Wear Rate Research Articles

Optimizing Cutting Parameters for Effective Turning of EN-31 Steel by Utilizing Vegetable-Based Cutting Fluids as a Coolant

<div>The primary objective of this article is to study the improvement of machining efficiency of EN-31 steel by optimizing turning parameters using newly developed cutting fluids with different proportions of aloe vera gel and coconut oil, utilizing the Taguchi technique. Furthermore, performance metrics including material removal rate (MRR), surface roughness, and tool wear rate (TWR) were assessed. Analysis of variance (ANOVA) suggested that as cutting speed and feed increase, the MRR is positively influenced, but likewise tool wear is intensified. The surface roughness exhibited a positive correlation with cutting speed, and a negative correlation with increasing both cutting speed and feed. It was found that the maximum MRR value was attained at a cutting speed of 275 m/min, a feed rate of 1.00 mm/rev, and a cutting fluid composition of 30% aloe vera and 70% coconut oil. For the best surface smoothness, it is advisable to adjust the cutting speed to 350 m/min and the feed rate to 0.075 mm/rev. A cutting speed of 275 m/min and a feed rate of 1.00 mm/rev led to a lower TWR. The results suggest that the combined use of coconut oil and aloe vera as cutting fluids improves the turning quality of EN-31 steel, particularly when employing a combination of 30% aloe vera and 70% coconut oil. As a possible solution for performance problems in achieving desired results during the turning of EN-31 steels, these recommendations may be used in industries to enhance turning performance.</div>

Enhanced tribological properties and cyto-biocompatibility of dental Ti6Al4V alloy via laser surface texturing

Currently, the application of titanium-based implants is hindered by challenges such as inadequate wear resistance and limited osseointegration. Surface texturing technique has been recognized as an effective strategy to improve the surface performances of metallic material. The present work adopts a nanosecond laser texturing technique to fabricate micro textures on the titanium substrate. Firstly, the influence of laser parameters on the texture morphology and quality were investigated. Subsequently, both isotropic and anisotropic surface textures were fabricated to examine the impacts of texture form on wettability, tribological behavior, and cell adhesion and proliferation. The obtained results reveal that both the two textures promote the surface wettability of Ti6Al4V alloy towards a hydrophobic direction. Furthermore, the anisotropic micro-groove texture and the isotropic micro-grid texture can reduce the wear rate of titanium alloy by 42.02% and 73.64%, respectively. However, from the perspective of cyto-biocompatibility, the anisotropic micro-groove texture is capable of triggering an excellent cell contact guidance phenomenon, leading to a dramatically accelerated proliferation rate and facilitating the bone tissue growth in a specific direction.

Gray relational analysis for parametric optimization of micro-EDM of thermo-mechanically processed AA7075 and AA7075/SiC/Gr composite

The AA7075 alloy and AA7075/SiC/Gr hybrid composite prepared by the stir-casting method have been further thermo-mechanically processed through unidirectional hot rolling and hot cross-rolling routes to eliminate casting defects like voids, blow holes etc. Three initial sample temperatures, that is, 350℃, 400℃, and 450℃, have been considered for the hot cross-rolling. The Al alloy and its hybrid composite prepared at different rolling temperatures are studied to investigate their micro-machining behavior through micro-electric discharge machining (µ-EDM). The micro-holes are made on the rolled samples along the rolling direction of the final rolling pass using a tool with twist drill bit geometry. Further, multi-objective optimization of the µ-EDM process parameters considering the response parameters viz. material removal rate (MRR) and tool wear rate (TWR) has been carried out using the gray relational analysis (GRA) technique. The µ-EDM parameters chosen to optimize in this study are voltage, pulse on time, and tool rotation. The obtained GRA results are further analyzed through normality and equal variance tests. The R-squared values of 95.02% and 95.53% for AA7075 alloy and hybrid composite, respectively, indicate that the data fit well with the statistical model. In material removal, the different electrical and thermal characteristics of the Al matrix and the reinforcements possibly generate sparks with a different characteristic that ultimately affects the MRR of the composite. Through scanning electron microscopy (SEM), the morphological study confirmed the presence of globules and voids on the machined surface. The formation of globules and voids is more significant in the AA7075 alloy than in the composite.

