Sliding Wear Behavior Research Articles

Microstructure, hardness and wear behavior of ZrC particle reinforced AZ31 surface composites synthesized via friction stir processing

Dry sliding wear behaviour of friction stir processed (FSP) AZ31 and AZ31/ZrC particles (5, 10, and 15 vol%) reinforced surface composite was investigated at different sliding speeds and loads. The samples were tested using a pin-on-disc apparatus with EN31 steel as the counter body to determine the role of FSP and ZrC reinforcement on the microstructure, hardness, and wear behaviour of AZ31. Base metal AZ31 alloy exhibits a hardness of 60 HV, whereas the 15 vol% ZrC-reinforced composites had the highest hardness of 108 HV. It was also identified that 15 vol% ZrC-reinforced composites exhibited lowest wear rate and friction coefficient under all testing conditions. Abrasion, delamination, oxidation, material softening, and plastic deformation are the primary wear mechanisms viewed from the wear tracks of the samples. Higher volume fraction of ZrC particles exhibited better wear resistance at all speeds and loads than AZ31 alloy. A wear map has been generated for different material compositions and wear conditions to identify the main wear mechanisms easily.

Significant reduction in friction and wear of an ultrafine-grained single-phase FeCoNi alloy through the formation of nanolaminated structure

Reducing friction and wear has long posed a challenge for metallic components under dry sliding conditions. This study unveils a significant reduction in friction and wear of a single-phase ultrafine-grained FeCoNi multi-principal element alloy (MPEA). Through a comparative analysis of the sliding wear behaviors of single-phase ultrafine-grained CoCrFeMnNi and FeCoNi alloys with different stacking fault energies and detailed microstructure characterization, we found that despite having a similar initial microstructure and even a 20% lower hardness, the FeCoNi alloy exhibited a remarkable 52% reduction in coefficient of friction, and more notably, a wear rate three orders of magnitude lower than that of CoCrFeMnNi. The significantly reduced friction and wear can be attributed to the remarkable disparities in wear-induced surface microstructures between the two alloys during repetitive sliding. The sliding wear of FeCoNi alloy triggers the formation of a nanolaminated structure with excellent strain-hardening capacity and substantial deformation plasticity, as evidenced by micropillar compression tests. Conversely, the twinning-active CoCrFeMnNi alloy induces the formation of an equiaxed nanograin layer which exhibits a high compressive strength but catastrophic failure behavior after the onset of yielding, and thus deteriorates the wear resistance. The findings provide significant insights into fundamental understanding of the plastic deformation of single-phase MPEAs during wear and guide the design of wear-resistant alloys.

High-temperature tribological properties of Co-29Cr-6Mo alloy fabricated by selective laser melting process

This paper discusses the experimental procedure and results of an investigation into the sliding wear behavior of Co-Cr-Mo specimens produced by selective laser melting (SLM) process. The sliding wear tests were carried out with different normal loads, sliding frequencies, and temperatures. The results showed that the coefficient of friction decreased as the applied normal load increased due to the temperature effect. The wear rate increased significantly at higher loads due to increased surface stresses. Testing the specimens at elevated temperatures resulted in a decrease in COF due to thermal softening and the formation of an oxide layer on the surface. The wear rate increased for specimens tested at 200°C due to a decrease in hardness and strength, but the wear rate decreased at higher temperatures due to the protective effect of the oxide layer. The obtained results showed the SLM-printed Co-Cr-Mo alloy exhibited good mechanical properties and wear resistance, making it a promising material for tribological applications, especially at elevated temperatures.

Evaluation of dry sliding wear behavior of thermally sprayed and microwave post-processed TiO2 reinforced tungsten carbide composite coating

Evaluation of dry sliding wear behavior of thermally sprayed and microwave post-processed TiO2 reinforced tungsten carbide composite coating

Effect of the Si Content on the Dry and Wet Sliding Wear Behavior of the Developed Ti-15Mo-(0-2) Si Alloys for Biomedical Applications

