Type Wear Research Articles

Wear behaviour of ceramic coating (Al2O3-40%TiO2) in dry condition for automotive applications

The objective of the current research is to examine the effect of varying loads on the wear behaviour of Al2O3-40%TiO2 ceramic coating deposited by flame spray process and to improve material functionality and increase lifecycle in a cost-effective method. To assess the wear behaviour of the deposition, wear test was conducted using a Pin-on-disk tribometer in accordance with ASTM G99 standards. This test was designed to analyse the wear experienced by the coating in practical applications. Surface morphology was examined using field emission scanning electron microscope (FESEM) and energy dispersion spectroscopy (EDS) technique while 3D-profilometer was utilised to further assess the surface roughness of the deposited coating. It was observed that specific wear rate of the deposition exhibited a decreasing trend with increasing load from 40 to 70 N and sliding velocity from 0.4 to 1 m/s. The lowest coefficient of friction was observed at 70 N and 1 m/s. Wear mechanism analysis revealed different types of wear, including abrasion, metal transfer, and brittle fracture, corresponding to the increasing load and sliding velocity. This study is significant for industries that require high-performance coatings for industries such as automotive, aerospace and manufacturing, where high-performance coatings are needed to withstand heavy loads and friction. The current research findings enhance wear resistance and reduce friction, helps manufacturers to adapt coating for specific operational requirements.

Study on type of magnetic suspension rotor groove and wear of drop touchdown bearing

The active magnetic bearing (AMB) is widely used in the field of flywheel energy storage system (FESS) in wind power generation. This study mainly studies the magnetic suspension rotor groove (MSRG) of FESS and the wear of drop touchdown bearing (DTB). The mathematical model of air gap magnetic field waveform on stator surface and Plath equation of control in air gap region were established. Contrastive analysis of conventional, second harmonic and third harmonic ‘petal-shaped’ MSRG in AMB. The life test of DTB on magnetic suspension rotor was carried out for 24000r/min and lasted for 1500 h. The second harmonic ‘petal-shaped’ MSRG could not only generate reluctance torque and increased the torque density of the motor, but also increased the fundamental component and excitation torque component by reducing the peak value of the magnetic field. The temperature ranges of front and rear DTB were ‘30℃–46℃’ and ‘26℃–40℃’, respectively. After service, the maximum thickness of metamorphic layer in the DTB raceway was 6 μm. After service, the content of Fe in the metamorphic layer of DTB raceway decreased by 10.11% and the content of C increased by 2.41%. Raceway hardness of DTB after service was 59.67 HV higher than that before service.

Effect of efficient structural tuning on the microstructure, corrosion resistance, and wear performance of AlCoCrFeNi/AT13 composite coatings

This study developed a rapid structure control technique for AlCoCrFeNi/AT13 (Al₂O₃–13 % TiO₂) composite coatings using plasma spraying and dual powder feeding. Four coatings were fabricated: pure HEA, HEA-D (dispersed), HEA-S1 (multilayer with outer HEA), and HEA-S2 (multilayer with outer AT13). The introduction of AT13 altered the internal stress distribution and enhanced corrosion resistance by lowering the electrochemical reaction rate. In layered coatings (HEA-S1, HEA-S2), the AT13 interlayer barrier reduced corrosion tendency. Additionally, pure HEA coatings exhibited adhesive wear. While HEA-D coatings experienced abrasive wear as AT13 particles improved plastic deformation and interface shearing. HEA-S1 reduced strain and wear via an internal AT13 layer. HEA-S2 achieved superior abrasion resistance through an outer AT13 layer, exhibiting typical abrasive wear mechanisms.

Intercomparison of Indexable Cutting Inserts' Wear Progress and Chip Formation During Machining Hardened Steel AISI 4337 and Austenitic Stainless Steel AISI 316 L.

