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Interplay between microstructural evolution and tribo-chemistry during dry sliding of metals

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Friction 2019年第6期7卷 637-650页

作者： Philipp GGRÜTZMACHER Sebastian RAMMACHER Dominic RATHMANN Christian MOTZ FrankMÜCKLICH Sebastian SUAREZ Chair of Functional Materials Saarland UniversityCampus D3.3Saarbrücken 66123Germany Chair of Experimental Methodology of Material Science Saarland UniversityCampus D2.2Saarbrücken 66123Germany

Understanding the microstructural and tribo-chemical processes during tribological loading is of utmost importance to further improve the tribological behavior of metals. In this study, the friction, wear and tribo-chemical behavior of Ni with different initial microstructures(nanocrystalline, bi-modal, coarse-grained) is investigated under dry sliding conditions. In particular, the interplay be-tween frictional response, microstructural evolution and tribo-oxidation is considered. Friction tests are carried out using ball-on-disk experiments with alumina balls as counter-bodies, varying the load between 1 and 5 N. The microstructural evolution as well as the chemical reactions beneath the samples’ surface is investigated by means of cross-sections. The samples with finer microstructures show a faster run-in and lower maximum values of the coefficient of friction(COF) which can be attributed to higher oxidation kinetics and a higher hardness. It is observed that with increasing sliding cycles, a stable oxide layer is formed. Furthermore, initially coarse-grained samples show grain refinement, whereas initially finer microstructures undergo grain coarsening converging towards the same superficial grain size after 2,000 sliding cycles. Consequently, the experimental evidence supports that, irrespective of the initial microstructure, after a certain deformation almost identical steady-state COF values for all samples are achieved.

关键词： dry sliding microstructural analysis tribo‐oxidation wear

Characteristics of Deformation Layer for Vermicular Iron under dry sliding Friction

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Journal of Iron and Steel Research International 2004年第3期11卷 44-47页

作者： SUN Le-min SHANG Guan-bao ZHANG Yong-zhen CHEN Yue Henan University of Science and Technology

At room temperature,dry sliding wear tests were carried out using pin-on-disc test rig,in which the pin is made of vermicular iron and the disc is made of 40 Cr *** microstructures of the frictional surfaces for the pin specimens were *** the action of both frictional heat and frictional shearing stress,aplastic deformation layer under the frictional surface is *** morphology and properties of the plastic deformation layer depend on specimen material,contact pressure and frictional shearing *** the plastic deformation layer,the phosphorous mass percent varies at different depth and results in different *** the outer side of surface,the hardness is the biggest and the phosphorous mass percent is the *** become gradually small from outer side to inner side of the surface.

关键词： vermicular iron dry sliding plastic deformation layer

Fractal Characteristics of dry sliding Surfaces Based on 3-D Measurements

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Tsinghua Science and Technology 2004年第3期9卷 308-311页

作者：张永振孙乐民刘维民朱均上官宝 School of Materials Science and Engineering Henan University Technology Luoyang 471003 China State Key Laboratory Solid Lubrication Lanzhou Institute Chemical Physics Chinese Academy Sciences 730000 Bearing and Lubrication Theory Institute Xi’an Jiaotong UniversityXi’an 710048China

D surface morphology measurements of compact graphite irons were used to analyze the frac-tal characteristics of the surfaces to relate the dry sliding surface morphology to the fractal dimension. The measurements show that the fractal dimensions (Df ) of the sliding surfaces vary from1 to 2 and are closely related to the surface morphologies. Increasing depths of grooves or pits increases the Df values. At the same time, increasing densities of the grooves also causes the Df values to increase. The data can be used to discuss relationship between Df and the friction coefficient as well as the wear rate.

关键词： dry sliding fractal analysis 3-D surface

Tribological characteristics of compacted graphite cast iron in dry sliding condition

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China Foundry 2006年第1期3卷 16-25页

作者： CHEN Yue ZHANG Yong-zhen ZHANG Ran-yang School of Material Science and Engineering Henan University of Science and Technology Luoyang 471003 Henan P. R. China

The dry sliding wear and friction behaviors of compacted graphite cast iron (C. G. iron) were analyzed. The influence of the operating conditions (i.e. velocity,pressure), chemical composition and microstructure on the dry sliding tribological characteristics of the cast iron was studied. The 3-D topographical properties and wear surface temperature characteristics of C. G. iron were discussed. The results suggested that, compared with spheroidal graphite cast iron (S. G. iron) and grey cast iron, C. G. iron has the lowest wear rate,the highest friction coefficient, the lowest attenuation quantity in friction coefficient and is suitable for brake materials. The wear resistance and friction coefficient of C. G. iron can be substantially increased by introducing alloy elements such as phosphorus. The good tribological properties of C. G. iron under dry sliding condition have been further explained from mechanism by analyzing the 3-D surface topography and temperature field of dry sliding surface of specimen.

关键词： C. G. iron dry sliding friction-wear tribology

Comparative study on tribological properties of isostatic graphite and carbon graphite under dry sliding and water-lubricated conditions

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Journal of Southeast University(English Edition) 2020年第3期36卷 273-277页

作者： Ding Hongqin Jiang Shuyun School of Mechanical Engineering Southeast University Nanjing 211189 China

The tribological properties of isostatic graphite and carbon graphite under dry sliding and water lubricated conditions were *** friction test was conducted by using a pin-on-disc *** friction coefficient and the wear rate were employed to evaluate the tribological performances of the two materials,and wear morphology was used to analyze the wear *** results show that the friction coefficient of the isostatic graphite is larger than that of the carbon graphite under the dry sliding condition,and the wear rate is lower than that of the carbon *** the water lubricated condition,the friction coefficients and the wear rates of the isostatic graphite decrease *** main wear form of the isostatic graphite is abrasive wear,while the main wear form of the carbon graphite is spalling ***,the tribological mechanism of the isostatic graphite under dry sliding and water lubricated conditions were systematically analyzed.

