Change In Wear Mechanism Research Articles

Effect of ZrB2 and ZrC and mixing method on Mechanical properties and wear behaviour of Al7075 based composites for aircraft aerofoil surfaces

Developing lightweight materials with notable properties for aerospace applications is a great challenge. The impact of ZrB2 and ZrC reinforcement on the mechanical and wear behaviour of stir-cast Al7075-ZrB2-ZrC composites is investigated with a weight percentage of 2, 4, 6 and 8% ZrB2, and fixed 2% ZrC. The results showed notable improvements with a hardness of 96 HRB, tensile strength of 423MPa and compressive strength of 385MPa; hardness increased by 14%, tensile strength increased by 11% and compressive strength was enhanced by 13% when compared with pure Al7075. The wear behaviour has been analysed by pin-on-disc wear test at room temperature with loads of 10N and 20N against the sliding distance of 400m to 1200m; the wear resistance is improved by 17% and CoF is reduced by 11% compared to pure Al7075. SEM micrographs display the wear mechanism and microstructural changes happened during the wear test. Al7075-ZrB2-ZrC composites are the optimum replacement for aerofoil surfaces because of their remarkable properties.

Microstructure and Wear Behavior of AlxCoCuNiTi (x = 0, 0.4, and 1) High-Entropy Alloy Coatings

AlxCoCuNiTi (x = 0, 0.4, and 1) high-entropy alloy coatings on 45 steel substrates were prepared by laser cladding, and their phase structure, microstructure, element partition, and wear behavior were investigated. The results show that the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings have a dual-phase structure of FCC and BCC. With the increase of x from 0 to 1, the content of the FCC phase decreases from 66.9 wt.% to 14.3 wt.%, while the content of the BCC phase increases from 33.1 wt.% to 85.7 wt.%. When x = 0.4, the lattice constants of the two phases are the largest, and their densities are the smallest. The microstructure of the AlxCoCuNiTi (x = 0, 0.4, and 1) coatings is composed of BCC-phase dendrites and FCC-phase interdendrite regions. Ti is mainly enriched in the primary phase or BCC dendrites, Cu is enriched in the interdendrite regions, and Al is enriched in the dendrites. The friction coefficients of AlxCoCuNiTi (x = 0, 0.4, and 1) coatings during wear tests are 0.691, 0.691, and 0.627, respectively. The lowering of the wear friction coefficient when increasing the Al content is mainly related to the change in phase structure, microstructure, and wear mechanism.

Wear Mechanism and Three-phase Synergistic Effect of Self-mated SiC/Si/Graphite Composites in Unlubricated Sliding

With the aim of applying SiC/Si/graphite composites as thrust-bearing pads and runners under conditions of dry friction start-stop cycles and a transient absence of lubrication, the tribological behaviors of self-mated SiC/Si/graphite composites were investigated using pin-on-disc tribology tests under various applied loads and sliding speeds without lubricants. The results show that the friction coefficient values range between 0.10 and 0.21, and the total specific wear rates of the discs and pins are below 9.5×10-6 mm3/N·m. When the flash temperature is greater than 1500 °C, the main wear mechanism changes from two-body abrasive wear between SiC and graphite to oxidation wear of SiC and Si, three-body abrasive wear and adhesive wear of graphite and tribological film. The synergistic effects of Si, SiC, and graphite on wear reduction and tribological film formation were also elucidated.

Fabrication and Performance Assessment of CuFeNiMnTi High Entropy Alloy through Mechanical Alloying and Spark Plasma Sintering

High Entropy Alloys (HEAs) have drawn significant attention due to their outstanding properties and potential for industrial applications. The present study investigates the fabrication and evaluation of CuFeNiMnTi HEA, synthesized by means of mechanical alloying (MA) and spark plasma sintering (SPS). The sample that was optimally prepared at 920 °C using the SPS technique was selected and subjected to comprehensive characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) to examine microstructural changes and evaluate mechanical properties, including Vickers microhardness, fracture toughness, shear strength, and wear resistance. The addition of carbon from the process control agent (PCA) and the interaction between titanium and carbon resulted in the formation of titanium carbides, while oxide compounds served as lubricants, thereby reducing friction. The sintered CuFeNiMnTi alloy showed a fracture toughness of 9.24±0.5MPamat the room temperature. Mechanical testing exhibited significant improvements, yielding a microhardness of 563±22 HVN and Ultimate Shear Strength (USS) of 439±19MPa. The alloy demonstrated outstanding mechanical properties, structural stability, and improved wear resistance, making it suitable for advanced engineering applications. The improved wear performance at higher temperature, compared to lower temperature, could be attributed to surface oxidation and a change in the dominant wear mechanism. This study highlights the effectiveness of MA and SPS techniques in the manufacturing of high-performance HEAs, emphasizing its flexibility in customizing alloys with specific desired properties.

