Chemical vapor deposition （CVD） diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don＇t have enough a...Chemical vapor deposition （CVD） diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don＇t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond （BD-UM-FGCD） film is fabricated by a three-step method adopting hot filament CVD （HFCVD） method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond （BDD） layer, the extremely high hardness of the middle undoped microcrystalline diamond （UMCD） layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond （FGD） layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional components.展开更多
This work focused on the deposition characteristics and wear behavior of Ni-coated graphite mixed with40 vol.% Al（Ni-Gr/Al） composite coatings sprayed on an Al alloy and a steel substrate by cold spraying（CS）. The...This work focused on the deposition characteristics and wear behavior of Ni-coated graphite mixed with40 vol.% Al（Ni-Gr/Al） composite coatings sprayed on an Al alloy and a steel substrate by cold spraying（CS）. The morphology of the flattened Ni-Gr particles was examined by single-impact tests. Crosssectional microstructure and wear performance of the Ni-Gr/Al composite coatings were studied. Results showed that a larger number of Ni-Gr particles were finally bonded with the steel substrate, whereas many craters existed on the Al alloy substrate after the single-impact tests. The coating on the steel substrate had a high thickness, high graphite content and low coeficient of friction（COF） compared to those on the Al alloy substrate. In addition, the CS coatings presented a homogeneous distribution and uniform morphology of graphite, and a comparative COF to that of conventional thermal sprayed coatings. It was shown that CS could avoid the decomposition and transformation of graphite phase.展开更多
The wear behavior of AZ91 alloy was investigated by considering different parameters,such as load(10−50 N),sliding speed(160−220 mm/s)and sliding distance(250−1000 m).It was found that wear volume loss increased as lo...The wear behavior of AZ91 alloy was investigated by considering different parameters,such as load(10−50 N),sliding speed(160−220 mm/s)and sliding distance(250−1000 m).It was found that wear volume loss increased as load increased for all sliding distances and some sliding speeds.For sliding speed of 220 mm/s and sliding distance of 1000 m,the wear volume losses under loads of 10,20,30,40 and 50 N were calculated to be 15.0,19.0,24.3,33.9 and 37.4 mm3,respectively.Worn surfaces show that abrasion and oxidation were present at a load of 10 N,which changes into delamination at a load of 50 N.ANOVA results show that the contributions of load,sliding distance and sliding speed were 12.99%,83.04%and 3.97%,respectively.The artificial neural networks(ANN),support vector regressor(SVR)and random forest(RF)methods were applied for the prediction of wear volume loss of AZ91 alloy.The correlation coefficient(R2)values of SVR,RF and ANN for the test were 0.9245,0.9800 and 0.9845,respectively.Thus,the ANN model has promising results for the prediction of wear performance of AZ91 alloy.展开更多
The fabrication of high volume fraction （HVF） M7C3 （M=Cr, Fe） reinforced Fe-based composite coating on ASTM A36 steel plate using plasma transferred arc （PTA） welding was studied. The results showed that the vol...The fabrication of high volume fraction （HVF） M7C3 （M=Cr, Fe） reinforced Fe-based composite coating on ASTM A36 steel plate using plasma transferred arc （PTA） welding was studied. The results showed that the volume fraction of carbide M7C3 was more than sixty percent, and the relative wear resistance of the coating tested on a block-on-ring dry sliding tester at constant load （100 N） and variable loads （from 100 to 300 N） respectively was about 9 and 14 times higher than that of non-reinforced a-Fe coating. In addition, under constant load condition the friction coefficients （FCs） of two coatings increased first and then decreased with increasing sliding distance. However, under variable loads condition the FCs of non-reinforced a-Fe based coating increased gradually, while that of HVF MTC3 reinforced coating decreased as the load exceeded 220 N. The worn surface of non-reinforced a-Fe based coating was easily deformed and grooved, while that of the HVF M7C3 reinforced coating was difficult to be deformed and grooved.展开更多
The effects of Zn content on strength and wear performance of Al-12Si-3 Cu alloy synthesized by gravity casting were systematically investigated.The microstructure and mechanical properties of the alloys were evaluate...The effects of Zn content on strength and wear performance of Al-12Si-3 Cu alloy synthesized by gravity casting were systematically investigated.The microstructure and mechanical properties of the alloys were evaluated using OM,XRD,SEM as well as hardness,tension,compression and Charpy impact tests.Their dry sliding wear tests were carried out with a ball-on-disk tester.Microscopic examinations revealed that the microstructure of the base alloy consisted of theα(Al)dendrites,needle-type and coarse Si particles,and CuAl2(θ)phase.The addition of Zn to this alloy resulted in the formation ofα-solid solution phase and the increase of coarse Si particles.The hardness,yield,tensile and compressive strengths,elongation to fracture and impact toughness of the Al-12Si-3 Cu-Zn alloys increased with increasing Zn content,but tendency in the tensile and compressive strengths and ductility reversed after adding 1.5%-2%Zn.In addition,the friction coefficient and volume loss of the Al-12Si-3 Cu-Zn alloys decreased with increasing Zn content.The study showed that the addition of Zn to Al-12Si-3 Cu alloy can improve its potential applications as tribological material.展开更多