Enhancing Lubrication Performance of Ga–In–Sn Liquid Metal via Electrochemical Boronising Treatment

ABSTRACTAs one of the liquid metals, Ga–In–Sn liquid metals can function as an advanced lubricant with high conductivity in a tribology system. It has already revealed advancements in several applications, such as coolants and electromechanical relays. However, Ga–In–Sn liquid metal shows poor lubrication performance on industrial metallic materials, which limits its application in engineering. In this study, the electrochemical boronising strategy was applied to improve the lubrication effect of Ga–In–Sn liquid metal on steel friction pairs. Electrochemical boronising treatment was performed to the base material AISI 52100, and a boronised layer with a thickness of around 64 μm was generated. Tribology tests were carried out on both boronised and original samples with the lubrication of Ga–In–Sn liquid metal (68.5 wt% Ga, 21.5 wt% In and 10 wt% Sn). Results show that the wear resistance of the tribo‐system reveals great improvement: The coefficient of friction decreases by 59% and the wear rate drops 85% compared to the steel/steel friction pair. EDS and XPS results show that a tribofilm consisted of Fe/Ga was in situ–generated on the wear scar of the boronised sample, which results in the synergy effect between the boronised layer and the Ga–In–Sn liquid metal. Therefore, we provided a robust strategy to enhance the lubrication performance of Ga–In–Sn liquid metal on a steel friction pair by using electrochemical boronising treatment, which could broaden the application field of Ga–In–Sn liquid metals.

Pulse dynamic regulation of electrochemical discharge milling by utilizing the slotted tube electrode

Electrochemical discharge machining (ECDM) has a splendid application potential for machining difficult-to-cut materials. It is a challenge to limit and control the discharge energy and area of DC power supply in ECDM. Owing to the uncertainty and randomness of the position and range of the single discharge, the unpredictable discharges deteriorate the surface quality of the workpiece, alter the size of the inter-electrode gap (IEG), and influence the distribution of the multi-physical fields. Therefore, to regulate the machining state and energy, the ideology of pulse dynamic machining is introduced, and a method of pulse dynamic ECDM utilizing the slotted electrodes is proposed. With the tool electrode rotating, the tube electrode transforms the pure electrochemical machining (pure-ECM) stage and the electrochemical discharge machining (ECDM) stage periodically through the slots at the bottom of it. The machining current waveform, surface roughness and sidewall taper of machined grooves, material removal rate (MRR), and relative tool wear rate (RTWR) are investigated. Additionally, the discharge types of the ECDM are explicitly defined and statistically classified. The experimental results show that the pulse dynamic regulation of hybrid machining using the slotted electrodes is beneficial to regularize the machining current waveform and optimize the machining quality.

Preparation of molybdenum disulfide/bentonite nanohybrid and its tribological properties as lubricant for water-based drilling fluids

In recent years, with the increase in energy demand and gradual scarcity of medium and shallow oil and gas resources, oil and gas exploration has shifted to special wells such as deep wells, ultra-deep wells, and extended reach wells. These complex wellbore structures inevitably increase the torque and friction between the casing and the drill pipe during drilling, which aggravates friction and wear, and leads to accidents such as drill sticking and drill breakage in severe cases. In this study, molybdenum disulfide/bentonite (MoS2/Bent) nanohybrids as drilling fluid lubricant were synthesized by hydrothermal method using sodium molybdate (Na2MoO4) and thiourea (CH4N2S) as raw materials and bentonite as carrier. The as-synthesized MoS2/Bent nanohybrid was characterized by X-ray powder diffractometer, transmission electron microscopy, Fourier transform infrared spectroscopy, and the high temperature resistance and tribological properties of MoS2/Bent nanohybrid were evaluated in base slurry. The results show that the friction coefficient of MoS2/Bent nanohybrid drilling fluid before aging is reduced by 74 % and the wear rate is reduced by 97 % compared with the base slurry. After high-temperature aging at 240 °C, the friction coefficient is reduced by 77 % and the wear rate is reduced by 90 %. The excellent friction reducing and antiwear performance is attributed to the formation of low shear strength MoS2 deposition film and oxide tribofilm on the surface of the friction pair during the rubbing process.