This article deals with a mutual comparison of indexable cutting inserts of the CNMG 120408 type from two different manufacturers during the machining of hardened steel AISI 4337 and austenitic stainless steel AISI 316 L. The main goal is to analyse the different wear processes depending on the difference in the manufacturer's design and also depending on the properties of the different machined materials. The progress of the wear of the main spine of the tool, the types of wear and the service life of the cutting edge were monitored, with the achievement of the critical value VBmax = 300 µm being the standard. In addition to the wear of the inserts, the production of chips was monitored in terms of their shape, average size and number of chips per 100 g of chips produced. In order to understand the relationships arising from the obtained data, an SEM equipped with an elemental analyser was used to analyse the coating layers and the substrate of the unworn inserts and the types of wear and the intensity of the surface damage of the worn inserts. A several-fold difference in the lifetime of the cutting edge was found, both in terms of design and in terms of the selected machined material, while in both cases the cutting edge with Al2O3 and TiCN layers of half thickness achieved a better result in liveness. From the point of view of chip formation, very similar results in shape and average length were observed despite the different designs of chip breakers. Cutting inserts with half the thickness of the coating layers achieved longer cutting edge life in the non-primary material application compared to the target workpiece material. At the same time, it was observed that a thinner coating layer has a positive effect on chip formation in terms of its length and shape.

Studies on Tribological Characteristics and Wear Mechanisms of (TiN + TiC) Hybrid Nanocomposite Claddings Deposited on TC4-Grade Titanium Alloy Substrate by the Tungsten Inert Gas Cladding Process

Abstract This investigation explored the viability of tribological properties enhancement with the deposition of TiC + TiN nanoparticulate-reinforced hybrid composite claddings in TC4-grade titanium alloy to meet the ever-increasing functional performance requirements employed under aggressive tribological environments. The composite claddings are processed by using the tungsten inert gas cladding process. The tribological performance of the hybrid composite cladding deposition was evaluated against the claddings with simplex reinforcement compositions such as TC4/TiC and TC4/TiN composite claddings and the substrate alloy. Initially, the formation and microstructural characteristics of the composite cladding depositions are studied based on the scanning electron microscope, X-ray diffraction, and energy dispersive spectroscopic analyses to confirm their successful formation. The average microhardness achieved with the deposition of composite claddings such as TiC/TC4, TiN/TC4, and (TiC + TiN)/TC4 is 936.25 HV0.2, 858.88 HV0.2, and 1116. 72 HV0.2, respectively, while the TC4 substrate alloy is about 332.38 HV0.2. The (TiC + TiN)/TC4 hybrid composite cladding composition has shown significantly increased surface hardness which is about 30% and 18%, respectively, compared with the TiC/TC4 and TiN/TC4 composite cladding compositions while about 235% enhancement compared with the TC4 substrate alloy. Compared with the TC4 substrate alloy, the wear resistance enhancement achieved with the deposition of TiC/TC4 and TiN/TC4 composite claddings is up to 22.62% and 38.92%, respectively, while with the (TiC + TiN)/TC4 hybrid composite claddings is up to 49.87%. Similarly, the average CoF of the TC4 substrate alloy, TiC/TC4, TiN/TC4, and (TiC + TiN)/TC4 composite claddings observed are 0.76, 0.49, 0.58, and 0.44, respectively, which indicates that 36%, 23%, and 43% are the enhancements achieved with the respective composite claddings. The SEM analysis of worn surfaces of the composite claddings reveals typical wear mechanisms such as adhesive, abrasive, oxidation, and delamination that are represented by various regions identified on the generated wear maps. The adhesive and delamination wear regions are relatively wider for the TiN/TC4 composite cladding than the TiC/TC4 composite cladding. The wear mechanism of the composite cladding with multiphase TiC and TiN reinforcement particulate has shown an increased prevalence of abrasive wear as a consequence the abrasive wear region is wider while decreasing the window for adhesive and delamination wear.