It is one of the future trends to create materials in situ by laser additive manufacturing. AlSi7Mg/nano-SiCp composites were successfully in situ prepared by selective laser melting in our previous study. After addin...It is one of the future trends to create materials in situ by laser additive manufacturing. AlSi7Mg/nano-SiCp composites were successfully in situ prepared by selective laser melting in our previous study. After adding 2 wt% nano-SiC particles, the tensile stress and strain increased to 502.94 ± 6.40 MPa and 10.64 ± 1.06%, respectively. For the first time in the present study, we systematically studied and compared the wear performance and corrosion behavior of AlSi7Mg with its composite. We conducted the ball-on-fl at frictional wear test at room temperature, potentiodynamic polarization, electrochemical impedance spectroscopy(EIS), and the immersion corrosion tests in 3.5 wt% NaCl solution. The results showed that composite had higher wear resistance, while AlSi7Mg was more resistant to pitting corrosion. However, the further pitting corrosion of composite was restrained because of the in situ phase nano-Al4C3 and the residual nano-SiCp.展开更多
The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing...The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing are investigated by using X-ray diffractometry （XRD） , scanning electron microsopy （SEM） and energy dis- persive spectroscopy （EDS）. Moreover, the microhardness of the substrate and the coating are investigated using Vickers mierohardness tester, the friction and wear behaviors of the substrate and the coating are investigated by using a block-on-ring tribometer under dry sliding conditions with the load of 245 N. The results show that both γ-Al2O3 and α-Al2O3 phases are observed in the as-sprayed coatings, the mian phase is γ-Al2O3. There are white particulates Al2O3 on its surface. The Al2O3-13 wt. % TiO2 coating possesses higher mierohardness which is about 1018HV and 1.6 times that of the substrate. The wear performance of coating is better than that of the substrate. In a practical application, the life of the extrusion wheel which is plasma sprayed Al2O3-13 wt. % TiO2 coating on the surface is 1.2 times that of the conventional extrusion wheel, and the life is about 330 h.展开更多
This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubric...This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubrication systems during navigation.The research focuses on three representative ship tail-bearing composites:polymer material(K4),thordon material(SR),and tenmat material(FR).Various volume fractions of oil-water mixtures were prepared,and the rheological properties of these mixtures were examined using a rotational rheometer(MCR102).Additionally,the variation of friction coefficients of the composites about load and linear velocity under different oil-water mixtures was analyzed using a Ring-Block Friction and Wear Testing Machine.Following the experiments,the surface morphology of the composites was assessed,and the wear mechanisms were analyzed using a laser interferometric surface profiler(LI-type),a confocal laser microscope(CLSM),and a scanning electron microscope(SEM).The findings indicate that,under all lubrication conditions,the friction coefficients of the three materials exhibit a gradual decrease with increasing load and linear velocity.Furthermore,the wear of the materials initially increases and then decreases with rising oil content,with higher oil concentrations in the oil-water mixture correlating with reduced wear.The study reveals that the three materials experience significant abrasive and adhesive wear under adverse oil-water mixing conditions.This research offers valuable insights for developing friction substitutes for oil-water mixing bearings in specialized operational environments and guides the design of friction components in such bearings.展开更多
Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear proc...Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear process, wear mechanism and failure modes of the physical vapor deposition(PVD)-AlTiN and TiAlN coated tools under dry milling and water-based minimum quantity lubrication(MQL) conditions. The scanning electron microscope(SEM) morphological observation and energy dispersive X-ray spectroscopy(EDX) elements analysis methods were adopted. Moreover, under the water-based MQL condition, the surface integrity such as surface roughness, dimensional and shape accuracy, microhardness and microstructure alteration were researched. The results demonstrated that the tool edge severe adhesion with the work material, induced by the high Al content in the PVD-AlTiN coating caused the catastrophic tool tip fracture. In contrast, the PVD-TiAlN tool displayed a steady and uniform minor flank wear, even though the material peeling and slight chipping also occurred in the final stage. In addition, due to the high effective cooling and lubricating actions of the water-based MQL method, the PVD-TiAlN coated tool demonstrated intact tip geometry; consequently it could be repaired and reused even if the failure criterion was attained. Moreover, as the accumulative milling length and the tool wear increased, all indicators of the surface integrity forehand were deteriorated.展开更多
To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes(CNTs)chemically reacted with Ta to form reinforcement phase(TaC),while the other CNTs were retained as lubrication phase.Subsequently,t...To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes(CNTs)chemically reacted with Ta to form reinforcement phase(TaC),while the other CNTs were retained as lubrication phase.Subsequently,the CoCrAlYTa-xCNTs(x=0,1,2,and 4;wt%)composite coatings were prepared by laserinduction hybrid cladding(LIHC),and the microstructure and wear resistance of coatings were systematically analyzed.Results show that the coatings are mainly composed of TaC,y-(Co,Cr)andβ-(Co,Cr)Al.As the CNTs content increases from 0 wt%to 4 wt%,the volume fraction of TaC increases from 13.11 vol%to 16.12 vol%.Meanwhile,the nano-hardness ofγ-(Co,Cr)andβ-(Co,Cr)Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,respectively.As a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4×10^(-3)to 6.1×10^(-3)mg·m^(-1),and the average friction coefficient decreases from 0.55 to 0.44.The good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.展开更多
