Conveyor belt wear is an important consideration in the bulk materials handling industry. We define four belt wear rate metrics and develop a model to predict wear rates of new conveyor configurations using an industry dataset that includes ultrasonic thickness measurements, conveyor attributes, and conveyor throughput. All variables are expected to contribute in some way to explaining wear rate and are included in modeling. One specific metric, the maximum throughput-based wear rate, is selected as the prediction target, and cross-validation is used to evaluate the out-of-sample performance of random forest and linear regression algorithms. The random forest approach achieves a lower error of 0.152 mm/megatons (standard deviation [SD] = 0.0648). Permutation importance and partial dependence plots are computed to provide insights into the relationship between conveyor parameters and wear rate. This work demonstrates how belt wear rate can be quantified from imprecise thickness testing methods and provides a transparent modeling framework applicable to other supervised learning problems in risk and reliability.

In the present work, mechanical, tribological, and electrochemical behaviors of Al Alloy 6061–(0–10) % B4C–(0.25–1.2) % graphene nanoplatelets (GNPs) composites, prepared by a combination of solution mixing and powder metallurgy, were investigated. Properties such as hardness, compressive strength, wear rates, and coefficient of friction (COF) were used to investigate the effects of GNPs on mechanical and self-lubricating tribological behavior. The corrosion resistance of composites was investigated using potentiodynamic polarization and electrochemical impedance techniques. Scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and EDS mapping were employed to study the distribution, the fracture profile, and wear mechanism. The AA 6061–10% B4C–0.6% GNPs composites exhibited sharp increase in hardness and compressive strength and significant decrease in wear rates and COF. However, for GNPs contents exceeding over 0.6 wt%, mechanical properties and wear performances deteriorated. Pulling out of sheared pultruded GNPs was observed during the fracture of composites. Worn surfaces of GNPs-containing composites showed the smeared graphene layer with some macro-cracks exhibiting delamination wear. It was found that the corrosion inhibition efficiency of GNPs was more pronounced in H3BO3 environment than in NaCl solution.

To maintain functional tolerances of gear sets over their lifetime, especially in polymer-seel gear sets, the wear behaviour must be considered. The state of the art in wear modelling does not take the run-in behaviour of polymer-metal contacts into account. This results in oversizing of wear allowances in the stationary wear phase and undersizing in the run-in phase. Therefore, a modified wear model is presented in this paper. With this method the issues of over- and undersizing can be eliminated.

The method is then applied in a case study to show two things. Firstly, using the presented method the calculated necessary wear allowances were reduced by 30%. Secondly, the effect of surface structures on the wear behaviour was investigated. It is shown that the run-in process is not dependent on roughness in sliding direction, but on overall contact area. Thus, the state of the art, i.e. tolerating only the roughness in sliding direction, is insufficient. Considering the process-induced surface topology during design of gear sets can decrease run-in wear. Together with the optimised wear model, this allows wider manufacturing tolerances and thus lower costs during production.

Coatings with low friction coefficient and excellent anti-wear and anticorrosion performances are of great interest for fundamental research and practical applications. In the present study, Cobalt–nickel–phosphorus/graphene oxide (Co–Ni–P/GO) composite coating is prepared by a pulse electrodeposition method. Effect of the embedded GO sheets on the microstructures, microhardness, and electrochemical and tribological behaviors of the Co–Ni–P/GO composite coating are researched in detail. The results reveal that the co-deposition of GO sheets significantly improves the microhardness of the as-prepared Co–Ni–P/GO composite coating and changes the morphology of the Co–Ni–P coating from hemispheric structure to nodule structure with smaller globular particles for the Co–Ni–P/GO composite coating. In addition, friction and wear tests show that the incorporation of GO sheets endows the Co–Ni–P/GO composite coating with remarkable friction reduction and improved wear resistance. Electrochemical corrosion tests demonstrate that the Co–Ni–P/GO composite coating possesses better corrosion resistance than the Co–Ni–P coating.

