High Temperature Tribological Behavior Research Articles

Microstructure, thermostability and tribological behavior of composite CoCrFeNiTix high-entropy alloy coatings fabricated by laser cladding

CoCrFeNiTix (x = 0,0.25,0.5,0.75,1.0) high-entropy alloy (HEA) coatings were prepared on 45 steel by laser cladding, to explore the microstructural evolution, thermostability and the high-temperature tribological behavior of the coating. Ti-doping promotes more intergranular hard BCC phase and TiO2 intermetallics to precipitate from the ductile matrix of FCC phase, resulting in an increase in the averaged microhardness. The favorable thermostability of the heterogeneous microstructure and the oxide layer induced by friction endow the laser cladded HEA coating with excellent dry sliding wear-resistance in a wide temperature range from room temperature to 800 °C. Taking the place of the adhesive wear at room temperature, the oxidative wear becomes dominant in the wear process when the temperature exceeds 200 °C, contributing to the decrease in the wear rate before 600 °C. The formation of spherical particles on the wear track, as well as the oxide layer at elevated temperature, are revealed from the perspective of thermodynamic. It is found that the protective oxide layer is susceptive to delaminate due to the synergetic effect of strength reduction, internal stress accumulation and the destruction of the bonding, which explains the rise of the wear rate from its lower value of 1.84 × 10−5 mm3/(N·m) at 600 °C to 9.64 × 10−5 mm3/(N·m) at 800 °C.

High Temperature Tribological Behavior of Electroless Plating Ni-P-Si3N4-WS2 Composite Coatings

Electroless nickel composite coatings have the potential for high-temperature tribological applications, and a combination of high wear resistance and low friction factor is one of the desirable solutions but still a tricky problem. The addition of self-lubricating WS2 and hard Si3N4 nanoparticles to the Ni-P coatings is expected to obtain good high-temperature tribological performance. In this work, Ni-P-Si3N4-WS2 composite coatings with various contents of WS2 nanoparticles were prepared using electroless plating and subsequently annealed at 400 °C in an inert atmosphere. The tribological properties of the coatings were evaluated using a ball-on-disc wear instrument at operating temperatures from 25 to 600 °C. The microstructure, chemical composition, and surface morphology of the coatings were characterized by X-ray diffractometry (XRD), energy disperse spectroscopy (EDS), and scanning electron microscopy (SEM). Upon increasing the WS2 dosage in the bath, the WS2 content in the coating increased and the micro-hardness of the as-plated coating increased from 539 to 717 HV. After heat treatment, the coating underwent a crystallization process, and the hardness increased from 878 to 1094 HV. The main wear mechanism of the coating changed from adhesive wear in the as-plated state to abrasive wear in the annealed state. The annealed Ni-P-Si3N4-WS2 coating with a WS2 dosage of 2.5 g/L in the bath exhibited excellent mechanical properties, with a hardness of 10.9 GPa, a friction coefficient of ~0.51, and a wear rate of 8.4 × 10−15 m3N−1⋅m−1 at room temperature, and maintained optimal performance at high temperatures. At operating temperatures of 200, 400, and 600 °C, the form of wear was adhesive wear for coatings with a WS2 dosage <1.5 g/L and abrasive wear for coatings with a WS2 dosage ≥1.5 g/L. The synergism of WS2 and Si3N4 particles refined the grains of the Ni-P matrix in as-plated coatings and obviously reduced the friction coefficient of friction pairs in annealed coatings at all operating temperatures.

Microstructure and wear behavior of (ZrTaNb)C/N quaternary ceramic coatings prepared by double-cathode glow plasma surface alloying on titanium alloy

Multi-principal component coating is a new type of surface protection material developed in recent years. To improve the surface hardness and wear resistance of aviation titanium alloy, (ZrTaNb)C, (ZrTaNb)N and ZrTaNb coatings were prepared by double cathode glow plasma surface alloying. The microstructure, mechanical properties and high temperature tribological behavior of quaternary ceramic coatings were studied. The results show that the quaternary ceramic coating has an FCC cubic structure, which is different from the BCC structure of the ZrTaNb coating. Meanwhile, the solid-soluble C and N elements improve the surface hardness and toughness of the multi-principal component coating, resulting in a significant reduction in wear rate, which is only 1/10 and 1/5 of that of the substrate and pure metal coating (25 °C). When the temperature increases to 500 °C, the compliant islets of oxidized and compacted debris are gradually activated as a wear-resistant oxidation glaze layer. The gradient structure of amorphous-nanocrystalline composite is formed in the subsurface layer, which can effectively improve the surface strength and wear resistance. This study provides an effective strategy for improving the wear resistance of titanium alloy surface in a wide temperature range.

