Adhesive Wear Mechanism Research Articles

The Correlation Analysis of Microstructure and Tribological Characteristics of In Situ VCp Reinforced Iron-Based Composite.

In this study, four kinds of heat treatments were performed to obtain a certain amount of retained austenite, which can result in good toughness and low brittleness accompanied with wear resistance of an in situ VC particle reinforced iron-based composite (VCFC). Microstructure, mechanical properties and wear resistance of the samples under heat treatment of QP, QPT, MQP and MQPT were compared. The experimental results indicated that there is a huge difference in microstructure between MQPT and the other heat treatments. High-proportion retained austenite and white net-like precipitates of M7C3 carbide existed in the MQPT-treated sample, but thick M7C3 carbide with brittleness was discovered in the other sample. Thereby, high-proportion retained austenite contributed to its low hardness of 634 HV and high tensile strength of 267 MPa, while a maximum hardness of 705.5 HV and a minimum tensile strength of 205 MPa were exhibited in the QPT-treated sample with a V-rich carbide of high hardness, a Cr-rich carbide of brittleness and a high-proportion martensite. Meanwhile, a phase transformation from retained austenite to martensite could increase the hardness and enhance wear resistance based on the transformation-induced plasticity (TRIP) effect; its wear rate was only 1.83 × 10−6 mm−3/(N·m). However, the wear rates of the samples under QP, QPT and MQP heat treatments increased by 16.4%, 44.3% and 41.0%, respectively. The wear mechanism was a synergistic effect of the adhesive wear mechanism and the abrasive wear mechanism. The adhesive wear mechanism was mainly considered in the MQPT-treated sample to reduce the wear rate attributed to high-proportion retained austenite and the existence of wear debris with a W element on the surface of the wear track. However, the abrasive wear mechanism could exist in the other samples because of a lot of thick, brittle M7C3, thereby resulting in a higher wear rate due to immediate contact between the designed material and the counterpart.

Investigation of indentation response, scratch resistance, and wear behavior of tungsten carbide coatings fabricated by two-step interstitial carburization on tungsten

In the present study, we fabricated tungsten carbide (WC) coatings on tungsten using a recently proposed two-step interstitial carburization method and systematically investigated their mechanical behavior, including their responses to indentation, scratch, and wear. The coatings comprised WC and a very small amount of W2C dispersed at the coating–substrate interface. The volume fraction of the carbide phases nearly reached 100 %, and the grain size of WC increased with increasing distance from the surface, thus exhibiting a distinct gradient microstructure with columnar WC grains. Indentation experiments on the coating surface showed that the coating attained a hardness of 25 GPa and cracks were generated when the indentation load exceeded 5 N. The fracture toughness of the coating was estimated to be 2.5 MPa m1/2. The response of the coating to scratching was not sensitive to the scratching speed, and an increase in the scratching speed did not alter the geometry of the grooves, but it resulted in an earlier occurrence and a higher density of cracks; further, it leads to increased acoustic emission. Delamination of the coating did not occur when the normal load was in the range of 0–100 N, indicating that the adhesion strength of the coating was greater than 100 N. We studied the wear behavior using a ball-on-disc tribometer and found that the WC coatings exhibited extraordinarily high wear resistance, and both abrasive wear and adhesive wear mechanisms acted concurrently during wear. Therefore, we verified that the WC coatings prepared by interstitial carburization have a high hardness and excellent scratch and wear resistance.