The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves...The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves the hardness, tensile strength and abrasion resistance of medium carbon and high C - low Cr steels. The results indicate that the material removal during abrasion is controlled by a number of factors, such as hardness, chemical composition, microstructure and heat treatment conditions. The conclusion is that the heat treated high C - low Cr steel and mild steel carburized by using coaltar pitch provide the best hardness and abrasion resistance and thus appear to be the most suitable materials for making agricultural tools.展开更多
Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infilt...Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infiltration (CVI). The composition and microstructure of the SiC/PyC materials were investigated in detail by XRD, SEM and EDS, etc. The effects of the deposition temperature on the section features and wear resistance of the SiC/PyC were studied. The results show that the PyC layers were deposited onto SiC substrates spontaneously at a lower deposition temperature. The SiC substrates deposited with PyC can significantly reduce the wear rate of the self-dual composite materials under dry sliding condition. The wear tests suggest that the SiC/PyC composite materials own a better wear resistance property when the deposition temperature is 800 °C, and the wear rate is about 64.6% of that without the deposition of PyC.展开更多
To investigate the key factors that cause ZrB_(2)/AA6111 and(ZrB_(2)+Al_(3)Zr)/AA6111 aluminum matrix composites(AMCs)made via in situ reaction to behave differently in terms of friction and wear.Room-temperature dry ...To investigate the key factors that cause ZrB_(2)/AA6111 and(ZrB_(2)+Al_(3)Zr)/AA6111 aluminum matrix composites(AMCs)made via in situ reaction to behave differently in terms of friction and wear.Room-temperature dry sliding tribological behavior of AA6111 Al alloys,ZrB_(2)/AA6111,and(ZrB_(2)+Al_(3)Zr)/AA6111 AMCs against silicon nitride(Si_(3)N_(4))counterparts were investigated.The study showed that AA6111/Al alloy had the highest wear rate and the most unstable coefficient of friction(COF),indicating the worst abrasion resistance.(ZrB_(2)+Al_(3)Zr)/AA6111 AMCs exhibit a lower wear rate and higher COF than ZrB_(2)/AA6111 AMCs.The result proved that the Al_(3)Zr particles prepared by the in-situ reaction are strongly bonded(lattice misfitδ=2.7%)to the Al matrix and are not easily stripped from the substrate.ZrB_(2)/AA6111 AMCs exhibited a lower COF attributed to the tribochemical reaction inducing the formation of more boric acid(H_(3)BO_(3))films with a graphite-like structure having a lubricating effect.展开更多
As is well known,titanium alloy precipitates when subjected to aging treatment,which poses great influence on its mechanical properties.Thus,solution and solution-aging treatments were conducted in this work,and the w...As is well known,titanium alloy precipitates when subjected to aging treatment,which poses great influence on its mechanical properties.Thus,solution and solution-aging treatments were conducted in this work,and the wear performance was investigated under diff erent normal loads.The results showed that acicularα′martensite in the original selective laser melted Ti–6 Al–4 V was decomposed intoα+βphases after the solution treatment,and then Ti;Al nanoparticles clusters were further formed in theα-matrix after the solution-aging treatment.The coefficient of friction decreased straightly as the normal load was increased from 20 to 100 N,and the wear mechanisms were characterized by abrasion,adhesive and oxidative wears.The wear rate of solution and solution-aging treated samples increased significantly comparing to the as-built counterpart,but the increment of the solution-aging treated sample was smaller than that of the solution-only treated sample,because of the Ti;Al precipitation in the solution-aging treated sample.These particles provided ball-like effect,reduced material losses and stabilized the wear process.All these factors contributed to the improvement in wear properties of the parts made by selective laser melting.展开更多
AlCrN coating was prepared on the surface of TiC-based cermet cutting tool with cathodic arc ion plating,and the surface-interface morphologies,compositions of chemical elements,and phases were analyzed by scanning el...AlCrN coating was prepared on the surface of TiC-based cermet cutting tool with cathodic arc ion plating,and the surface-interface morphologies,compositions of chemical elements,and phases were analyzed by scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD),respectively.Bonding strength of the coating-substrate interface was measured with scratching test,and the wear mechanism and friction coefficient of TiC-based cermet cutting tool and AlCrN coating were investigated with friction and wear testing machine.The results show that the interface binding of AlCrN coating is metallurgical mode,and its binding strength is 83 N.The average friction coefficient of TiC-based cermet cutting tool under the load of 6 N is 0.8409,while that under the load of 8 N decreases by about 11%,and the wear mechanism of TiC cermet cutting tool is fatigue wear,abrasive wear,and oxidation wear.The average friction coefficient of AlCrN coating is 0.6363 under the load of 6 N,and the change is relatively stable,decreasing by about 25%than that of TiC-based cermet cutting tool;when the load increases to 8 N,the average friction coefficient of AlCrN coating decreases by 9%.The wear mechanism of AlCrN coating is abrasive wear and oxidation wear,showing lower friction coefficient and good wear resistance.展开更多
