Improved Wear Resistance Research Articles

Microstructural evaluation and optimization of wear behaviour of vacuum arc melted AlFeCrNiSi high entropy alloy

High-entropy alloys (HEA) are equiatomic, multi-element systems that, while having several elements with various crystal geometries to form a single phase. In this study, a novel equiatomic AlFeCrNiSi HEA is prepared using the vacuum arc melting process. The resulting microstructure featured dendritic and inter-dendritic structures with formations of intermetallic compounds such as Al₃Fe₂Si, NiAl, and AlCrNi phases. EDS analysis confirmed the presence of alloying elements and EBSD analysis revealed refined grains with an average size of 1 ± 0.15 µm size. Pin-on-Disc wear test with varying test parameters is conducted to optimize the wear parameters. Signal-to-noise ratio and analysis of variance identified the most significant wear parameters, with load being the most influential, followed by sliding distance and velocity. The wear rate is minimum at the lowest conditions of applied load, sliding distance, and sliding velocity. The improved microhardness also contributed to the improved wear resistance of the cast alloy. The subsequent worn morphology revealed the formation of grooves, microcracks, and oxide layers on the worn surface.

Influence of enhanced Laves phase shape and distribution on atomic-scale frictional wear mechanisms in nickel-based single crystal alloys

This study aims to simulate the influence of different shapes and distribution states of Laves phases on the friction-wear behavior of nickel-based alloys using molecular dynamics (MD). The investigation systematically examined the mechanical properties, friction coefficient, number of worn atoms, dislocations, temperature, and other micro-deformation behaviors of materials incorporating horizontally and vertically distributed short rod-shaped, spherical, and short strip-shaped Laves phases. The presence of the Laves phase significantly impedes temperature transfer, defect motion, and atomic displacement in the workpiece, resulting in reduced dislocation glide rate and shorter average dislocation lengths. High dislocation densities accumulate at the Laves/γ phase interface, enhancing surface wear resistance. The short rod-shaped Laves phase, due to its large surface area at the Laves/γ interface, impedes defect motion more effectively than spherical and short strip-shaped phases. dislocation tangle, higher friction force, fewer worn atoms, a higher friction coefficient, and improved wear resistance. However, vertically distributed short strip-shaped and short rod-shaped Laves phases exhibit less effective defect interaction, resulting in increased wear and significant deformation. The spherical Laves phase, with its geometric symmetry, shows consistent wear resistance regardless of distribution state. Short rod-shaped Laves phase provides the best reinforcement due to its effective defect motion impedance, while the spherical Laves phase offers stable performance across different distribution states, making it the most suitable shape for Laves phase reinforcement.

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

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

A review: Enhancing tribological properties of journal bearings composite materials

Abstract Tribology is the science of studying friction, wear, and lubrication. Composite materials consist of two or more constituents (phases): the discontinuous phase represents the reinforcement and the continuous phase represents the matrix. Journal bearing is manufactured from various composite materials. This article reviews the literature on improving the tribological properties of journal bearings made of composite materials (polymer matrix composite materials and metal matrix composite materials) by dividing the previous studies into six primary sections depending on the kinds of composite materials. An efficient method was utilized to solve the problems of composite journal bearings in water lubrication such as wear resistance, reduced friction, and increased service life of journal bearings in various applications especially in ships. The impact of composite materials, which were added through thermoplastic such as polytetrafluoroethylene (PTFE), polyether-ether-ketone, POM, and PA66, thermoset such as epoxy, polyester, and phenolic reinforced with fibers, and thermoplastic with thermoset (PTFE/epoxy composite) to reduce wear rate and coefficient of friction, and also the addition of nanomaterials to composite journal bearing to enhance the tribological properties in various applications were examined. The last section used metal matrix composite reinforced to other metal or alloy to give the attractive mechanical properties used to improve wear resistance and friction coefficient of journal bearing. The novelty of this article lies in the comprehensive analysis of various composite materials and their effect on the tribological properties of journal bearings, providing future insights into bearing design and optimization to improve performance.