Effect of Graphene Addition in Cutting Fluids Applied by MQL in End Milling of AISI 1045 Steel

The cutting fluids applied to the machining processes by the MQL process aim to reduce the machining temperatures and tool wear as well as improve the surface and dimensional finishing of the parts. To increase the efficiency of these fluids, graphene lubricating platelets are added. This work investigated the performance of three different cutting fluids with graphene sheets added and applied via MQL, considering the tool life, wear, and wear mechanisms acting on TiAlN-coated cemented carbide cutting tools in the end milling of AISI 1045 steel. We evaluated two vegetable- (MQL15 and LB1000) and one mineral-based (MQL14) neat oils and the same fluids with the addition of 0.05 and 0.1%wt graphene nanoplatelets. Dry cuts were also performed and investigated for comparison. The experiments were conducted under fixed cutting conditions (vc = 250 m/min, fz = 0.14 mm/tooth, ap = 1 mm, and ae = 20 mm). The end-of-tool-life criterion followed the guidelines of ISO 8688-1 (1989). To analyze the results, ANOVA and Tukey’s test were applied. The addition of graphene sheets in the vegetable-based cutting fluids effectively increased the lubricating properties, partially reducing the wear mechanisms acting on the tools. In addition, there was a predominance of thermal fatigue cracks and mechanical cracks as well as adhesive and abrasive wear mechanisms on the tools used in the cutting with the MQL15 and MQL14 fluids, indicating greater cyclical fluctuations in temperature and surface stresses.

Tool wear, hole quality, power consumption and chip morphology analysis for drilling Ti-6Al-4V using LN2 and LCO2

For the first time, thrust force, power consumption, flank tool wear using FE-SEM and line scan EDS analysis; hole quality indicators and hole surface analysis using FE-SEM, microhardness and chip morphology for drilling Ti-6Al-4V using cryogenic coolants (LN2 and LCO2) and flood coolant are comprehensively investigated. 146 blind holes are drilled for all three cooling conditions. 72% and 50% lesser tool wear is observed for LCO2 and LN2 respectively, compared to flood machining. Adhesion wear mechanism is found to be the predominant factor leading to higher tool wear during flood machining. The demonstrated superior performance of LCO2 for all the machinability indicators in this research is a significant finding for machining Ti-6Al-4V for the high-value manufacturing industries.

Research on cutting performance in high-speed milling of TC11 titanium alloy using self-propelled rotary milling cutters

Titanium alloys are widely used in many areas, such as aerospace, biomedical, and automotive industries, due to their excellent chemical and physical properties. However, its difficult-to-machine characteristic causes various problems in the machining process, such as serious tool wear and elastic deformation of workpieces. To achieve high efficiency and quality of machining titanium alloy materials, this paper conducted an experimental research on the high-speed milling of TC11 titanium alloy with self-propelled rotary milling cutters. In this paper, the wear mechanism of self-propelled rotary milling cutters was explored; the influence of milling velocity was analyzed on cutting process, and the variation laws with the change in milling length were obtained of milling forces, chip morphology, and machined surface quality. The calculation method of self-propelled rotary velocity was proposed, based on the experimental research. The results showed that in the early and middle stages of milling, the insert coating peeled off evenly under the joint action of abrasive and adhesive wear mechanisms. As the milling length increased, the dense notches occurred on the cutting edge of the cutter, the wear mechanism converted gradually into fatigue wear, and furthermore, coating started peeling off the cutting edge with the occurrence of thermal fatigue cracks on the insert. As the milling length was further extended, the milling forces tended to intensify, the chip deformation worsened, and the obvious cracks occurred at the bottom of chips. The increase in milling velocity intensified the friction between chips and self-propelled rotary milling cutters, and decreased the ratio of self-propelled rotary velocity to milling velocity. This caused the drop in cutting performance of cutters and the growth in tool wear rate.

Chevrel phase-based solid lubrication coating for wear resistant electrocontact friction pairs in vacuum

The work comparatively studies the wear kinetics of copper friction pairs with Chevrel phase-based coating (Cu-Mo-S) and without it in vacuum of 1.5x10−3 Pa. The coating is deposited on test pads by the ion-plasma method. The tribological investigations scheme were used the “disk – coated pad”. The detected falling of the wear rate of the friction pair with the coating is explained by the change of the adhesive wear mechanism to fatigue one.

