Wear Studies Research Articles

Solid particle erosion behaviour of industrial epoxy resin composite against different parameters

The aim of this research is to improve slurry impeller material erosion wear analysis. The impeller of the pump was made of epoxy resin. The purpose of this erosion test was to see how the rotational speed, solid concentration, time period, and particle size were affected. As the erodent substance, water was utilized. Different particle sizes, rotating speeds, time durations, and solid concentrations were used in the erosion wear studies. These tests were conducted at 4 to 6 distinct speeds of 30, 60, 90, 120, 150 and 180 m/s, with time periods of 30, 60, 90, and 120 min. For assessing the erosion resistance of epoxy resins, a Solid Particle Erosion (SPE) tester is used. Significant wear resistance to erosion has been observed. The following were the process factors that affected erosion wear loss: velocity > angle > concentration > particle size > time. The signal-to-noise ratio of epoxy resin varies with velocity from 0.012 to 0.0053, 0.0118 to 0.0067, and 0.0042 to 0.0114., Taguchi technique was used to examine the effect of controlled process parameters on slurry erosion wear of pump impeller material.

Numerical wear study of metal‐on‐ultrahigh molecular weight polyethylene‐based cervical total disc arthroplasty by coupling finite element analysis and multi‐body dynamics

In this study, the effects of in vivo (head flexion-extension, lateral bending, and axial rotation) and in vitro (ISO 18192-1) working conditions on the wear of ultrahigh molecular weight polyethylene (UHWMPE)-based cervical disc prosthesis were studied via numerical simulation. A finite-element-based wear prediction framework was built by using a sliding distance and contact area dependent Archard wear law. Moreover, a pre-developed cervical spine multi-body dynamics model was incorporated to obtain the in vivo conditions. Contact mechanic analysis stated that in vitro conditions normally led to a higher contact stress and a longer sliding distance, with oval or crossing-path-typed sliding track. In contrast, in vivo conditions led to a curvilinear-typed sliding track. In general, the predicted in vivo wear rate was one order of magnitude smaller than that of in vitro. According to the yearly occurrence of head movement, the estimated total in vivo wear rate was 0.595 mg/annual. While, the wear rate given by the ISO standard test condition was 3.32 mg/annual. There is a significant impact of loading and kinematic condition on the wear of UHMWPE prosthesis. The work conducted in the present study provided a feasible way for quantitatively assessing the wear of joint prosthesis.

N95 vs Half-face Respirator Wear in Surgical Trainees: Physiologic and Psychological Effects of Prolonged Use.

ObjectivesAs specialists of the upper airway, otolaryngologists are at high risk for COVID-19 transmission. N95 and half-face respirator (HFR) masks are commonly worn, each with advantages in functionality and comfort. In this study, physiologic and psychological parameters of prolonged N95 vs HFR wear were compared.Study DesignProspective crossover cohort study.SettingSingle academic tertiary care hospital.MethodsA prospective crossover cohort study was performed. Healthy otolaryngology trainees and medical students (N = 23) participated and wore N95 and HFR masks continuously for 3 hours each on separate days. Various measures were analyzed: vitals, spirometry variables, scores on the State-Trait Anxiety Inventory and HIT-6 (Headache Impact Test–6), distress, and “difficulty being understood.”ResultsThe average age was 26.3 years (SD, 3.42). There were no significant differences in vital signs and spirometry variables between N95 and HFR wear. N95 wear was associated with decreases in oxygen saturation of approximately 1.09% more than with HFRs (95% CI, 0.105-2.077). State-Trait Anxiety Inventory scores increased more with HFR wear when compared with mean changes with N95 wear (95% CI, 1.350-8.741). There were no significant differences in HIT-6 scores or distress levels between masks. The proportions of participants reporting difficulty being understood was significantly higher with HFRs.ConclusionsOxygen saturation decreases with prolonged N95 wear, but anxiety and difficulty being understood are greater with HFR wear. Although HFRs have less resistance to gas exchange, N95 respirators may produce less anxiety and distress in clinical situations. Further studies are warranted to evaluate the clinical significance of these differences.Level of Evidence2.

An experimental study of tool wear during end milling of carbon fibre reinforced polymer in cutting fluid condition.