Failure mechanisms and influencing factors on orthopaedic knee implant failure – A comprehensive review

Background Total knee replacement (TKR) is an effective orthopaedic surgical procedure to confront osteoarthritis and restore bone joint mobility, relieve pain, and enhance the quality of life. The improvements in implant design and the use of high-wear resistance polyethylene bearings improve the survival of implants. Despite the advancements, the implants still failed and required revision surgery. Also, with an increase in the trend of young patients getting knee replacements, there is a possibility of a higher revision rate. Thus, understanding the failure cause, failure mechanisms and the influencing factors is pertinent. Methods A systematic review of the available literature was performed for different modes of failure. All the observations are collated and found the more predominant failure modes. Also, the data pertaining to the failure mechanisms, and the influencing factors of the failure mechanisms are collected from various literature and provided comprehensively. Results Infection (30%) becomes the primary cause of implant failure followed by loosening (20%) and instability (18%). The types of wear on knee implants are polyethylene wear, backside wear, impingement wear, and corrosive wear. The factors influencing these wear are material processing, shelf age, implant design, surface topography, and activity level. Conclusions Moderately cross-linked, and sequentially processed polyethylene has better wear resistance. Less conformal contact with minimum shelf age provides less wear at articulation and backside. A polished tibial tray with a sophisticated locking mechanism reduces the backside wear of PE, and proper design consideration could reduce impingement wear.

Quantitative evaluation of pyramid belt wear using light-reflection characteristic of agglomerate coating and image processing

As a new generation of coated abrasive products with a unique pyramid-shaped structure, pyramid belt offers finer and more uniform grinding effects, and has been increasingly applied in precision grinding. However, belt wear occurs inevitably, challenging the control of shape accuracy and surface quality of ground components. Current research on pyramid belt wear is relatively limited, still lacking a universal, rapid method for observing and evaluating belt wear. In response, this paper proposes a quantitative evaluation method for pyramid belt wear using light-reflection characteristic of agglomerate coating and image processing. Firstly, a detailed analysis of the wear types and characteristics of pyramid belt is conducted. Then, focusing on the agglomerate flat wear, a method utilizing the light-reflection characteristic of agglomerate coating for observing belt wear morphology is proposed, enabling clear image capture of belt wear contours. Based on this, a wear coefficient based on the geometric characteristics of agglomerate is defined, and a quantitative evaluation method for belt wear using image processing is further proposed. The wear experiment of the belt is conducted on a robotic belt grinding platform, and experimental results show that the evaluation deviation of the proposed method from the evaluation results based on optical profilometer is within 5% at a 95% confidence interval, demonstrating the effectiveness of this method. Additionally, this method has advantages such as high computational efficiency, low cost, and good usability. Finally, the temporal evolution processes and spatial distribution patterns of belt wear and material removal rate are investigated and analyzed.

Environment-dependent tribochemical reaction and wear mechanisms of Diamond-like carbon: A reactive molecular dynamics study

Diamond-like carbon (DLC) is widely utilized in various fields as a promising solid lubricating material. However, the lubricity and wear behaviors of DLC are highly sensitive to the environment, and the relevant mechanisms are hidden by complex tribochemical reactions at the friction interface. In this study, we performed reactive molecular dynamics (RMD) simulations of DLC to clarify the wear mechanisms in various environments (vacuum, water, and oxygen environments). Two types of tribochemical reaction-induced wear were observed: chemical wear induced by the triboemission of CxHy and CxHyOz compounds and mechanical wear induced by the formation of interfacial C–C bonds. Moreover, the results revealed that the environment affects the tribological behavior of DLC primarily through its impact on the surface chemical state, that is, the quantity and type of surface terminations. In terms of the number of surface terminations, the more surface terminations there are, the more chemical wear and less mechanical wear they cause. In particular, oxygen-containing terminations (e.g., C–OH and C=O) are more resistant than H terminations to interfacial bond formation and mechanical wear. The present work provides important insights into the wear mechanisms of DLC, aiding in the reduction of DLC wear by controlling the environment.