Regulation of reinforced phases and its influence on the properties of (Ni2B+C)/Cu composite by heat and mechanical treatments

In this paper, (Ni2B+C)/Cu composites were prepared by hot pressing sintering (HP), and then heat treatment (HT) and multidirectional forging (MDF) were carried out to regulate the amount, size and distribution of reinforced phases. The evolution behavior of local structure and its effect on properties during heat treatment and multidirectional forging were studied. Results show that the Vickers hardness and electrical conductivity of (Ni2B+C)/Cu composite after solid solution, multidirectional forging, and aging treatment can reach 171.1 HV and 46.5 %IACS, respectively, which are increased by 55.3 % and 69.1 % compared with the as-sintered. The tensile strength can reach 355.1 MPa, and the facture elongation is increased to 5.2 % compared with the as-sintered (0.3 %), achieving a transition from brittle fracture to plastic fracture. In addition, the dry friction and wear mechanism of the composite is mainly abrasive wear, while the current-carrying friction and wear mechanism changes from abrasive wear to a coexistence of abrasive wear and oxidation wear. This work provides a new way to improve the properties of (Ni2B+C)/Cu composites.

High-temperature tribological performance of Y2O3-Doped Cu-Zn self-lubricating composite by SPS

The rare earth oxide Y2O3 exhibits excellent wear resistance and stability in engineering applications. Copper-zinc-based wear-resistant composites with varying Y2O3 contents were prepared using spark plasma sintering. Their mechanical tribological properties were studied over a wide temperature range from room temperature to 300 °C. The results indicated that the composites have good densification, and uniformly distributed matrix components. Adding an appropriate amount of Y2O3 can significantly refine the grain and improve the matrix's mechanical and tribological properties. In the above temperature range, the friction coefficient and wear rate appear the lowest values when the concentration is 1 %, and the wear mechanism changes from abrasive wear to adhesive wear with the increase of temperature.

Oxidation and wear behaviors of MoNbTaW high entropy alloy fabricated via laser energy deposition at elevated temperature

The microstructure, mechanical properties at room temperature, oxidation, and wear behaviors of the MoNbTaW refractory high-entropy alloy (RHEA) at elevated temperatures are investigated. The as-deposited MoNbTaW RHEA maintains a single BCC structure and a dendritic morphology. Furthermore, it demonstrates a high yield stress of 1478 MPa and an ultimate yield stress of 1787 MPa at room temperature. The oxidation tests reveal that the oxidation rate constant initially decreases from 0.83 mg2 cm−4 h−1 to 0.78 mg2 cm−4 h−1, then increases to 12.43 mg2 cm−4 h−1 as the temperature rises from 500 °C to 800 °C. Additionally, a linear oxidation kinetic is observed at 500 and 600 °C, while at 800 °C, the parabolic oxidation kinetics is observed. The transition is linked to the development of a multilayer oxide layer structure and the formation of a thicker oxide scale. The results of wear tests at high-temperature show that the wear depth at 600 °C is about 24.886 μm, which is 3.9 times as much as 500 °C (6.437 μm). This indicates that the wear resistance is reduced at 600 °C. In addition, with the increase in temperature, the wear mechanism changes from adhesive wear to abrasive wear.