Carbon fibre reinforced polymer (CFRP) is replacing metallic components and become a valuable material that has been used in many industrial applications including biomedical, marine and automobile. This is due to their excellent performance in term of reliability, high strength and light weight. However, the machining of CFRP is challenging because the abrasiveness of their reinforcement component often resulted in high tool wear rate. This experiment was carried out to investigate the effect of cutting parameters (cutting speed and cutting condition) on tool wear of uncoated tungsten carbide end mill tool, and to observe the wear mechanism of the carbide tool mill during milling of CFRP. In this study, machining test was carried out with the presence of coolant to aid in removing the cutting heat during machining. The effect of cutting speed of 132 m/min, 151 m/min and 170 m/min with a constant feed rate of 2100 mm/min during milling process of CFRP by using uncoated tungsten carbide end mill tool were discussed. Based on the result obtained, it was found out that the value of tool wear at cutting speed of 170 m/min is higher compared to the wear value at cutting speed of 132 m/min due to the high frequency friction of tool against machined surface. Analysis of tool wear using Scanning Electron Microscope (SEM) found out that the primary wear observed is abrasive wear due to the rubbing action between the tool and the surface of workpiece. The cutting tool is observed to have the lowest tool wear when low cutting speed is implemented along with the presence of coolant.

Studies on Wear Behaviour of Coated RHA-TIO2-LM24 Aluminium Alloy Composite

Liquid metallurgy method based aluminium matrix composites (AMCs) are extensively utilized in diverse engineering applications including shipbuilding, structural, non-structural, automotive, and aerospace owing to their superior strength, weightless, low density, excellent corrosion, and wear resistance. In the present research work, liquid state technique is employed to prepare the LM4/RHA/TiO2 composites containing four different mass proportion of RHA and TiO2. The weight proportion of reinforcements ie RHA-1,3&5 and TiO2 2,5&6 respectively.From the dry sliding wear studies, it is evident that the incorporation of RHA and TiO2 particles into the LM24 aluminium matrix alloy increases the wear resistance properties up to 45% as compared with the dry sliding behaviour of pure aluminium LM4 alloy. Dry sliding wear results revealed that the parameters like varying weight percentage, sliding speed, and applied load are the direct impact on the wear behaviour of the hybrid composites. A reduction of up to 34 % wear rate was observed by incorporation of 5% of RHA and 1% & 6 %of TiO2 particles as compared with the remaining percentage of reinforcements. The developed Coated RHA-TIO2 -LM24 aluminum alloy composite exhibits excellent mechanical properties, can be used in long-term applications in which saving weight is an important feature, such applications include and automotive engine parts and aerospace industry. In automotive industry, it can be used for making Brake disc, Turbo-compressors, Pump supporting parts, rear axle, differential housing.

Pilot Demonstration of Hot Sheet Metal Forming Using 3D Printed Dies.

Since the popularization of press hardening in the early noughties, die and tooling systems have experienced considerable advances, with tool refrigeration as an important focus. However, it is still complicated to obtain homogeneous cooling and avoid hot spot issues in complex geometries. Additive Manufacturing allows designing cavities inside the material volume with little limitation in terms of channel intersection or bore entering and exit points. In this sense, this technology is a natural fit for obtaining surface-conforming cooling channels: an attractive prospect for refrigerated tools. This work describes a pilot experience in 3D-printed press hardening tools, comparing the performance of additive manufactured Maraging steel 1.2709 to conventional wrought hot work tool steel H13 on two different metrics: durability and thermal performance. For the first, wear studies were performed in a controlled pilot plant environment after 800 hot stamping strokes in an omega tool configuration. On the second, a demonstrator tool based on a commercial tool with hot spot issues, was produced by 3D printing including surface-conformal cooling channels. This tool was then used in a pilot press hardening line, in which tool temperature was analyzed and compared to an equivalent tool produced by conventional means. Results show that the Additive Manufacturing technologies can be successfully applied to the production of press hardening dies, particularly in intricate geometries where new cooling channel design strategies offer a solution for hot spots and inhomogeneous thermal loads.

Indenter wear study and proposal of a simple method for evaluation of indenter blunting

Indenter wear study and proposal of a simple method for evaluation of indenter blunting

A study of friction, wear and particulate emissions during the bedding stage of a Cu-free friction material

In this study, the tribological behaviour and airborne particulate emissions during a bedding procedure for a Cu-free friction material for brake applications were investigated. Different tribological stages were identified. During the first stage, called run-in, friction coefficient, system wear, and emissions increased. At the end of the first stage, the friction coefficient reached a stable value. On the other hand, wear continued to increase, albeit at an increasingly lower rate, and the emissions of airborne particles started decreasing. Subsequently, also system wear and the emission of airborne particles reached a steady-state stage. The obtained results were explained considering the evolution of the characteristics of the friction layer that forms on the friction material during braking.

CORR Insights®: Deep-freezing Temperatures During Irradiation Preserves the Compressive Strength of Human Cortical Bone Allografts: A Cadaver Study.