TRIBOLOGICAL AND CORROSION PROPERTIES OF 45 AND 65G STEELS USED IN AGRICULTURAL MACHINERY AFTER ELECTROLYTIC-PLASMA HARDENING

The article examines the effect of electrolytic plasma hardening on the wear resistance and corrosion resistance of steels 45 and 65G, which are used in the production of agricultural machinery components. The presented results demonstrate the improvement of the surface properties of steel through the application of electrolytic plasma hardening. This technology provides rapid heating and cooling, which contributes to the formation of a fine-grained and hardened surface layer, as evidenced by microstructural studies conducted using an optical metallographic microscope. Tribological tests showed an improvement in wear resistance after electrolytic plasma hardening: the wear volume for steel 45 was 3,03×10-4 mm³, and for steel 65G it was 6,17×10-5 mm³, which is 7 and 4,5 times less than the wear volume for the initial samples, respectively. The analysis of polarization curves showed that the corrosion current density decreased compared to the initial sample. For steel samples 45 and 65G after three cycles of electrolytic plasma hardening, the corrosion current densities were 6,87×10^-6 A/cm² and 1,61×10^-7 A/cm², respectively. Additionally, a shift in the corrosion potential towards more positive values was noted, indicating an increase in corrosion resistance. The results of the study demonstrate significant improvements in the tribological and corrosion properties of steels 45 and 65G after electrolytic plasma hardening, providing valuable data for industrial applications.

THE INFLUENCE OF ELECTRON BEAM IRRADIATION ON THE TRIBOLOGICAL AND MECHANICAL PROPERTIES OF POLYTETRAFLUOROETHYLENE (PTFE) FOR ENGINEERING APPLICATIONS

The study demonstrates the significant effects of electron beam irradiation on the tribological and mechanical properties of polytetrafluoroethylene (PTFE). Electron beam irradiation, a method using highvelocity electrons to modify material properties, was applied to PTFE to potentially enhance its wear resistance and mechanical hardness, which are critical for applications under increased wear conditions. In the experiments, PTFE samples were irradiated at varying doses, and their wear resistance, microhardness, and surface roughness were evaluated post-irradiation. Tribological test results showed a notable improvement in wear resistance and microhardness with increasing radiation doses. Specifically, irradiated samples exhibited reduced wear volume and enhanced surface characteristics compared to the unirradiated sample. The irradiated sample (PTFE-2) showed the highest resistance to abrasive wear and a significant increase in surface hardness, indicating that electron beam irradiation effectively strengthens the material by inducing cross-linking and other structural modifications within the polymer matrix. Additionally, the study highlighted changes in surface roughness: irradiated samples exhibited altered roughness parameters that contributed to improved wear resistance. These changes can be explained by the physical and chemical transformations induced by electron beam exposure, which modify the surface and subsurface regions of the polymer. This study confirms that electron beam irradiation is an effective method for enhancing the mechanical and tribological properties of PTFE, making it more suitable for advanced engineering applications where high durability and resistance to extreme conditions are required. The findings open new avenues for the use of PTFE in sectors requiring high performance, extending its application beyond traditional fields.

The effect of Titanium Carbide (TiC) addition on the performance of Cupro-Tungsten (Cu-W) alloy for spark erosion electrodes used in machining carbide materials

This article focuses on the development and characterization of Copper-Tungsten (WCu) electrodes, enhanced with the addition of nickel and cobalt as activators and titanium carbide (TiC) for improved wear resistance. The electrodes were manufactured using powder metallurgy through cold pressing, followed by sintering-infiltration at 1250°C under a reducing atmosphere of H2. The characterization process involved measuring density, microhardness, electrical conductivity, and SEM/EDX microstructure. Additionally, technological tests were conducted on P35 carbide parts to assess parameters such as material removal rate (MRR), tool wear rate (TWR), and wear rate (WR). The results indicated that the W-Cu-Ni-TiC compact exhibited an improved density of 11.95, while the W-Cu-Co-TiC compact demonstrated the highest MRR. The W-Cu-Co-TiC compact also recorded a lower TWR. Overall, the W-Cu-Co-TiC compact offered the best compromise in terms of electrode-part wear, achieving superior microhardness values of 289Hv. These findings suggest that incorporating transition elements and TiC into WCu electrodes can significantly enhance their performance, making this study a valuable reference for future research aimed at improving electrode wear resistance through material and manufacturing advancements.