This study aims to investigate the sliding wear behavior of Al0.4FeCrNiCox (x = 0, 0.25, 0.5, 1.0 mol) high-entropy alloys (HEAs) under oil lubricating conditions at room temperature. Phase and microstructural characterizations of HEAs are performed by utilizing X-ray photoelectron spectroscopy (XRD) and scanning electron microscope (SEM). The compressive yield strength of Al0.4FeCrNiCox (x = 0, 0.25, 0.5, 1.0 mol) HEAs is observed to decrease from 1169.35 to 257.63 MPa. Plastic deformation up to 75% is achieved in the case of Al0.4FeCrNiCox=1 HEA. The microhardness of HEA samples is found to decrease from 377 to 199 HV after the addition of cobalt content from x = 0 to 1.0 mol. Thermal analysis is performed using a differential scanning calorimeter. It is confirmed that Al0.4FeCrNiCox (x = 0, 0.25, 0.5, 1.0 mol) HEAs do not undergo any phase change up to 1000 °C. The specific wear rate of Al0.4FeCrNiCox=1 HEA is observed to be highest in all wear conditions. The worn surfaces were analyzed by SEM with attached energy-dispersive spectroscopy, 3D profiling, and X-ray photoelectron spectroscopy (XPS).

The long-accepted theory to explain why snow is slippery postulates self-lubrication: frictional heat from sliding melts and thereby lubricates the contacting snow grains. We recently published micro-scale interface observations that contradicted this explanation: contacting snow grains abraded and did not melt under a polyethylene slider, despite low friction values. Here we provide additional observational and theoretical evidence that abrasion can govern snow kinetic friction. We obtained coordinated infrared, visible-light and scanning-electron micrographs that confirm that the evolving shapes observed during our tribometer tests are contacting snow grains polished by abrasion, and that the wear particles can sinter together and fill the adjacent pore spaces. Furthermore, dry-contact abrasive wear reasonably predicts the evolution of snow-slider contact area, and sliding-heat-source theory confirms that contact temperatures would not reach 0°C during our tribometer tests. Importantly, published measurements of interface temperatures also indicate that melting did not occur during field tests on sleds and skis. Although prevailing theory anticipates a transition from dry to lubricated contact along a slider, we suggest that dry-contact abrasion and heat flow can prevent this transition from occurring for snow-friction scenarios of practical interest.

In this investigation, an electron beam melting-processed γ-TiAl alloy (Ti–48Al–2Cr–2Nb, at.%) was oxidized in air to improve its in vitro tribological, electrochemical, and biocompatibility properties. The γ-TiAl alloy samples were oxidized at 400, 600, and 800 °C for 1 and 4 h. The oxidized layer thickness, composition, and surface morphology found to change with oxidation temperature. The oxidation thickness varied between 1.29 ± 0.2 and 2.18 ± 0.2 μm. The primary oxides on the surface were Al2O3 and TiO2 with minor concentrations of Cr2O3, Nb2O5, and nitrides of Ti. The surface hardness of the alloy increased by 1.7-fold with increasing temperature from 400 to 800 °C with 1 h soaking, and at 4 h, the maximum hardness was 12.26 GPa. The high hardness of the oxidized γ-TiAl alloy resulted in two orders of magnitude lower wear rate than the bare γ-TiAl alloy. Oxidation at 800 °C for 4 h resulted in significant reduction in corrosion current and no passivity breakdown was observed. In vitro cell culture experiments, using mouse preosteoblast cells, revealed high cell density on the oxidized γ-TiAl alloy, suggesting its enhanced cell proliferation compared to the bare γ-TiAl alloy and CP-Ti.

The primary objective of this research was to analyse the discrepancies in polymeric properties in Y12 aircraft tyres after 50 landings. Tensile strength and elongation test, abrasion test and hardness tests were carried out for the nose and main gear tyres after the completion of 50 landings. Surface morphologies of the tyre samples were observed using SEM. ISO specifications were followed for each experimental method during testing. There was a reduction in both median tensile strength and elongation at break in aircraft tyres after 50 landings but the reduction rate of both parameters were lower in Tyre 2 (nose wheel tyre) compared with Tyre 1 (left main wheel tyre) and Tyre 3 (right main wheel tyre). The highest percentage of mean volume loss was reported for Tyre 3 (3.88%). In addition, the least percentage of mean volume loss was obtained in Tyre 2 (2.98%). The percentage of hardness reduction was highest in Tyre 2 (6.9%). The surface roughness was induced to the tyre surface after completion of 50 landings.

