Minimum Wear Rate Research Articles

Evaluation of tribological parameters for boron carbide and graphite infused aluminium hybrid composite fabricated by stir casting technique

The present work focuses on suggesting Gr as a valuable self-lubricating reinforcement for hybrid composite samples and offering a minimum wear rate for sliding pairs with fewer mechanical surface defects at the same time. A series of samples were fabricated using the route by stir casting method considering B4C and Gr as the two reinforcements. The morphology of the sample has been studied using the X-ray diffraction graphs, Energy dispersive X-ray analysis and Scanning electron imaging stating the homogeneity of reinforcement in various composite cast. The theoretical and experimental density of the series of samples has been studied and compared stating the low porosity of the samples fabricated. A maximum wear rate (Wr) of 0.351 × 10−4 mm3/m. was found for pure aluminium sample against EN31 steel disc with 0.053 as friction coefficient (µ). Wr was somehow seen to reduce up to 0.286 × 10−4 mm3/m for Al-B4C composite with µ of 0.48. For hybrid samples, the wear rate was further seen to improve to 0.187 × 10−4 mm3/m for Al-B4C and Gr 2.0% weight with µ of 0.38. Least Wr was found for composite having Gr 3.5% weight, of 0.149 × 10−4 mm3/m. with µ of 0.36. SEM images of the worn surface give evident results for delamination and crack formation on the pin face for the pure-Al sample. Taguchi-ANOVA analysis has been carried out showing the valid contribution of pin type, load and sliding speed on Wr and friction coefficient as the P-value lies below 0.05 for input parameters considering the 95% confidence level of the model developed. An F-value of 44.57 with R2 of 0.895 is developed for Wr model and an F-value of 54.2 with R2 of 0.934 for the µ model.

Impacts of Zirconium Carbide Incorporated Magnesium Alloy Nanocomposite on Wear Properties

In the study, zirconium carbide nanoparticle (ZrC-50 nm) incorporated magnesium alloy (AZ61) nanocomposite was prepared by liquid state stir cast process, and its wear properties were evaluated by different load (U), sliding speed (V), and sliding distance (W). The impacts on wear rate (WR) and coefficient of friction (COF) of AZ61 alloy nanocomposite were studied. With the support of a pin-on-disc wear tester, the dry sliding wear characteristics were measured. Moreover, to find the optimum process parameter on minimum WR and better COF characteristics, the L27 orthogonal array utilized U, V, and W as the input factors, and the WR & COF were treated as output responses. Based on the analysis, load was found to be the most dominant input factor that influences the WR and sliding distance was the factor for fixing the COF.

Predicting specific wear rate of laser powder bed fusion AlSi10Mg parts at elevated temperatures using machine learning regression algorithm: Unveiling of microstructural morphology analysis

Precisely predicting the Specific Wear Rate (SWR) of AlSi10Mg components produced using Laser Powder Bed Fusion (LPBF) at high temperatures, which is an essential concern in additive manufacturing. This study aims to address the gap in literature by developing accurate predictive models for SWR via machine learning regression techniques. Experiments using a dry sliding wear rig shown that wear loss in AlSi10Mg print specimens increased with temperature and load, reaching a maximum wear rate of 1.5444E-06 mm3/Nm at 200 °C, 10 N, and 1.2 m/s, compared to the minimum wear rate of 6.4672E-07 mm3/Nm seen at 100 °C, 20 N, and 1.4 m/s. However, to accurately predict the wear rate at high temperatures, six different machine learning regression algorithms were used, namely Support Vector Machine (SVM), Linear Regression (LR), Random Forest Regression (RFR), Gaussian Process Regression (GPR), XGBoost regression (XGB) and Decision Tree (DT). R-squared values and various error functions were employed to validate these strategies against the anticipated outcomes. Within this set of models, GPR model has a lower Mean Absolute Error of 0.3177, Root Mean Square Error of 0.6704 and higher R2 value of 0.9686, resulting a prediction accuracy of 96.86%. From these findings, it is suggested that GPR is a very useful model for predicting the rate at which LPBFed AlSi10Mg printed parts wear under high temperature conditions in comparison with other developed models. These machine learning methods are anticipated to be beneficial for additive manufacturing enterprises.