Comparative Analysis of Tribological Behavior of 45 Steel under Intensive Quenching-High-Temperature Tempering and Queenching-Tempering Process

The intensive quenching process compared to traditional methods results in a lower quenching cracking tendency. The comprehensive mechanical properties of an intensive quenching workpiece has good advantages. In order to improve the performance and product quality of a 45 steel workpiece, the hardening–tempering treatment used in the traditional quenching process is replaced by an intensive quenching process. This study investigates the tribological properties of 45 steel and their differences and connection under the intensive quenching and high-temperature tempering process in comparison to when under the traditional hardening–tempering process. Both intensive quenching and tempering and hardening–tempering workpieces are composed of carburized particles and ferrite. Compared with hardening–tempering workpieces, intensive quenching and high-temperature tempering workpieces have a finer and more uniform microstructure and higher hardness, impact toughness, and yield strength. Wear tests show that intensive quenchingand tempered specimens have better wear resistance. At the same frequency, the coefficient of friction and relative wear rate of the intensive quenching and tempering specimens were lower than those of the hardening–tempering treatment, and the wear surface was flatter. The wear morphology shows that the main wear mechanisms of the intensive quenching and tempering workpieces and those of hardening–tempering are abrasive and adhesive wear, and that the main wear mechanism changes from adhesive wear to abrasive wear as the frequency increases.

Abnormal fretting wear behavior of Fe-based amorphous coating

To promote the application of Fe-based amorphous coating (AMC)-protected magnesium alloys in fretting wear conditions, a Fe-based AMC with a thickness of about 164 μm was deposited on AZ31B magnesium alloy substrate by detonation spraying. The microstructure and fretting wear behaviors against GCr15 counterpart ball in different frequencies of the Fe-based AMC were studied in detail. The results show that the Fe-based AMC has a substantially complete amorphous structure, the porosity and surface hardness are ≤1.2 vol %, and 764.7 ± 37.5 Hv0.1, respectively. Therefore, the Fe-based AMC presents excellent fretting wear resistance, and its wear rate is almost 1/10 of that of AZ31B magnesium alloy, and 1/5 of that of high-velocity oxygen-fuel sprayed 316L stainless steel coating on AZ31B magnesium alloy substrate. The fretting wear behavior of Fe-based AMC was found to be sensitive to the fretting frequency: as the frequency increases from 5 to 100 Hz, the average steady-state friction coefficient increases from 0.77 to 1.07, but the wear rate exhibits an anomalous phenomenon, decreasing from 5.26 × 10−5 mm3N−1m−1 to 3.47 × 10−5 mm3N−1m−1. The improvement in wear rate is mainly attributed to the formation of an oxygen-rich river-like friction layer on the worn surface as the transient contact temperature increases with frequency, effectively suppressing delamination wear. Additionally, the occurrence of high transient frictional temperatures at high frequencies leads to evident crystallization within the coating, accompanied by the formation of nanocrystals, oxide films, and a large area river-like friction layer consisting of debris-compacted layers, which strengthens the Fe-based AMC. Consequently, the wear mechanism changes from delamination wear and abrasive wear at low frequencies to oxidative wear and adhesive wear at high frequencies, resulting in superior fretting wear resistance of the Fe-based AMC at high frequencies.

The hardfacing properties of the nickel-based coating deposited by the PTA process with the addition of wc nano-particles: Wear investigation

The impact of the addition of tungsten carbide (1 to 7 wt%) on the microstructure and wear characteristics of the nickel–tungsten carbide composite layer fabricated by the plasma transferred arc (PTA) process was studied. With the addition of nanoparticles, the degree of segregation becomes lower while heterogeneous nucleation increases and refining of the microstructure enhances. Wear rate and coefficient of friction for all samples with increasing the load from 1 to 5 N decrease and wear mechanism changes from abrasive to adhesive. The higher wear resistance for samples with 3%wt is due to a decrease in the porosity of the composite coatings, strong interfacial bonding, and promotion in the deposition efficiency at the same time.