Effect of MWCNTs on micromechanical and high-temperature tribological behavior of ZTA-MgO ceramic composites

Correlating the microstructure and tribo-mechanical properties is a promising approach for evaluating the performance of any newly decorated high-temperature materials. Aiming to improve the mechanical and tribological performance of zirconia toughened alumina (ZTA)− 0.6 wt% magnesium oxide (MgO) ceramic matrix, extremely low amounts (0.05 wt% and 0.1 wt%) of multi-walled carbon nanotube (MWCNT) is added into matrix. MWCNT-reinforced ZTA-0.6 wt%MgO composites are fabricated through a colloidal mixing followed by hot-press sintering at 1500 °C. The ceramic composites exhibit excellent tribo-mechanical properties attributed to the microstructural modification through the effective interaction between matrix and reinforcement phases including spinel (MgAl2O4) formation and MWCNTs. Perceptible improvement of hardness and fracture toughness ascribes to the collective strengthening mechanism. The advanced micromechanical interlocking mechanism for 0.05 wt% MWCNT-reinforced composite derives from the length reduction of MWCNTs during the powder mixing. The rolling action of MWCNT clumps evolves into a prominent three-body abrasive wear including crack bridging and crack arrest. This impeccable anti-wear and lubrication performance refer to decreasing wear rate of ∼81% and coefficient of friction of ∼29% even at 500 °C temperature making ZTA-0.6 wt%MgO-0.05 wt%MWCNT composite appropriate for high-temperature wear resistance applications.

Structural design and high temperature tribological behavior of a new turbine blade tip protective coating

Severe damage to the blade tip usually occurs when the turbine blade tip scratches against the abradable coating. Therefore, blade tip strengthening is a hot research topic. To improve the wear resistance of turbine blade tips, NiAlTa coatings were prepared on K417G superalloy by electro spark deposition. The microstructure and phase composition of the coating were analyzed by scanning electron microscope and X-ray diffraction. Microhardness tester and scratch method were used to test the microhardness and bonding strength of the coating. Using ZrO2 balls as friction pair, the tribological behavior and wear mechanism of the coating were investigated by a self-developed tribometer at 25 °C and 800 °C. The NiAlTa coating mainly consists of the β phase NiAl and the laves phase NiTaAl. The laves phase NiTaAl encapsulates the NiAl phase, and this plant-like “cell wall” structure endows the coating with excellent mechanical properties, wear resistance, and cutting performance. Compared with the substrate, NiAlTa coating has higher microhardness (~797.18 HV0.2) and lower wear rate (~10−6 mm3·N−1·m−1). The wear process of NiAlTa coatings is dominated by plastic deformation, with little evidence of material loss from the brittle fracture. The competition between the anti-wear lubricating effect of the “glaze” layer and the plowing effect of oxides and ZrO2 debris affects the tribological behavior of the coating. The cutting performance of the NiAlTa coating can be attributed to the two-body or three-body abrasive wear caused by the oxides and ZrO2 debris embedded in the “glaze” layer.

High temperature tribological and electrochemical behavior of heat-treated Al2O3-base hybrid coating sprayed by HVOF thermal spray technique

In the present study, the hybrid coating was developed by HVOF over the cast iron substrate. The hybrid coating material comprises Al2O3 (80% w/w) enriched with graphite, MoS2, and fumed silica in w/w of 5%, 10%, and 5% respectively. Microstructure and phase composition of prepared coated samples were analyzed by SEM-EDS, XRD and Raman Spectroscopy. The coated samples were heat-treated and their mechanical, electrochemical and tribological behavior was compared with the as-coated samples. There was a considerable change observed in the micro-hardness and anti-corrosion properties of the coated material after heat treatment. The residual stresses in the heat-treated sample decreased compared to the as-coated sample. The high-temperature tribological investigation was carried out in non-lubricated conditions at three different temperatures 30 °C, 150 °C, and 300 °C with a constant load of 40 N and variable sliding speed. The coefficient of friction and wear rate was calculated and it was found that there was a decrement up to 36% in the wear rate of the heat-treated samples compared to the as-coated sample. The SEM morphologies of the wear track showed the presence of small cracks, adhesion, abrasion and smear regions due to plastic deformation.