Abrasiveness as an intrinsic property of rocks defines the extent of wear or loss when interacting with other materials.In engineering sectors like hard rock mining and tunnelling,comprehending rock abrasiveness holds...Abrasiveness as an intrinsic property of rocks defines the extent of wear or loss when interacting with other materials.In engineering sectors like hard rock mining and tunnelling,comprehending rock abrasiveness holds paramount importance due to its direct effect on tool wear during excavation.Among the diverse methods for assessing rock abrasiveness,the Cerchar abrasivity test emerges as the most widely used approach.Over time,the Cerchar test has garnered substantial attention from scholars,who have delved into the factors influencing test results due to testing conditions and examined the connection between the physical-mechanical parameters of rocks and their abrasiveness.Recent advancements in testing instrument have expanded our ability to measure additional parameters during rock cutting or drilling,yielding fresh insights for abrasiveness assessment,tool wear prediction,tool performance evaluation and rock excavatability estimation.The Cerchar abrasivity test,coupled with recent developments in testing instrument and parameter measurement,holds promising potential for enhancing our comprehension of rock abrasiveness and its practical implications.This review systematically traces the evolution of the test.It commences with an overview of the test origin and progression,emphasizing its pivotal role in assessing rock abrasiveness.Furthermore,it consolidates and categorizes the research contributions from various scholars regarding the test.This includes enhancements and refinements of the testing apparatus,as well as investigations into various testing orientations and their effects on different types of rocks.Moreover,this review illuminates the broader applications and interdisciplinary possibilities of this test,not only in material science but also in tribology.It underscores how the insights gleaned from the Cerchar test can be extrapolated to diverse areas of research beyond the scope of rock engineering.展开更多
The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area betw...The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.展开更多
The external hard TiN ceramic layer and an internal reinforced NiTi matrix were controlled by combining nitriding and solution treatment to achieve ultra-high micro-hardness and excellent wear performance.In addition,...The external hard TiN ceramic layer and an internal reinforced NiTi matrix were controlled by combining nitriding and solution treatment to achieve ultra-high micro-hardness and excellent wear performance.In addition,the effects of nitriding and solution treatment on the microstructure evolution,martensitic transformation,and mechanical and functional properties of 60NiTi alloys were investigated.Compared with 60NiTi alloy,a harder TiN layer appeared at the surface of 60NiTi alloy with nitriding treatment.Meanwhile,a Ni_(3)Ti layer formed under the bottom of TiN layer owing to the consumption of Ti in matrix induced by formation of TiN layer.Upon undergoing solution treatment,the precipitates evolved from the coexistence of Ni_(3)Ti and Ni_(3)Ti_(2)phase to Ni_(4)Ti_(3)phase.The introduction of the outer harder TiN ceramic layer had a constraint of martensitic transformation of 60NiTi alloy,which led to the reduction of martensitic transformation temperature(Ms)and the suppression of martensitic transformation.Importantly,the construction of outermost harder TiN ceramic layer at the surface of B2-NiTi matrix enhanced Ni_(4)Ti_(3)phase improved significantly the microhardness and wear performances by the nitriding and followed solution treatment.Meanwhile,the high compressive fracture strength,fracture strain and superior superelasticity of 60NiTi alloy can be maintained.展开更多
A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It...A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It was shown that a combination of high scan speed and high laser energy density made WC on the edge of WC-12 Co composite powders partially melt in liquid Co and 304 stainless steel matrix, and then new carbides consisting of lamellar WC and herringbone M3 W3 C(M=Fe,Co) were formed. Meanwhile, WC-12 Co composite coatings with no porosity, cracks and drawbacks like decarburization were obtained, showing high densification and good metallurgical bonding with the substrate. Furthermore, a considerably high microhardness of HV0.3 1500-1600, low coefficient of friction of 0.55 and wear rate of(2.15±0.31)×10-7 mm3/(N·m) were achieved owing to the synergistic effect of excellent metallurgical bonding and fine microstructures of composite coating under laser power of 1500 W.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51275302,51005154)Chenguang Program of Shanghai Municipal Education Commission of China(Grant No.12CG11)
文摘Chemical vapor deposition （CVD） diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don＇t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond （BD-UM-FGCD） film is fabricated by a three-step method adopting hot filament CVD （HFCVD） method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond （BDD） layer, the extremely high hardness of the middle undoped microcrystalline diamond （UMCD） layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond （FGD） layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional components.
