High-temperature Wear Tester Research Articles

Enhancing high-temperature wear resistance of cladded Inconel 718 through hybrid of directed energy deposition with ultrasonic nano-crystal surface modification

We present an innovative method for achieving highly durable and finely controllable internal microstructures within cladded 718 layers utilizing a hybrid cladding approach. This process alternates between two methods: laser directed energy deposition in which four layers of Inconel 718 built up using a laser power of 350 W and a scanning speed of 800 mm/min, and ultrasonic nanocrystal surface modification (UNSM), applied to every fourth deposited surface at elevated temperatures of 300 and 600 °C, with a frequency of 20 kHz and an interval of 0.05 mm, respectively. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) are used to analyze the effect of grain refinement and concentrated dislocation distribution induced by the hybrid cladding. Through the employment of high temperature UNSM treatment between the cladded Inconel 718 layers, profound grain refinement and dislocation enhancement occur, significantly bolstering the wear resistance of the intermediate layer under high temperature conditions. We conducted thorough analyses, employing finite element analysis and experiments, to investigate the diverse temperature conditions of UNSM treatment and their impact on increasing the affected depth of UNSM treatment. Furthermore, we closely examined the changes in microstructure and mechanical properties within the remelted and UNSM-treated zone of the internal layers. Our study confirms that the high temperature hybrid cladding process, operating below 600 °C, resulted in a 27 % reduction in overall material wear-loss compared to conventional cladding methods. Notably, even in high temperature wear tests ranging from 200 to 800 °C, the proposed method significantly mitigated wear amounts in each case, indicating its potential to enhance the mechanical integrity of various components operating under elevated temperature conditions.

Thermal shock resistance of WC–Cr3C2–Ni coatings deposited via high-velocity air fuel spraying

In this study, the high-velocity air fuel (HVAF) spraying technique was used to deposit WC–Cr3C2–Ni wear-resistant coatings on the surface of crystallization rollers to overcome the wear problem of the substrate of thin-strip continuous-casting crystallization rollers and thus improve their efficiency. The performance and durability of the WC–Cr3C2–Ni coatings on the surface of the roller body during the actual continuous casting process were investigated by performing thermal shock tests. It was found that the thermal shock resistance of the closed-curved surface coatings increased with their thickness. The coatings exhibited the best thermal shock resistance at a thickness of 300 μm, and the number of cycles they could withstand at 800 °C reached 15. The results of the high-temperature wear tests showed that the WC–Cr3C2–Ni coatings deposited on the surface of the crystallization roller via HVAF reduced the friction coefficient of the surface of the roller body (from 0.425 to 0.362), and greatly reduced the wear loss volume during the wear process (reduced by 83 %). The WC-Cr3C2-Ni coating showed excellent resistance to crack initiation and propagation during wear and can be stabilized in long-cycle production and protect the substrate of the crystallization roller effectively. This study provides a theoretical basis for the selection and preparation of surface coatings for thin-strip continuous-casting crystallization rollers.

Microstructure and tribological properties of laser cladded TiC reinforced WC-10Co4Cr coatings at 500 °C

WC-10Co4Cr-xTiC coatings were fabricated on H13 steel by laser cladding to improve their wear resistance. The effects of TiC mass fraction on the friction-wear properties at 500 °C were investigated using a high-temperature wear tester, and the wear mechanism was discussed in detail. The results show that the WC-10Co4Cr-xTiC coatings are composed of WC, W2C, Co3W3C, Cr7C3, and TiC phases, and the porosity is reduced by the addition of TiC. The average coefficients of friction of WC-10Co4Cr-xTiC coatings are increased with the TiC mass fraction; while the wear rates are opposite, showing that the addition of TiC plays a key role in wear resistance. Moreover, the wear mechanism of WC-10Co4Cr-xTiC coatings is primary abrasive wear, slight adhesive wear, and oxidative wear.