Microstructure and dry sliding wear evaluation of functionally graded coating deposited via atmospheric plasma spray

Surfaces are commonly enhanced with wear-resistant coatings to improve their resistance to abrasion, erosion, and other forms of wear. These coatings play a crucial role in extending the lifespan and improving the performance of materials and components exposed to challenging conditions. The objective of the current study is to deposit thermally sprayed 3-layer TiC–12Co–10ZrO2/NiCoCrAlMo functionally graded coatings on SS410 substrates using atmospheric plasma spray. The results revealed that by employing appropriate ceramic proportions, the microhardness of graded coatings increased to 990.4 HV, which is approximately 3.21 times higher than that of the substrate. Furthermore, the tribological properties of graded coating exhibited superior resistance compared to the substrate, where process settings were varied. Specifically, graded coating samples subjected to the applied load, sliding distance, and sliding velocity showed improved wear resistance of 78.51%, 68.42%, and 76.66% respectively in extreme conditions compared with uncoated samples. The characterization of the worn surface revealed a sequential occurrence of wear mechanisms: abrasive, adhesive, and delamination. The formation of TiO2 and Cr2O3 tribo-oxide film protects the surface against the wear mechanism and is applicable in extreme wear environments.

Engineering of multilayered coating on additively manufactured Ti-6Al-4V porous implants to promote tribological and fatigue performances

Despite the numerous advantages of additively manufactured Ti-6Al-4V porous implants surface modified by plasma electrolyte oxidation (PEO) coatings in biomedical applications, several challenges still persist regarding their tribological and fatigue performances. To address these challenges, this study aims to engineer an innovative multilayered coating based on physical vapor deposited (PVD) Nb/NbN coatings on PEO-treaded Ti-6Al-4V porous implants. Three configurations of Nb/NbN coatings, including one, two, and three PVD layers were deposited on PEO-treated Ti-6Al-4V implants to simultaneously assess the effects of both increased coating thickness and configuration on the surface topography and mechanical performances of Ti-6Al-4V implants. Results showed that increasing the thickness and number of coatings changed the surface morphology and reduced the surface roughness. The PVD/PEO treatment demonstrated enhanced wear resistance of Ti-6Al-4V samples compared to the PEO treatment, depending on the coating conditions. Noticeably, the samples with 2 Nb/NbN layers exhibited the highest wear resistance and decreased the wear rate by 90 % compared to the Ti-6Al-4V samples. Although PEO treatment resulted in a decrease in fatigue life, the deposition of Nb/NbN coatings, especially those with 2 and 3 layers, markedly improved fatigue resistance compared to the PEO-treated samples. These modified samples attained approximately 81 % and 84 % of the fatigue life of the not-treated Ti-6Al-4V samples, respectively. Overall, the deposition of multilayered PVD Nb/NbN coatings on PEO-treated Ti-6Al-4V implants demonstrated an effective improvement in wear resistance while maintaining acceptable fatigue life under cyclic loading, making it promising for biomedical implants.

Effect of introduction of MXene on low energy plasma electrolytic oxidation

This article discusses the development of 2D MXene-containing coatings on magnesium alloy LA91, which are produced using low-energy plasma electrolytic oxidation (LePEO) processing. The coatings enhance substrate corrosion resistance and offer improved wear resistance. Notably, the coatings exhibit increased corrosion and wear resistance, as well as higher microhardness, while simultaneously reducing the voltage required for the PEO process. The addition of MXene to electrolyte enhances its conductivity, leading to the incorporation of MXene into the oxide coating. Despite a reduction in coating thickness, the resulting coatings demonstrate excellent corrosion resistance, wear resistance, and hardness. The MXene-enriched PEO coatings show impressive performance metrics compared to the MgLi alloy substrate. The corrosion current density of the MXene-enriched coatings is only 3.3 % of that of the MgLi alloy, while the average friction coefficient is reduced to 39.9 %, and the hardness is 6.6 times greater. Additionally, the coatings exhibit enduring corrosion resistance during prolonged immersion and neutral salt spraying tests. These performance improvements are attributed to MXene's ability to hinder the transmission of corrosive media, as well as its interlayer shear and self-lubrication properties, which enhance wear resistance.

Recent Advancements in Fabrication of Metal Matrix Composites: A Systematic Review.