Effect of microstructure, mechanical and wear on Al-CNTs/graphene hybrid MMC’S

ABSTRACT The current research focuses on developing an Aluminium/Gr-CNT hybrid composite with two nanoscale reinforcements (Graphene and CNT). Stir casting was used to create hybrid composites with different weight fractions of graphene (1, 2, 3, and 5 Wt. %.) and a fixed CNT content of 2 Wt.%. The influence of varying graphene content with fixed CNT content on density, microstructure, hardness, and wear on hybrid MMC's was investigated. Hardness and wear tests were carried out as per ASTM E384 and G99 standards. Microstructure showed a relatively uniform dispersal of reinforcements (Gr and CNT) in pure Al matrix. The study revealed that the hardness of Al/Gr/CNT hybrid composites is higher than that of pure aluminium. The increase in hardness and addition of reinforcements lead to a significant reduction in wear rate. Wear surface morphology studies reported that pure aluminium had undergone an adhesion wear mechanism, whereas Al/Gr/CNT hybrid composites had undergone abrasion wear.

Microstructure and high-temperature properties of laser cladded AlCoCrFeNiTi0.5 high-entropy coating on Ti 6Al-4V alloy

In this study, AlCoCrFeNiTi 0.5 high-entropy alloy (HEA) coating was deposited on Ti-6Al-4V alloy by laser cladding, aiming at enhancing the high-temperature wear and oxidation resistance . The microstructure, hardness, oxidation performance as well as high-temperature wear of the coating were characterized respectively. The results indicated that the coating was composed of dendrite (DR) and interdendrite (IR) phases. The DR phase had FCC structure being rich in Al, Co, Ni and Ti. The IR phases had BCC structure, for which, the IR1 was rich in Fe and Cr, and the IR2 was rich in Fe, Cr, Ti, Co and Ni. The coating possessed much better oxidation resistance than Ti-6Al-4V alloy at 600 °C due to a more compact oxide surface and the sluggish diffusion effect, which impeded the subsequent oxidation effectively. The average oxidation rate of the coating was about one tenth that of Ti-6Al-4V alloy. Moreover, the oxide scale was about one fifth that of Ti-6Al-4V alloy. The average micro-hardness of the coating was 706.3 HV about 2.32 times that of Ti-6Al-4V alloy. The HEA coating exhibited a mixture wear mechanism of adhesive and oxidative wear at 600 °C, having a wear volume loss about one thirteenth that of Ti-6Al-4V alloy. • AlCoCrFeNiTi 0.5 coating was fabricated on Titanium alloy by laser cladding. • Microstructure, behaviors of wear and oxidation at 600 °C were investigated. • The wear and oxidation resistance was improved by 12 and 9 times respectively. • The oxides of the coating was mainly Al 2 O 3 and Cr 2 O 3 at 600 °C. • The coating endured both adhesive and oxidative wear at 600 °C.

Effect of velocity and interference depth on the tribological properties of alumina sliding with Cu: A molecular dynamics simulation

The friction performance of alumina sliding against copper was studied by molecular dynamics simulation to understand the wear mechanism of ultrasonic motors (USM) from an atomic dimension. Importantly, the influence of velocity and interference depth on the nanotribological properties of Cu-Al2O3 was studied. The simulated results showed that both friction and normal force increased with an increasing velocity and interference depth. Wear rate also increased with an increasing interference depth. The adhesive wear mechanism dominated the wear process of interface. This study will provide a theoretical guidance for exploring the wear mechanism of USM from a nanoscale.

