Slight Oxidation Wear Research Articles

Grain refinement and mechanical properties improvement of AlCuFeCoNi high-entropy alloy coatings fabricated by resonant ultrasonic assisted laser cladding

Laser cladding technology has gained significant popularity for the preparationof high-entropy alloy (HEA) coatings. This is primarily due to its notable benefits, such as a low dilution rate and a robust bonding capability. However, the laser cladding process’s rapid solidification effect and the high entropy impact led to the formation of defects in the coatings, such as non-uniform organization and elemental segregation. In this paper, the resonant ultrasonic vibration was used to regulate the organization and improve the microhardness and friction properties of the AlCuFeCoNi HEA coatings. The experimental findings demonstrate that ultrasonic vibration enhances both the width and depth of the coating’s molten state, while simultaneously reducing the height of the coating. Before and after the introduction of ultrasonic vibrations, the coating consists of two phases, body-centered cubic (BCC) and face-centered cubic (FCC). However, the magnitude of the FCC phase significantly increased with higher power. The internal grains of the coating were significantly refined by ultrasonic vibration, and the average grain size was refined from 68.34 μm to 35.28 μm, and the area occupied by equiaxial grains also increased with the increase of ultrasonic power, and the segregation of the FCC phase dominated by Cu elements was suppressed. When the ultrasonic power was 30 %, the microhardness of the coating was increased from 553.19 ± 5.15 HV0.2 to 600.47 ± 3.61 HV0.2. The addition of ultrasonic vibration increased the wear resistance of the coating and lowered the coefficient of friction from 0.558 to 0.409. Furthermore, the friction mechanism of the coatings before and after the addition of ultrasonic vibration did not change, and both were abrasive wear with slight oxidative wear.

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.

Effect of element N on microstructure and tribological properties of CoCrFeNiV alloy at severe temperature

In this study, CoCrFeNiV non-equiatomic high entropy alloys (HEAs) with varying N content were prepared using vacuum hot-press sintering. The effects of N content on the alloy's microstructure, mechanical properties, and tribological behavior at different temperatures were investigated. The results indicate that the N-added alloys primarily maintain an FCC phase. With increasing N content, the σ phase in the alloy gradually decreases, while the VN content increases, leading to grain refinement. This results in a 10.7 % increase in hardness, a 9 % increase in compression strength, and a 56 % increase in compression deformation. Below 400 °C, the primary wear mechanisms are adhesive wear, spalling wear, and slight oxidative wear, while above 600 °C, oxidative wear dominates. The addition of N reduced the wear rates of the alloy by 33.8 %, 8.1 %, and 31.3 % at RT, 200 °C, and 600 °C, respectively, and decreases the coefficient of friction at all temperatures. In summary, N addition improves the alloy's tribological performance at various temperatures.

Research on microstructure, mechanical property and wear mechanism of AlCoCrFeNi/WC composite coating fabricated by HVOF

In this study, HVOF spraying technology was utilized to prepare AlCoCrFeNi/WC composite coatings with varying WC content on 40CrMnMoA steel substrate. The microstructure, elemental distribution, phase structure and chemical valence states of wear scratches of the composite coatings were analyzed using the SEM, EDS, XRD and XPS. Microhardness was measured using single-point digital microhardness tester, while nanohardness and elastic modulus were determined using a nano-indenter. The bonding strength of the composite coatings was evaluated using a tensile tester. Friction and wear tests were conducted to assess the wear behavior of the composite coatings. The results indicated that the microstructure, microhardness, nanohardness and elastic modulus of AlCoCrFeNi HEA coating increased with the addition of WC, attributed to the hard phase effects of WC. However, the bonding strength first decreased and then increased. Compared to the W 0 coating, the wear rates of the other composite coatings decreased by 30.5 %, 46.1 %, 65.3 %, and 82.1 %, respectively, which demonstrating that the effect strengthening of WC. After the friction and wear tests, the wear mechanism of the W 0 and W 1 coatings represents adhesive wear, abrasive wear and severe oxidation wear. In contrast, the W 2 and W 3 coatings exhibited slight adhesive wear, slight abrasive wear and slight oxidation wear, while the W 4 coating showed the slightest abrasive wear, the slightest adhesive wear and the slightest oxidation wear.