The mechanics of snow friction are central to competitive skiing, safe winter driving and efficient polar sleds. For nearly 80 years, prevailing theory has postulated that self-lubrication accounts for low kinetic friction on snow: dry-contact sliding warms snow grains to the melting point, and further sliding produces meltwater layers that lubricate the interface. We sought to verify that self-lubrication occurs at the grain scale and to quantify the evolution of real contact area to aid modeling. We used high-resolution (15 µm) infrared thermography to observe the warming of stationary snow under a rotating polyethylene slider. Surprisingly, we did not observe melting at contacting snow grains despite low friction values. In some cases, slider shear failed inter-granular bonds and produced widespread snow movement with no persistent contacts to melt (μ < 0.03). When the snow grains did not move and persistent contacts evolved, the slider abraded rather than melted the grains at low resistance (μ < 0.05). Optical microscopy revealed that the abraded particles deposited in air pockets between grains and thereby carried heat away from the interface, a process not included in current models. Overall, our results challenge whether self-lubrication is indeed the dominant mechanism underlying low snow kinetic friction.

Metal working tools are generally exposed to hard conditions, and the control of their excessive wear is of a crucial importance for the metal working process. Indeed, tribo-layers as mechanically mixed layers and wear debris are completely involved in the wear behavior. This paper undertakes the study of the frictional behavior and wear of X40CrMoV5 (AISI H13) tool steel as a function of speed rotation at room temperature. The utmost objective of this research work is to assess some wear mechanisms of this tool steel used at room temperature. The tribological experiments were accomplished on high temperature pin-on-disc tribometer with an open sliding contact. The pin material was X40CrMoV5 steel and the disc material was Fe360B steel. The investigations were accomplished for different rotatory speeds of the disc ranging from 25 rpm to 100 rpm, and different nominal pressure. SEM and EDS explored the development surface damage and oxides tribo-layers. It was concluded that the increase of the rotation speed of the disc and the nominal pressure reduce the friction coefficient by the creation of a wear protective layer.

Hydrogenated diamond like Carbon (H-DLC) is a promising lubricious coating that attracted a great deal of interest in recent years mainly because of its outstanding tribological properties. In this study, the nano-mechanical and -tribological properties of a range of H-DLC films were investigated. Specifically, four kinds of H-DLC coatings were produced on Si substrates in pure acetylene, pure methane, 25% methane + 75% hydrogen, 50% methane + 50% hydrogen discharge plasmas using a plasma enhanced chemical vapour deposition (PECVD) system. Nano indentation was performed to measure the mechanical properties such as hardness and young's modulus and nanoscartching was performed to investigate the frictional behavior and wear mechanism of the H-DLC samples in open air. Moreover, Vickers indentation method was utilized to assess the fracture toughness of the samples. The results revealed that there is a strong correlation between the mechanical properties (hardness, young's modulus, fracture toughness) and the friction coefficient of DLC coatings and the source gas chemistry. Lower hydrogen to carbon ratio in source gas leads to higher hardness, young's modulus, fracture toughness and lower friction coefficient. Furthermore, lower wear volume of the coated materials was observed when the friction coefficient was lower. It was also confirmed that lower hydrogen content of the DLC coating leads to higher wear resistance under nanoscratch conditions.

Laser metal deposition (LMD) additive manufacturing was used to deposit Inconel 625 matrix composites reinforced with nano-TiC particles. The effects of laser energy input per unit length (E) on the densification level, microstructural features, mircohardness, and wear property were investigated. The relatively low E induced insufficient liquid with higher viscosity, thus inhibiting the melted liquid from spreading out smoothly. As a result, a large number of micropores and reduced densification level of LMD-processed parts were obtained. When the E of 100 kJ/m was properly settled, the obtainable densification level generally approached 98.8%. The TiC reinforcements experienced successive microstructural changes from agglomeration to uniform distribution with coarsening grain, as the applied E increased. The nearly fully dense parts using optimal experimental parameters achieved an increased average microhardness of 330 HV0.2, resultant considerably low coefficient of friction of 0.41 and reduced wear rate of 5.4 × 10−4 mm3/(N m) in dry sliding wear tests.