The effects of different strengthening treatments on wear performance of ZL109 aluminum alloy at high temperature

Enhancing strength or hardness is a widely employed strategy to improve wear resistance of ZL109 aluminum alloy at elevated temperatures. This study aimed to investigate the effects of various strengthening treatments on the wear performance of ZL109 aluminum alloy. Three strengthening methods, namely structural refinement, strain hardening, and precipitation strengthening, were employed to achieve a similar hardness level. Subsequently, the wear tests were conducted using a reciprocating ball-on-disk tribometer under different temperature conditions. The results showed that all the strengthening samples exhibited a similar wear rate (approximately 7.0 × 10−4 mm3/N·m) at room temperature. However, at 250 °C, the precipitation strengthening sample performed best with a wear rate of 1.32 × 10−3 mm3/N·m, followed by the strain hardening and structural refinement samples (approximately 1.7 × 10−3 mm3/N·m). This superior performance was attributed to the precipitation phase, which could effectively maintain material strength through dislocation pinning. By contrast, dynamic recovery and recrystallization behavior weakened the effectiveness of strain hardening, while crystal growth diminished the efficacy of structural refinement. In addition, the wear mechanisms transitioned from abrasion to adhesion and slight oxidative wear as the temperature increased.

Study on the effect of TiC/B on the performance of laser cladding in-situ fabricating wear-resistant self-lubricating coatings

To improve the wear resistance of IN718, coatings containing the self-lubricating phase h-BN were prepared and the coating properties were analyzed in relation to the variation of laser power. The results show the TiC added to the cladding powder partially decomposes and in-situ fabricates new reinforcing phases TiN, B4C, etc. The lubricating phase h-BN was in-situ fabricated by adding B into the powder. As the laser power increased from 1.6 kW to 2 kW and 2.5 kW, eutectic microstructures of high melting point reinforcing and lubricating phases were observed. Due to the decomposition of TiC and in-situ fabricated of TiC2, TiN and B4C concentrations changing with the laser power, the surface hardness of the coatings prepared at 2.5 kW was the highest at 391.03HV0.5. Which is 1.096 and 1.108 times of 1.6 kW and 2 kW. At room temperature, the coating fabricated by 2 kW has the highest average friction coefficient of 0.537. This is because the self-lubricating phase h-BN is a high-temperature lubricating phase and the wear surface has a low oxide content, and is influenced by the hardness of the coating. At 500°C, the coating fabricated with 2.5 kW has the lowest average friction coefficient due to the best synergistic effect of the lubricating and reinforcing phases at 0.376. The 2.5 kW coating has the best wear resistance, with wear rates 0.69 and 0.54 times at room temperature and 0.82 and 0.8 times at 500°C of 1.6 kW and 2 kW. The wear mechanism at room temperature is abrasive wear, and at 500°C is mainly a combination of h-BN and oxide synergistic lubrication.

Effect of current on the tribological behavior of Cu-Fe-P immiscible alloy produced by laser powder bed fusion

Cu-based immiscible alloys have significant potential application value in the field of electrical contacts. This study investigated the tribological behavior of Cu-Fe-P immiscible alloys produced via laser powder bed fusion (LPBF) under current-carrying conditions. The alloys consist of softer ε-Cu phase and harder Fe-rich phases. The Fe-rich phase acts as a protective reinforcement during current-carrying friction and wear tests, improving the wear resistance of the alloy. With the increasing current, the coefficient of friction initially rose and then decreased, whereas the wear rate showed a gradual increase. At low currents (0, 2, 3 and 5 A), mechanical wear predominantly governs the wear mechanism. As the current increases, the mechanical wear gradually transitions from adhesive wear to abrasive wear, accompanied by weak oxidative wear. At higher currents (7 A and 10 A), the wear mechanism is dominated by arc erosion wear and oxidative wear. Notably, when the current exceeded 2 A, an oxide film consisting of CuO, Fe2O3, and Fe3O4 formed, enhancing the frictional properties of the alloy. Once the current surpassed 5 A, the arc discharge occurred at high currents, forming molten phases and arc erosion pits on the worn surface of the Cu-Fe-P immiscible alloy.