Investigation on tribological properties of high-velocity air fuel spraying WC–Cr3C2–Ni coating on the surface of continuous casting crystallization rollers

To overcome the wear problem of the substrate of thin-strip continuous casting crystallization rollers and improve economic efficiency, high-velocity air fuel (HVAF) technology was used to deposit WC–Cr3C2–Ni wear-resistant coatings on the surface of the crystallization rollers. The existing performance and wear condition of curved WC–Cr3C2–Ni coatings during continuous casting were investigated by the ring-block wear system. The experimental results showed that the WC–Cr3C2–Ni coating with a thickness of 300 μm effectively reduced the coefficient of friction (by 16.4 %) and the wear rate (by 82.5 %) on the surface of the crystallization roller and significantly reduced the roughness of the wear interface (by 71.2 %), which provided reliable protection for the substrate. The results of high-temperature (200 °C) wear tests showed that the WC–Cr3C2–Ni coating deposited via HVAF protected the substrate in actual long-cycle production and exhibited an excellent resistance to the emergence and expansion of failure cracks. This study provided a theoretical basis for the selection and preparation of surface coatings for thin strip continuous casting crystallization rollers.

Improvement of wear and hot melt loss resistance of metal carbide layers on H13 steel

Abstract In this paper, H13 steel was pre-carburized. Then niobizing and vanadizing layers were prepared by pack cementation method. The high temperature friction and wear properties and hot melt loss properties of different layers and substrates were studied by microhardness tester, metallographic microscope, scanning electron microscope, energy dispersive spectrometer, high temperature friction and wear tester, optical profilometer and Raman spectrometer. The results show that the thickness of the vanadizing layer is 12.7 μm, and the microhardness of the niobizing layer and the vanadizing layer is close, which is about 5 times that of the matrix. The lowest wear rate at 500 °C of the vanadizing layer is 1.03 , which is about 1/6 of the matrix. The vanadizing layer and niobiumizing layer can effectively reduce the friction coefficient, greatly improve the surface hardness and wear resistance of H13 steel, and prolong its service life. The comprehensive performance of vanadizing layer is the best. The vanadizing and niobiumizing treatment can significantly improve hot melt loss resistance of H13 steel and it can be used to prolong the serving life of hot die casting mold for Al.

Influence of Axle Weight and Frequency on the Tribological Properties of Laser-Repaired 316L Stainless Steel Coatings in Railway Wheel Tread Braking

The impact of the complex braking environment on the service performance of the repair fusion cladding was studied, which is of great significance to improve the ability of the train wheel track system to resist the extremely harsh environment. In this paper, a 316L stainless steel coating was prepared using laser fusion cladding repair technology for the local damage location of the train wheel tread. The MS-HT1000 high-temperature wear tester was used for the experiment. Then, the influence of different braking conditions on the friction and wear performance of the repaired specimens at room temperature and high temperature was analyzed. The results showed that the microstructure of the laser-repaired 316L stainless steel coating was dendritic and eutectic, and its physical phase was mainly composed of austenite, Fe-Cr, and carbides. The wear rate increases with the rise in the shaft weight load, indicating that the higher the contact load, the more severe the wear. In contrast, the influence of the friction coefficient in a room temperature environment is less variable. With an increase in the braking frequency, the wear of the specimen firstly rises and then decreases, and when the frequency is 1 Hz, the value of the wear rate at room temperature is the largest, and the wear surface appears as more peeling layers, and a large amount of wear debris is randomly distributed, which manifests as the wear mechanism being characterized by abrasive wear and adhesive wear. Therefore, different factors affect the wear level of the material differently, with the axle weight load having the greatest influence. The relevant results help to provide corresponding theoretical references for the optimization of parameters under the braking condition of the wheel tread, which ensures the normal operation of the braking system when driving.