Mechanical properties and galling resistance of API grade steels: A comparative study

Galling is a type of wear that affects the oil and gas industry causing loss of profits due to unexpected stops in the exploration and extraction process. In the present work, the galling resistance of four API grade steels (L80 type 1, T95 type 2, P110, and Q125) used in the industry was evaluated by means of cross-cylinder tests. The surfaces were analyzed, and a Galling Tendency number was computed in order to rank the materials. Additionally, tensile and hardness tests were conducted to analyze the influence of the mechanical properties on galling. It was found that P110 exhibited the worst response and T95 the best one. For materials with the same ductility, an increase in strength is associated with higher galling resistance. A new index, based on the ductility and yield strength of the material, is proposed to predict the galling performance, demonstrating a strong correlation with the galling tendency.

Study on the Influence Law of Micro-Scale Abrasive Wear on a Wind Turbine Brake Pad

The hard particles in the copper-based powder metallurgic material of a brake pad for a wind turbine brake falls off and presses into the surface of the brake disc to form abrasive particles under high-speed and heavy-load working conditions. The presence of abrasive particles will produce abrasive wear with micro-scratch and micro-scribe on the copper-based material of the brake pad. The critical scratch depth effect in the abrasive wear process is proposed based on the critical depth effect of the metal removal process at the micro-scale. The abrasive wear is divided into two types: scratch wear and scratch wear, which is proposed according to the comparison of the actual scratch depth and the critical scratch depth. The range of braking speeds and friction coefficients in abrasive wear is determined by the recommended parameters of the disc brake. The ABAQUS2020 software is used to simulate and analyze the micro-scale abrasive wear of a brake pad. The brake strain/stress curves of the brake pad under different brake speeds and friction coefficients are compared and analyzed for two abrasive wear types based on the range of braking parameters, and the key factors affecting abrasive wear are proposed.

Laser Cladding of a Ti–Zr–Mo–Ta–Nb–B Composite Coating on Ti60 Alloy to Improve Wear Resistance

To improve the wear resistance of the Ti60 alloy, laser cladding was used to obtain a composite coating containing a high-entropy (Ti0.2Zr0.2Mo0.2Ta0.2Nb0.2)B2 boride phase, with Ti, Zr, Mo, Ta, Nb, and B powders as the raw materials. The microstructure and wear characteristics of the coating were studied using XRD, SEM, EDS, and the pin-on-disc friction wear technique. The results show that the coating mainly consists of six phases: (Ti0.2Zr0.2Mo0.2Ta0.2Nb0.2)B2, ZrB2, TiB, TiZr, Ti1.83 Zr0.17, and Ti0.67Zr0.67Nb0.67. The average microhardness of the coating was 1062.9 HV0.1 due to the occurrence of the high-entropy, high-hardness (Ti0.2Zr0.2Mo0.2Ta0.2Nb0.2)B2 boride phase, which was about 2.9 times that of the Ti60 alloy substrate. The coating significantly improved the wear resistance of the Ti60 alloy substrate, and the mass wear rate was about 1/11 that of the Ti60 alloy substrate. The main types of wear affecting the coating were abrasive, adhesive, and oxidation wear, while the main wear affecting the Ti60 alloy matrix was abrasive wear, accompanied by a small amount of adhesive and oxidation wear.

The effects of Nb on the microstructure and performance of laser-cladded Fe50-xMn30Co10Cr10Nbx high entropy alloy coatings