Metal matrix composites (MMCs) are essential materials in various industries due to superior properties, such as high strength-to-weight ratios, better corrosion resistance, improved wear resistance and adaptability, developed by continuous improvements in their fabrication methods. This helps to meet the growing demand for high-performance and sustainable products. The industries that stand to gain the most are automotive and aerospace, where MMCs are used for car parts, airplane frames, and jet engines that need to be strong and lightweight. Furthermore, MMCs are being extensively used in the biomedical industry for implants and medical equipment because of their suitable mechanical integrity and corrosion resistance. Applications in heavy construction, defense, and even space exploration are noteworthy. The advancements in fabrication of MMCs have revolutionized the composite industry with their improved mechanical, tribological, and metallurgical properties. This review article offers an introduction and thorough examination of the most recent advancements (mostly within the last five years) in fabrication methods of MMCs. The novelty and modernization in the traditional processes and advanced processes are covered, along with discussing the process parameters' effects on the microstructure and properties of the composites. The review focuses on features and prospective applications of MMCs that have been greatly improved and extended due to such advancements. The most recent methods for developing MMCs, including friction stir processing (FSP), ultrasonic-assisted stir casting, and additive manufacturing, are discussed. Artificial intelligence and machine learning interventions for composite manufacturing are also included in this review. This article aims to assist researchers and scholars and encourage them to conduct future research and pursue innovations to establish the field further.

Improvement of High Temperature Wear Resistance of Laser-Cladding High-Entropy Alloy Coatings: A Review

As a novel type of metal material emerging in recent years, high-entropy alloy boasts properties such as a simplified microstructure, high strength, high hardness and wear resistance. High-entropy alloys can use laser cladding to produce coatings that exhibit excellent metallurgical bonding with the substrate, thereby significantly improvement of the wear resistance of the material surface. In this paper, the research progress on improving the high-temperature wear resistance of high entropy alloy coatings (LC-HEACs) was mainly analyzed based on the effect of some added alloying elements and the presence of hard ceramic phases. Building on this foundation, the study primarily examines the impact of adding elements such as aluminum, titanium, copper, silicon, and molybdenum, along with hard ceramic particles like TiC, WC, and NbC, on the phase structure of coatings, high-temperature mechanisms, and the synergistic interactions between these elements. Additionally, it explores the potential of promising lubricating particles and introduces an innovative, highly efficient additive manufacturing technology known as extreme high-speed laser metal deposition (EHLMD). Finally, this paper summarizes the main difficulties involved in increasing the high-temperature wear resistance of LC-HEACs and some problems worthy of attention in the future development.

Research and analysis of rock breaking mechanical model of single-roller PDC compound bit

In order to improve wear resistance and rock breaking efficiency of single-roller bit, a new type of bit, single-roller PDC compound bit is designed. The mechanical model of interaction between PDC teeth and rock of single-roller PDC compound bit is established, and the theoretical calculation formula of resultant force and torque generated by interaction between PDC teeth and rock on cone and bit is obtained. The rock-breaking experiment on the single-roller PDC compound bit are carried out. The results show that with the increase of front inclination angle, the axial force and radial force of PDC teeth decrease greatly at first and then tend to be stable, while the tangential force of PDC teeth decreases at first and then increases slightly; the axial force, radial force and tangential force all increase with the increase of the cutting depth; the maximum values of the three forces all appear at the position of the combined effect of the maximum cutting depth and the minimum front inclination angle. The maximum value of moment [Formula: see text] and [Formula: see text] both appear at the minimum value of h C and δ, while the maximum value of moment [Formula: see text] appears at the minimum value of δ. In order to reduce the acting moment generated by PDC cutter on the roller, the PDC cutter at different position heights can be designed with different front inclination angles. The rock breaking experiment results show that compared with the common single-roller bit, the single-roller PDC compound bit has higher rock breaking efficiency and better development prospect. When drilling in hard limestone, the single-roller PDC compound bit is more energy-efficient under higher WOB.

Enhancement on the thermal and tribological behaviors of polyurethane/epoxy-based interpenetrating network composites by orientationally aligned CNF/MXene/WPU aerogels

Tribological behaviour of polyurethane/epoxy interpenetrating polymer network (PU/EP IPN) as friction materials was investigated. This was a combination of the good flexibility of PU and high hardness of EP to realize polymer synergistic effect of interpenetrating network structure, aiming to broaden and develop the application of polymer-based composites in friction engineering materials. A novel CNF/MXene/WPU aerogel (CMW) was prepared by employing flexible NCO-terminated waterborne polyurethane prepolymer (WPU) as the supporting skeleton of aerogel, and synchronously combining the reinforcing-phase carbon nanofibers (CNF) and lubricating-phase MXene. Subsequently, the prepared ultralight porous yet mechanically robust CMW aerogels were encapsulated with IPN by vacuum impregnation. As expected, the addition of aerogel imparted IPN matrix with enhanced thermal and tribological properties due to the thermal dispersion and enhancement effects conferred on the matrix by the highly aligned and ordered three-dimensional interconnected structure of aerogel. Meanwhile, CMW reinforced IPN composites were explored for the formation of a high-quality transfer film on the contact surface during friction. The transfer film prevented direct contact between the friction couples, which facilitated the improvement of wear resistance of composites, thus giving this material great potential for tribological applications.