Microstructure and properties of Al/FeCoNiCrMo coatings prepared by different plasma spraying currents on carbon fiber reinforced plastic surfaces

Al/FeCoNiCrMo high-entropy alloy (HEA) coatings were prepared on the surface of carbon fiber reinforced plastic using plasma spraying technology. The microstructure of the HEA coatings was characterized under different spraying currents, and the hardness, interfacial bonding, corrosion resistance and friction and wear properties of the coatings were tested. The results showed that with the increase of the current, the unfused particles in the coatings decreased, and the coating porosity and thickness also decreased gradually; the hardness, corrosion resistance and friction and wear resistance properties increased with the increase of the current, in which the maximum hardness was 740.3 HV0.1, and the minimum self-corrosion current was 1.21 × 10−5 A·cm−2, and the minimum volumetric wear rate was 7.66 × 10−5 mm3·N−1·m−1.

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Synergistic approach to wear rate forecasting in AZ31/5% Yttria stabilized zirconia reinforced composite through response surface methodology-genetic algorithm integration

In this work, the wear behavior of a novel AZ31 magnesium alloy reinforced with 5% yttria-stabilized zirconia (YSZ) composite was evaluated using a hybrid Response Surface Methodology (RSM) and Genetic Algorithm (GA) approach. The composite was fabricated using ultrasonic-assisted stir squeeze casting technique, ensuring homogeneous distribution of spherical YSZ particles, as validated by the scanning electron microscope integrated with energy dispersive spectroscope. Wear tests were carried out according to the ASTM standards using a pin-on-disc (POD) tribometer, with applied load (AL), sliding speed (SS), and sliding distance (SD) as the main parameters. An empirical wear rate regression model was developed using RSM/Box-behnken design, and Genetic Algorithm was deployed for parametric optimization, achieving a minimal wear rate of 0.0144 g/m under a load of 30 N, sliding speed of 260 rpm, and sliding distance of 400 m. Confirmation tests were performed to validate the GA predictions. The wear mechanisms were observed, showing reduced wear in GA-optimized samples due to optimized load distribution resulting minimized ploughing, grooving and delamination. This work highlights the efficacy of the hybridized RSM / GA for the wear performance in advanced magnesium alloy matrix composites.

Optimization and Analysis of Dry Sliding Wear Behavior of AlCrTiSiN Coated SKD61 Steel Using Response Surface Methodology

The aim of this research is to investigate the wear behavior of SKD61 steel coated with AlCrTiSiN using the Filtered cathodic arc plasma deposition coating method while adhering to VDI 3198 standards for coating adhesion assessment. Dry sliding wear tests, conducted according to ASTM G133-05. The experiment is designed using response surface methodology (RSM) to determine the response parameter as the wear rate, with independent parameters of interest including load, sliding velocity, and sliding distance ranging from 5 to 11N, 0.1 to 0.2 m/s, and 250 to 550 m, respectively. Additionally, wear characteristics are analyzed using SEM-EDS analysis. The wear test results demonstrate that load had the most significant impact on the wear rate, followed by distance and speed, respectively. The target of achieving minimal wear rate was attained with a load of 5 N, a sliding velocity of 0.11 m/s, and a sliding distance of 550 m. Model significance testing revealed that the determination coefficient (R2) and adjusted determination coefficient values, indicating the accuracy of the model, were equal to 93.96% and 88.53%, respectively.

Analysis of co-relation on LPBF process parameter on wear characteristics of Cu-Cr-Zr alloy

Copper alloy bearings, gears, and fasteners have a significant impact on industrial sectors. However, due to the defect formation and void generation during the manufacturing of copper alloy parts using (Laser Powder Bed Fusion) LPBF technique, the wear resistance of the copper alloy was significantly affected. Hence, the prime novelty of the current research is enhancing wear resistance by analyzing the interaction of combined LPBF parameters. In order to decrease cavity forms and reduce the wear rate of the printed Cu alloy components, the important LPBF process parameters such as Scan Velocity (SV) of 550, 750, and 950 mm s−1, Laser Power (LP) of 460, 540, and 620 W, and Re-melting Range (RR) of 5, 25, and 45% were selected and studied. The results of the experimental investigation were supported by the use of Grey Relation Analysis (GRA). A comparative study was conducted with five distinct parameter combinations to investigate the relative influence of each parameter on the relative density, wear rate and elastic modulus. The research findings verify that the application of optimal SV of 750 mm s−1 and RR of 45% with maximum LP of 460 W resulted in the maximum relative density of 99.91%, minimal wear rate of 0.52 × 10−5 mm3/Nm, and maximum elastic modulus of 140.22 GPa.