High-temperature tribological performance of functionally graded Stellite 6/WC metal matrix composite coatings manufactured by laser-directed energy deposition

Wear-driven tool failure is one of the main hurdles in the industry. This issue can be addressed through surface coating with ceramic-reinforced metal matrix composites. However, the maximum ceramic content is limited by cracking. In this work, the tribological behaviour of the functionally graded WC-ceramic-particle-reinforced Stellite 6 coatings is studied. To that end, the wear resistance at room temperature and 400 °C is investigated. Moreover, the tribological analysis is supported by crack sensitivity and hardness evaluation, which is of utmost importance in the processing of composite materials with ceramic-particle-reinforcement. Results indicate that functionally graded materials can be employed to increase the maximum admissible WC content, hence improving the tribological behaviour, most notably at high temperatures. Additionally, a shift from abrasive to oxidative wear is observed in high-temperature wear testing.

Enhanced high-temperature wear behavior of high-speed laser metal deposited Al0.3CrFeCoNi coatings alloyed with Nb and Mo

In this study, oscillating wear tests were carried out on the high-speed laser metal deposited (HS-LMD) high-entropy alloys (HEAs) Al0.3CrFeCoNi, Al0.3CrFeCoNiNb0.5 and Al0.3CrFeCoNiMo0.75 at temperatures of 25 °C, 500 °C, 700 °C, and 900 °C. The microstructure was analyzed using scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). In addition, the crystal structure was investigated by X-ray diffraction (XRD). Furthermore, the Vickers hardness (HV0.1) was determined on cross-sections. All tests were performed before and after the high-temperature wear tests. The wear depth was measured using laser scanning microscopy. Increasing the temperature leads to decreased wear depth, particularly for the Nb- and Mo-containing HS-LMD coatings. The wear mechanisms change from abrasive, adhesive and oxidative wear to pronounced oxidative wear. The adhesion of the oxide layer is most important for high wear resistance at elevated temperatures. Strong adhesion is attributed to compact, thin and mechanical clamped oxide layers, which are found for the Nb-containing HS-LMD deposited coating resulting in the lowest wear depth.

A Comparative Study on Characterization and High-Temperature Wear Behaviors of Thermochemical Coatings Applied to Cobalt-Based Haynes 25 Superalloys

This study investigated the characteristic properties of aluminizing, boronizing, and boro-aluminizing coatings grown on Haynes 25 superalloys and their effects on the high-temperature wear behavior. The coating processes were conducted in a controlled atmosphere at 950 °C for 3 h. Characterization studies were performed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction analysis, nanoindentation testing, and high-temperature wear tests. It was determined that the thickness values of aluminide, boride, and boride–aluminide coatings were 140 ± 1.50 µm, 37.58 ± 2.85 µm, and 14.73 ± 1.71 µm, and their hardness values were 12.23 ± 0.9 GPa, 26.34 ± 2.33 GPa, and 23.46 ± 1.29 GPa, respectively. The hardness of the coatings resulted in reduced wear volume losses both at room temperature and at 500 °C. While the best wear resistance was obtained in the boronized sample at room temperature due to its high hardness, the best wear resistance at 500 °C was obtained in the boro-aluminized sample with the oxidation–reduction effect of Al content and the lubricating effect of B content in the boro-aluminide coating. This indicates that the presence of aluminum in boride layers improves the high-temperature wear resistance of boride coatings. The coated samples underwent abrasive wear at room temperature, whereas at 500 °C, the wear mechanism shifted to an oxidative-assisted adhesive wear mechanism.

Effect of boriding on high temperature tribological behavior of CoCrMo alloy

In the present work, CoCrMo alloy surfaces were subjected to powder-pack boriding at 950 ℃ for 5-hour and 7-hour treatment periods. The obtained boride layers were characterized with scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, nanoindentation and high temperature wear tests. Characterization results show that boride layers are composed of CoB, Co2B, CrB and Co2MoB2 phases. Up to 4-fold increase is achieved in nanohardness values due to the boride layers in addition to increased elastic moduli. Increased surface hardness coupled with the high temperature stability of boride layers led to nearly 12, 7 and 10-fold increase in the wear resistance of CoCrMo alloys, worn at room temperature, 250 ℃ and 500 ℃, respectively.