A laser cladding technique was employed to produce a Fe50-XMn30Co10Cr10NbX (X = 2.5, 5, 7.5, 10at%) high entropy alloy coating. This study delved into the influence of Nb concentration on the coating’s phase constitution, microstructural features, hardness, and wear resistance. The high entropy alloy coating exhibited a multifaceted structural composition, encompassing FCC (Face-Centered Cubic), HCP (Hexagonal Close-Packed), and BCC (Body-Centered Cubic) structures, along with the presence of Laves phase. Notably, the incorporation of Nb led to an augmentation in the Laves phase and modifications within the microstructure. The hardness of the cladding layer is higher than that of the substrate. With the increase of Nb content, the hardness of the cladding layer increases first and then decreases; the average hardness of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer is the highest, the maximum hardness is 429.8Hv, and the average hardness is 382.3Hv. The friction coefficient and weight loss of the cladding layer decreases first and then increases with the increase of Nb content. The friction coefficient and weight loss of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer are the smallest, which are 0.0132 g and 0.5974, showing the best wear resistance. The wear types of high entropy alloy cladding layer are both adhesive wear and abrasive wear. The addition of Nb into high entropy alloy will form the Laves phase, which can improve the mechanical properties of high entropy alloy.

Current-carrying friction behavior of CrN coatings under the influence of DC electric current discharge

CrN coatings are renowned for their low friction coefficients, high chemical inertness, excellent corrosion resistance, and substantial hardness, making them ideal for the tribological demands of bearings and gears in electric vehicles. This study investigated the current-carrying friction behavior of CrN coatings when sliding against steel balls under both non-electrified and electrified conditions. The friction coefficient (CoF), wear volume, wear type, and mechanism of the coating were reported by adjusting the direct current (DC) intensity and lubrication status. The findings indicate that while the current significantly exacerbates substrate wear during dry friction, its impact on the CrN coating is minimal. Even at a maximum DC current of 1.5 A, the wear rate of CrN coating during dry friction is only 1.9 × 10−4 mm3·(N·m)−1, representing a reduction by 79.1 % compared to the steel substrate. This effect is further pronounced when lubricated with PAO oil. The wear of CrN coating shows minimal change even as the current increased, and surface wear remains very slight. At a current of 1.5 A, the wear rate of CrN coating decreases to as low as 9.7 × 10−6 mm3·(N·m)−1, indicating a reduction by 98.7 % compared to its substrate. It is observed that under electrified conditions, the oxidation and degradation of CrN coating are accelerated, thereby resulting in the formation of a loose and low-hardness Cr2O3 oxide layer on the surface. The oxide layer is primarily attributable to the deterioration in frictional properties of the CrN coating under electrified conditions. Finally, CrN coatings exhibit minimal changes in tribological behavior under electrified conditions, thereby offering effective protection for substrates against electrical damage. Therefore, CrN coatings are ideal for applications involving electrical contacts.

The influence of scoring subjectivity and competition clothing exposure on athletes' body image

Purpose: The purpose of the study is to explore the impact of scoring criteria and competition clothing on body image. Past research has not considered the impact of scoring standards and the exposure level of competition clothing on body image at the same time. Therefore, this study wants to explore the impact of scoring standards and exposure level of competition clothing on athletes' body image. Methods: This study recruited a total of 175 voluntary participants, all of whom were over 18 years old and had been training in this sport for more than three years. The average age was 21±3.67 years old. They participated in the highest level events including international competitions, national games, and national games. The inquire about utilized two rebellious: a fundamental data sheet and the Multidimensional Body-Self Connection Survey (MBSRQ). The fundamental data sheet included member socioeconomics such as sex, wear type, age, a long time of engagement within the don, cooperation within the highest-level competition, height, and weight. Results: The overall Cronbach's α for the whole scale was 0.89, and for the three subscales, Cronbach's α was 0.86 for Appearance Assessment, 0.92 for Appearance Introduction, and 0.83 for Body Zones Fulfillment. These values illustrate great inside consistency. With respect to sex contrasts, the think about found that in outside appearance assessment and fulfillment with different body parts, guys scored higher than females, whereas in outside appearance introduction, females scored higher than guys. Conclusions: Within the setting of the athletes' critical others, such as family individuals, giving warmth, solid bolster, companionship, and support in everyday life can contribute emphatically to athletes' mental well-being. Hence, lessening feedback or negative dialect around appearance among partners can avoid negative impacts on athletes' body picture and execution. Empowering positive intuitive and communication between partners can have a positive effect on athletes' body picture and mental improvement.