基金financially supported by the National Natural Science Foundation of China(No.51574196)the 111 Project(No.B08040)+1 种基金the support from programs of China Scholarship Council(No.201404490058)Marie-Curie(No.268696)
文摘This work focused on the deposition characteristics and wear behavior of Ni-coated graphite mixed with40 vol.% Al（Ni-Gr/Al） composite coatings sprayed on an Al alloy and a steel substrate by cold spraying（CS）. The morphology of the flattened Ni-Gr particles was examined by single-impact tests. Crosssectional microstructure and wear performance of the Ni-Gr/Al composite coatings were studied. Results showed that a larger number of Ni-Gr particles were finally bonded with the steel substrate, whereas many craters existed on the Al alloy substrate after the single-impact tests. The coating on the steel substrate had a high thickness, high graphite content and low coeficient of friction（COF） compared to those on the Al alloy substrate. In addition, the CS coatings presented a homogeneous distribution and uniform morphology of graphite, and a comparative COF to that of conventional thermal sprayed coatings. It was shown that CS could avoid the decomposition and transformation of graphite phase.
文摘The wear behavior of AZ91 alloy was investigated by considering different parameters,such as load(10−50 N),sliding speed(160−220 mm/s)and sliding distance(250−1000 m).It was found that wear volume loss increased as load increased for all sliding distances and some sliding speeds.For sliding speed of 220 mm/s and sliding distance of 1000 m,the wear volume losses under loads of 10,20,30,40 and 50 N were calculated to be 15.0,19.0,24.3,33.9 and 37.4 mm3,respectively.Worn surfaces show that abrasion and oxidation were present at a load of 10 N,which changes into delamination at a load of 50 N.ANOVA results show that the contributions of load,sliding distance and sliding speed were 12.99%,83.04%and 3.97%,respectively.The artificial neural networks(ANN),support vector regressor(SVR)and random forest(RF)methods were applied for the prediction of wear volume loss of AZ91 alloy.The correlation coefficient(R2)values of SVR,RF and ANN for the test were 0.9245,0.9800 and 0.9845,respectively.Thus,the ANN model has promising results for the prediction of wear performance of AZ91 alloy.
基金Funded by the National Natural Science Fundation of China(No.51171116)the Ministry of Science and Technology of China(No.2009DFB50350)+1 种基金the Research Foundation of Education Bureau of Hubei Province,China(No.Q20122304)the Foundation of Hubei University of Automotive Technology,China(No.BK201205)
文摘The fabrication of high volume fraction （HVF） M7C3 （M=Cr, Fe） reinforced Fe-based composite coating on ASTM A36 steel plate using plasma transferred arc （PTA） welding was studied. The results showed that the volume fraction of carbide M7C3 was more than sixty percent, and the relative wear resistance of the coating tested on a block-on-ring dry sliding tester at constant load （100 N） and variable loads （from 100 to 300 N） respectively was about 9 and 14 times higher than that of non-reinforced a-Fe coating. In addition, under constant load condition the friction coefficients （FCs） of two coatings increased first and then decreased with increasing sliding distance. However, under variable loads condition the FCs of non-reinforced a-Fe based coating increased gradually, while that of HVF MTC3 reinforced coating decreased as the load exceeded 220 N. The worn surface of non-reinforced a-Fe based coating was easily deformed and grooved, while that of the HVF M7C3 reinforced coating was difficult to be deformed and grooved.
文摘The effects of Zn content on strength and wear performance of Al-12Si-3 Cu alloy synthesized by gravity casting were systematically investigated.The microstructure and mechanical properties of the alloys were evaluated using OM,XRD,SEM as well as hardness,tension,compression and Charpy impact tests.Their dry sliding wear tests were carried out with a ball-on-disk tester.Microscopic examinations revealed that the microstructure of the base alloy consisted of theα(Al)dendrites,needle-type and coarse Si particles,and CuAl2(θ)phase.The addition of Zn to this alloy resulted in the formation ofα-solid solution phase and the increase of coarse Si particles.The hardness,yield,tensile and compressive strengths,elongation to fracture and impact toughness of the Al-12Si-3 Cu-Zn alloys increased with increasing Zn content,but tendency in the tensile and compressive strengths and ductility reversed after adding 1.5%-2%Zn.In addition,the friction coefficient and volume loss of the Al-12Si-3 Cu-Zn alloys decreased with increasing Zn content.The study showed that the addition of Zn to Al-12Si-3 Cu alloy can improve its potential applications as tribological material.
基金financially supported by the Natural and Science Foundation of China(Grant Nos.51775208,51922044)the Hubei Science Fund for Distinguished Young Scholars(No.0216110085)+2 种基金the National Key Research and Development Program“Additive Manufacturing and Laser Manufacturing”(No.2016YFB1100101)the Wuhan Plan of Science and Technology(No.2018010401011281)the Academic Frontier Youth Team(Nos.2017QYTD06,2018QYTD04)at Huazhong University of Science and Technology(HUST)。
文摘It is one of the future trends to create materials in situ by laser additive manufacturing. AlSi7Mg/nano-SiCp composites were successfully in situ prepared by selective laser melting in our previous study. After adding 2 wt% nano-SiC particles, the tensile stress and strain increased to 502.94 ± 6.40 MPa and 10.64 ± 1.06%, respectively. For the first time in the present study, we systematically studied and compared the wear performance and corrosion behavior of AlSi7Mg with its composite. We conducted the ball-on-fl at frictional wear test at room temperature, potentiodynamic polarization, electrochemical impedance spectroscopy(EIS), and the immersion corrosion tests in 3.5 wt% NaCl solution. The results showed that composite had higher wear resistance, while AlSi7Mg was more resistant to pitting corrosion. However, the further pitting corrosion of composite was restrained because of the in situ phase nano-Al4C3 and the residual nano-SiCp.