Enhancing Corrosion Resistance and Tribomechanical Characteristics of Powder Coatings via the Integration of Functionalized HF‐Free MXene Reinforcements

AbstractMXene, a new generation of 2D materials, is gaining attention for anti‐corrosion applications due to its large surface area, electrical conductivity, and self‐healing properties. Its low shear strength and self‐lubricating properties enhance wear resistance. Herein, silane functionalized HF‐Free MXene nanosheets “MS‐f_Ti3C2 and MS‐f_Ti3C2@Zn” synthesized through the molten salt method are integrated into the environmentally sustainable powder coating. The electrochemical tests indicate that a powder coating containing a well‐dispersed 1.5 wt.% f_Ti3C2@Zn nanosheets exhibit the highest polarization resistance (1.1 × 106 Ω cm2), lowest Icorr (2.15 × 10−8 A cm−2) and superior anti‐corrosion performance after 42 days of immersion in 3.5 wt.% NaCl. The polarization resistance (Rp) and corrosion current (Icorr) of the untreated coating are measured to be 1.6 × 103 Ω cm2 and 1.6 × 10−5A cm−2, respectively. In addition, the incorporation of MXene material reduces crack development and spalling, and enhances wear resistance during the friction process. The loading of 1.5 wt.% f_Ti3C2@Zn reduces the coefficient of friction (COF) and improves wear rate by 45% and 51%, respectively Analysis of composites via nanoindentation reveals such enhanced mechanical properties. This study presents an effective and sustainable approach to improve the mechanical, tribological, and long‐term corrosion protection of organic coating, thereby exhibiting great potential for using HF‐Free MXene as a multipurpose additive.

High-silicon spring steel transformation to carbide-free bainitic (CFB) steel: a mechanical and tribological approach under rolling/sliding conditions

The present study concentrates on the development of carbide-free bainite steel and explores its tribological and mechanical characteristics using a newly devised disk-on-disk tribometer. The microstructure of the treated samples was examined through heat treatment at various holding temperatures (300, 350, and 400 °C) and durations (10, 20, and 30 min), along with isothermal transformation. The wear rate demonstrated significant sensitivity to holding duration, transformation temperature, phase fraction, and the stability of retained austenite. The microstructural analysis encompassed atomic force microscopy (AFM), FE-SEM, x-ray diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS). The study extensively investigated the robust correlation among mechanical properties, microstructure, wear behavior, and the presence of retained austenite (RA) and bainite volume fraction. The findings indicate that carbide-free bainite steel holds promise for replacing conventional railway wheel track steel in the steel industry. The structural property correlations have developed of high silicon steel, hardness reduced with increasing temperature and isothermal preserving time; resulting in a gradual increase in the wear rate of CFB steel. The salt bath soaking temperature of 350 °C with a period of 30 min was found to be the preeminent wear properties condition for CBF steel.

Enhancing the anti-wear performance of graphene sheets embedded carbon films through interface nanotexture fabricated on the substrate

The effect and mechanism of surface texture on friction have been extensively explored, such as storing the abrasive and reducing the real contact area. However, studying the impact of the interface texture remains crucial, especially as the texture size approaches the nanoscale. In the present work, the silicon substrate with different parameters nanotexture was fabricated using a metal-assisted chemical etching process, and the graphene sheets embedded carbon (GSEC) film was deposited on the nanotextured substrate via a low-energy electron irradiation process to produce the interface nanotextured carbon films. After the addition of the interface nanotexture, the tribological performance of carbon films exhibited significant enhancement, with the degree of improvement being influenced by the parameters of the interface nanotexture. A super-low wear rate was achieved, with a value of 6.54 ± 0.70 × 10−8 mm3/N m. The improved tribological performance is due to the enhancement of film-substrate adhesion strength facilitated by interface nanotexture, and its role in promoting the rapid formation of a stable transfer film on the counter-grinding ball. The carbon film with nanotexture displays a small size of the abrasive particles, which contributes to the stabilization of the friction process.

Biomimetic joints inspired soft and hard combined 2D diamond solvent-free nanofluids with multi-layer structure for superior lubrication