Enhanced mechanical and tribological properties of copper matrix composites reinforced by copper-coated graphite and Ti3AlC2

To solve the poor mechanical properties of graphite-reinforced copper matrix composite, the effect of Ti3AlC2 content on the mechanical properties and dry sliding properties of copper-coated graphite reinforced copper matrix composites was investigated. The results show that the in-situ TiCx-Ti3AlC2-Cu(Al) gradient interface is formed due to the decomposition of partial Ti3AlC2 particles, which can improve the interface bonding strength and enhance the mechanical properties of the composites. With the Ti3AlC2 content increasing, the hardness, yield strength, and tensile strength of the composites increase, while the elongation decreases. The composite reinforced by copper-coated graphite and 5 wt% Ti3AlC2 shows a higher yield strength and tensile strength, increased by 86.2% and 28.6% over the neat Cu, respectively. Besides, the composites exhibit better wear resistance compared with the neat Cu. The wear rate of the composites decreases as the increase of Ti3AlC2 content. The wear mechanism changes from delamination wear of pure Cu to adhesive wear, abrasive wear, and oxidative wear for the composites reinforced by copper-coated graphite and 10 wt% Ti3AlC2.

Effect of Flame Remelting on the Microstructure, Wear and Corrosion Resistance of HVOF Sprayed NiCrBSi Coatings

As a post treatment, thermal remelting is an effective method to eliminate pores and establish a metallurgical bonding for thermal sprayed coatings. However, it is rather difficult to obtain simultaneously high corrosion and wear resistance, since additional energy input usually leads to more homogeneous microstructure in coatings, which deteriorates mechanical hardness. In this work, flame remelting has been imposed to high velocity oxygen-fuel sprayed self-flux NiCrBSi coatings. The remelting effects on microstructure were characterized in terms of porosity and phase analysis. The microhardness, wear resistance and corrosive behaviors were compared among substrate steel, as-sprayed and as-remelted coatings. Results show that the lamellar boundaries and internal defects in the as-sprayed coatings have been eliminated by remelting. The coating porosity has substantially reduced from 7.36% to 0.75%, and a metallurgical bonding at the coating/substrate interface has been formed. Comparing with the as-sprayed coatings, the microhardness of the remelted coatings increases about 21% and the wear weight loss reduces about 42%. By flame remelting, the wear mechanism changes from furrow and abrasive wear to micro-cutting and local fracture. The remelted coatings have also exhibited better corrosion resistance by means of salt spraying and potentiodynamic tests.

Tailored carburization gradient microstructure and enhanced wear properties of M50NiL steel via introduced prior cold rolling

M50NiL (Chinese grade G13Cr4Mo4Ni4V) steel is widely used in aircraft bearing raceways that require excellent wear resistance under harsh service conditions. However, the impact of cold rolling, as an advanced forming process for bearings, on the carburization process and wear properties is still unknown. Therefore, the gradient microstructure and dry sliding wear performance of the cold-rolled M50NiL disc against Si3N4 ceramic ball have been investigated. The results show that with the increase of cold rolling reduction to 40 %, the carbon concentration of surface is increased by 17.1 % due to the growing percentage of grain boundaries (GB) and dislocation density. The carbide content is increased by 29 % with average size declined by 21.2 %, which contributes to a 7.4 % increase in the surface hardness. Additionally, the wear test indicates that the average friction coefficient and wear rate are respectively reduced by 17.3 % and 47.1 % when the rolling reduction increases to 40 %. After prior rolling, the wear mechanism changes from severe abrasion to adhesion and tribochemical reactions accompanied with the enhancement of wear properties, which is mainly attributed to the uniform distribution of finer carbides with higher fraction on the surface and subsurface.

Corrosion resistance and tribological behavior of FeCoCrNi@GO/Ni high entropy alloy-based composite coatings prepared by electrodeposition

The preparation of high entropy alloy (HEA) coatings onto a stainless-steel substrate is crucial to pursue improved corrosion and wear resistance but are still challenging. Herein, FeCoCrNi@GO/Ni coatings are innovatively cross-integrated with stainless steel by introducing a nickel transition layer to break through the “bottleneck” of stainless steel. Meanwhile, variation of the coating corrosion resistance in 3.5 wt% NaCl solution and tribological behavior against GCr15 steel balls was also deeply explored. The addition of graphene oxide (GO) delayed the movement of corrosive medium and improved the corrosion resistance. Interestingly, the coatings with low GO content and high GO content show different wear mechanisms respectively, and the lower GO content is conducive to the formation of oxidized lubrication layer, thus protecting the substrate from severe friction and wear. However, the high content of GO coating will cause damage and spalling of oxide layer and GO, and the wear mechanism changes from oxidative wear to the co-wear of oxidative wear and abrasive wear. This work will provide a novel idea for the development of HEA coatings in the future.