Effects of graphite contents on the microstructure evolution, mechanical properties and high temperature tribological behavior of Cu–Ni–Al/Gr solid-lubricating composites

High temperature copper matrix self-lubricating composites are essential for industrial applications. This paper fabricated the Cu–Ni–Al/Gr solid-lubricating composites with 2.5–10 wt% graphite. Effects of graphite contents on the tribological behavior at room temperature to 500 ℃ were thoroughly studied. The conclusions present that the addition of graphite significantly improves tribological properties while no further enhancement can be made when graphite reaches 7.5–10 wt%, which shows the friction coefficient of 0.04–0.22 and wear rate of (1.02–10.12)× 10−5 mm3/Nm. The excellent tribological performance at 25–500 ℃ is attributed to the synergistic effects of the self-lubricating property provided by graphite lubricant and the tribo-oxide layer formed during the sliding process.

Development of Ni-B electroless coating from stabilizer free bath and characterization of high temperature tribological behaviour, scratch and corrosion resistance

The current work investigates the effects of variation of coating bath temperature on friction and wear behaviour of electroless Ni–B (ENB) coatings developed from stabilizer free bath. Coating is applied to specimens made up of AISI 1040 steel. Coatings were deposited at three different coating bath temperatures (85 °C, 90 °C and 95 °C). Field emission scanning electron microscopy, inductively coupled plasma-optical emission spectrometer, and x-ray diffraction were used to characterize the coating for surface morphology, chemical composition, and phase structure respectively. Pin-on-disc tribo-tester was used to estimate the friction and wear behaviour of ENB coatings at room temperature (25 °C), 100 °C, 200 °C and 300 °C. The coefficient of friction was higher at high temperature due to higher roughness of the coatings obtained from stabilizer free bath, adhesion and ploughing. The wear rate at 200 °C or 300 °C was lower compared to 100 °C. Additionally, the ENB coatings were subjected to thermogravimetric analysis which reveals higher thermal stability of coatings obtained at 95 °C. A scratch tester at constant (6 N) and progressive load (5–24 N) was used to estimate the coatings scratch hardness and adhesion. The corrosion behaviour of ENB coatings in 3.5% NaCl was studied using potentiodynamic polarization tests. The Ni-B coated specimens could efficiently provide barrier protection to steel substrate. But the corrosion potential was lower compared to lead stabilized bath.

Effect of temperature on the tribocorrosion and high-temperature tribological behaviour of strong amorphization AlCrNiTiV high entropy alloy film in a multifactor environment

Here, we fabricated an AlCrNiTiV high entropy alloy amorphous film (HEAAF) by co-filter cathode vacuum arc deposition (Co-FCVAD). The systematic experiments demonstrate that excellent mechanical properties and a stable dense microstructure are important contributing factors in a friction-corrosion coupling environment, in which the AlCrNiTiV HEAAF oxidized at 600 °C exhibits optimal tribocorrosion resistance with a minimum Δ open circuit potential (ΔOCP), friction coefficient (COF) and wear rate of 0.015, 0.01 and 2.36 × 10−6 mm−3 N−1•m−1, respectively. Through study of the oxidation behaviour, it is found that the diffusion barrier formed in situ by the Al2O3, NiCr2O4 and Cr2O3 composite inner oxide layer after oxidation at 800 °C can effectively impede the outward diffusion of metal ions and inward diffusion of O ions, but the film shows a deterioration in hardness and a loose microstructure, which are the main failure factors under a friction-corrosion coupling environment. Additionally, the AlCrNiTiV HEAAF shows excellent high-temperature tribological performance under a friction-temperature (600 °C) coupling environment with the lowest COF (0.22) and wear rate values (1.1 × 10−5 mm3 N−1•m−1). However, a brittle oxide film composed of rutile TiO2 on the worn track is found to be responsible for the weak high-temperature tribological performance under a friction-temperature (800 °C) coupling environment.