Microstructure characterization and high-temperature wear mechanism of high-entropy alloy matrix composite coating fabricated by laser cladding

The development of diecasting technology requires hot die steels with high-temperature resistance. In this study, a high-entropy alloy (HEA) was combined with ceramic particles to generate a CoCrFeNiMo0.2Nb0.2/WC composite coating via laser cladding. The coating consisted of a face-centered cubic (FCC) matrix with unmelted WC particles, eutectics and nanoscale (Mo)NbC phases. With the strong lattice distortion caused by the sequestration of W atoms, a nanoscale amorphous layer existed between the Laves and HEA matrix phases. A transition layer with the same structure as the Laves phase was facilitated between the WC particles and the HEA matrix. Due to the hard phases in the HEA matrix and their interfaces, the composite coating with a high proportion of WC exhibited excellent wear resistance under high-temperature dry friction conditions. When the WC was 60 wt%, a minimum wear rate reached to 0.74 × 10−5 mm3/(N·m) at 600 ℃ and 1.46 × 10−5 mm3/(N·m) at 800 ℃. The destruction pattern of the composite coating at 600 ∼ 800 °C was due to the interaction of the adhesive, oxidative and abrasive wear. The composite coatings fabricated in this study provide a route to enhance the high-temperature wear resistance of die-casting molds.

Experimental investigation of hybrid reinforced A356 aluminium alloy synthesised by stir casting technique

Abstract One of the most significant alloys to be employed in the automotive, aerospace, and military industries in recent years is A356 aluminium. Because of A356's excellent compatibility with other metals and nanoparticles, novel hybrid composites may be made using it. The characteristics of these hybrid composites are mostly the result of the additives' interaction with the A356 alloy's current elemental composition. Aluminium composites were synthesized through stir casting method by reinforcing 2%, and 4% SiC, 2% and 4 % Al2O3 and 0.5%, 1%, 1.5%, 2% and 2.5% SiC and Al2O3 both. The homogeneous distribution of SiC and Al2O3 microparticles in reinforced composite is revealed by scanning electron microscopy (SEM). The addition of SiC and Al2O3 reinforcements greatly improved the mechanical characteristics of the synthesised composites; for example, a composite with 4% SiC reinforcement reached its maximum hardness and maximum tensile strength of 165 HV and 257MPa respectively. Maximum elongation of 6.72 % was observed for 0.5% SiC and 0.5% Al2O3 reinforced composite. Minimum wear rate is observed for 4% SiC reinforced composite material. This study aims to identify gaps in the potential variations and compatibility of various additives with one another in order to create a brand-new hybrid reinforced alloy suitable for automotive braking system applications: brake rotors made of a disc or a brake pad, depending on the properties of the hybrid reinforced alloy that was made. Hence, the current work presented focuses on the preparation of hybrid reinforcement of A356 with silicon carbide and alumina powders.

Effect of process parameters on mechanical and tribological characteristics of FDM printed glass fiber reinforced PLA composites

PurposeAdditive manufacturing of polymer composites is a transformative technology that leverages the benefits of both composite material and 3D printing to produce highly customizable, lightweight and efficient composites for a wide range of applications.Design/methodology/approachIn this research work, glass fiber-reinforced polylactic acid (PLA) filament is used to print the specimen via fusion deposition modeling process. The process parameters such as infill densities (40%, 50% and 60%) and raster angle/orientations (0°, 45° and 90°) are varied, and the specimens for tensile, flexural, impact, hardness and wear testing are prepared as per their respective ASTM standards.FindingsThe results revealed that with an increase in infill density, the mechanical properties of glass fiber-PLA specimens increase progressively. Optimal tensile properties and flexural properties are obtained at 0° and 90° raster angle orientations and 60% infill density. Minimum wear rate is achieved at 0° raster angle orientation and it increases at 45° and 90° raster angle orientations.Originality/valueUsing SEM, the microscopic analysis of the fractured specimen was analyzed to study the interface between the fibers and matrix and it indicates the presence of good adhesion between the layers at 60% infill density and 0° print orientation.