Fabrication of In Situ rGO Reinforced Ni-Al Intermetallic Composite Coatings by Low Pressure Cold Spraying with Desired High Temperature Wear Characteristics.

In this study, the surface of aluminum powder was uniformly coated with in situ reduced graphene oxide (r-GO) sheets (Al/r-GO). The Ni powder, Al2O3 powder, and Al/r-GO powders were mixed uniformly in a mass ratio of 20:6:4. In situ rGO-reinforced Ni-Al intermetallic composite coatings were successfully prepared using low-pressure cold spraying and subsequent heat treatment. The microstructure and phase of the composite coatings were characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The high-temperature wear test was conducted at 200 °C, 400 °C, and 600 °C to understand the mechanism. The results indicate that the in situ rGO-reinforced Ni-Al intermetallic composite coatings exhibit a 33.3% lower friction coefficient and 26% lower wear rate in comparison to pure Ni-Al intermetallic coatings, which could be attributed to the generation of an easy-shearing transferred film between the coating and grinding ball.

Nb and Mo Influencing the High-Temperature Wear Behavior of HVOF-Sprayed High-Entropy Alloy Coatings

To qualify high-entropy alloys (HEAs) as resource-saving and high-temperature wear-resistant coating materials, high-velocity oxygen fuel (HVOF) coatings produced from the inert gas-atomized powder of Al0.3CrFeCoNi, Al0.3CrFeCoNiNb0.5 and Al0.3CrFeCoNiMo0.75 were investigated in reciprocating wear tests at temperatures at 25, 500, 700 and 900 °C. In addition to the high-temperature wear tests, the microstructure and chemical composition of the three HEAs were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). In particular, HVOF coatings are characterized by high hardness (Vickers hardness HV0.1) and low porosity, which were also determined. After high-temperature wear tests, the wear depth was measured using laser scanning microscopy (LSM). It was found that adding Nb and Mo to Al0.3CrFeCoNi significantly reduces the wear depth with increasing temperature. The wear mechanisms change from abrasive wear and delamination (25 °C and 500 °C) to a combination of (abrasion), delamination, adhesion and oxidative wear. Thereby, oxidative wear will be the primary mechanism at 900 °C for all the HVOF coatings investigated. The most important finding is that the adhesion of the oxide layer formed is improved by adding Nb and Mo, resulting in significantly reduced wear depth at 900 °C.

Tribological performance of AZ91D/HfCp magnesium composite prepared through stir-ultrasonic-squeeze casting technique

The present work investigates the influence of hafnium carbide, an ultra-high temperature ceramic reinforcement on the dry sliding wear behaviour of AZ91D magnesium composite. AZ91D/5 wt.% hafnium carbide composite and AZ91D alloy were fabricated using stir-ultrasonic treatment-squeeze casting method followed by heat treatment (T6). Microstructure and intermetallic phase studies were performed using scanning electron microscopy and X-ray diffraction techniques. Density, porosity and hardness of the materials were determined. Wear tests at room temperature were conducted at various sliding speeds (0.25–1 m/s) and normal loads (12.5–50 N), using a pin-on-disc tribometer. The temperature of wear varied from 50–200 °C for high-temperature wear tests. Compared to alloy, the composite showed better wear performance under all test conditions. Increasing the normal load increased the wear rate of both materials, but the wear rate decreased with an increase in sliding speed. The friction at the sliding interface decreased with an increase in normal load and sliding speed. The mechanisms of wear for both materials were abrasion, delamination, and oxidation at room temperature. At high temperatures, there was a dramatic increase in the wear rate of the alloy at 150 °C, whereas the wear resistance of composites improved up to 150 °C due to the presence of small amounts of hafnium carbide ultra-high temperature ceramic reinforcement. Abrasion, oxidation, delamination, and plastic yield were the primary wear mechanisms at high temperatures.