关键词： isostatic graphite carbon graphite friction and wear water lubrication dry sliding

Fractal Analysis on 3-D Surfaces of C.G. Irons under dry sliding

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Fractal Analysis on 3-D Surfaces of C.G. Irons under Dry Sli...

dry Friction Characteristics of Ti-6Al-4V Alloy under High sliding Velocity

第三届表面工程国际会议

作者： Yongzhen Zhang,Lemin Sun,Weimin Liu,Jun Zhu,Bao Shangguang,Yue ChenBearing and lubrication Theory Institute,Xi’an Jiaotong University,Xi’an,710048,PR China Dept. of Materials,Luoyang Institute of Technology,Luoyang 471039,PR China State Key Laboratory of Solid Lubrication. Lanzhou Institute of Chemical Physics. Chinese Academy of Sciences,Lanzhou,730000,PR China

＜正＞ Based on 3-D surface morphology measurements of ***,the fractal analyses were made on relationship between dry slid morphology and the fractal *** is revealed that the values of fractal dimensions （Df） of sliding surfaces are in the range be which are closely related to the surface *** the increase in depths of grooves or pits,the Df values *** the sam increases in densities of the grooves also cause the Df values to *** last,relationship among Df and friction coefficient as well a is discussed.

关键词： dry sliding fractal analysis 3-D surface

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Journal of Wuhan University of Technology(Materials Science) 2007年第4期22卷 582-585页

作者：邱明 School of Mechatronic Engineering Henan University of Science and Technology Theory of Lubrication and Bearing Institute Xi'an Jiaotong UniversityXi'an 710049China

Tribological behaviours of Ti-6Al-4V alloy pins sliding against GCr15 steel discs over a range of contact pressures （0.33-1.33 MPa） and sliding velocities （30-70 m/s） were investigated using a pin-on-disc tribometer under unlubricated conditions. The wear mechanisms and the wear transition were analyzed based on examinations of worn surfaces using SEM, EDS and XRD. When the velocity increases, the friction coefficient and the wear rate of the Ti-6Al-4V alloy show typical transition features, namely, the critical values of sliding velocities for 0.33 and 0.67 MPa are 60 and 40 m/s, respectively. The experimental results reveal that the tribological behaviours of Ti-6Al-4V alloys are controlled by the thermal-mechanical effects, which connects with the friction heat and hard particles of the pairs. A tribolayer containing mainly Ti oxides and V oxides is formed on the worn surface of Ti-6Al-4V alloy.

关键词： Ti alloy dry sliding friction behavior contact temperature wear mechanism

Impact of surface roughness on the coefficient of friction of polymer-on-polymer contacts for deflection pulley-rope systems in the lift industry

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Friction 2024年第9期12卷 2126-2138页

作者： Ainhoa GUINEA Andrea AGINAGALDE Wilson TATO Iñigo LLAVORI Pablo GARCIA Leire ARRAIAGO Alaitz ZABALA Mechanical and Industrial Production Department Mondragon UnibertsitateaMondragon 20500Spain Orona EIC Orona IdeoHernani 20120Spain

The coefficient of friction(CoF)between the deflection pulley and rope in a lift strongly affects the life span of the *** surface roughness is a key factor affecting the metallic pulley–rope CoF,its effect on polymeric pulleys is *** present study analyses the effect of roughness and working conditions on cast polyamide 6(PA6G)deflection pulley–thermoplastic polyurethane(TPU)-coated rope *** statistical analysis revealed that the effect of surface roughness on the CoF for low-load tests was *** present study contributes significantly to parameter selection in deflection pulley machining to minimise friction between the pulley and rope.

关键词： polymer-on-polymer friction roughness dry sliding

Gradient nanostructured tungsten and the thermal shock response

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Tungsten 2023年第4期5卷 548-557页

作者： Yan Jiang Ping Huang Zhi-Qiang Jiang Jing Hou Zhong Xu En-Hui Wu Jun Li Vanadium and Titanium Resource Comprehensive Utilization Key Laboratory of Sichuan Province Panzhihua UniversityPanzhihua617000China

In fusion reactor or spallation neutron source environment,damage of tungsten components begins at the *** enhance the surface toughness,strength,and hardness of tungsten,a nano-to-micro sc ale lamellar gradient surface layer(thickness up to~50μm)was produced on as-rolled pure tungsten using a dry-sliding surface *** dry-sliding temperature and time were established by observing the grain-size evolution from room temperature to 750℃and the coefficient of friction on the surface layer after sliding from 10 to 50 *** grains changed into a slender fibrous structure at 250℃,which is higher than the ductile-brittle transition temperature but lower than the dynamic recrystallization temperature(750℃).The coefficient of friction of the surface layer decreased with sliding time and stabilized at approximately 50 min,indicating near-s aturation of the surface *** repetitive thermal loads of 10,20,and 30 MW·m^(-2)on the gradient modified layer,it exhibited mainly recrystallization and grain *** proportion of low-angle grain boundaries(<10°)reached50.6,42.2,and 17.3%,respectively,and the hardness decreased to 602,582,and 488HV.A heat load of 30 MW·m^(-2)was the threshold for the fast grain *** with unmodified tungsten,the recrystallization and grain growth are relatively ***,the gradient layer could suppress the formation of pits and protrusions in the as-rolled tungsten sample.

关键词： Gradient layer Tungsten dry sliding Coefficient of friction