Microstructure and high temperature tribological behaviour of self-lubricating Ti-TiBx composite doped with Ni[sbnd]Bi

It is a well-established fact, that the tribological performance of titanium and its alloys at high temperatures is poor, especially for self-mated titanium‑titanium pairs. Previous work has shown a significant improvement in mechanical and high temperature tribological behaviour (700–900 °C) for pure Ti sintered with TiB2 ceramic, occasioned by the in-situ formed boric acid lubricant. The current work explores the possibility to extend the lubrication temperature range (below 700 °C) of Ti-TiB2 composites through the incorporation of a nickel‑bismuth mixture (NiBi) as a solid lubricant using laser melting. To this end, phase equilibrium diagrams have been calculated for the Ti-B-NiBi quaternary system using the CALPHAD method to evaluate the possibility of the formation of different phases due to dilution between the substrate and deposit, as well as their possible interactions. The self-lubricating NiBi samples feature a formation of Bi-Ni-Ti-TiBx functional surface. The functional surface demonstrates a compact and unique microstructure of a hard B-rich phase encapsulated inside a lubricous Bi-rich phase. A two-fold increase in hardness of the surface in comparison to the underlying substrate was noted for NiBi laser-melted samples. Further, the NiBi samples were studied under a reciprocating sliding configuration against a Ti-alloy flat-pin counterbody at temperatures including RT, 400 and 600 °C. The resulting wear scars were analysed utilizing SEM, XRD and 3D profilometry to understand the prevalent wear mechanisms. A significant decrease in coefficient of friction and wear rate was observed for the NiBi laser-melted samples sliding at 400 °C and 600 °C due to the formation of a self-lubricating tribo-oxide layer rich in Bi-compounds. The results are reported in comparison to the unmodified reference Ti-TiB2 composite.

Microstructure, mechanical properties and high temperature tribological behavior of NiAl-based composites

NiAl-based composites were fabricated in-situ using vacuum hot-press sintering technology. The Ti3AlC2, TiC and Ti3Al were formed during the sintering process, and the intensity of peaks grow higher with the addition of Al, Ti and C powder contents, respectively. The microhardness of the composites was significantly improved by adding these powders and gradually increased with the incremental content of Al, Ti and C powders. Meanwhile, the tribological properties of the composites at high temperature were also improved. The worn surface formed during the tribo-oxidation reactions and produced the glaze film in the high-temperature friction process, which could improve the composites' tribological properties. The TiO2 and Al2O3 phases were observed on the worn surface after the friction test, which could act as a high-temperature lubricant and improve the composites’ tribological properties.

The high temperature tribological behavior of an iron oxide strengthened iron compound obtained from an industrial byproduct

This new material is based on an oxide dispersion strengthened iron, obtained by a partial chemical reduction of ground mill scale for subsequent compaction and sintering. The mechanical properties depend on the porosity level and the quantity of the iron oxide reinforcement. Having into account the characteristics of the reinforcement, the tribological behavior was evaluated at two types or ironox compounds under dry sliding conditions. The effect of porosity was evaluated and a comparison with an AISI 1040 steel was done. Experimental test was carried out using a pin on disk tribometer at different temperature. It was found that, on the contrary of AISI 1040 steel, the wear rate of ironox compounds with temperature tends to slow down.

Effect of preheating on the mechanical and high temperature tribological behaviour of reusing marble dust with aluminium composite

ABSTRACT In this paper the effect on the mechanical and tribological behaviour of aluminium alloy (AA 7175) reinforced with marble dust has been studied. The waste powder of marble developed during its processing, which is a huge environmental waste as its disposal is very difficult. The remarkable wear and friction resistant properties of marble dust make to promising material to be used in MMC. Marble dust used untreated may result in defective MMC due to the presence of moisture and chemical contamination. In this article the marble dust was preheated at a temperature of 150°C and 300°C to remove the volatile chemical contamination and moisture. The composite of preheated marble dust and AA 7175 was formed by stir casing. The optical microscopy and XRD analysis was carried for examining the microstructure and dispersion of marble dust particles in the AA 7175 matrix. The microhardness of the MMC sample improved but the tensile strength slightly decreased. The high-temperature tribological study of the developed composite was performed using the Pin-on-Disc tribometer. The scanning electron microscopy was done to study the worn out surfaces. There was considerable improvement in the tribological behaviour of composite prepared by pre-heating the marble dust.