Microstructural Modification of Cold-Sprayed Ti-Cr3C2 Composite Coating by Laser Remelting

Laser processing is an effective post-treatment method for modifying the structure and improving the properties of cold-sprayed coatings. In the present work, the possibility of fabricating a hard and wear-resistant Ti-based cermet coating by cold spray followed by laser remelting was studied. A mixture of titanium and chromium carbide powders in a ratio of 60/40 wt.% was deposited by cold spray onto a titanium alloy substrate, which ensured the formation of a composite coating with a residual chromium carbide content of about 12–13 wt.%. The optimal values of laser beam power (2 kW) and scanning speed (75 mm/s) leading to the qualitative fusion of the coating with the substrate with minimal porosity and absence of defects were revealed. The microstructure and phase composition of as-sprayed and remelted coatings were examined with SEM, EDS and XRD analysis. It was shown that the phase composition of the as-sprayed coating did not change compared to the feedstock mixture, while the remelted coating was transformed into a β-Ti(Cr) solid solution with uniformly distributed nonstoichiometric TiCx particles. Due to the change in microstructure and phase composition, the remelted coating was characterized by an attractive combination of higher microhardness (437 HV0.1) and lower specific wear rate (0.25 × 10−3 mm3/N × m) under dry sliding wear conditions compared to the as-sprayed coating and substrate. Laser remelting of the coating resulted in a change in the dominant wear mechanism from oxidative–abrasive to oxidative–adhesive with delamination.

Effect of abrasive grit grade on the abrasion wear behaviour of long banana-jute fibers reinforced hybrid epoxy composites

The effect of abrasive grit geometry on two-body abrasion wear behavior of long banana and jute fiber reinforced epoxy composites has been investigated. Epoxy (EP), Epoxy/4 wt% Banana fiber (BF)/4 wt%Jute fiber (JF) (EP8), Epoxy/8 wt%BF/8 wt%JF (EP16), Epoxy/12 wt%BF/12 wt% JF (EP24), and Epoxy/16 wt% BF/16 wt%JF (EP32) were the composite materials systems used for the investigation. These composites were processed and fabricated using hand—lay-up technique. The two body abrasion wear test was carried out in accordance with ASTM G99 under the influence of different SiC grit particles (180, 320, 400, and 600 SiC grit). The test was conducted at a room temperature under the abrasion load of 10 N and abrasion speed of 1 m s−1 over a distance of 100 m. The findings of the experiments revealed that wear response of composites depends on pressure, geometry of abrasion particles and their composition. The wear volume loss and specific wear rate decreases with increase in the rank of grit grade. Further, 16 wt% of fibers in composites exhibits the superior abrasion wear resistance. But the higher volume fraction of natural fibers in composites impaired the abrasion wear resistance. Higher rank of grit number was associated with the lesser wear volume loss because of the change in wear mechanism from abrasion to adhesion. In comparison to epoxy based composites, EP16 composite shows superior wear resistance. SEM images were used to examine the worn surfaces.

Effect of Mo on microstructure and sliding wear performance of CoCrFeNiMox high entropy alloy coatings by laser cladding

The CoCrFeNiMox (x = 0, 0.5, 1, 1.5 in molar ratio) high-entropy alloys (HEAs) coating were prepared on AISI1045 steel by laser cladding. The microstructure, hardness and tribological properties were investigated through x-ray diffraction, scanning electron microscopy (SEM), microhardness tester and reciprocating tribometer. The result shows that the coating is metallurgically bonded to the substrate and exhibits columnar and equiaxed grains microstructure consisted of main face-centered cubic (FCC) solid solution and few body-centered cubic (BCC) struture when x≤ 1.0. The (Fe, Cr, Mo)-riched σ phase shows up in the CoCrFeNiMo1.5 FCC matrix due to excess Mo addition. CoCrFeNiMox HEA coatings shows an obvious increase of surface hardness from 261 HV0.2 to 793 HV0.2 by increasing the Mo content to 1.5 in the molar ratio, and exhibited the most excellent wear resistance among all the compositions designed in this work. The wear resistance of the CoCrFeNiMo1.5 alloy coating is about 2.2 times higher than that of the coating without Mo. The wear mechanism changes with increasing Mo content, though abrasive wear is a common mechanism, more adhesive wear occurred at low Mo content but few oxidation and fatigue wear occured at high Mo content.