文摘The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing are investigated by using X-ray diffractometry （XRD） , scanning electron microsopy （SEM） and energy dis- persive spectroscopy （EDS）. Moreover, the microhardness of the substrate and the coating are investigated using Vickers mierohardness tester, the friction and wear behaviors of the substrate and the coating are investigated by using a block-on-ring tribometer under dry sliding conditions with the load of 245 N. The results show that both γ-Al2O3 and α-Al2O3 phases are observed in the as-sprayed coatings, the mian phase is γ-Al2O3. There are white particulates Al2O3 on its surface. The Al2O3-13 wt. % TiO2 coating possesses higher mierohardness which is about 1018HV and 1.6 times that of the substrate. The wear performance of coating is better than that of the substrate. In a practical application, the life of the extrusion wheel which is plasma sprayed Al2O3-13 wt. % TiO2 coating on the surface is 1.2 times that of the conventional extrusion wheel, and the life is about 330 h.
基金supported by the National Natural Science Foundation of China(U2341284,51579198)the Postdoctoral Fellowship Program of CPSF under Grant Number GZB20240584the Fundamental Research Funds for the Central Universities(WUT:3120624441).
文摘This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubrication systems during navigation.The research focuses on three representative ship tail-bearing composites:polymer material(K4),thordon material(SR),and tenmat material(FR).Various volume fractions of oil-water mixtures were prepared,and the rheological properties of these mixtures were examined using a rotational rheometer(MCR102).Additionally,the variation of friction coefficients of the composites about load and linear velocity under different oil-water mixtures was analyzed using a Ring-Block Friction and Wear Testing Machine.Following the experiments,the surface morphology of the composites was assessed,and the wear mechanisms were analyzed using a laser interferometric surface profiler(LI-type),a confocal laser microscope(CLSM),and a scanning electron microscope(SEM).The findings indicate that,under all lubrication conditions,the friction coefficients of the three materials exhibit a gradual decrease with increasing load and linear velocity.Furthermore,the wear of the materials initially increases and then decreases with rising oil content,with higher oil concentrations in the oil-water mixture correlating with reduced wear.The study reveals that the three materials experience significant abrasive and adhesive wear under adverse oil-water mixing conditions.This research offers valuable insights for developing friction substitutes for oil-water mixing bearings in specialized operational environments and guides the design of friction components in such bearings.
基金supported by the National Natural Science Foundation of China(Grant No.51375082)
文摘Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear process, wear mechanism and failure modes of the physical vapor deposition(PVD)-AlTiN and TiAlN coated tools under dry milling and water-based minimum quantity lubrication(MQL) conditions. The scanning electron microscope(SEM) morphological observation and energy dispersive X-ray spectroscopy(EDX) elements analysis methods were adopted. Moreover, under the water-based MQL condition, the surface integrity such as surface roughness, dimensional and shape accuracy, microhardness and microstructure alteration were researched. The results demonstrated that the tool edge severe adhesion with the work material, induced by the high Al content in the PVD-AlTiN coating caused the catastrophic tool tip fracture. In contrast, the PVD-TiAlN tool displayed a steady and uniform minor flank wear, even though the material peeling and slight chipping also occurred in the final stage. In addition, due to the high effective cooling and lubricating actions of the water-based MQL method, the PVD-TiAlN coated tool demonstrated intact tip geometry; consequently it could be repaired and reused even if the failure criterion was attained. Moreover, as the accumulative milling length and the tool wear increased, all indicators of the surface integrity forehand were deteriorated.
基金financially supported by the National Natural Science Foundation of China(Nos.52005217 and 51261026)the Basic and Applied Basic Research Fund Project of Guangdong Province in China(Nos.2023A1515012684,2021A1515010523 and 2020A1515110020)+4 种基金the University Research Platform and Research Projects of Guangdong Education Department(No.2022ZDZX3003)the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials(No.2022GXYSOF18)Guanxi Key Laboratory of Information Materials(No.221012-K)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2021WNLOKF010)the Fundamental Research Funds for the Central Universities(No.21622110)。
文摘To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes(CNTs)chemically reacted with Ta to form reinforcement phase(TaC),while the other CNTs were retained as lubrication phase.Subsequently,the CoCrAlYTa-xCNTs(x=0,1,2,and 4;wt%)composite coatings were prepared by laserinduction hybrid cladding(LIHC),and the microstructure and wear resistance of coatings were systematically analyzed.Results show that the coatings are mainly composed of TaC,y-(Co,Cr)andβ-(Co,Cr)Al.As the CNTs content increases from 0 wt%to 4 wt%,the volume fraction of TaC increases from 13.11 vol%to 16.12 vol%.Meanwhile,the nano-hardness ofγ-(Co,Cr)andβ-(Co,Cr)Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,respectively.As a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4×10^(-3)to 6.1×10^(-3)mg·m^(-1),and the average friction coefficient decreases from 0.55 to 0.44.The good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.