Effects of the tantalum intermediate layer on the nanomechanical properties and biocompatibility of nanostructured tantalum/tantalum nitride bilayer coating deposited by magnetron sputtering on the nickel titanium alloy

Nanostructured tantalum nitride coatings are widely used in biomedical engineering due to the good hardness, wear resistance, and corrosion resistance. In this work, TaN and Ta/TaN nanostructured coatings were deposited on the NiTi alloy by magnetron sputtering for 150 min at a pressure of 3.8 × 10–3 mbar using a power of 143 W. The phase, structure, morphology, and thickness were evaluated by X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM), respectively. The nanomechanical properties such as Young's modulus (E) and hardness were determined by nano-indentation and nano-scratch tests. To assess the biological properties of the coatings, the antimicrobial activity was monitored by the disk diffusion antibiogram technique using E.coli as the model gram-negative bacteria and S. aureus as the gram-positive bacteria and the biocompatibility was also studied. A homogeneous, uniform, and crack-free of TaN monolayered and Ta/TaN bilayered coating with a thickness 1050 and 1310 nm, respectively, were produced by magnetron sputtering. As a result of the Ta middle layer in the Ta/TaN coating, the hardness increased by 22% from 6.3 ± 0.5 GPa to 7.6 ± 0.5GPa under a load of 700 µN and 6% from 6.1 ± 0.2 GPa to 6.5 ± 0.3 GPa under a load of 1000 µN. The critical load also increased from 3.7 ± 0.2 to 4.1 ± 0.6 N in the presence of the Ta intermediate layer which improved the adhesion strength of the Ta/TaN bilayer compared to the TaN monolayer. In addition, the Ta intermediate layer increased the flexibility leading to a adhesive wear mechanism for the friction behavior of Ta/TaN. The bacteriostatic ability against gram-negative bacteria and bacteriocidal ability against gram-positive bacteria increase. Our results demonstrate that the nanostructured Ta/TaN bilayer coating provides a better bioactive surface for the growth and proliferation of MG-63 ossicular osteosarcoma cells growth as well.

Sliding Wear Properties of HVOF Sprayed WC-10Co4Cr Coatings With Conventional Structure and Bimodal Structure Under Different Loads

Abstract The WC-10Co4Cr coatings with conventional structure and bimodal structure were sprayed by high-velocity oxygen fuel (HVOF) technology. The phase compositions and morphologies of the WC-10Co4Cr powders and coatings were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microhardness, porosity, bonding strength, elastic modulus, and indentation fracture toughness of the conventional coating (Conventional) and the bimodal coating (Bimodal) were also studied. The sliding wear properties of the Conventional and the Bimodal against Si3N4 counterballs under different loads at room temperature (∼25 °C) were investigated using a friction and wear tester. Compared with the Conventional, the Bimodal has denser microstructure, lower porosity, more excellent mechanical properties, and the Bimodal has better wear resistance than the Conventional under different loads. The two coatings under 15 N and 30 N only exhibit abrasive and slightly adhesive wear mechanism, while in the load application of 45 N, additional mechanism which is fatigue is detected and causes flaking of the coating.

A novel method for investigating drilling machinability of titanium alloys using velocity force maps

During the manufacture of critical aerospace components from metastable β titanium alloys, excessive tool wear and machining cost can be significant obstacles. Although tools are highly optimised for drilling the α+β alloy Ti–6Al–4V (Ti-64), insufficient information is available to efficiently improve tools for use on higher strength alloys due to the cost intensive processes required to design and optimise new drills. To reduce this cost, a novel method is presented which enables rapid comparisons of machinability between different alloys, (Ti-64; Ti–6Al–2Sn–4Zr–6Mo (Ti-6246); and Ti–5Al–5Mo–5V–3Cr (Ti-5553)), to quickly assess the performance of specific tool characteristics using industrially relevant drilling parameters. Rapid assessment and comparison of microstructural damage at selected forces was made possible through the development of 3D tool velocity force maps (VFM) for coated TiAlN and uncoated WC/Co tools at different cutting feeds and speeds. Microstructural damage depth has been shown to decrease with increasing alloy strength even for cases where the thrust force between the work piece and the tool was the same ~1600 ​N. In addition, a lower damage depth was measured when using uncoated tools. The machinability evaluation of tool coating and its interaction with force, torque, and material properties showed that TiAlN coated tools responded differently in the case of each alloy, displaying significantly different torque profiles, thus indicating different optimum cutting speeds and feeds. Abrasive and adhesive wear mechanisms were identified in the coated tools, while the majority of wear in uncoated tools was abrasive.