CORR Insights®: Deep-freezing Temperatures During Irradiation Preserves the Compressive Strength of Human Cortical Bone Allografts: A Cadaver Study.

Ultralow Wear Poly(tetrafluoroethylene): A Virtuous Cycle of Wear Reduction and Tribochemical Accumulation

Certain nanofillers have demonstrated a remarkable wear-reducing effect on poly(tetrafluoroethylene) (PTFE), a common solid lubricant polymer. In these unusual cases, ultralow wear rates are accompanied by tribochemical changes that stabilize surfaces by anchoring polymer chains to dispersed nanoparticles and the countersurface. The leading hypothesis is that nanofillers catalyze these favorable tribochemical processes, which ultimately causes ultralow wear rates. However, the extent to which reduced wear rates contribute to the accumulation of favorable tribochemistry remains untested. In this study, we used indexed reciprocation to eliminate the protective effects of transfer films, control the wear rate, and independently determine how wear rate and filler morphology affect these tribochemical outcomes. Despite large and important differences between the fillers tested (from nanoparticles to microparticles), we observed surprisingly little effect from the filler on tribochemistry when controlling the wear rate. By contrast, tribochemistry was extremely sensitive to the changes in wear rate regardless of the filler. Standard reciprocation, which promoted the development of protective transfer films, caused low wear rates and significant tribochemical accumulation for all three filler conditions. By removing the protective effects of transfer films, indexed reciprocation increased wear rates by 100-fold while effectively eliminating tribochemical accumulation and tribofilm formation on the polymer pin. In contrast to prior studies, which demonstrate that tribochemical accumulation enables ultralow wear rates, this study demonstrates that a pre-existing condition of low wear is needed to enable tribochemical accumulation. The results from this study and prior studies of PTFE wear appear to be most consistent with the hypothesis that protective transfer films initiate low wear rates, that low wear rates enable tribochemical accumulation, and that tribochemical accumulation reduces wear rates in a virtuous cycle.

Investigations on Microstructure, Mechanical, Thermal, and Tribological Behavior of Cu-MWCNT Composites Processed by Powder Metallurgy

Copper (Cu) metal matrix composite (MMC) was developed with multiwall carbon nanotubes (MWCNT) as reinforcement by using powder metallurgy (PM) technique. The composition of the composites is Cu, Cu-4 wt% MWCNT, Cu-8 wt% MWCNT, and Cu-12 wt% MWCNT. The Cu and MWCNTs were blended for 6 hours in a ball mill and compacted at a 6 ton pressure to form green compacts using a 10 ton hydraulic press. Using a tubular furnace, the heat was applied at 900°C for 1.5 hours to impart strength and integrity to the green compacts. Milled composite blends were studied to analyze its characterization through SEM and EDAX analysis. Characterization studies such as SEM and EDAX confirm the presence and even dispersion of Cu and MWCNT constituents. The relative density, hardness, and ultimate compressive strength have been studied, and a remarkable improvement in properties has been obtained by the inclusion of MWCNTs. The composites reinforced by 8 and 12 wt% MWCNT were recorded with low thermal conductivity than the Cu composite reinforced by 4 wt% MWCNT. A wear study was analyzed using Taguchi technique for determining the effect caused by the wear test parameters and MWCNT content on wear rate. The optimized parameter that contributes minimum wear rate was identified as 12 wt% MWCNT content, 10 N applied load, 2 m/s sliding velocity, and 500 m sliding distance. Based on the obtained results, it could be understood that the produced composites can be utilized for various applications like relay contact springs and switchgear, rotor bars, and bus bars.

Tribological characteristics of AA8090-WC-ZrC metal matrix composites prepared by stir casting process for Aerospace applications

Purpose Aerospace field is demanding a material with superior strength and high resistance against wear, tear and corrosion. The current study aimed to develop a new material with high performance to be applicable in aerospace field Design/methodology/approach A metal matrix composite AA8090-WC-ZrC was fabricated using stir casting method and its tribological behavior was investigated. Totally, five composites viz. AA/Z, AA/W, AA/WZ (1:3), AA/WZ (1:1) & AA/WZ (3:1) were prepared. Micro hardness, tensile and wear study were performed on the fabricated composites and the results were compared with AA8090 alloy Findings Vickers hardness test resulted that the AA/W composite showed the higher hardness value of 160 HB compared to other materials due to the reinforcing effect of WC particles with high hardness. Tensile test reported that the AA/W composite displayed the maximum tensile strength of 502 MPa owing to the creation of more dislocation density. Further, wear study showed that the AA/W composite exhibited the least wear rate of 0.0011 mm3/m because of the more resisting force offered by the WC particles. Furthermore, the AA/W composite showed the slightest mass loss of 0.0028 g and lower COF value of 0.31 due to the hinder effect of WC particle to the movement of atoms in AA8090 alloy Originality/value This work is original in the field of aerospace engineering and materials science which deals with the fabrication of AA8090 alloy with the reinforcement particles such as tungsten carbide and zirconium carbide. The impact of the combination of hybrid particles and their volume fractions on the tribological properties has been investigated in this work. This work would provide new scientific information to society.