The articulating joints consist of a three-layer lubricating structure, which combines soft and hard materials, including cartilage, polymer brushes, and a hydration layer. This structure leverages the synergistic effects of fluid and boundary lubrication to maintain ultra-low friction under different pressures on the same frictional surface. In this study, a biomimetic multilayer lubricating structure inspired by joint tissues is constructed using single-crystalline diamond nanosheets (SCND) as the hard phase material. Through a facile chemical reduction method and employing polydopamine (PDA) as a "bridge", a soft phase material is deposited onto the SCND surface to produce diamond composite silver nanocomposites (SCND@PDA@Ag). Subsequently, two solvent-free SCND@PDA@Ag nanofluids are prepared by grafting organic canopy substances onto the SCND@PDA@Ag surface via ionic bonds or covalent bonds, referred to as SCND@PDA@Ag-ionic bonding nanofluid and SCND@PDA@Ag-covalent bonding nanofluid, respectively. The findings reveal that the SCND@PDA@Ag-covalent bonding solvent-free nanofluid exhibits superior lubricating performance for steel/SiC contacts. The friction coefficient and wear rate for steel/SiC are significantly reduced by 93.2 % and 63.1 %, respectively, compared to dry friction, it's noteworthy that these results outperform those achieved by individual components of the lubricant. During the friction process, SCND and silver particles on the surface of SCND@PDA@Ag-covalent bonding solvent-free nanofluid work together to enhance lubrication synergistically. Furthermore, silver particles on the surface of SCND are released and fill into the worn surface, providing a repairing effect. This study highlights that the design of soft-hard multilayer structures offers a novel approach for researching nanocomposite materials in the field of tribology.

A novel strategy to significantly improve wear resistance of amorphous alloys by immersion in NaOH solution

The application of amorphous alloys in tribology is constrained by their inherent brittleness. An alkaline treatment (AT) can address this limitation by hydrogen generated rejuvenation. Following AT in a 3 mol/L NaOH solution for 3 days, the hardness of as-cast Ti-based amorphous alloys decreased by about 10 %, while the relaxation enthalpy increased approximately 2.2 times. Concurrently, the average coefficient of friction (COF) decreased by more than 15 % under all test loads except at 10 N. Additionally, the wear rate significantly decreased by over 20 %, with a notable reduction of about 25 % under a 7 N load. The improvements in tribological properties are primarily attributed to increased plasticity and surface oxidative ability, resulting from the hydrogen absorption during chemical reactions. Thus, AT offers a practical and effective way to significantly enhance the tribological performance of amorphous alloys.

Impact of different parameters in tribological properties of enset ventricosum/ terminalia arjuna fibers /SiO2 filler incorporation

Natural fiber composites have garnered considerable interest in recent years as sustainable substitutes for synthetic materials, owing to their environmental advantages, including renewability, biodegradability, and cost-effectiveness. Notwithstanding these benefits, there is a vital need to improve the mechanical and tribological characteristics of these composites for applications involving significant wear. This work used compression molding to make hybrid composites with natural fibers (NFs) and nano silicon dioxide (nSiO2) filler. The matrix material was epoxy, and the natural reinforcements were Enset ventricosum (EV) and Terminalia arjuna (TA) fibers. Tensile (TS), flexural (FS), and impact (IS) characteristics improved using 1:1 SiO2 filler and EV/TA fiber reinforcement. The combination of 6 wt% SiO2 and 45 wt% EV/TA improved mechanical performance. A high SiO2 filler (6 wt%) in polymer-based composites decreased Specific Wear Rate (SWR), according to Taguchi optimization. A better fiber-matrix interaction improves the mechanical characteristics of materials with fillers. This study optimized several responses using the new combined compromise solution (CoCoSo) method. Multi-criteria decision making is used here. This study introduces Method based on the Removal Effects of Criteria (MEREC) to determine objective criteria weights. Conclusions from experiments show ideal results. CoCoSo's optimization study showed that Enset ventricosum and Terminalia arjuna fiber (EV/TA) hybridization affected composites' tribological behavior.This hybrid fiber combination carried the most influence, followed by fillers. The optimal results were obtained with 6 wt% SiO2/25 wt% EV/TA Hybrid fiber, 1000 m Sliding distance (SD), 2 m/s Sliding speed (SS), and 10 N axial load (AL).