Investigation on elevated-temperature wear performance and wear failure mechanism of a tungsten-system hot-working die steel

A pin-on-disk high temperature wear tests under 50–150 N and 50, 100 r min−1 at 400 °C–600 °C were performed for a typical tungsten-system hot-working die steel (AISI H21). The results demonstrated that H21 steel presented different wear behavior and wear resistance under various sliding conditions at 400 °C–600 °C. In most cases at 400 °C–500 °C, H21 steel possessed good wear resistance. However, regardless of sliding speed, the wear performance of H21 steel started to deteriorate under 150 N at 500 °C, and totally deteriorated at 600 °C, exhibiting extremely poor wear resistance. A particular wear failure mechanism was found to be brittle-induced wear failure.

Enhancing mechanical properties of Ti(C, N)-based cermets via preparation with (Ti, W)(C, N) multi-component powder

Using the traditional preparation method of TiC+TiN powder mixture or simply the Ti(C, N) solid-solution powder to prepare cermet cannot properly avoid the direct contact between TiC, TiN or Ti(C, N) phase and (CoNi) binder phase with undesirable wettability, which is disadvantageous to the strength and toughness of cermet. Here, we introduced a new routine using the (Ti, W)(C, N) solid-solution powder and studied the resultant phase constitutions, microstructures and properties of the Ti(C, N)-based cermets, where the cermets prepared with TiC + TiN + WC and Ti(C, N) + WC were taken as counterparts. The X-ray diffraction (XRD) results showed that regardless of the powder combination, two phases, i.e. fcc-(Ti, M)(C, N) and fcc-(CoNi), were formed, and the lattice constants of these phases varied in different samples, which is attributed to the specific phase stability (TiN > Ti(C, N) > (Ti, W)(C, N) > TiC) calculated based on the CALPHAD (CALculation of PHAse Diagrams) approach. Transmission electron microscopic (TEM) observations further depicted that besides the already-known core-rim structure, the cermet prepared using (Ti, W)(C, N) uniquely incorporated black-gray rimless grains and black-white-gray rimless grains. Two critical mechanical properties, i.e. hardness (H) and fracture toughness (KIC), were subsequently determined using the Vickers indentation method. It was found that the KIC values of the cermet prepared using (Ti, M)(C, N) were improved by 5.1% ~ 29.2% while maintaining the similar level of H as other cermet samples. The segregation of W and Ti in (Ti, W)(C, N) powders led to the formation of cleavage facets in ceramic grains, which could contribute to the hinderance of crack propagation. Eventually, the high-temperature (750 °C) wear tests were conducted to examine the durability of cermet samples. The cermet prepared using (Ti, M)(C, N) generally exhibited enhanced wear resistance, benefiting from the well-balanced H and KIC as well as the restraint of oxidational wear. Thus, this work suggested that preference should be given to (Ti, W)(C, N) solid-solution powders when fabricating high-performance Ti(C, N)-based cermets.

Microstructure stability and high temperature wear behavior of an austenite aging steel coating by laser cladding

An austenite aging steel coating was prepared by laser cladding on H13 steel in order to overcome the poor thermal stability and high-temperature wear resistance of the latter. The microstructure, element and phase distribution of the austenite aging steel coating were investigated by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), and recrystallization were determined by quasi-in-situ EBSD. High temperature wear tests for the austenite aging steel coating and H13 steel were performed on a high temperature pin-on-disk friction and wear tester, and their wear resistance was comparatively evaluated. The austenite aging steel coating was dominated by γ-Fe as matrix phase, while micrometer-grade NiAl and nano-scale Ni3Ti existed as strengthening phases. These fine particles existing in the grain boundary of the coating could effectively improve the recrystallization resistance and thermal stability, which was confirmed by quasi-in-situ EBSD and thermal stability tests. Owing to such superior thermal stability, oxidative mild wear prevailed for the austenite aging steel coating in most of sliding conditions except for 600 °C and 150 N, where a mild-to-severe wear transition of oxidative wear occurred. In particular, the plastic extrusion wear of H13 steel at 600 °C and 150 N was impeded due to the existence of laser-cladded austenite aging steel coating.