Experimental investigation on combustion-performance-emission characteristics of nanoparticles added biodiesel blends and tribological behavior of contaminated lubricant in a diesel engine

This present investigation focuses on combustion-performance-emission characteristics of cerium oxide (CeO2) added palm biodiesel blends in a single cylinder diesel engine. Experiments are conducted in a natural aspirated single cylinder diesel engine at constant speed and varying load (low, medium and full). The experimental result reveals that the addition of CeO2 nanoparticles (50, 100, and 150 ppm) to palm biodiesel blends enhanced brake thermal efficiency (BTE) with reduction in brake specific energy consumption (BSEC) due to improved ignition characteristics of the modified blends. Maximum reduction of CO, HC and NOx emissions have been observed 50, 48.45, and 11.1% at full load respectively. Later on, friction and wear study has been conducted to investigate tribological behavior of cylinder liner-piston materials under lubrication (using contaminated lubricant). The whole friction and wear study has been performed on pin-on-disc tribometer at different speed (300, 400, and 500 rpm) and load (10, 30, and 50 N). The dilution of CeO2 added biodiesel blends with the lubricant resulted low coefficient of friction (COF) and specific wear rate. At varying speed of 300, 400, and 500 rpm: 6.07, 8.5, and 10.9%; and at varying load of 10, 30, and 50 N: 6.07, 10.96, and 11.77% lower average COF have been observed respectively for nanofuels contaminated lubricant compared to diesel contaminated lubricant. Similarly, 7.94, 30, & 28.06% and 7.94, 30.33, & 17.04% lower specific wear rate at varying speed and load have been observed respectively for nanofuels contaminated lubricant.

Micromechanical characterization and dynamic wear study of DC-Arc coated cemented carbide cutting tools for dry titanium turning

The present study investigates the micromechanical properties of ceramic coated WC/Co tools and their influence on wear performance during dry Ti6Al4V turning. Physical and micromechanical characterization have been performed for the evaluation of the PVD coating properties. Higher hardness, elastic modulus, and adhesion strength have been obtained for dual-layer (AlTiN/AlCrN) coated tool than monolayer AlTiN and AlCrN coated tools. Micromechanical properties influence the wear mechanisms in thermally activated and abrasion dominant crater zones. Dual-layer coated tools reduced the flank wear at the corner radius and crater wear by 35–50% and 40%, respectively. Dynamic wear and abrasion-dissolution wear mechanisms have been explored over the tool rake face. Dual-layer coatings have improved wear performance by diminishing delamination, micro-fracturing of WC grains, binder dissolution and fractured interface boundaries.

Experimental and Numerical Study of Erosion Wear of Fan Blades in Microgrid

As one of the most important components of wind turbines, the fan blade is prone to erosion being exposed to multiphase flow environment, which affects the operation efficiency of wind turbines. In order to reduce the loss caused by the erosion of the fan blade, the erosion rate tests of the fan blade were carried out in this paper. The relevant function values of the simulation mathematical model were calculated from the test results, which were verified by a simplified two-dimensional case. Additionly, a numerical simulation of the three-dimensional full-size gas-solid two-phase flow around the fan blade was conducted, and then the variations of a single blade erosion rate with different wind speeds, sand sizes and impact angles were studied. The results showed that the sample erosion rate was increased with wind speeds and impact angles. The blade tip region was the most susceptible area to erosion, of which protection should be strengthened.

Wild versus lab house mice: Effects of age, diet, and genetics on molar geometry and topography.