High-Temperature Tribological Behavior of HDPE Composites Reinforced by Short Carbon Fiber under Water-Lubricated Conditions

The polymer water-lubricated bearing is widely used in marine transmission systems, and the tribological properties can be improved by addition of inorganic nano-fillers. The aim of this study is to investigate the effect of SCFs and temperature on the water-lubricating properties of high-density polyethylene (HDPE) composites. HDPE composites reinforced by varying content of short carbon fibers (SCFs) were fabricated via twin-screw extrusion and injection molding techniques to study the hardness and surface wettability of those composites. The tribological properties under water-lubricated conditions were investigated through a pin-on-disk reciprocating tribometer under different temperatures. The results showed that the increase in hardness of HDPE composites reached maximum to 42.9% after adding 25 wt % SCFs. The contact angle also increased with the increase in SCFs content and reached a maximum of 95.2° as the amount of SCFs increased to 20 wt %. The incorporation of SCFs increased the wear resistance and lubricating property of HDPE composites at different temperatures. The HDPE composite containing 20 wt % SCFs showed the lowest friction coefficient of 0.076 at 40 °C, and the wear track depth reached a maximum of 36.3 mm at 60 °C. Based on the surface wetting property and wear analysis, potential effect mechanisms of fillers and temperature were discussed. The knowledge from this study is useful for designing the anti-wear water-lubricated polymer bearing.

High-temperature tribological behavior of CoCrFeNiV high-entropy alloys: A parallel comparison with CoCrFeNiMn high-entropy alloys

The present work investigates the high-temperature tribological behavior of CoCrFeNiV fabricated by vacuum hot pressing sintering, and parallel experiments were conducted with CoCrFeNiMn as a comparison. It was found that the wear rate of CoCrFeNiV is almost an order of magnitude lower than for CoCrFeNiMn. Compared with CoCrFeNiMn of a single FCC, the precipitation of the hard sigma (σ) phase from the addition of V element made CoCrFeNiV possess excellent hardness (975 ± 11 HV) and high-temperature wear-resistance. The detailed characterization of the worn surface revealed that mild adhesion and oxidative wear are the dominant wear mechanisms of CoCrFeNiV. With the increase of temperature, the tribo-oxidation composed of V2O5, NiO and Cr2O3 play an excellent anti-oxidation lubrication role during the friction process. The higher volume fraction of the hard σ phase and the dense oxide glaze layer resulted in wear of approximately 0.289 × 10–4 mm3/Nm at 800 °C.

Microstructure and High-Temperature Tribological Behavior of Plasma-Sprayed FeCoCrAlNi High Entropy Alloy Coatings Under Higher Load Condition

Microstructure and High-Temperature Tribological Behavior of Plasma-Sprayed FeCoCrAlNi High Entropy Alloy Coatings Under Higher Load Condition

High-temperature tribological behavior of Ti containing diamond-like carbon coatings with emphasis on running-in coefficient of friction

Diamond-like carbon (DLC) coatings show a low coefficient of friction (COF) and high wear resistance against aluminum at elevated temperatures, yet they exhibit a high running-in COF (μ R ) prior to reaching a low and stable steady-state COF (μ s ). This study shows that incorporating titanium (Ti) atoms into the DLC structure would reduce the μ R . During pin-on-disk tests conducted on Ti incorporating hydrogenated-DLC (Ti-H-DLC) with 6.2 at.% Ti subjected to dry sliding against 319 Al (Al-6.5% Si), μ s values decreased from 0.27 at 25 °C to 0.11 at 200 °C. The specific wear rate of Ti-H-DLC decreased from 2.44 × 10 −5 mm 3 /Nm at 25 °C to 0.71 × 10 −5 m 3 /Nm at 200 °C. A typical DLC with 40 at.% H (H-DLC) tested at 200 °C showed a low μ s of 0.08 and a wear rate of 1.11 × 10 −5 mm 3 /Nm. However, at 200 °C, Ti-H-DLC showed a lower μ R of 0.16 compared to μ R = 0.78 of H-DLC, and the duration of the running-in period for Ti-H-DLC, t R = 3 revolutions, was shorter than H-DLC with t R of 200 revolutions. Comparisons made with other DLCs, including, NH-DLC, W-DLC, ta-C, and Si-O-H-DLC, in addition to H-DLC, all tested using the same method, revealed that, in the temperature range of 100–250 °C, Ti-H-DLC showed a better running-in behavior making Ti-H-DLC a suitable tool coating for manufacturing processes where high-temperature running-in sliding friction is important, including warm forming and (single-point) turning of aluminum alloys . • High-temperature tribological behavior of Ti-H-DLC against 319 Al was studied. • Low running-in COF and short running-in duration were recorded at 100 and 200 °C. • Compared to other DLC coatings, the lowest μ R and t R were obtained using Ti-H-DLC. • Ti-H-DLC tool coatings are useful for Al warm forming, machining operations ~200 °C.