Tribological evaluations of spark plasma sintered Mg–Ni composite

ABSTRACT Elemental nickel particle was incorporated into magnesium matrix using blend-spark plasma sintering powder metallurgy technique without the use of ball milling and its effect on the hardness and tribological behaviour of magnesium was evaluated. Ball-on-disc wear tests were carried out using a 440C hardened stainless steel ball as a counter-face with a constant linear speed of 0.1 m/s under varying normal loads of 2.5, 5 and 10 N, respectively. The wear track on the disk samples was characterised using a FESEM equipped with energy dispersive spectrometer to investigate the wear mechanisms and features. Results showed that the reinforced magnesium composite showed excellent tribological properties as compared to the monolithic samples in terms of a reduction of up to 27.5% in the coefficient of friction and a reduction of up to 53.7% in weight loss. Microstructural analysis of the wear track established different wear mechanisms of abrasion, adhesive, delamination and oxidative wear.

Effects of inert gas environment on the sliding wear behavior of AZ91/B4C surface composites

Tribological characteristics of AZ91/B4C surface composites were studied under air and argon gas environments. Tests were conducted under a constant normal load of 10 N, with a sliding velocity of 0.06 m/s using a linear reciprocating tribometer. Wear tracks and debris were analyzed using scanning electron microscopy, three-dimensional contour topography, and energy-dispersive X-ray spectroscopy in order to understand the wear mechanisms. The wear rate of the specimen tested under the argon environment was found to be lower (∼60%) in comparison with that of the specimen tested under the open-air environment. The value of the friction coefficient was found to be minimum under the argon environment compared with the air environment. In the air environment, the major material loss from the test specimen was attributed to oxidation wear; whereas under the argon environment, strain-hardening effect was dominant, and the material was found to be removed by delamination wear. In addition, the worn surface morphology of the wear tracks and counter surfaces showed the involvement of abrasion and adhesion wear mechanisms. The results of the study pave the pathway for the design of lightweight surface composite material systems such as AZ91/B4C toward an efficient and robust tribo-pair applicability for a controlled environment.

On the role of capillary and viscous forces on wear and frictional performances of natural fiber composites under lubricated polishing

This paper aims to investigate the frictional and wear performances of natural flax fibers reinforced polypropylene composites subjected to lubricated mechanical polishing. Particularly, the interactions between the biocomposite surfaces and two different liquids (oil and water) are considered using a rotary tribometer where the counter-face is fed by silicon carbide (SiC) abrasive papers. Friction and wear at dry, water and oil-lubricated polishing are hence studied. The biocomposite worn surfaces are examined using a scanning electron microscope (SEM) and an atomic force microscope (AFM). Results show a significant influence of the lubricant type on the wear and frictional performances of flax fiber composites. The lubricated friction behavior is dependent on both the hydrophilic and oleophilic properties of flax fibers. In addition to the abrasive wear, while the thermal softening of the biocomposite controls the adhesive wear mechanism at dry polishing, changing the lubricant type from water to oil leads to modify the adhesive wear sources from only capillary forces to capillary and viscous forces, which contributes to increasing the wear of flax fiber composites under oil-lubricated polishing.

Microstructural, Mechanical, and Fracture Characterization of Metal Matrix Composite Manufactured by Accumulative Roll Bonding

Accumulative roll bonding is a severe plastic-forming process proposed to manufacture ceramic particle-reinforced multilayered metal matrix composites. In this work, low-cost composite multilayered laminate was produced by roll bonding commercially pure aluminum 1100 with 5% in volume of reinforcing microscale silicon carbide particles. Microstructural features, hardness, tensile properties in the presence of stress concentrators, and wear resistance were assessed. Fracture surface inspection was carried out to determine operating failure mechanisms. Hardness was significantly enhanced, whereas tensile properties only moderately improved by ceramic particles incorporation. The main reasons were some degree of recrystallization, work-hardening relief due to periodic annealing, minimum grain refinement, and somewhat agglomerated carbide particles. Though tensile properties increments were not much attractive, exceptional increase in wear performance was achieved due to the addition of particulate carbon-rich ceramic phase, which acted as solid lubricant mitigating abrasion, adhesion, and delamination wear mechanisms. The manufactured composite laminate can be worthwhile in applications where low cost, notch insensitivity, and superior wear and weather resistances are design requirements, as outdoor decks and patios.