Microstructure and tribological behaviors of laser cladded CuAlMnTi–xTiC composite coatings at elevated temperature

CuAlMnTi-xTiC composite coatings were prepared on Ti6Al4V alloy by laser cladding to enhance its tribological properties. The effects of TiC mass fraction on the friction–wear properties of CuAlMnTi–xTiC composite coatings at high–temperature were investigated using an ball–on–disc tester. The results show that the grains of CuAlMnTi–xTiC composite coatings are refined by the addition of TiC, and the metallurgical bonding is formed between the coating and the substrate. The hardness of CuAlMnTi–15%TiC composite coating is higher 1.98 times than that of CuAlMnTi coating, in which the TiC as wear–resistant framework prevents micro–cutting to enhance wear resistance. The average coefficients of friction of CuAlMnTi–0%TiC, –5%TiC, –10%TiC and –15% TiC composite coatings in the stable wear period are 0.465, 0.491, 0.514, and 0.587, respectively, and the corresponding wear rates are 116.8, 111.3, 107.8, and 95.4 μm3•N–1•mm–1, respectively, showing that the wear rate is decreased with the increase of TiC mass fraction. The wear mechanism is transferred from adhesive wear to abrasive wear and slight oxidation wear by the addition of TiC, which is attributed to the improvement of hardness by the refined grain strengthening effect of TiC.

The Effect of Micron-Sized TiB2 Particles on the Properties of Al6061 Strengthened with 4% TiB2 Nano-TiB2.

Dual-scale (nano and micron) particle-reinforced TiB2/6061Al matrix composites with different contents of TiB2 were prepared using powder metallurgy, and then analyzed via microstructure observation and tests of microhardness, tensile properties, and friction and wear properties. The 6061Al powders' particles changed from spherical to flaky after two rounds of high-energy ball milling, and the TiB2 enhancer was embedded in or wrapped by the matrix particles after high-energy ball milling. Metallurgical bonding between TiB2 particles and the matrix was achieved, and Al3Ti was synthesized in situ during sintering. The hot-pressing process eliminated the internal defects of the composites, and the TiB2 particles were diffusely distributed in the matrix. The best comprehensive mechanical properties (hardness and tensile strength) were achieved when the mass fraction of TiB2 was 5% (1% micron + 4% nano); the hardness and tensile strength of the composites reached 131 HV and 221 MPa-79.5% and 93.9% higher than those of the pure matrix, respectively. The composites' average coefficient of friction and volumetric wear rate were reduced. Composites with a TiB2 mass fraction of 7% (3% micron + 4% nano) had the highest average coefficients of friction and the lowest volumetric wear rate of 0.402 and 0.216 mm3∙N-1∙m-1, respectively. It was observed that adhesion influences the friction mechanism, which transitions from adhesive wear with slight oxidative wear to abrasive wear.

A novel electrochemical deposited Fe[sbnd]Ni coating designed by laser-induced periodic current density: Effect of microstructure on microhardness and wear resistance improvement

A novel FeNi coating with refined grain size and alternated distribution of element content was designed via laser-assisted electrochemical deposition. The formation of this microstructure is attributed to a specific laser scanning strategy, forming the periodic current waveform. This novel coating is expected to enhance the microhardness and wear performance within the grain size range of the inverse Hall–Petch (HP) relationship. The critical size of the HP relationship was estimated at 13 nm based on the relationship between different grain sizes and microhardness. Compared to the coating prepared by electrochemical deposition, the average grain sizes decrease from 8.4 ± 1.4 nm to 4.5 ± 1.6 nm. In addition, the microhardness was enhanced by approximately 28 %; the wear rate was decreased by approximately 58 %. The main mechanisms include abrasive, fatigue, and slight oxidation wear. This unique structure may enhance the resistance to grain boundaries mediated plastic deformation.

Tribological behaviors of Ta-10W alloy at elevated temperature

Ta-10W alloy has great potential in the aerospace and nuclear industries due to its good formability, high melting point and excellent high-temperature strength. The purpose of this study was to experimentally research the tribological behaviors of Ta-10W at elevated temperatures and the effects of temperatures on the friction coefficient and the wear rate of Ta-10W in sliding wear. It was found that the main wear mechanism of the material at 100°C was abrasive wear, as well as adhesive wear and slight oxidative wear occurred at 200°C and 300°C. The friction coefficients increased as the temperature rose, which was attributed to the increase in metal viscosity at elevated temperatures. The wear rate gradually decreased with the temperature rising, such that there was a conversion from severe wear to light wear. At 200°C and 300°C, a large amount of stable oxide film covered the scar surface, resulting in decreased wear rate.