Examining the Flexural Behavior of Thermoformed 3D-Printed Wrist-Hand Orthoses: Role of Material, Infill Density, and Wear Conditions.

This paper examined the mechanical properties of wrist-hand orthoses made from polylactic acid (PLA) and polyethylene terephthalate glycol (PETG), produced through material extrusion with infill densities of 55% and 80%. These orthoses, commonly prescribed for wrist injuries, were 3D-printed flat and subsequently thermoformed to fit the user's hand. Experimental and numerical analyses assessed their mechanical resistance to flexion after typical wear conditions, including moisture and long-term aging, as well as their moldability. Digital Imaging Correlation investigations were performed on PLA and PETG specimens for determining the characteristics required for running numerical analysis of the mechanical behavior of the orthoses. The results indicated that even the orthoses with the lower infill density maintained suitable rigidity for wrist immobilization, despite a decrease in their mechanical properties after over one year of shelf life. PLA orthoses with 55% infill density failed at a mean load of 336 N (before aging) and 215 N (after aging), while PETG orthoses did not break during tests. Interestingly, PLA and PETG orthoses with 55% infill density were less influenced by aging compared to their 80% density counterparts. Additionally, moisture and aging affected the PLA orthoses more, with thermoforming, ongoing curing, and stress relaxation as possible explanations related to PETG behavior. Both materials proved viable for daily use, with PETG offering better flexural resistance but posing greater thermoforming challenges.

Methods of recovery of centrifugal water pump resources

In the article presents the results of researches of the device of centrifugal pumps of type «D», operating conditions of pumps, processes of deterioration of details, factors infiuencing occurrence of defects in details, moderning of technology of restoration of a resource of detalis of water pumps. A combined method for restoring the resource of the casing is proposed, taking into account the resurts of researches of wear of the working surface and working conditice hudro abrasive, cavitations,hudrogen and other types of wear. Recommendations are qiven to the choice of processing and taking into account the infiuence of technological and operational factors on the adhesive strength of the joint of the massing. Figs.: 17. Tabl. 3. Refs.: 10 titles.

Wear behavior and impact breakage characterization of PCD teeth of circular saw blades during high-speed sawing of hard aluminum alloy

Polycrystalline diamond (PCD) wear is a classic issue limiting the widespread use of PCD circular saw blades, impairing the final cost and productivity. However, previous studies have rarely focused on the wear of PCD layers of saw teeth considering the vibration effect. Hence, this study aimed to elucidate the wear behavior and impact breakage characteristics of PCD teeth in sawing hard aluminum alloys. Sawing experiments were conducted, while vibration signals and force signals were captured in real-time. Then, wear morphologies of different zones of the PCD tooth were finely characterized and studied by SEM. The results suggested that the main wear types of cutting edges are abrasion, chipping, and adhesion. The abrasive wear was found on the cutting edges, side edges, rake faces, and flank faces. Interestingly, the breakage in chipping zones is mostly marked by grain spalling and cleavage fracture due to binder strength limitations. Adhesive wear occurs in wear zones by EDS analysis. A schematic of the impact wear evolution mechanism is given to explore in detail the wear morphologies of PCD layers. The wear behavior and morphological characterization of the PCD layer are finely discussed considering impact load and sawing factors (e.g., adhesive chips). This study sheds insight into the wear behavior of PCD teeth and guides the design of PCD layers.