Al–12Si (80 vol%)–Ti52.4Al42.2Nb4.4Mo0.9B0.06 (at.%) (TNM) composites were successfully produced by the selective laser melting (SLM). Detailed structural and microstructural analysis shows the formation of the Al6MoTi intermetallic phase due to the reaction of the TNM reinforcement with the Al–12Si matrix during SLM. Compression tests reveal that the composites exhibit significantly improved properties (∼140 and ∼160 MPa higher yield and ultimate compressive strengths, respectively) compared with the Al–12Si matrix. However, the samples break at ∼6% total strain under compression, thus showing a reduced plasticity of the composites. Sliding wear tests were carried out for both the Al–12Si matrix and the Al–12Si–TNM composites. The composites perform better under sliding wear conditions and the wear rate increases with increasing loads. At high loads, the wear takes place at three different rates and the wear rate decreases with increasing experiment duration.

The Mn-steel matrix composite locally reinforced with in situ TiC–TiB2 ceramic particulate was successfully fabricated using a thermal explosion-casting route in a Cu–Ti–B4C system with various B4C particle sizes. With the increase of B4C particle size, the ignition temperature increased, the combustion temperature decreased, and the size of the TiC and TiB2 ceramic particulates became smaller. The hardness, friction coefficient, and wear resistance of the composite were higher than those of the Mn-steel matrix. With the increase of B4C particle size, the size of the TiC and TiB2 ceramic particulates fabricated in the local reinforcing region decreased, the interface bonding between reinforcing region and matrix became poor, and the number of pores in the local reinforcing region increased. Moreover, the composite with ∼3.5 μm B4C showed the best antiwear property. At a low load of 20 N, the dominant wear mechanisms of the Mn-steel matrix composite were microcutting and abrasive wear. While, at a high load of 80 N, the dominant wear mechanisms were microcutting and adhesion wear associated with the formation of delamination layer.

Boriding is a thermochemical diffusion-based process of achieving ultra-hard surface on metals. Two distinct crystalline phases, i.e. tetragonal Fe2B and orthorhombic FeB can exist in the surface layer penetrated by boron ions. In our contribution, we have studied the microstructure, the hardness, and the spatial distributions of both phase composition and residual stresses (RS) in samples exhibiting either single-phase Fe2B or duplex Fe2B-cum-FeB character. The indispensable knowledge of the elastic constants used in the stresses calculations from the measured strains by X-ray diffraction were gained from the refined lattice parameters of both iron borides employing density functional theory implemented in CASTEP software by Materials Studio. In the studied case, there is only minor occurrence of preferred orientation in the Fe2B phase and the evaluated RS have compressive character gradually decreasing from its maximum value on the very surface.

This article aims to provide a fundamental understanding of the deformation mechanisms of NiTi shape memory alloy (SMA) during the wear process at different temperatures when different microstructures are present. Three temperature regimes were selected namely, T < Mf, As < T < Af, and T > Af, where fully martensitic, martensite co-existing with austenite, and fully austenitic microstructures were formed, respectively. When T < Mf, it was observed that the coefficient of friction had decreased initially and thereafter stabilized at a lower value with increasing wear cycles. More decrease was found when the temperature was near to As. Furthermore, when tested above Af, the coefficient of friction had decreased more significantly under higher load. Difference in the trend of coefficient of friction at different temperatures is originated from the different deformation mechanisms involved in the wear process, particularly the martensite detwinning process, the stress-induced phase transformation process, and the plastic deformation of martensite.