Structure and tribological behavior of a polyetherimide/polytetrafluoroethylene matrix filled with negative thermal expansion zirconium tungstate particles

Thermal expansion mismatch stresses may be a reason for premature failure of sealing and bearing components made of polymer composites that are rubbed against metallic surfaces at elevated temperatures. It is of particular importance for polymer matrix composites loaded with anti-friction inclusions of polytetrafluoroethylene (PTFE) that possesses high coefficient of thermal expansion. In this regard, a study was undertaken to elucidate the effect of the thermal mismatch on wear and friction of amorphous polyetherimide (PEI) matrix loaded with either polytetrafluoroethylene (PTFE) particles (i) or PTFE particles covered with negative thermal expansion zirconium tungstate (ZT) α-ZrW2O8 (ii) at temperatures 23 °C, 120 °C and 180 °C. The ball-on-disk testing scheme was used according to standard with AISI 52100 steel balls rubbed against a polymer composite disks at normal force P = 5 N and sliding velocity V = 0.3 m/s. The PEI/PTFE/ZT composite demonstrated a tendency for wear rate (WR) reduction in sliding at 120 °C and 180 °C as compared to corresponding WR enhancement on the PEI/PTFE. The rationale is provided that the ZT additive effectively reduced thermal expansion of the PTFE in the PEI matrix and thus improved wear resistance of the composite. New thermal expansion-controlled wear and friction instability mechanism has been proposed and discussed.

Effect of crystallization behavior on wear properties of polytetrafluoroethylene composites modified by irradiation above melting point

AbstractIn this paper, the reasons for the improved wear resistance of irradiation‐modified Polytetrafluoroethylene (RM‐PTFE) and its composites above the melting point were investigated from the microcrystalline point of view by using methods such as crystallization kinetics, and it was found that the linear wear rate of RM‐PTFE was only 0.3 um/km, with a 1000 times increase in wear resistance, which was due to the transformation of its crystals from flake crystals that were easily dislodged to spherical crystals that were more resistant to abrasion. It was also found that the linear wear rate of Polytetrafluoroethylene (PTFE) with coke and graphite was 0.2 and 0.1 μm/km, respectively, and the abrasion resistance was further improved, which was attributed to the lowering of spherical crystal grain size by coke and graphite, which had better mechanical properties. These studies lay the foundation for future research on the frictional wear mechanism of RM‐PTFE above the melting point.Highlights Irradiation‐modified PTFE above the melting point Wear resistance of PTFE increases 1000 times Changes in crystal morphology dramatically increase wear resistance Use of crystallization kinetics to study the crystalline form of PTFE Small grain size improves wear resistance

Preparation and performance study of silicon modified polyurethane-based magnetorheological elastomeric polishing pad

Abstract By employing Magnetorheological Elastomers (MREs) as polishing pads for chemical mechanical polishing (CMP), the magnetorheological properties are utilized to effectively control the flexible removal of materials in CMP. This study presents a method for preparing a Silicon modified Polyurethane (SPU)-based MRE polishing pad, aimed at demonstrating improved magnetorheological properties while preserving mechanical properties. The SPU-based MRE polishing pad was synthesized through the copolymerization of hydroxypropyl silicone oil and polyurethane prepolymers, with subsequent evaluation of its mechanical properties and polishing performance. Fourier Transform Infrared (FTIR) analysis confirmed the successful incorporation of the soft polydimethylsiloxane main chain from organosilicon into the polyurethane main chain, forming a soft segment that intertwines with the polyurethane main chain to create a soft-hard segment crosslinked structure. Comparison to Polyurethane (PU)-based MRE, SPU exhibits significantly reduced hardness but improved wear resistance, as well as enhanced resistance to acid and alkali corrosion. Due to the presence of a soft matrix, SPU shows better magnetorheological effects than PU-based MRE. Under a magnetic field intensity of 845 mT, the magnetorheological effect of PU-based MRE is only 18%, while Si-15.96 and Si-16.79 SPU-based MREs can reach 84% and 110%, respectively. Although the Material Removal Rate (MRR) of single-crystal SiC decreases after polishing with SPU compared to PU-based MRE, a higher surface quality is achieved, and the glazing degree of the polishing pad is significantly reduced. In the magnetic field-assisted polishing of single crystal SiC, the MRR increased by 38.4% when polished with an SPU-based MRE polishing pad, whereas the MRR was only 8.7% when polished with a PU-based MRE polishing pad. This study provides further evidence for the development and application of MRE in CMP.