Microstructure and tribological behavior of Al–12Si – Nano graphene composite fabricated by laser metal deposition process

To improve the wear resistance of the Al-based alloys and extend its application spectrum, graphene nano-platelets (GNPs) reinforced Al–12Si matrix composites were fabricated by laser melting deposition (LMD) technology. The microstructure, wear morphologies and surface roughness were characterized by scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD) setups and 3D confocal microscopy. The microhardness and high-speed reciprocating frictional properties both Al–12Si and GNPs/Al–12Si composites were evaluated. The addition of graphene significantly refines the microstructure and improves the wear resistance of the matrix. The formation of a relatively stable mechanically mixed layer (MML) reduces the contact area between the friction pair material and the wear surface, the wear rate and roughness of the Al–12Si – 0.5 wt% GNP reinforced composites decrease with the increase of sliding speed, and the wear mechanism changes from adhesive wear accompanied by abrasive wear to fatigue wear. Meanwhile, as the load increases, the wear rate and roughness increase. The wear mechanism of the composite changes from abrasive wear to a mixed mode (combination of both adhesive and abrasive). This research not only offers valuable information about the Al–Si-based composites but provides theoretical light on their industrial applications.

Improving Wear Resistance of Highly Porous Titanium by Surface Engineering Methods

The wear resistance of highly porous titanium in the tribo-pair with bronze under boundary lubrication condition was investigated. According to analyses of worn surfaces of highly porous titanium, it was shown that the main reason of poor wear resistance were subsurface pores that led to nucleation of micro-cracks in the subsurface layer and thereby intensified fatigue (delamination) wear. For improvement of wear resistance of highly porous titanium, the surface engineering methods, such as deformation (ball burnishing, BB), diffusion (gas nitriding, GN), and their combination—deformation–diffusion treatment (DDT), were considered. It was shown that surface hardening of highly porous titanium by BB, GN, and DDT reduces the weight wear intensity and the friction coefficient of the tribo-pairs by 1.4, 3.5, 4.0 and 1.8, 2.3, 3.2 times, respectively. Such an improvement in the tribological properties of highly porous titanium after surface hardening is explained by changes in the main wear mechanism of the tribo-pairs from adhesive and fatigue to abrasive. The highest wear resistance of highly porous titanium was observed after surface deformation–diffusion treatment, as this treatment provides a combination of the positive effects of both ball burnishing (closing of surface pores) and nitriding (formation of a surface chemically inert and hard nitride layer).

Evaluation of crane wheels restored by hardfacing two distinct 13Cr-4Ni martensitic stainless steels

Depositing two martensitic stainless steel filler metals with chemically different composition, crane wheels were restored to study the development of mechanical properties and wear resistance. For this purpose, a two-layer clad was deposited using each filler metal through submerged arc welding process. Microstructural evolution shows that solidification modes are different in the hardfaced clads due to the discrepancy in the ratio of chromium equivalent to nickel equivalent (Creq/Nieq). A reduction in Creq/Nieq leads to the enrichment of liquid metal in austenite-promoter elements, resulting in the presence of austenite phase in the matrix, as identified by XRD pattern. Following a post-weld heat treatment in the constant temperature of 500 °C for an hour, apart from the tempered martensite, fresh martensite as a consequence of transforming austenite phase is formed in the matrix. This transformation significantly increases the mean value of microhardness from 360 to 462 HV0.3. Also, uniaxial tensile test shows that the formation of fresh martensite approximately limits the elongation of the clad. The fractography studies show that the fracture mode in both clad is the same and ductile, with embedded carbides in dimples. Tribological behavior of the clads shows that the formation of fresh martensite in the clad results in higher wear resistance, with specific wear rate of 1.8 × 10−5 mm3/Nm at the maximum load. In addition, oxidative wear mechanism is dominant at lower load of 10 N, while the wear mechanism changes at higher load of 60 N to severe plastic deformation.