The durability of a metallic biomaterial to withstand weight loss is a key factor in determining its service life and performance. Therefore, it is essential to create biomaterials with high wear resistance to ensure the biomaterial has a long service life. Thus, this study aims to explore the dry and wet sliding wear characteristics of the developed Ti-15Mo-xSi as-cast alloys (where x equals 0, 0.5, 1, 1.5, and 2 wt.%) in order to assess the impact of the Si addition on the microstructure, mechanical properties, and wear resistance and to consider them for biomedical applications. The wear experiments were conducted using a pin-on-desk wear testing machine at a load of 20 N and a sliding distance of 1000 m with and without applying simulated body fluid (SBF). Different techniques were utilized in the evaluation of the developed Ti-15Mo-xSi alloys. The results showed that significant grain refining was attained with the Si addition. The hardness, compressive strength, and wear resistance of the Ti-15Mo-xSi as-cast alloys increased with the increase in Si content. The Ti-15Mo-2Si as-cast alloy exhibited the highest dry and wet wear resistance of all the Ti-15Mo-xSi alloys. The worn surfaces were investigated, the roughness and main features were reported, and the wear mechanisms were also discussed.

Enhancing the tribological performance of PLA-based biocomposites reinforced with graphene oxide

Poly(lactic acid) (PLA) reinforced with graphene has gained substantial interest as a biomaterial, where the tribological and mechanical behavior of PLA/graphene composites are major concerns. This study aims to develop PLA-based biocomposites reinforced with graphene oxide (GO) that have enhanced tribological capabilities. First, homogenous dispersions of GO and GO treated with the anionic surfactant dioctyl sulfosuccinate sodium salt (AOT) were retained. Then, poly(L-lactic acid) (PLLA) biopolymer and PLLA/GO, PLLA/GO(AOT), PLA/GO(AOT), and PLLA/polyethylene glycol (PEG)/GO biocomposite samples were produced via hot pressing, and their tribological behavior was examined in detail. The worn surface characteristics were examined using scanning electron microscopy (SEM), 3D confocal microscopy, and atomic force microscopy (AFM). Results showed that GO reinforcement considerably affected the sliding wear behavior of PLA. Contrary to anticipated, surface treatment of GO does not improve the PLLA/GO wear resistance; rather, it increases the wear rate. PEG positively affects the sliding wear performance of PLLA/GO. PLLA/GO and PLLA/PEG/GO biocomposites exhibited the lowest wear rate at normal loads of 5 and 8 N, respectively, which was decreased by about 50% compared to unreinforced PLLA samples. With the addition of GO, the wear mechanisms of the PLA-based biocomposites changed from adhesive wear to abrasive wear. These findings might increase the applicability of PLA-based biocomposites where tribological performance is the main concern, such as biodegradable implants for load-bearing bone fractures or scaffolds, opening up new opportunities for their use.

Influence of Surface Finish on the Dry Sliding Wear and Electrochemical Corrosion Behaviour of 316L Stainless Steel

316L stainless steel is known for its high corrosion resistance and extensively being used for biomedical implants and for the fabrication of the parts in nuclear reactors, and fuel cells. In the current study, 316L stainless steel samples were grounded using different grades of surface grits (400, 1200, and mirror-finished) by mechanical polishing, and influence of surface finish on the wear and corrosion characteristics was studied. The dry sliding wear experiments were carried out on ball-on-plate setup against hardened steel ball and the corresponding friction curves were obtained and specific wear rates were measured. The wear mechanisms were identified by examining the worn-out surface using scanning electron microscope and Raman spectrometer. It was evident that the formation and removal of iron oxides is the dominant mechanism for material loss from the samples during wear tests. The higher wear resistance of the mirror-finished sample was attributed to the formation of stable chromium oxide layer on the wear track. Potentiodynamic polarization tests were performed on the samples and better corrosion resistance was observed for the mirror-finished sample.

Steady state analysis on sliding wear behavior of waste marble dust filled kenaf‐polyester composites

AbstractIn view of the rising demand of natural fiber reinforced polymers in engineering applications, the current research is taken on to study the effects of particulate filling in polyester‐kenaf fiber composite in terms of its sliding wear performance. A set of polyester‐based hybrid composites are fabricated with fixed kenaf fiber content and varied quantities of waste marble dust (0 wt. %, 16 wt. % and 32 wt. %). These composites are subjected to dry‐sliding wear trials as per ASTM G‐99 05 under different test conditions and the specific wear rate are estimated. The test results are analyzed to obtain the parametric appraisal of the wear process using response surface method. The analysis reveals that the filler content followed by sliding velocity, normal load and sliding distance has the detrimental impact on the specific wear rate of such hybrid composites. A morphological study is performed using a scanning electron microscope to identify prominent wear mechanisms and it is found that the wear loss is primarily due to the formation of wear tracks, cracks, craters, plastic deformation, wear debris and the removal of matrix layer etc. during the sliding process.