High-temperature wear behavior of a Zr-based metallic glass

Due to the fascinating application prospects of Zr-based bulk metallic glass (BMG), it is of practical engineering interest to study its wear behavior and mechanism under various temperature conditions. In this work, the wear behavior and mechanism of a commercially available Zr35Ti30Be26.75Cu8.25 BMG at room temperature (RT) to 500 °C were investigated. The results demonstrated that the wear rate increased from ∼24.7 × 10−5 mm3 N−1 m−1 to ∼196.8 × 10−5 mm3 N−1 m−1 as the temperature increased from RT to 500 °C. Accordingly, the coefficient of friction (COF) is reduced from an average of 0.45–0.18 due to the lubricating effect of the oxide layer. At low temperatures of RT and 200 °C, the predominant wear mechanisms are abrasive wear and adhesive wear. However, in the supercooled liquid region (SCLR) of at 350 °C, the dominant wear mechanism is a combination of superplasticity-dominated abrasive wear, severe fatigue wear, and slight oxidative wear. Above the crystallization temperature (Tx) at 500 °C, the primary wear mechanisms are severe abrasive wear and oxidative wear. Our results can provide important guidance for determining the applicable temperature, service life and failure mode of BMG components.

Microstructure and Tribological Properties of Fe-Based-Al2O3-B4C Composite Coatings Prepared by High-Velocity Arc Spraying

Fe-based-Al2O3-B4C coating was prepared on the low-carbon steel substrates using high-velocity arc spraying. The effects of voltage, current, and distance on the porosity and microhardness of the coating were studied by an orthogonal test, and the optimum spraying parameters were determined. The microstructure and properties of Fe-based-Al2O3-B4C coatings prepared under optimum process parameters were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), microhardness and friction wear tester. The results showed that the optimum process parameters were a spraying voltage of 41 V, a spraying current of 200 A, and a spraying distance of 150 mm. The porosity was 2.24 ± 0.32%, and the microhardness was 1543 ± 145 Hv0.1, which was 8 times that of the substrate. Under the same load of 4.2 N and varying sliding speeds of 500 t/min, 750 t/min, and 1000 t/min, the coefficient of friction of the coating was less than that of the low-carbon steel, and the wear rate of the coating was 65%, 70%, and 63% lower than that of the low-carbon steel, respectively. The main wear mechanism of the coating was material spalling, accompanied by slight oxidative wear and abrasive wear.

Microstructure and Wear Resistance of FeCuNiTiAl High-Entropy Alloy Coating on Ti6Al4V Substrate Fabricated by Laser Metal Deposition

In order to improve the hardness and wear resistance of titanium alloys, an equimolar ratio high-entropy alloy (HEA) FeCuNiTiAl coating was fabricated on the surface of titanium alloy Ti6Al4V by means of laser metal deposition for the first time. The microstructure and composition of the HEA coating and the transition zone were observed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that HEA coating and Ti6Al4V have suitable metallurgical bonding, and no defects, such as cracks, are found at the interface. The hardness of the HEA coating is between 450 and 500 HV0.5, which is about 1.5 times that of the Ti6Al4V substrate. Wear tests show that the wear rate of HEA coating is 0.89 × 10−5 mm3/(N·m), while that of Ti6Al4V reaches 53.97 × 10−5 mm3/(N·m), and the wear resistance of substrate is increased 60 times by the HEA coating. The wear mechanism of the Ti6Al4V substrate is mainly abrasive wear, and the wear mechanism of FeCuNiTiAl HEA coating is mainly adhesive wear, accompanied by slight oxidation wear and abrasive wear.

Influence of synergistic strengthening effect of B4C and TiC on tribological behavior of copper-based powder metallurgy

High-speed rail brake pads mainly face the lack of stability of tribological performance under high temperature. An effective approach that is often employed is to reinforce copper-based powder metallurgy (PM) with single ceramic particle to obtain superior properties. In this paper, preparation of the dual ceramic particles (B4C–TiC) reinforced copper-based PM by powder metallurgy route, and paired as friction discs using the self-made carbon-ceramic composite. Influence of synergistic strengthening effect of B4C and TiC on tribological behavior and wear mechanisms were investigated. The result reveals that the more content of TiC (less 5%) in B4C–TiC, the greater the performance improvement, especially when the ratio of TiC/B4C is 5:3, the copper-based PM obtains exceptional mechanical and thermal performance, but different tribological behavior at different braking speed. The main factor affecting the tribological behavior at middle-speed (4500 rpm) is TiC, while is B4C at high-speed (6000 rpm) due to the generation of B2O3 tribo-film. With the ratio of TiC/B4C increases, the generation of B2O3 tribo-film goes through a change of first increased to the maximum, and then disappeared. While wear mechanism of copper-based PM goes through the transitional stage from abrasive wear to slight oxidative wear, severe oxidative wear, abrasive wear and adhesive wear, respectively.

Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe-Cr-Mo-Ni-B Coating.

In this study, an Fe–Cr–Mo–Ni–B coating was prepared using plasma cladding on Cr5 steel substrate. The microstructure, phase evolution and tribological performance of the Fe–Cr–Mo–Ni–B coating were investigated. The microstructure is mainly composed of Mo2FeB2, Fe2B, α-Fe, γ-Fe and MoB. The process of phase evolution in the coating was observed in situ by HT-CLSM. The Mo2FeB2 phase with good thermodynamic stability can exist in the high-temperature liquid phase. It also has a phenomenon of connection and merging and turns into different morphology during the plasma cladding process. The hardness value of coating was much higher than the base metal, and the hardness value of Mo2FeB2 (785.5 HV) was higher than the eutectic matrix (693.2 HV). The wear mechanisms of the cladding under dry sliding were primarily caused by adhesive wear, accompanying slight oxidation wear. The Mo2FeB2 phase has an important effect on the wear resistance property.

The Microstructure and Tribological Behavior of Ultrasonic Electroless Ni-P Plating on TC4 Titanium Alloy with Heat-Treatment

The ultrasonic electroless Ni-P plating is fabricated on the TC4 titanium alloy pretreated by zinc double immersion and alkaline pre-plating, and then is carried out heat-treatment at different temperature. The effects of heat-treatment on the microstructure and phase structure of the ultrasonic electroless Ni-P plating and their tribological behavior are investigated by SEM/EDS, XRD, a Vikers indenter, and a pin-on-disk wear testing machine. It is observed that the morphology of the ultrasonic electroless Ni-P plating has the typical cauliflower-like nodular structure and the average size of nodular is approximately 7 μm. EDS studies suggest that the phosphorous content of the plating is as high as 11 at%. The ultrasonic electroless Ni-P plating exhibits obvious amorphous structure characteristics by XRD analyzers. After heat-treatment at 400 °C, the structure of the ultrasonic electroless Ni-P plating changes from amorphous to crystalline state, and the interface of the nodular structure becomes clear and the nodular size is refined. It is because the dispersed Ni3P second-phase particles are uniformly and continuously distributed in the nickel solid solution. Compared with the TC4 substrate, the microhardness and the wear resistance of the ultrasonic electroless Ni-P plating are greatly improved, especially for the heat-treatment at 500 °C. The wear mechanism of the TC4 substrate is severe adhesion and abrasion wear, with slight oxidation wear, while the ultrasonic electroless Ni-P plating shows plastic deformation and microabrasion wear. After heat-treatment, the wear mechanism of the ultrasonic electroless Ni-P plating is slight abrasion wear.

Study on Friction and Wear Behaviors of M42 High Speed Steel

Taking Chinese-made (C-M42) and Japanese-made (J-M42) high-speed steel as research objects, the friction and wear tests were carried out and the wear mechanism was analysed. The microstructure and hardness of the two steels were observed by means of scanning electron microscope and hardness tester. Results show that J-M42 steel possesses a better wear resistance than C-M42 steel. This is related to relatively higher hardness, smaller average carbide size and higher volume fraction of carbide. There exists groove, adhesive patch and oxide layer in the worn surface. It manifests that the wear mechanisms of the two samples are adhesive wear, abrasive wear and slight oxidation wear. The overall surface roughness after wear is similar between the two steels whereas the plastic deformation layer in the vertical section of J-M42 steel is shallower than that of C-M42 steel.

Dry sliding wear behaviour of AZ31 magnesium alloy strengthened by nanoscale SiCp

In this work, the wear and friction behavior of nanoscale SiCp (1 vol.%) reinforced Mg composite were investigated. Experiments were carried out by rubbing a GCr15 steel ball on the surface of pin specimens with the different sliding velocities of 0.1, 0.3 and 0.5 m/s at distinctive normal loads of 10, 20, and 30 N, respectively (without the aid of lubricant). Detailed analysis demonstrated that SiCp efficiently block the grain growth and improve the mechanical properties of the composite due to grain refining and dislocation strengthening. As a result, the wear resistance of composite was more prominent s compared with the initial alloy under all test condition. With the increase of sliding speed or load, the wear rate of composite increases gradually. The wear rate is reduced by 12% compared to the alloy, particularly in high load condition. Under low speeds, abrasive wear and slight oxidative wear were prevalent. Subsequently, the wear mechanism transitions to the initial delamination wear as the sliding speed increases. Severe plastic deformation occurs on the surface of the friction sample under high load, and the surface damage is serious.