Molar morphology is shaped by phylogenetic history and adaptive processes related to food processing. Topographic parameters of the occlusal surface, such as sharpness and relief, can be especially informative regarding diet preferences of a species. The occlusal surface can however be deeply modified by wear throughout an animal's life, potentially obliterating other signals. Age being difficult to assess in wild populations, especially small rodents, experimental studies of wear through age in laboratory populations may constitute a powerful way to assess its impact on molar geometry and topography, and to validate descriptors of molar morphology that could mitigate this issue. Molar morphology was therefore quantified using 3D geometric morphometrics and topographic estimates in four groups of house mice: wild-trapped mice, lab-bred offspring of these wild mice, typical laboratory mice, and their hybrids. Three descriptors of the molar morphology were considered: the surface of the whole molar row, the surface of the first upper molar, and a truncated template of the first upper molar mimicking advanced wear. Increasing wear with age was demonstrated in the different groups, with a more pronounced effect in the wild-trapped population. The geometry of the molar row is not only modified by wear, but also by the relative position of the late developing molars on the jaw due to loading during mastication. As a consequence, the alignment of the molars is modified in wild mice, showing a qualitative difference between wild animals and their lab-bred offspring. Results obtained from the lab should thus be transferred with caution to the interpretation of differences in wild populations. Topographic estimates computed for the first upper molar seems to provide more stable parameters than those based on the whole molar row, because issues related to non-planar occlusal surface along the molar row are discarded. The truncated template was proven efficient in discarding the wear effect to focus on genetic differences, allowing an efficient characterization of the hybridization signature between wild and lab mice. Dominance of the wild phenotype for the first molar shape supports that the lab strain evolved in a context of relaxation of the selective pressures related to nutrition.

Reciprocal dry sliding wear of SiCp/Al–7Si-0.3 Mg functionally graded composites: Influence of T6 treatment and process parameters

The present work discusses an attempt to enhance the mechanical and reciprocal wear response of Al–7Si-0.3 Mg alloy through the addition of 10 wt% SiC as reinforcement and subsequent T6 treatment. Friction and reciprocating wear behavior of both untreated and heat treated functionally graded composites were studied under unlubricated sliding conditions, employing a linear reciprocating pin-on-plate system over a range of applied load (10–50 N) and sliding distance (500–2500 m). Microstructural studies revealed reinforcement particle gradation across the cast thickness for untreated composite with minimal particle clusters whereas, heat treated composite showed the presence of fine α-spheroidised eutectic silicon. The outer layer of heat-treated composite when compared to outer layer of as-cast composite, revealed an 18 % increase in hardness, 70 % increase in tensile strength and 8 % decrease in wear rate. Wear studies confirmed a linear dependency between wear rate and applied load whereas, coefficient of friction displayed fluctuating trends. Wear mechanisms were identified, with worn morphology and EDS analyses in agreement with the results obtained and was correlated with the observed metallurgy and mechanical properties. These composites were identified as potential candidates for applications such as brake drums/rotors, cylinder liners, cylinder blocks and pistons.

Mechanism and patterns of wear of chrome steels with a surface-modified layer

The paper presents the results of contact wear studies of surface layers of 6Cr4Mo2VSi steel under the action of pulsating contact stresses. Differences in wear resistance of surface layers of materials are shown, in interrelation with modes of synthesis of their structure and properties. The features of the evolution of the structure of modified layers strengthened by nitrocarburizing are revealed. The modes of thermo-chemical treatment for achieving maximum resistance to the action of pulsating contact stresses are determined.

Investigation on the role of microstructure and temperature on tribological characteristics of fine-grained ZE41 Mg alloy

ABSTRACT In the current work, ZE41 Mg alloy was processed by friction stir processing (FSP) to achieve grain refinement. In addition to grain refinement, decreased intermetallic phase (MgZn) was also observed after FSP. Increased micro-hardness was observed for the processed ZE41 Mg alloy compared to the unprocessed base alloy. X-ray diffraction (XRD) studies demonstrated the texture characteristics in FSPed ZE41. Reciprocating wear studies conducted at three different temperatures, i.e. room temperature, 125 °C, and 250 °C showed lower mass loss for the processed alloy compared to that of the base alloy, particularly at elevated temperatures. This behavior can be understood by considering the benefit gained from the smaller grains and decreased amount of intermetallic phase in the processed alloy, which reduced the abrasion wear. Hence, the present study suggests that the grain refinement and decreased MgZn phase significantly improve the temperature-dependent tribological characteristics of ZE41 Mg alloy.

Tribological behavior of AZ91D magnesium alloy composite: effect of hybrid WC – SiO2 nanoparticles

PurposeAviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO2).Design/methodology/approachIn this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO2 and AZ91D – (WC + SiO2) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus.FindingsResults showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO2 particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO2) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO2 particles. Hence, the proposed AZ91D – (WC + SiO2) composite could be a suitable candidate to be used in the aviation applications.Originality/valueThis work is original which deals with the effect of hybrid particles, i.e. WC and SiO2 on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.