Mechanical properties of CoCrFeNi-X (X = Ti,Sn) high entropy alloy and tribological properties in simulated seawater environment

Five multimajor element CoCrFeNi-X(X = Ti,Sn) high entropy alloys (HEA) were prepared by vacuum hot press sintering. The phase composition, mechanical properties and tribological properties of CoCrFeNi-X(X = Ti,Sn) alloys in simulated seawater were investigated. The phase structure of CoCrFeNiTi high-entropy alloy is solid solution FCC phase, R phase, σ phase, and Laves phase. But after addition Sn elements, the phase structure become the FCC phase and Ni-Sn solid solution phase. CoCrFeNiTi alloy has lower density (7.17 g/cm3) and higher hardness (750 HV) than that of CoCrFeNiSn. The compressive yield strength of CoCrFeNiTi HEA is better than CoCrFeNiSn HEA. The CoCrFeNiSn high-entropy alloys showed lower wear rates. The main reason is that SnO2 is generated on the wear scar surface, which has good wetting and corrosion inhibition effects, so CoCrFeNiSn HEA shows better wear resistance in simulated seawater. The main wear mechanism of the CoCrFeNiSn HEA is abrasive wear, oxidative wear, exfoliation wear and corrosive wear.

Near-zero-wear with super-hard WB4 and a self-repairing tribo-chemical layer

Achieving near-zero-wear remains a major challenge in mechanical engineering and material science. Current ultra-low wear materials are typically developed based on the self-consumption strategy. Here, we demonstrate a new self-repairing approach to achieve near-zero-wear. We find that the WB4-βB/WC tribo-pair has a low wear rate of 10−8 mm3 N−1 m−1 in low vacuum conditions, under a maximum Hertzian contact stress of 2.23 GPa over 1 × 105 friction cycles. Additionally, we observe an abnormal wear phenomenon after 5 × 104 friction cycles, characterized by an increase in the dimensions of the tribo-pair. This near-zero-wear mechanism is attributed to the synergistic action of the super-hard WB4-βB substrate and the self-repairing tribo-oxide layer. This research provides a new approach for advancing wear-resistant materials and enhancing material longevity.

Enhanced machining of Al 10%SiCmicro 1%SiCnano hybrid composite using rotary tool rotary workpiece EDM with bio dielectrics and treated tools

A sustainable approach was proposed to address environmental pollution, carbon footprint and economic efficiency challenges in Electrical Discharge Machining (EDM). This approach involved the use of Bio-dielectric such as biodiesel and Bio fuel (distilled water with 10% ethanol). The EDM process performance was further optimized by experimenting with both electrodes’ rotation (i.e., in same direction, opposite direction, no rotation) and the use of treated tools (no treatment, heat treatment, cryogenic treatment). Biodiesel as a bio-dielectric showed promise by delivering the highest Material Removal Rate (MRR) and the lowest Tool Wear Rate (TWR). Bio-fuel (distilled water with 10% ethanol) resulted in the lowest Surface Roughness (SR) and cleaner machined surface with least carbon deposition. Additionally, electrode rotation improved flushing and enhanced performance parameters, with opposite direction rotation yielding the highest MRR and the lowest SR. However, no rotation of electrodes resulted in the lowest TWR. The use of treated tools, specifically heat-treated and cryogenically treated tools, also improved performance and reduced energy consumption, with cryogenic treatment providing the highest MRR, heat treatment giving least SR, and no treatment providing least TWR. Certain interactions between factors significantly impacted performance parameters. Grey relational analysis revealed that using distilled water with 10% ethanol as a dielectric, employing cryogenically treated copper tools, and having no rotation of both electrodes yielded the best performance parameters.

Effect of plasma nitriding on microstructure and wear behavior of electrodeposited FeCoNiCr coating

An (FeCoNiCr)N high-entropy alloy coating with a single FCC phase was fabricated on 304 stainless steel by electrodeposition and plasma nitriding. The results indicated that the FeCoNiCr coating exhibited typical granular morphologies and a nearly equiatomic ratio of four elemental compositions. After nitriding, the coating primarily consisted of a high-entropy solid solution phase and a CrN phase, with the microstructure of the (FeCoNiCr)N coating being significantly refined due to the effect of crystallization. The microhardness of the (FeCoNiCr)N coating was 781.30 ± 20.3 HV0.5, considerably higher than that of the FeCoNiCr coating, which was 496.48 ± 21.82 HV0.5. Additionally, the (FeCoNiCr)N coating demonstrated a low friction coefficient and a wear rate of 0.59 and 6.8 × 10−8 mm3/N mm, respectively. The fine microstructure and high resistance to plastic deformation, attributed to solid solution strengthening and dispersion strengthening, were the primary factors contributing to the excellent wear performance of the (FeCoNiCr)N coating.

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.