Prediction of tribological performance of Cu-Gr-TiC composites based on response surface methodology and worn surface analysis

In the current study, the prediction of tribological performance of Cu-Gr-TiC composites and its correlation with surface topography has been studied. For this purpose, the Cu-Gr composites reinforced with TiC ceramic particles were prepared via the powder metallurgy route. The prepared composites microstructure, mechanical characteristics, and dry sliding wear behaviour were assessed. A pin on disc setup was taken for tribological testing where sliding velocity is 1.5 m s−1. Wear behaviour of composites was examined using a central composite design (CCD) with three levels. The wear behavior optimization was accomplished through the utilization of response surface methodology (RSM). The input parameters in RSM consisted of sliding distance, varying load, and weight percentage (wt%) of reinforcements, while the wear rate and coefficient of friction served as the two responses. An analysis of variance (ANOVA) using RSM was conducted to identify the significant parameters influencing the wear rate and coefficient of friction. A quadratic model was suggested based on best fit and a regression equation was established for predicting the tribological properties at any given input parameter. Comparative of experimental and predicted values show close tolerance. It was observed that RSM is significant tool for predicting and optimizing the tribological properties. The composite having 3.08 wt% of TiC particles was optimized for minimum wear rate & COF at 20 N load and 2000 m sliding distance.

Effect of Caesalpinia decapetala on the Dry Sliding Wear Behavior of Epoxy Composites

The present research investigates the wear characteristics of an epoxy composite reinforced with a novel Caesalpinia decapetala (CD) shell. The CD is available abundantly worldwide, especially in Ethiopia, particularly in East and West Oromia near West Harar. The composite specimens were processed in the open mould casting technique by varying the vol.% of CD in 10, 20, and 30. EDS is used to evaluate the important elements present in the CD. The density of composites increases with the increase in the content of CD, while the void content estimations reveal good control over the composite fabrication. The wear response of composites is investigated by varying the sliding distance and load and by maintaining a fixed velocity (5 m/s). At a 5 km slide distance and 50 N load, the 30 vol.% Caesalpinia decapetala composition depicts better wear resistance and friction coefficient than other compositions. Experimental results are used to envisage the ideal wear factors and to assess the influence of parameters over the two wear objectives, wear rate and CoF. The grey relational analysis- (GRA-) coupled artificial neural network (ANN) hybrid technique was employed for the prediction and validation. It has been observed that a trivial error of 0.49% amidst GRA and ANN estimation is observed.

Investigation on the effect of SiC and TiB2 ceramic particles on mechanical and tribological properties of Al7075 hybrid metal matrix composites prepared through conventional stir casting technique

Materials with lightweight construction, high strength and wear resistance are preferred in the automotive sector and aluminium is found to be a natural choice for the manufacturers. In this work, Al7075 hybrid metal matrix composites enhanced with SiC (6% weight fraction) and TiB2 (2%–6% weight fraction) particles were fabricated by stir casting technique. The characterisation of internal structure of the developed composites was done by subjecting them to scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). It was found that the reinforced particles were uniformly distributed in the aluminium matrix alloy, and only a few clusters were found in the matrix alloyed with 6% TiB2. The tensile strength, hardness and flexural strength of the hybrid composites increased with increase in the weight percentage of reinforcements and attained a maximum of 233.34 MPa, 220 Hv and 458 MPa, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. The elongation percentage and the impact strength of the hybrid composites start to decrease with an increase in reinforcement percentage and attained a minimum of 6.74% and 1.2 J, respectively, when reinforced with a maximum of 6% SiC and 6% TiB2. By adjusting the input parameters such as load, sliding speed, and sliding distance, the sliding wear behaviour of the hybrid metal matrix composites was explored. It was discovered that the wear rates and coefficient of friction of the hybrid composites decreased with an increase in reinforcement percent. As a result of exhibiting superior mechanical and tribological capabilities, the results show that Al7075 with 6 wt.% SiC and 6 wt.% TiB2 hybrid composite performs the best over all other hybrid composites.