Development of high hard TiB–TiB2 coatings on Ti implants for bio-tribological applications; applying Box-Behnken design and actual wear analyzing in simulated body fluids

This research focuses on the enhancement of the tribological behavior of commercial pure titanium (Cp-Ti) in a simulated body fluid (SBF) via surface reinforcement by titanium borides. The protective boride coatings were formed through the pack cementation process at two different temperatures (950 and 1050 °C) to create diverse hard compositions of TiB and TiB–TiB2 in the coating, with hardness of 1032 and 1291 Hv, respectively. The roughness and wettability of top surfaces were evaluated before the tribology studies due to their impacts on the tribology behavior. Box-Behnken design (BBD) was applied to investigate the effects of the wear parameters in dry and SBF environments. The duration of the wear tests was 53, 35, and 26 min for low, medium, and high speed. It was found that the abrasion wear type was dominant at the beginning of sliding, and then changed to the plastic deformation in the dry conditions, while there is no sign of the abrasion and adhesion wear features at the surface of the reinforced samples abraded in the SBF solution. Results confirmed a high coincidence between BBD predictions and actual findings. The released debris from the coatings was also investigated to find origins. Results showed that majority of the debris in the SBF solution belonged to the calcium phosphate particles demonstrating the bioactivity of the TiB–TiB2 coatings. According to findings, hard TiB–TiB2 coatings could significantly improve the tribological behavior of the Ti implants, which could in turn result in expanding the biological application of Cp-Ti.

Research on production of microgroove arrays on TiAl intermetallic alloy by micro milling

TiAl intermetallic alloy is a superior lightweight material with excellent performance, and its micro features or components have promising applications in manufacturing fields. In this work, an investigation of micro milling of microgroove arrays on TiAl alloy was studied. The effects of cutting parameters including the feed per tooth (fz) and depth of cut ( ap) on the milling force, surface morphology, surface roughness and burr size of the micro-slots were investigated. The wear types and mechanisms of the micro end mills were also studied. The results showed that the optimal cutting parameters were fz = 3.5 μm/z and ap = 4 μm, which provided the best surface roughness Sa of 152 nm, top-burr heights on up- and down-milling sides of 19 and 19.5 μm respectively. Using the optimized cutting parameters, microgrooves with a width of 500 μm, aspect ratio of 5 and array period of 10 were fabricated successfully. Surface topography, dimensional accuracy and perpendicularity of the microgroove arrays were characterized. Results demonstrated that an increase in the microgroove number, microgroove edge chipping as well as burrs of the entrance and exit increased gradually. The dimensional error between the obtained width and the designed width of the microgroove was less than 2%, and the slope of the sidewalls reached more than 89°. The wear mechanisms of the micro end mills were abrasive wear and adhesive wear, and wear types were coating delamination, cutting edge chipping, and tool nose breakage.

Effect of aging temperature on the lubricated wear resistance of multi-directionally forged Al-40Zn-3Cu alloy

The effect of aging temperature on the lubricated wear behavior of multi directionally forged Al-40Zn-3Cu alloy was systematically investigated at different loads and sliding speeds. Microstructural and worn surface examinations of the alloy samples were performed by scanning electron microscopy, scanning transmission electron microscopy and energy dispersive spectrometry while their tribological properties were investigated with a ball on disc type wear test apparatus. The results showed that aging treatment at different temperatures after multi-directional forging changed the morphology of Zn-rich nanoscale η precipitates and Cu-rich θ particles and their dispersion in α-Al matrix. Their changes brought about an increase in hardness, strength, and wear resistance of Al-40Zn-3Cu alloy but a decrease in its ductility. It was also observed that the aging temperature, load and sliding speed had a combined effect on their wear response. As the applied load and sliding speed increased, friction coefficient of the samples decreased while their mass loss increased continuously with load but decreased with sliding speed after showing an increase. The adhesion, abrasion and oxidation were observed to be operative wear mechanisms for the alloy. The wear results of the alloy samples were discussed in terms of their microstructures and mechanical properties, and oil lubrication. The aging treatment at 150 °C after multi-directional forging increased the wear resistance of Al-40Zn-3Cu alloy more than 50 percent by providing a moderate hardness (129 HB), yield strength (310.9 MPa), tensile strength (383.2 MPa), and ductility (9.9 %).