Effects of Multi-Axial Compression on the Mechanical and Fretting Wear Properties of Ti-45Nb Alloys

Biocompatible β-type Ti-45Nb alloy with a low elastic modulus is promising in alleviating the stress shielding effect of Ti-based hard-tissue replacement implants. In this work, the ultra-fine-grained (UFG) microstructures with different grain sizes were prepared by multi-axial compression (MAC) processing of Ti-45Nb alloys, and the mechanical properties and the fretting wear properties of Ti-45Nb alloys in different grain sizes were investigated. The results show that the yield strength and ultimate tensile strength of the sample processed by 27 passes MAC increase by 76% and 91%, respectively, with an elongation of more than 9%. After MAC processing, the friction coefficient and volume wear rate gradually decrease. In addition, before MAC processing, the Ti-45Nb sample shows a wear mechanism of severe adhesive wear, oxidative wear and fatigue delamination; while after MAC processing, the wear mechanism switches to abrasive wear and slight adhesive wear with slight oxidative wear, indicating that grain refinement helps to improve the anti-fretting properties of Ti-45Nb alloys.

Effect of graphite addition on wear behaviour of hybrid Cu/TiC-Gr infiltrated composites

A composite of interest for high-temperature applications, where high thermal conductivity, dimensional stability, and wear resistance are required, is the Cu/TiC-Graphite hybrid system. The wear behaviour of three different composites with a graphite volume of 1%, 3% and 5% was investigated, for a total volume of 60% of reinforcement, in a pin-on-disc arrangement with a steel sphere counterpart of 66 HRC hardness. The composites were synthesized by capillary liquid copper infiltration into porous TiC-Gr preforms, obtaining materials with acceptable matrix-to-reinforcement bonding, homogeneous distribution of the reinforcing particles and absence of second phases. The tribological characterization indicated that the coefficient of friction decreases with the volumetric fraction of graphite in the composites as it enriches the wear surface. The pure copper matrix showed a wear rate up to four times that of the composites under maximum wear conditions. In all materials, the wear rate increased with applied load and sliding velocity. A higher graphite content led to a lower rate of wear so that the adhesion wear mechanism of pure copper changed to abrasion and delamination with tribochemical products on the surfaces of the Cu/TiC and Cu/TiC-Gr composites forming a mechanically mixed layer. The wear systems with graphite additions showed partial lubrication of the contact surfaces.

On the mechanism of three-body adhesive wear in turning

The paper reveals a hypothesis regarding the adhesive mechanism in metal cutting and its mechanical dynamics. One steel grade, 34CrNiMo 6, 285 HB, and one set of coatings on the cutting tool are reviewed. The adhesive mechanism is a transient vibration, including a feedback system limited by the plastic deformation in the chip. The vibration shows as a cluster of waves with stochastic duration in time. It starts up again after a stochastic lapse of silence. The cycle frequency is around 12.5 kHz and the internal excitation is twice that frequency, as the cutting speed and feed are 200 m/min and 0.2 mm, respectively. The adhesive frequency and amplitude are influenced by the cutting speed and the current wear status. The adhesion is monitored by the sound waves emanating from vibrations in the chip, the part still in the workpiece.

Study on Wear Model and Adhesive Wear Mechanism of Brass under Boundary Lubrication

Study on Wear Model and Adhesive Wear Mechanism of Brass under Boundary Lubrication