Laser treatment of (Zr-Ta-W-Ti)C-SiC based high entropy carbide ceramics reinforced with carbon nanotubes, graphite and graphene nanoplatelets

This study investigates the effect of laser surface treatment on spark plasma sintered (Zr-Ta-W-Ti)C-SiC (ZTaWT-S) based high entropy ceramic (HEC) composites, reinforced with multiwalled carbon nanotubes (CNT) (ZTaWT-SC), graphite (ZTaWT-SG), and graphene nanoplatelets (GNP) (ZTaWT-SGNP). The increased hardness of the laser-treated composites (25–33 GPa) when compared to that of untreated composites (23–28 GPa) is attributed to the high compressive residual stresses, ranging from 1400 to 2900 MPa. The laser-treated ZTaWT-SGNP composite exhibited a minimum scratch wear rate of ∼0.9 × 10−1 mm3/N.m, representing a 57 % and 73 % reduction compared to the untreated ZTaWT-SGNP and the laser-treated ZTaWT-S, respectively. ZTaWT-SGNP composite demonstrated the best resistance to damage accumulation, due to the synergistic effects of laser treatment and GNP reinforcement, enhancing its suitability for extreme environments.

Tribological and electrochemical behaviour study of porous TiNiCu alloys manufactured by the powder metallurgy process

ABSTRACT The experimental work aims to study the effect of the Copper (Cu) addition on the tribological and electrochemical behaviour of porous Ti50Ni50-x-Cux alloys. In the first step pure metal powders of titanium (Ti), nickel (Ni), and Cu were ball-milled during 8 h in a planetary ball mill, and then compacted under a 4 ton load to obtain pre-alloyed powders. The final step is sintering at 950°C for 7 h in a tubular furnace under a controlled atmosphere. X-ray diffraction measurements (XRD), scanning electron microscopy (SEM) analyses, microhardness measurements, friction tests and electrochemical were carried out to characterise the tribological and electrochemical performances of the elaborated specimens. DRX results reveal the formation of four major phases: TiNi, Ti2Ni, TiNi3 and TiNi0.8Cu0.2. Potentiodynamic polarisation tests show the positive effect of adding Cu on corrosion resistance, where the 6% Cu sample exhibits the best corrosion behaviour. Tribological results show a decrease in the coefficient of friction and wear rate with the addition of Cu, compared to the initial state, without Cu addition. The minimum coefficient of friction (0.585) was recorded for the 2% Cu sample, while the minimum wear rate (Ws = 1.06. E−4mm3/N/m) was achieved for the 4% Cu sample.

Study on the Wear Behaviour of Aluminium foam Reinforced Glass Fibre Epoxy Composites

Hand layup was used to fabricate the glass fibre reinforced aluminium foam epoxy composites in this study. On the manufactured materials, dry sliding wear experiments were performed. The effect of wearprocess parameters such asapplying load (kg), speed (m/s), and sliding distance (m) on specific wear rate (Ws) was investigatedand the obtained results were compared with neat glass fibre reinforced epoxy composite in this work. The outcome of these results showed that specific wear rate (Ws) of glassfibre epoxy composite containing aluminium foam decreased as compared with neat glass fibre reinforced polymer composites. Experimental results showed that a minimum wear rate of 10.1 �m was attained for the sliding velocity (1.5 m/s), Applied load (2 kg), and sliding distance (1000 m) in the fabricated composite laminates. It was observed thatthe resistance to wear in glass fibre reinforced aluminium foam composite was mainly due to the bond strength between aluminium foam and epoxy.

Influence of manganese alloying on the structure and properties of electrospark coatings of EP741NP heat-resistant nickel LPBF alloy

The paper investigates the impact of Mn content (Mn = 0; 0.5; 0.6; 1; 1.5 at.%) in the composition of the electrodes of the Al–Ca–Mn system on the structure and properties of electrospark coatings formed on LPBF substrates made of EP741NP alloy. It was found that the highest weight gain of the substrate (5.8·10–4 g) was recorded when the Al–7%Ca–1%Mn electrode with a low degree of supercooling of the melt (Δt = 5 °C) was subject to electrospark treatment (EST). EST with this electrode with a fine eutectic structure enables the formation of coatings with minimal surface roughness (Ra = 3.51±0.14 μm). The nanocrystalline structure of the coatings was confirmed by transmission electron microscopy, including HRTEM. Comparative tribological tests revealed that the coating with maximum hardness (10.7±0.8 GPa) formed during EST with an electrode containing 1.5 at.% Mn had the minimal wear rate (1.86 ·10–5 mm3/(N· m)). We proved that EST with Al–Ca–Mn electrodes enables to reduce the specific weight gain of the LPBF EP741NP alloy during isothermal (t = 1000 °C) curing in air due to in situ formation of a complex thermal barrier layer consisting of oxides (α-Al2O3, CaMoO4) and intermetallides (γ ′-Ni3Al and β-NiAl). We determined the concentration limit of Mn (1.0 at.%) in the electrode, at which the barrier layer retains its integrity and functionality.