CoCrMo alloy was deposited on a metallic substrate using laser engineered net shaping (LENS™) – a laser-based additive manufacturing technique. Several samples with five layers of deposit were fabricated at different combinations of laser power, powder feed rate, and scan velocity to study their influence using L4 Orthogonal array. The deposits were evaluated for their microstructure, hardness, wear resistance, and electrochemical performance. Grey relational grade analysis and analysis of variance were applied to identify optimum process parameters. The x-ray diffraction and microstructural analysis of the deposits showed uniform and fine microstructural features. Our experimental results revealed that the coatings fabricated using high laser power (350 W), low powder feed rate (5 g/min), and high scan velocity (20 mm/s) provide the highest hardness (446 ± 2.87 Hv) and wear resistance (1.80 ± 0.0007 mm3/Nm). However, the corrosion resistance was observed to be high for the deposits fabricated using low laser power (200 W), low powder feed rate (5 g/min), and low scan velocity (10 mm/s).

Selective laser melting (SLM) process was used to prepare the nanocrystalline titanium carbide (TiC)-reinforced Inconel 718 matrix bulk-form nanocomposites in the present study. An in-depth relationship between SLM process, microstructures, properties, and metallurgical mechanisms was established. The insufficient laser energy density (η) input limited the densification response of shaped parts due to the formation of either larger-sized pore chains or interlayer micropores. The densification of SLM-processed part increased to a near-full level as the applied η was properly settled. The TiC reinforcements generally experienced successive changes from severely agglomerated in a polygon shape to the uniformly distributed with smoothened and refined structures on increasing the applied η, while the columnar dendrite matrix exhibited strong epitaxial growth characteristic concurrently. The optimally prepared fully dense part achieved a high microhardness with a mean value of 419 HV0.2, a considerably low friction coefficient of 0.29, and attendant reduced wear rate of 2.69 × 10−4 mm3/N m in dry sliding wear tests. The improved densification response, SLM-inherent nonequilibrium metallurgical mechanisms with resultant uniformly dispersed reinforcement microstructures, and elevated microhardness were believed to be responsible for the enhancement of wear performance.

The effect of annealing on the tribological and corrosion properties of Al–12Si samples produced by selective laser melting (SLM) is evaluated via sliding and fretting wear tests and weight loss experiments and compared to the corresponding material processed by conventional casting. Sliding wear shows that the as-prepared SLM material has the least wear rate compared to the cast and heat-treated SLM samples with abrasive wear as the major wear mechanism along with oxidation. Similar trend has also been observed for the fretting wear experiments, where the as-prepared SLM sample displays the minimum wear loss. On the other hand, the acidic corrosion behavior of the as-prepared SLM material as well as of the cast samples is similar and the corrosion rate is accelerated by increasing the heat treatment temperature. This behavior is due to the microstructural changes induced by the heat treatment, where the continuous network of Si characterizing the as-prepared SLM sample transforms to isolated Si particles in the heat-treated SLM specimens. This shows that both the wear and corrosion behaviors are strongly associated with the change in microstructure of the SLM samples due to the heat-treatment process, where the size of the hard Si particles increases, and their density decreases with increasing annealing temperature.

Sol-gel coatings show an excellent chemical stability, oxidation control and enhanced corrosion resistance for metal substrates. An organic-inorganic hybrid consisting of poly (methyl methacrylate) (PMMA) and silica (SiO2) was successfully synthesized in the form of solution, by using 3-(trimethoxysilyl) propyl methacrylate (TMSPM) as a coupling agent and cohydrolyzed with tetraethyl orthosilicate (TEOS) to afford chemical bondings to the forming silica networks by a sol-gel method. The as-synthesized hybrid material was subsequently characterized by Fourier Transformation infrared (FTIR) spectroscopy. PMMA-SiO2 was applied as a protective film on hardness steel substrates by dip-coating. The thickness of the coating was 25 µm, while the roughness Ra = 0.6 µm. The wear and friction behavior of the coating on hardened steel (HS) was evaluated by a ball-on-disk test in dry conditions with a AISI steel ball as counterface applying 2, 4, 6, 8 and 10 N normal loads. Friction coefficient values (µk) were in the range of 0.76 to 0.99, whereas the lowest wear rate (k) was observed at 6N with a value of 1.30x10-4 (mm3(Nm)-1).