文摘The low stress abrasion behaviours of heat treated mild, medium carbon and high C - low Cr steels, which are generally used in making farm implements, have been investigated. The simple heat treatment greatly improves the hardness, tensile strength and abrasion resistance of medium carbon and high C - low Cr steels. The results indicate that the material removal during abrasion is controlled by a number of factors, such as hardness, chemical composition, microstructure and heat treatment conditions. The conclusion is that the heat treated high C - low Cr steel and mild steel carburized by using coaltar pitch provide the best hardness and abrasion resistance and thus appear to be the most suitable materials for making agricultural tools.
基金Project(2011CB605801)supported by the National Basic Research Program of ChinaProject(2011M500127)supported by the China Postdoctoral Science Foundation+2 种基金Projects(51102089,50802115)supported by the National Natural Science Foundation of ChinaProjects(12JJ4046,12JJ9014)supported by the Natural Science Foundation of Hunan Province,ChinaProject(74341015817)supported by the Post-doctoral Fund of Central South University,China
文摘Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infiltration (CVI). The composition and microstructure of the SiC/PyC materials were investigated in detail by XRD, SEM and EDS, etc. The effects of the deposition temperature on the section features and wear resistance of the SiC/PyC were studied. The results show that the PyC layers were deposited onto SiC substrates spontaneously at a lower deposition temperature. The SiC substrates deposited with PyC can significantly reduce the wear rate of the self-dual composite materials under dry sliding condition. The wear tests suggest that the SiC/PyC composite materials own a better wear resistance property when the deposition temperature is 800 °C, and the wear rate is about 64.6% of that without the deposition of PyC.
基金Supported by National Natural Science Foundation of China(Grant No.51605206)Postgraduate Research&Practice Innovation Program of Jiangsu Province of China(Grant Nos.SJCX21_1769,SJCX22_1941)Ministry of Science and Technology High-end Foreign Experts Introduction Program Project of China(Grant Nos.G2022014043,G2022014134L).
文摘To investigate the key factors that cause ZrB_(2)/AA6111 and(ZrB_(2)+Al_(3)Zr)/AA6111 aluminum matrix composites(AMCs)made via in situ reaction to behave differently in terms of friction and wear.Room-temperature dry sliding tribological behavior of AA6111 Al alloys,ZrB_(2)/AA6111,and(ZrB_(2)+Al_(3)Zr)/AA6111 AMCs against silicon nitride(Si_(3)N_(4))counterparts were investigated.The study showed that AA6111/Al alloy had the highest wear rate and the most unstable coefficient of friction(COF),indicating the worst abrasion resistance.(ZrB_(2)+Al_(3)Zr)/AA6111 AMCs exhibit a lower wear rate and higher COF than ZrB_(2)/AA6111 AMCs.The result proved that the Al_(3)Zr particles prepared by the in-situ reaction are strongly bonded(lattice misfitδ=2.7%)to the Al matrix and are not easily stripped from the substrate.ZrB_(2)/AA6111 AMCs exhibited a lower COF attributed to the tribochemical reaction inducing the formation of more boric acid(H_(3)BO_(3))films with a graphite-like structure having a lubricating effect.
基金financially supported by the National Natural Science Foundation of China(Grant No.51905279)the Major Projects of Scientifi c and Technological Innovation(2025)of Ningbo City(Grant Nos.2018B10007 and 2019B10078)。
文摘As is well known,titanium alloy precipitates when subjected to aging treatment,which poses great influence on its mechanical properties.Thus,solution and solution-aging treatments were conducted in this work,and the wear performance was investigated under diff erent normal loads.The results showed that acicularα′martensite in the original selective laser melted Ti–6 Al–4 V was decomposed intoα+βphases after the solution treatment,and then Ti;Al nanoparticles clusters were further formed in theα-matrix after the solution-aging treatment.The coefficient of friction decreased straightly as the normal load was increased from 20 to 100 N,and the wear mechanisms were characterized by abrasion,adhesive and oxidative wears.The wear rate of solution and solution-aging treated samples increased significantly comparing to the as-built counterpart,but the increment of the solution-aging treated sample was smaller than that of the solution-only treated sample,because of the Ti;Al precipitation in the solution-aging treated sample.These particles provided ball-like effect,reduced material losses and stabilized the wear process.All these factors contributed to the improvement in wear properties of the parts made by selective laser melting.