Experimental evaluation of tribo-performances of bump foil journal bearing with different materials of foil

In this paper, the bump foil journal bearing (FJB) is developed with five different foil materials: Inconel X750 (IN-X750), Stainless steel 316 (SS316), Beryllium copper (BC), Spring steel EN42J (SP EN42J) and Phosphor bronze (PB). A complete fabrication process is described in detail, along with the design of fixtures, to develop the bump FJB. This fabrication process includes various machining operations such as milling, rolling, cutting, threading, forming etc. The forming load versus deflection curve is obtained for all the foil materials with the metal forming operation. After fabricating it, the load-deflection test is performed to evaluate the structural characteristics (stiffness, energy dissipation and damping coefficient) of these developed bump FJB. Further, the tribological characteristics of bump FJB such as wear rate and surface roughness are evaluated by the experimental study. Moreover, the interface temperature of bump FJB is also captured by using the thermal imager. This study shows that the metal forming operation is the most challenging step among all the fabrication steps of bump FJB Among all the foil materials, the minimum wear rate and maximum surface roughness of bump FJB are observed for the IN-X750. The maximum spring-back effect in bump FJB is found for the Spring steel EN42J. These results demonstrate that the maximum energy dissipation and stiffness of bump FJB are observed for the Phosphor bronze and Inconel-X750 respectively. In addition, the damping coeffcient of bump FJB is evaluated.

Effect of Carbon Fiber and Potassium Titanate Whisker on the Mechanical and Impact Tribological Properties of Fe-Based Impregnated Diamond Bit Matrix.

Various contents of carbon fibers (CFs) and potassium titanate whiskers (PTWs) were added to an Fe-based impregnated diamond bit (IDB) matrix to enhance its adaptability to percussive-rotary drilling. A series of mechanical tests were conducted successively to find the effects of the reinforcing materials on the properties of the Fe-based IDB samples. Then, the fracture surfaces of the samples were analyzed via scanning electron microscopy (SEM) and energy-dispersive spectroscopy, and the worn surfaces and abrasive debris of the samples were analyzed using a laser scanning confocal microscope and SEM. The results show that both the CF and PTW can effectively improve the hardness and bending strength of an Fe-based IDB matrix, and those parameters reached their maximum values at the additive amount of 1 wt%. However, the CF had a better enhancement effect than the PTW. Furthermore, the CF improved the impact wear resistance of the IDB matrix, with a minimum wear rate of 2.38 g/min at the additive amount of 2 wt%. However, the PTW continuously weakened the impact wear resistance of the IDB matrix with increases in its content. Moreover, the morphologies of the worn surfaces indicated that the minimum roughness of the CF-reinforced IDB matrix decreased significantly to as low as 4.91 μm, which was 46.16% lower than that without CF, whereas the minimum roughness of the PTW-reinforced samples decreased by 11.31%. Meanwhile, the abrasive debris of the CF-reinforced samples was more uniform and continuous compared to that of the PTW-reinforced samples. Overall, the appropriate addition of CF or PTWs can enhance the mechanical properties of Fe-based IDB matrices, which can be used on different formations based on their impact wear resistance.

