发展领域。本文基于绿色制造基础上,针对空气油雾介质和氮气油雾介质下,对钛合金TC4的高速铣削过程中的刀具磨损机理进行了比较系统的试验研究。通过对试验研究结果分析,初步将刀具的磨损归结为粘结磨损、氧化磨损、剥落与崩刃和扩散磨损。     

工具电极耐磨性和液体组分对电流变加工的影响

实验研究了基于电流变效应即效微型砂轮研抛加工过程中具有不同耐磨性电极材料(淬火钢电极、不锈钢电极、黄铜电极、石墨电极)、不同组分电流变液对玻璃材料去除率的影响,探讨了其作用机理。结果表明:淬火钢和不锈钢锥状电极的加工效率明显高于黄铜和石墨锥状电极,即采用耐磨性好的工具电极材料具有更好的加工效果;沸石粉电流变液的材料去除率高于二氧化硅电流变液的材料去除率。其作用机理是,锥状工具电极材料的耐磨性决定了工具尖端与工件表面之间的加工间隙的保持性,电流变液组分直接影响了电流变效应的强度,从而影响了电流变效应即效微型砂轮对工件表面的研磨压力,形成了不同的材料去除率。     

Ti2AlNb基合金等离子表面渗铬层组织结构对耐磨性能的影响

低硬度和较差的耐磨性制约了钛铝基合金在航空领域的应用。为了提高Ti2AlNb合金的表面硬度和耐磨性,采用双层辉光等离子表面合金化技术对Ti2AlNb合金表面进行渗Cr处理,并对其微观组织、扩散特性及显微硬度和耐磨性进行了分析测试。结果表明：经等离子渗铬处理后,可获得约25μm的合金层;渗层中Cr含量随渗层深度有显著变化且在高温条件下因各原子扩散能力的差异,以基体中Al和Nb量的变化为主,在渗层的不同区域形成不同的相,表层以含Cr2Nb的Laves相和Al8Cr5相为主,而在渗层和基体的交界处形成新的无序O相（Ti25.36Al18.44Nb）;渗层硬度值由外层的HV1125逐渐过渡到基体的HV432,渗层与基体的界面处由于无序O相的析出而硬度最低。渗Cr处理将合金的摩擦因数由原来的0.24降低到0.15,磨损率降低了60%以上。     

The Effect of pH on the Wear of Water-Lubricated Alumina and Zirconia Ceramics

The effects of tribochemically induced dissolution of alumina and zirconia ceramics, and the surface-charge modulation within the tribocontact were investigated using a reciprocating sliding test in various chemical environments. For the pH range 1–13, the wear rate in both materials was observed to vary by as much as an order of magnitude, with the highest wear being observed at the isoelectric point of each material. The observed results at extreme pH values can be understood in terms of localized chemical dissolution of each material, assisted by mechanical microcracking, whereas the highest wear rate at around the isoelectric point results mainly from the formation and fracture of the tribochemical layer.     

PVA-Silk复合水凝胶的摩擦磨损性能研究

选用高分子聚乙烯醇(PVA)和蚕丝(Silk)为原料,采用反复冷冻-解冻法制备PVA-Silk复合水凝胶。在往复式微摩擦试验机上研究PVA-Silk复合水凝胶的摩擦磨损性能,采用激光位移传感器测量PVA-Silk复合水凝胶的磨损深度,在扫描电镜上观察PVA-Silk复合水凝胶磨损后的微观形貌。结果表明,PVA-Silk复合水凝胶在摩擦磨损过程中随载荷的增大,启动摩擦因数增大,平均摩擦因数的增幅减小;随着滑动速率的增加,启动摩擦因数呈先减小后增大的趋势,平均摩擦因数的增幅减小。最大磨损深度随着磨损时间和载荷的增加而增大,磨损宽度没有明显变化,经过10min放置后磨损深度可恢复66.7%。磨损后表面存在明显的往复滑动褶皱,但没有明显的材料黏着剥落现象,放置一段时间后材料会产生恢复,褶皱消失。