Sliding friction behaviors of TiCN/Cr3C2-NiCr and TiCN/WC-CoCr duplex coatings fabricated by combining HVOF and HT-CVD procedures

Hard films play essential roles in the wear protection of metal moving components. In this study, the TiCN/Cr3C2-NiCr and TiCN/WC-CoCr duplex coatings were designed and fabricated by utilizing the high-velocity oxygen fuel and the high-temperature chemical vapor deposition processes. The effects of two cermet interlayers on the microstructure, mechanical characteristics, stress distribution, and sliding wear behavior of the top TiCN films were thoroughly explored. Results evidenced that the TiCN/WC-CoCr duplex coating had a smoother surface than the TiCN/Cr3C2-NiCr duplex coating. The load-bearing capacity and fracture toughness of TiCN/WC-CoCr duplex coating were superior to TiCN/Cr3C2-NiCr duplex coating due to WC-CoCr coating possessing higher hardness, elastic modulus and high-temperature stability. The TiCN/WC-CoCr duplex coating also exhibited lower Von Mises stress compared to TiCN/Cr3C2-NiCr duplex coating, and the stress concentration zone was further away from the interface between the TiCN film and the cermet interlayer. The wear resistance of TiCN/WC-CoCr duplex coating was approximately 2 and 1.5 times that of the single TiCN film and TiCN/Cr3C2-NiCr duplex coating under 20 N load. Moreover, the wear mechanisms of the duplex coatings involved abrasive wear, adhesive wear and oxidative wear. This work significantly enhanced the wear resistance of TiCN films, which will broaden the application of TiCN film in non-load-bearing metal moving components.

Tribological Behavior of Cast Aluminum Matrix Composites After Multiple Remelting

One of the limiting factors for expanding the applications of aluminum alloy castings in many high-tech industries is the insufficient level of tribological properties, especially under conditions of dry and abrasive wear. Reinforcing of aluminum alloys with hard ceramic particles, i.e., transition to aluminum matrix composites, allows significantly increasing their resistance against dry sliding friction, scuffing, and seizure in wide temperature and force intervals of operation. Among the numerous problems related to the industrial implementation of cast aluminum matrix composites, the problem of their recycling takes the important place. This work is aimed at establishing the influence of metallurgical processes during remelting on the change in tribological properties of cast Al-Si-B4C aluminum matrix composites. For this purpose, tribological tests in conditions of dry friction according to the ball-on-disc scheme were used. Reinforcing of an AlSi12 matrix alloy with B4C particles leads to a decrease in the composite friction coefficient and the mass wear in the as-cast state in comparison with an unreinforced matrix alloy. During remelting, the tribological properties of the aluminum matrix composites do not deteriorate. Repeated remelting leads to the improvement in particle distribution uniformity, formation of the Al3BC phase at the matrix/particle interfaces, fragmentation of reinforcing B4C particles due to cyclic thermal loads as well as an increase in the porosity fraction. The changes in the structural-phase composition during remelting have a direct influence on the level of tribological properties. Typical effects associated with dry friction, such as plastic deformation of the matrix material and the formation of areas of adhesion-cohesive fracture, indicative of scuffing, were revealed by SEM analysis of the wear tracks of an unreinforced matrix alloy. For the composite material, these effects manifested to a much lesser extent. A qualitatively similar sliding wear behavior was observed for all composite samples, regardless of the remelting iteration. The study suggests that the formation of a transitional tribolayer may occur during dry sliding friction of aluminum matrix composites, which can reduce the friction coefficient.

Investigation on the characterization of hot extruded AA7075 based metal matrix composites developed by powder metallurgy

Higher compressive stress and greater density after extrusion contribute to stronger bonds, which in turn improves mechanical and tribological properties were analyzed. In order to minimize manufacturing defects, a cosine-profiled die with mathematically precise contours was used in the thermo mechanical process. It was requested that more mechanical characterization tests, such as a compression testing and a three-point bending test, be directed to better define the material’s density, hardness, and ductility. Before and after extrusion, the prepared AMCs were put through pin-on-disc (POD) wear testing, during which the RPM of the counter disc, load (N) and track diameter (mm) were varied to simulate different two-body dry sliding wear behaviors. Hot extrusion of AA7075 aluminium matrix composites (AMCs) was investigated for its effect on the materials’ mechanical and tribological properties. These AMCs were manufactured by controlled atmospheric sintering, powder metallurgy and double axial cold compaction. The finely dispersed graphite (Gr) particles shear off at the tribo-surface, creating a solid lubricant that slows the rate of wear. The wear mechanism was found to be more complex when the loading and sliding velocities were increased.