基金financially supported by the Jiangsu Province Science and Technology Support Program(Industry)(No.BE2014818)。
文摘AlCrN coating was prepared on the surface of TiC-based cermet cutting tool with cathodic arc ion plating,and the surface-interface morphologies,compositions of chemical elements,and phases were analyzed by scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD),respectively.Bonding strength of the coating-substrate interface was measured with scratching test,and the wear mechanism and friction coefficient of TiC-based cermet cutting tool and AlCrN coating were investigated with friction and wear testing machine.The results show that the interface binding of AlCrN coating is metallurgical mode,and its binding strength is 83 N.The average friction coefficient of TiC-based cermet cutting tool under the load of 6 N is 0.8409,while that under the load of 8 N decreases by about 11%,and the wear mechanism of TiC cermet cutting tool is fatigue wear,abrasive wear,and oxidation wear.The average friction coefficient of AlCrN coating is 0.6363 under the load of 6 N,and the change is relatively stable,decreasing by about 25%than that of TiC-based cermet cutting tool;when the load increases to 8 N,the average friction coefficient of AlCrN coating decreases by 9%.The wear mechanism of AlCrN coating is abrasive wear and oxidation wear,showing lower friction coefficient and good wear resistance.
文摘Abrasiveness as an intrinsic property of rocks defines the extent of wear or loss when interacting with other materials.In engineering sectors like hard rock mining and tunnelling,comprehending rock abrasiveness holds paramount importance due to its direct effect on tool wear during excavation.Among the diverse methods for assessing rock abrasiveness,the Cerchar abrasivity test emerges as the most widely used approach.Over time,the Cerchar test has garnered substantial attention from scholars,who have delved into the factors influencing test results due to testing conditions and examined the connection between the physical-mechanical parameters of rocks and their abrasiveness.Recent advancements in testing instrument have expanded our ability to measure additional parameters during rock cutting or drilling,yielding fresh insights for abrasiveness assessment,tool wear prediction,tool performance evaluation and rock excavatability estimation.The Cerchar abrasivity test,coupled with recent developments in testing instrument and parameter measurement,holds promising potential for enhancing our comprehension of rock abrasiveness and its practical implications.This review systematically traces the evolution of the test.It commences with an overview of the test origin and progression,emphasizing its pivotal role in assessing rock abrasiveness.Furthermore,it consolidates and categorizes the research contributions from various scholars regarding the test.This includes enhancements and refinements of the testing apparatus,as well as investigations into various testing orientations and their effects on different types of rocks.Moreover,this review illuminates the broader applications and interdisciplinary possibilities of this test,not only in material science but also in tribology.It underscores how the insights gleaned from the Cerchar test can be extrapolated to diverse areas of research beyond the scope of rock engineering.
基金This project is supported by National Innovation Foundation for TechnologyBased Firms, China (No.01C26213300872).
文摘The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.
基金supported by the Development Plan of Shandong Province Young Innovation Team of Higher Education Institutions,China(No.2023KJ242)the National Natural Science Foundation of China(Nos.52371181,52101231,52101232,and 52175192)the Natural Science Foundation of Shandong Province,China(Nos.ZR2024QE019,and ZR2021QE044)。
文摘The external hard TiN ceramic layer and an internal reinforced NiTi matrix were controlled by combining nitriding and solution treatment to achieve ultra-high micro-hardness and excellent wear performance.In addition,the effects of nitriding and solution treatment on the microstructure evolution,martensitic transformation,and mechanical and functional properties of 60NiTi alloys were investigated.Compared with 60NiTi alloy,a harder TiN layer appeared at the surface of 60NiTi alloy with nitriding treatment.Meanwhile,a Ni_(3)Ti layer formed under the bottom of TiN layer owing to the consumption of Ti in matrix induced by formation of TiN layer.Upon undergoing solution treatment,the precipitates evolved from the coexistence of Ni_(3)Ti and Ni_(3)Ti_(2)phase to Ni_(4)Ti_(3)phase.The introduction of the outer harder TiN ceramic layer had a constraint of martensitic transformation of 60NiTi alloy,which led to the reduction of martensitic transformation temperature(Ms)and the suppression of martensitic transformation.Importantly,the construction of outermost harder TiN ceramic layer at the surface of B2-NiTi matrix enhanced Ni_(4)Ti_(3)phase improved significantly the microhardness and wear performances by the nitriding and followed solution treatment.Meanwhile,the high compressive fracture strength,fracture strain and superior superelasticity of 60NiTi alloy can be maintained.
基金Project(20171ACE50018)supported by the Key Research and Development Program of Jiangxi Province,ChinaProject(2017-YZD2-16)supported by the Key Research Project of Jiangxi Academy of Sciences,China。
文摘A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It was shown that a combination of high scan speed and high laser energy density made WC on the edge of WC-12 Co composite powders partially melt in liquid Co and 304 stainless steel matrix, and then new carbides consisting of lamellar WC and herringbone M3 W3 C(M=Fe,Co) were formed. Meanwhile, WC-12 Co composite coatings with no porosity, cracks and drawbacks like decarburization were obtained, showing high densification and good metallurgical bonding with the substrate. Furthermore, a considerably high microhardness of HV0.3 1500-1600, low coefficient of friction of 0.55 and wear rate of(2.15±0.31)×10-7 mm3/(N·m) were achieved owing to the synergistic effect of excellent metallurgical bonding and fine microstructures of composite coating under laser power of 1500 W.