Development of wear resistant Cu-12Sn-1.5Ni alloy via minor addition of Fe during casting process

The evolution of microstructure and mechanical properties in as-cast Cu-12Sn-1.5Ni-(0–1.5)Fe (wt. %) alloys was investigated in the previous work. Herein, the effect of minor Fe (0, 0.053, 0.63 wt%) addition on wear behavior of the alloy surface was explored. The coefficient of friction (COF) (0.61 to 0.51 at load of 10 N, 0.67 to 0.42 at 5 N) and wear rate (42.0 × 10−5 to 23.1 × 10−5 mm3/(N·m) at 10 N, 18.7 × 10−5 to 3.6 × 10−5 mm3/(N·m) at 5 N) decreased with addition of Fe. A transition in wear mechanisms was noticed with applied load. Abrasion wear was the dominant mechanism at 10 N together with slight oxidative wear, while adhesion and tribo-oxidation mechanisms controlled the wear at 5 N. The delamination and wear debris on worn surfaces lessened with increasing Fe both at 10 and 5 N, in line with the variation in COF and wear rate. The mechanisms underlying the improved wear behavior were evaluated in terms of microstructural optimization, densification and enhancement in mechanical properties. This work indicates the advantage of minor amount of Fe addition to achieve better wear resistance of nickel bronze alloys.

Effects of Multi-Axial Compression on the Mechanical and Fretting Wear Properties of Ti-45Nb Alloys

Biocompatible β-type Ti-45Nb alloy with a low elastic modulus is promising in alleviating the stress shielding effect of Ti-based hard-tissue replacement implants. In this work, the ultra-fine-grained (UFG) microstructures with different grain sizes were prepared by multi-axial compression (MAC) processing of Ti-45Nb alloys, and the mechanical properties and the fretting wear properties of Ti-45Nb alloys in different grain sizes were investigated. The results show that the yield strength and ultimate tensile strength of the sample processed by 27 passes MAC increase by 76% and 91%, respectively, with an elongation of more than 9%. After MAC processing, the friction coefficient and volume wear rate gradually decrease. In addition, before MAC processing, the Ti-45Nb sample shows a wear mechanism of severe adhesive wear, oxidative wear and fatigue delamination; while after MAC processing, the wear mechanism switches to abrasive wear and slight adhesive wear with slight oxidative wear, indicating that grain refinement helps to improve the anti-fretting properties of Ti-45Nb alloys.

Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment.

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

Surface alloying of FeCoCrNiMn particles on Inconel-718 using plasma-transferred arc technique: microstructure and wear characteristics.

Inconel-718 (IN-718) is a commonly used nickel-based superalloy in various fields, such as gas turbine and power generation applications. However, the lower wear and oxidation resistance hinder their wide usage. In this work, FeCoCrNiMn particles were mechanically ball-milled and preplaced on the IN-718 substrate. Then, the preplaced FeCoCrNiMn particles were scanned by heat source using plasma-transferred arc (PTA) technique. The effect of PTA alloying on the phase changes, microstructure, nanohardness and wear resistance has been investigated. The result showed that the PTA region contained different phases, such as FCC, BCC and intermetallic. No cracks were observed in the PTA alloyed region. Moreover, the porous free structure was viewed in the alloyed region, which revealed that the PTA alloying process was effectively used to perform the alloying process. More hard phases, such as NiFe, CoMn, Cr9Mn25Ni21, MnNi, FeCo, FeMn and MnCo, were formed on the PTA-alloyed region. The obtained wear rate of the substrate specimen at 30 N applied load is 2.45 × 10−3 mm3 m−1 and 1.79 × 10−3 mm3 m−1 for the PTA specimen. Similarly, the wear rate of the substrate specimen at 50 N is 5.38 × 10−3 mm3 m−1 and for the PTA sample, it is 2.29 × 10−3 mm3 m−1. The PTA specimen showed lower CoF than the substrate specimen due to increased surface hardness and minimum deformation of asperities. The primary wear type was mildly abrasive, accompanied by slight oxidative wear. Oxygen reacted with the surface alloying elements and formed different oxides, such as CoO, Cr2O3, MnO2, Mn2O3, Mn3O4, FeO and Fe2O3. These dense oxidation films covered the working surface and enhanced the wear resistance. The worn-out PTA surface showed that the wear scar depths were shallow and lower than the substrate, and reduced the roughness.