Insights into the microstructural evolution and wear behavior of underwater friction stir processed CoCrFeNiMn high-entropy alloy

The equiatomic CoCrFeNiMn high-entropy alloy (HEA) has demonstrated excellent strength-ductility-toughness synergy over a wide range of temperatures, especially at cryogenic temperatures, but poor wear resistance. Herein, we explored the feasibility of constructing ultrafine-grained (UFG) surface layer on the CoCrFeNiMn HEA by underwater friction stir processing (FSP) and evaluated its dry sliding wear behavior. During air-FSP of CoCrFeNiMn HEA, continuous and discontinuous dynamic recrystallization (CDRX and DDRX) compete with each other responsible for grain refinement. Water-FSP promotes the occurrence of DDRX and inhibits the growth of recrystallized grains, leading to the formation of an UFG surface layer with average grain size of 1.14 ± 0.78 μm. The surface hardness of base material is about 179 HV, which is increased to 216 HV for the air-FSPed sample and 275 HV for the water-FSPed sample. Nonetheless, the three samples exhibit similar wear behavior, mainly adhesive wear and oxidation wear. This is mainly attributed to a combination of the formation of oxides on the worn surfaces during sliding and the significantly reduced strain-hardening effect with decreasing grain size. This work provides a fundamental understanding of the microstructural evolution of CoCrFeNiMn HEA during FSP as well as its sliding wear behavior before and after FSP.

Neural Network Approach on Influence of Ceramics on Dry Sliding Wear in Al-Cu-Zr Metal Matrix Composite

This research aims to investigate the dry sliding wear behavior of Al-Cu-Zr (ACZ) metal matrix composite (MMC) at various Aluminium oxide (AOX) Nano particles compostion. ACZ alloy is widely used in on road and space mobility applications where the focus is on wear resistance. To enhance the resistance towards wear, Al alloy is reinforced with AOX nanoparticles at 3%, 6%, and 9% addition using stir casting process. The wear assessment is conducted at varying Composition (COMP), load (LD), speed (Ns), and sliding distance (SLDN). The wear rate (WRT) and Frictional force (FRFC) are analysed for different process parameters. To optimize the experiments, Taguchi signal-to-noise ratio (STNR) is used. Taguchi analysis show that the optimal conditions for minimum WRT and FRFC are at 6% AOX addition, 12.5 N load, 500 rpm speed, and 35 mm SLDN. Furthermore, an artificial neural network model (ANNM) is developed to forecast the WRT and FRFC. The neural network model is trained using the experimental data and the optimized process parameters. The neural network is a powerful tool that can learn the complex relationship between input and output variables. The model is validated using the experimental data, and the results show that the neural network model can predict the WRT and coefficient of friction with high accuracy. The Taguchi optimization and neural network model can provide a systematic approach to optimizing the process parameters and predicting the WRT and coefficient of friction. This approach can be applied to other materials and processes to improve their performance and reduce costs.

Analyses of the sliding wear behavior of NiTi shape memory alloys fabricated by laser powder bed fusion based on orthogonal experiments

Laser powder bed fusion of NiTi (LPBF-NiTi) alloys is gaining increasing attention and applications because of its flexible design for complex structures with excellent superelasticity and shape memory effects. Their wear behavior has a strong influence on the serviceability and safety, but the effects of their usage condition on the wear behavior are not clarified clearly. In the present work, the wear resistance of LPBF-NiTi (55.4 wt%Ni) alloys against 100Cr6 steel on a ball-on-slab tribometer and its response to sliding speed, normal load and sliding time were studied through orthogonal experiments. The results confirm that the wear rate of LPBF-NiTi alloys ranges from 1.1–2.5 × 10−3 mm3/m, which is comparable to that of NiTi alloys fabricated by conventional methods. In addition, the sliding speed has the largest influence with a range of 5.1 × 10−5 mm3/Nm, followed by normal load with a range of 4.2 × 10−5 mm3/Nm. The effect of the interaction between the normal load and sliding speed is significantly greater than the effect of the sliding time. Finally, the wear mechanism of the worn surface and microstructure of the subsurface under the wear track were discussed in detail. The dominant wear modes are adhesion, abrasion and delamination.