High-Temperature Tribological Behavior of Al0.3Cr0.5Fe1.5Mn0.5Ni High-Entropy Alloys With Addition of Titanium and Carbon

In this study, the Al0.3Cr0.5Fe1.5Mn0.5Ni high-entropy alloys (HEAs) with addition of titanium and carbon was prepared. The as-cast alloys were composed of FCC solid solution and TiC particles, and were further aged and strengthened by precipitation of B2-NiAl phase at 700°C for 10 h to increase hardness from Hv 200 to Hv 400. Tribological properties of the HEAs and commercial tool steel (AISI M2) against Al2O3 under dry sliding condition at room-temperature and elevated temperatures are compared. After high-temperature wear testing, the HEAs demonstrated exceptional oxidation resistance and a lower friction coefficient than M2 steel since the dense glazed layer on the surface of the HEAs served as a lubricant to decrease the friction coefficient, and protected the substrate from oxidation.

Microstructure evolution and high-temperature tribological behavior of AlCrBN coatings with various B contents

The boron content affects the microstructures and high-temperature tribological performance of AlCrBN coatings. AlCrBN coatings with various B contents (0 at.%, 1.5 at.%, 2.9 at.%, 4.8 at.%,) were synthesized by multi-arc ion plating. The microstructure, mechanical and high-temperature tribological properties were investigated. TEM results show that addition of 1.5 at.% of B results in solid solution (Al, Cr, B)N and a small amorphous a-BNx within the (Al, Cr, B)N columnar structure. Further addition of B contents of 2.9 at.% and 4.8 at.% leads to the composite structure comprising of nano-grains surround by amorphous a-BN x . As the B content increases, the amount of nano-grains decreases, and the thickness of the amorphous layer increases. The hardness measurements also indicate that the AlCrBN coating with 1.5 at.% B content had the highest hardness of 38.3 GPa due to the solution strengthening. On the other hand the AlCrBN coating with 2.9 at.% B content had the best toughness with higher values of H / E (0.073) and H 3 / E * 2 (0.169 GPa). High-temperature tribological measurements showed that the friction coefficients decreased with temperature for all such AlCrBN coatings. At 400 °C, AlCrBN coatings with B contents of 0 at.%, 1.5 at.%, and 2.9 at.% exhibited low wear rates due to their high hardness, while AlCrBN coating with a B content of 4.8 at.% showed the lower wear rate at 800 °C due to the formation of a continuous B 2 O 3 /B(OH) 3 film on the coatings. • Microstructure of AlCrBN coatings is closely related with B contents. • Addition of 1.5 at.% of B results in the coherent fcc -BN/ fcc -AlCrBN interfaces. • Microstructures, mechanical and tribological properties were investigated. • Various friction oxide films depend on the different temperatures.

Enhancing mechanical and tribological properties of Ni3Al-15vol%TiC composite by high current pulsed electron beam irradiation

Effects of high current pulsed electron beam irradiation (HCPEBI) on the surface microstructure, mechanical properties, room and high temperature tribological behavior of the Ni3Al-15vol%TiC composite were investigated. The HCPEBI process refines the TiC particles down to nano scale and distributes them homogeneously throughout the modified layer. It also decreases grain size of the Ni3Al down to 400 nm. Grain refinement and homogeneous distribution of the TiC nanoparticles by irradiation process increase surface hardness from 538 HV0.025 to about 728 HV0.025. The HCPEBI process increases also the wear resistance of Ni3Al-15vol%TiC composite at both room temperature and elevated temperature of 600 °C due to the increasing hardness and roughening the surface of the sample. Adhesive wear was found to be the dominant wear mechanism for both as-received and irradiated samples at room temperature beside with the delamination. At the elevated temperature of 600 °C, oxidative wear and delamination of the oxide layers occur as the main wear mechanisms in the as-received sample. In the irradiated sample, on the other hand, wear starts with the abrasive wear with micro-cutting of surface hills of irradiated sample, and continues with oxidative and delamination wear mechanisms.