Microstructure and tribological behavior of Al–TiC composite strips fabricated by a multi-step densification method

This study aims to enhance the tribological properties of automotive applications by examining the effects of TiC content on the microstructure, mechanical properties, and wear behavior. This study investigates the production of Al–TiC composite strips using a novel multi-step densification process combining mechanical alloying and hot rolling with TiC concentrations ranging from 0 to 12 vol%. The novelty of this work lies in its comprehensive approach to developing and analyzing Al–TiC composite strips using a multistep densification method. This study integrates microstructural analysis, mechanical property evaluation, and detailed tribological behavior assessment under different wear loads (5–25 N). A key innovation is the application of the Abbott Firestone method to analyze worn surfaces, providing insights into optimal wear conditions. The study reveals that increasing the TiC content to 12 vol% significantly improves densification, hardness (up to 268.8% increase), and wear resistance (up to 95% improvement at a 5N load). Dry ball-on-flat sliding wear tests at loads of 5–25N demonstrate that TiC particles hindered complete delamination wear in the composite strips. The Abbott Firestone method analysis of worn surfaces indicated an optimal exploitation zone in the Al-6 vol% TiC composite at both low and high wear loads. This comprehensive approach provides valuable insights into optimizing Al–TiC composites for enhanced performance in automotive components that require improved wear resistance.

Influence of post heat treatment on tribological and microstructural properties of plasma wire arc additive manufactured maraging steels

Abstract Metallic alloys are increasingly being produced using wired arc additive manufacturing (WAAM). In this study, 18Ni300 defect-free maraging steels were produced using the WAAM technique. A traditional solution treatment, direct aging, and cryogenic heat treatment processes were applied to the WAAM produced maraging steels. The influence of conventional and novel cryogenic heat treatments on microstructural, mechanical, and tribological properties were examined. The microstructure of the as-built materials obtained by WAAM thermal cycling has mainly been homogenized through the solution, direct-aging, and cryogenic heat treatments. As a result, homogeneously distributed precipitate phases were obtained and the hardness increased by 30 % with a combination different post heat treatments. The cryogenic heat treatment improved the martensitic transformation and facilitated the formation of various Fe–Ni–Mo–Ti-containing intermetallic precipitates. Similarly, because of the different heat treatments, the wear resistance improved by a factor of 2–5.5 relative to the as-built material. Adding the cryogenic heat treatment to the traditional heat treatment procedure improves wear resistance by a factor of 1.2–2.9.

Investigation of effects of environmental conditions on wear behaviors of glass fiber reinforced polyester composite materials

AbstractGlass fiber reinforced polymer (GFRP) composites can be subjected to different environmental conditions such as temperature, humidity, ultraviolet radiation, hydrothermal cycle, acidic and alkaline solution in environments where they operate. These environmental conditions cause different damage mechanisms in composites such as pore formation, micro‐cracks, delamination, fiber breakage, fiber/matrix interface separation, plasticization, swelling and surface color change. In this study, wear properties of hybrid glass fiber reinforced polymer composites exposed to various environmental conditions for constant load (60 N), speed (500 rpm) and 2 h were examined comprehensively, depending on material content and environmental conditions. In this experimental study, the service conditions in glass fiber reinforced composites were simulated using different artificial aging environments such as acidic environment, hydrothermal cycle and UV radiation. In addition to the material content, it appears that the environmental conditions to which composites are exposed has a significant effect on friction coefficient. Considering environmental conditions, it is seen that the acid environment and hydrothermal cycle have reduced wear resistance of GFRP composites, while UV radiation improved wear resistance of the composites. In C2 sample, the wear rates under different conditions are 1.87 × 10−14 m3/Nm in non‐treated sample, 6.05 × 10−14 m3/Nm in acid environment, 4.79 × 10−14 m3/Nm in hydrothermal cycle and 0.59 × 10−14 m3/Nm in UV radiation.Highlights Friction coefficient of glass fiber reinforced polyester (GFRP) is higher under aged condition compared to non‐treated. Glass fibers used in correct proportions can reduce friction coefficient in GFRP. GFRP exposed to environmental conditions has an important effect on wear. Acid environment and hydrothermal cycle has reduced wear resistance of GFRP. UV radiation improved wear resistance of GFRP composite.