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.

Effect of Si content on the microstructure and properties of Ti–Si–C composite coatings prepared by reactive plasma spraying

In this study, Ti–Si–C composite coatings were synthesized via plasma spraying of agglomerated powders prepared by a spray drying/precursor pyrolysis technology using Ti, Si, and sucrose powders. The influence of Si content, ranging from 0 wt% to 24 wt%, on the microstructure, mechanical properties, and oxidation resistance of the composite coatings was investigated. Results show that the phase composition of the Ti–Si–C composite coatings changes with the increasing Si content. The coatings without Si addition consist of TiC and Ti3O; the coatings with 6–18 wt% Si are composed of TiC, Ti5Si3, and Ti3O; the coatings with Si content of 24 wt% form only TiC and Ti5Si3 phases. As the Si content increases, the hardness of the Ti–Si–C composite coatings increases first and then decreases, depending on the intrinsic hardness of the ceramic phases, the brittleness of Ti5Si3, and the defects such as pores and cracks. The Ti–Si–C composite coatings have high wear resistance due to the in-situ synthesized high-hardness TiC and Ti5Si3. Owing to the high brittleness of Ti5Si3, the increasing Si content leads to higher wear volume loss at room temperature, which can be partially improved in high-temperature wear tests. The oxidation resistance of Ti–Si–C composite coatings increases with the increase of Si content, and the higher the oxidation temperature, the more obvious the influence of the Si addition on oxidation resistance.

Effects of laser power on microstructure and friction–wear performances of direct energy deposited ZrO2–8%Y2O3–NiCoCrAl coatings on Ti6Al4V alloy

To enhance the hardness and wear resistance performance of Ti6Al4V alloy (TA), ZrO2–8%Y2O3 (8YSZ) coatings with NiCoCrAl as bond coat (BC) were fabricated on TA by laser direct energy deposition (LDED). The morphologies, chemical elements, phases and hardness of obtained coatings were systematically analyzed, and the effects of laser power on the friction–wear performances of 8YSZ coatings were investigated using a high temperature wear tester, and the wear mechanism was also discussed in detail. The results show that the dendrite structures of 8YSZ coatings become small and the eutectic areas decrease with the increase of laser power, and the coating hardness is 933–1078 HV0.5 higher than the TA. The average coefficients of friction (COFs) of 8YSZ coatings decrease with the increase of laser power, which are attributed to the enhancement of coating hardness. The wear rates of 8YSZ coatings deposited at the laser power of 1200, 1500 and 1800 W are reduced by 92.58%–98.52% compared with the TA, and the wear mechanism is dominated by abrasive wear, accompanying with tiny adhesive wear.

Double Glow Plasma Nitriding Pretreatment of TiAlN-Coated TA15 Alloy for Enhancement of Bonding Strength and Mechanical Properties

As a classic hard coating, titanium aluminum nitride (TiAlN) coating is widely applied in the aviation field due to its extremely high hardness and strength. Unfortunately, the large difference in hardness and thermal expansion coefficient between the coating and the substrate could also lead to the reduction of bonding force. In this paper, Double-glow plasma nitriding (DGPN) pretreatment followed by RF magnetron sputtering was used to prepare DGPN-TiAlN coating on the surface of TA15 alloy. The adhesion and the bearing capacity of DGPN-TiAlN coating is characterized by scratch and indentation tests. The gradient hardness support and stress transition effect of the nitriding layer are significant, and the bonding strength of TiAlN coating and the substrate are significantly improved. In addition, the high temperature wear resistance and erosion resistance of DGPN-TiAlN coating were detected through high-temperature wear tests and sand erosion tests. At 500 °C, the surface of DGPN-TiAlN coating formes a dense Al2O3 lubricating film with good adhesion, and the friction coefficient is lower than that of TiAlN coating. Under different erosion speeds and erosion angles, the erosion rate of DGPN-TiAlN coating is lower than that of TiAlN coating, and the coating surface defects are less.