Optimization of porosity behavior of hybrid reinforced titanium metal matrix composite through RSM, ANN, and GA for multi-objective parameters

Titanium matrix composites (TMCs) have high specific strength and stiffness, and high-temperature TMCs can reduce weight by up to 50% when compared with monolithic super alloys while preserving equal stiffness and strength in jet engine systems for propulsion. The purpose of this work examines the use of mathematical models and learning approaches to optimize response such as porosity and control variables in synthesized hybrid titanium metal matrix composites (HTMMCs) reinforced by B4C-SiC-MoS2-ZrO2. To further understand the impacts of process factors on porosity reduction, the study employs methodologies such as the response surface methodology (RSM), integrated artificial neural networks (ANN), and genetic algorithm (GA). The findings indicate that these strategies have the potential to contribute to the industry. The optimal combination of 7.5wt.% SiC, 7.5wt.% B4C, 7.5wt.% ZrO2, 4wt.% MoS2, and 73.5wt.% Ti compositions was determined utilizing process factors such as milling period (6h), compaction pressure (50MPa), compact duration (50min), sintering temperature (1200°C), and sintering time (2h) as compared to pure Ti grade 5. The mechanical properties of the optimum combination of reinforcement weight percentage and process parameters resulted in a minimum porosity of 0.118%, density of 4.36gcm3, and micro-hardness of 63.4HRC boosted by 1.76%, and compressive strength of 2500MPa increased by 2.6%. In addition, these HTMMCs had a minimal wear rate of 0.176mm3/Nm and a corrosion resistance rate of 2.15×10-4mmpy. The investigation result analysis discovered that the RSM and combined ANN-GA models considerably enhanced the forecasting of multidimensional interaction difficulties in composite material production that were highly statistically connected, with R2 values of 0.9552 and 0.97984. The ANN-GA model provided a 95% confidence range for porosity predictions, which increased the production use of titanium-based particle composites. Furthermore, HMMCs can be utilized in the automotive and aviation industries with enhanced corrosion and wear resistance.

Tribological investigation of ceramic incorporated novel compositionally graded multilayer tungsten alloys

In this study, novel compositionally graded tungsten alloys incorporating ceramics were prepared using mechanical alloying and pressure-assisted vacuum hot press (VHP) sintering. Three distinct tungsten compositions (W1, W2, and W3) were developed with varying alloying elements and reinforcements, were stacked layer-wise, and then sintered using VHP. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were employed to analyze the morphology and microstructural features of synthesized alloys. The effect of alloying elements and reinforcements on mechanical properties and wear behavior was examined. The results showed improvement in mechanical characteristics and enhanced wear resistance of the compositionally graded tungsten alloys. The hardness was increased due to the formation of carbide phases during milling and sintering. The W1 side exhibited a hardness of 8.4 GPa, while the W3 side reached a hardness of 13.3 GPa. Additionally, the wear behavior of both sides (W1 and W3) was also investigated under different applied loads. At a load of 10 N, the W1 surface exhibited a minimum specific wear rate of 3 × 10−6 mm3/Nm, attributed to the presence of MWCNTs and WC phase. However, the W3 surface reinforced with TiC and cBN showed a minimum specific wear rate of 9 × 10−7 mm3/Nm at a higher load of 20 N. This indicates that the W3 side possessed superior hardness and wear resistance ability as compared to the W1 side of compositionally graded tungsten alloys. The novel compositionally graded approach is useful for developing tungsten alloys with tailored mechanical properties for wear resistance applications.

Multi-Objective Optimization of Tribological Characteristics for Aluminum Composite Using Taguchi Grey and TOPSIS Approaches

In this study, a multi-objective optimization regarding the tribological characteristics of the hybrid composite with a base material of aluminum alloy A356 as a constituent, reinforced with a 10 wt.% of silicon carbide (SiC), size 39 µm, and 1, 3, and 5 wt.% graphite (Gr), size 35 µm, was performed using the Taguchi method, gray relational analysis (GRA), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) decision-making methods. Tribological tests were carried out on a “block on disc” type tribometer with lubrication. Load, sliding speed, and graphite mass concentration were analyzed as input parameters. As output parameters, wear rate and coefficient of friction were calculated. An analysis of variance (ANOVA) was conducted to identify all parameters that have a significant influence on the output multi-response. It was found that the normal load has the highest influence of 41.86%, followed by sliding speed at 32.48% and graphite addition at 18.47%, on the tribological characteristics of composites. Multi-objective optimization determined that the minimal wear rate and coefficient of friction are obtained when the load is 40 N, the sliding speed is 1 m/s, and the composite contains 3 wt.% Gr. The optimal combination of parameters achieved by GRA was also confirmed by the TOPSIS method, which indicates that both methods can be used with high reliability to optimize the tribological characteristics. The analysis of worn surfaces using scanning electron microscopy revealed adhesive and delamination wear as dominant mechanisms.