Fractural analysis, microstructural, mechanical and tribological behaviour of vanadium trioxide-reinforced copper metal matrix composite by ultrasonic-assisted stir casting technique

In this work, pure copper is reinforced with vanadium trioxide (V2O3) at various weight percentages, such as Cu–0.5V2O3, Cu–1V2O3, Cu–1.5V2O3, and Cu–2V2O3. This copper metal matrix composite (CMMC) with primary copper element and secondary V2O3 is fabricated through an ultrasonic-assisted stir casting technique. The uniform distribution of secondary particles is achieved using ultrasonic waves generated by the probe and mechanical stirrer. The characterization of developed CMMC is done by X-ray diffraction and energy-dispersive X-ray spectroscopy. The samples are subjected to grain measurement using an optical microscope, which showed the relationship between grain size and enhancement of mechanical properties. The fabricated samples are also subjected to mechanical testing to determine their tensile strength, ultimate strength, Vickers hardness and impact strength. Fractography is also done by using a scanning electron microscope to understand the mechanism for the failure of tensile specimens. Dry sliding wear behaviour is also carried out to determine the wear resistance of CMMC. The results of numerous experiments showed that the grain size of CMMC improved with V2O3 addition. The increased strength-to-weight ratio leads to obtaining better properties at low cost. The enhancement in wear behaviour and mechanical properties of CMMC also paves the way for a newly developed material with V2O3 as secondary reinforcement along with copper as the primary element to be used in various applications.

Sliding wear behaviour of austempered ductile iron, boron steel and AISI 1045 steel of similar hardness: effect of microstructure, yield strength, and strain hardening

ABSTRACT A study on dry sliding wear investigated four alloys: fully austenitized ADI (F-ADI), intercritically austenitized austempered ductile iron (I-ADI), hardened and tempered Boron steel (B-Steel), and hardened and tempered AISI 1045 steel (EN-Steel). Despite their similar hardness levels, these alloys differ in composition and microstructure. Testing was conducted using a Ball-On-Disc setup (ASTM G99-05) with a chrome steel ball, maintaining a constant sliding speed of 0.6 m/s and applying loads between 20 and 80 N. This study aimed to understand the influence of yield strength (σy ), strain hardening coefficient (n), and microstructure on sliding wear under uniform hardness conditions. The findings indicated a strong connection between sliding wear resistance, strain hardening coefficient, toughness, and yield strength. Wear mechanisms varied slightly among materials; F-ADI and I-ADI exhibited deformed layers with increased hardness and oxide formation, while B-Steel and EN-Steel showed micro-cutting and micro-ploughing. F-ADI's high-carbon austenite film and I-ADI's proeutectoid ferrite contributed to improved wear performance. The hardness of the deformation layer on FADI and I-ADI's worn surfaces highlighted the benefits of strain hardening in dry sliding wear.

Sliding wear behaviour of conventional and cryotreated PM Cr-V (Vanadis 6) ledeburitic tool steel

Cryogenic treatment is a widely accepted method for extending the tool life of tool steels. This study focuses on investigating the tribological properties of PM Cr-V cold work tool steel subjected to conventional and cryogenic treatments. The aim of the study is to compare the reciprocal sliding wear performance of Cr-V cold work tool steel under different treatment conditions. The Cr-V tool steel specimens were cryotreated at temperatures of −75 °C, −140 °C, or −196 °C, followed by double tempering at 170 °C or 530 °C for 2 h. Cryotreated specimens exhibited a 10% increase in hardness compared to conventionally treated specimens after tempering at 170 °C. However, specimens cryotreated and tempered at 530 °C showed a 7% drop in hardness. Reciprocating sliding wear tests were conducted at room temperature using an Al2O3 ball as the counter-body to simulate abrasive wear. The results indicate that the friction coefficient is primarily influenced by the applied load and sliding velocity rather than the material treatment. Cryogenic treatment at 170 °C improved the wear performance by approximately 24% compared to conventionally treated specimens, while cryotreated specimens tempered at 530 °C did not exhibit any improvement in wear performance compared to conventionally treated specimens.