Sliding Wear Tests Research Articles

The Technological Factors and Operating Conditions Influence on the Molybdenum Disulfide Coatings Tribological Properties

Molybdenum disulfide is a widely used solid lubricant operates successfully under extreme conditions such as vacuum, high or low temperatures, high loads etc. Magnetron sputtering is one of the most common method of application MoS2 coatings. It allows one to apply thin antifrictional films with high rate of purity on different substrates. The surface before application is usually prepared by abrasive processing. The aim of the work is to evaluate the magnetron deposition modes, substrate surface preparation, substrate roughness on the molybdenum disulfide coatings tribological properties. For the purpose mentioned a linearly reciprocating Ball-on-Flat (ASTM G133) Sliding Wear tests in vacuum (pressure less than 10-4 mbar) and high temperature (250 ¬¬¬0C) were conducted. The two different materials as a coating substrate was used (stainless steel and brass). The substrate surface was sandblasted. The coating surfaces structure after wear and chemical composition have been studied. The friction coefficient in vacuum at 250 °C was about 0.02–0.05. The least value was observed for the AISI 316L steel substrate treated by sandpaper and Ra 0.10 µm roughness coatings. The negative bias voltage (–20 V) during magnetron deposition leads to 16–42% lower coefficient of friction. Oxygen decreases the anti-friction properties.

Experimental optimization of tribological properties of aluminum bronze alloys made by the forging method

Aluminum bronze alloys produced by various methods are preferred materials in many fields of the industry due to their high wear resistance and good sliding properties. This study investigated the tribological properties of aluminum bronze alloys produced by forging from Cu, Al, Fe, and Mg elements. Dry sliding wear tests were carried out on a pin-on-disc wear device. Three tribological properties, wear, friction coefficient, and temperature of aluminum bronze alloys were investigated. Experimental studies were carried out for different loads, sliding speeds, and sliding ways. The factorial experiment design method was applied in the MINITprogram. A SEM visualized the samples microstructures to examine the material wear characteristics. As a result of the study, it was deter-mined that the applied load, sliding speed, and sliding way were effective parameters on the amount of wear and friction coefficient. The maximum amount of wear was 0.352 mg at 100 N load, 3 m/s sliding speed, and 3000 m sliding way conditions. The maximum temperature between materials under these conditions is 299 oC. The minimum amount of wear was obtained when 25 N load, 1 m/s sliding speed, and 1000 m sliding way were applied.

Engineering Design Process in Developing a Pin-on-Disk Apparatus to Perform Dry or Lubricated Sliding Wear Test

Engineering Design Process in Developing a Pin-on-Disk Apparatus to Perform Dry or Lubricated Sliding Wear Test

Erosion and wear analysis of fly ash filled GFRP composite

The present work involves the solid particle erosion behaviour and the dry sliding wear characteristics of glass fiber reinforced polymer (GFRP) matrix composite using fly ash as filler material is investigated. Five different composite samples (with 0, 5, 10, 15 and 20 wt.% of filler) are fabricated using the traditional hand lay-up method and characterized for their density and hardness properties. Subsequently, the erosion and wear behaviour of the presently prepared composite samples are investigated on air erosion tester and pin-on-disc tribometer, respectively. For the erosion test experiments are performed according to a full-factorial design of experiment (DOE) by considering the hardness of the composite and the impingement angle as the controllable parameters. For conducting the dry sliding wear test, the type of composite, load and speed are taken as input parameters and the experiment is carried out as per Box-Behnken DOE of Response Surface Methodology (RSM). The composite with 15 wt.% of filler depicted the highest hardness value. The wt.% of filler is found to have a significant effect on the erosion and wear behaviour with moderate filler (10 wt.%) providing the optimum result in both cases.

Synthesis and wear properties of near eutectic Al-Si-TiB2/Al2O3 hybrid composites

In metal matrix composites a metal/alloy is often combined with non-metallic/inter-metallic phases to produce a novel material possessing attractive engineering attributes of its own. AMCs or Aluminium matrix composites refer to the group of light weight, high performance, aluminium based material systems which are employed to meet the demand of automotive and aerospace sectors. The present study emphasises on casting of Al–11.8 wt% Si metal-matrix composites with the help of an exothermic reaction among the melt and halide salts (K2TiF6 and KBF4) to incorporate 2 and 3 wt% TiB2 in the base alloy matrix. Al2O3 particles (0.5, 1 and 2 wt%) were also mixed with these in-situ prepared composites to produce hybrid composites which were characterized using optical microscopy. Optical Emission Spectroscopy revealed some amount of silicon loss during casting. XRD analysis indicated the presence of Al2O3 and TiB2 in the cast composites. Hardness, density and dry sliding wear tests were carried out and analysed. The results of the present investigation revealed that the wear rate of the composites decreases when there is an increase in the TiB2 content but this behaviour is limited to 1 wt% reinforcement in case of Al2O3. Increasing load promoted wear rate. At higher sliding distances wear rate decreased though wear volume was more. Density values of the composites were found to increase with increasing amounts of reinforcements. Increasing Al2O3 up to 1 wt%, the hardness of the composites was found to increase. Further increase in Al2O3 to 2 wt% revealed lower hardness values of the composites due to agglomeration of the particles.

Investigations on wear behaviour of Al 6061-GNP metal matrix composites by using Taguchi L<SUB align="right">16 approach

High strength Al 6061 metal matrix composites with graphene in different weight percentages were fabricated through stir-casting followed by equal channel angular pressing. Dry sliding wear tests were conducted as per Taguchi-based L16 orthogonal array with control factors such as: 1) reinforcement (wt. %); 2) load (N); 3) sliding speed (m/sec); 4) sliding distance (m). Wear rate and coefficient of friction (COF) was the response characteristics studied. Subsequently, analysis of variance (ANOVA) was applied to evaluate the significance of each control factor on the response characteristics. Reinforcement and load were identified as the highly influencing significant parameters on the wear rate and COF using ANOVA analysis. Furthermore, a confirmation test was also performed to verify the experimental results. Analysis of SEM of the worn surface reveals that abrasive and oxidation were the dominant wear mechanisms during the tribo-test of Al 6061-graphene composites.

Tribological Behaviour of Aluminium 6061 Reinforced with Graphite and Chicken Bone Ash by using Stir Casting

Blending or supplementing metals with cutting-edge Metal Matrix Composites (MMCs) endeavours to improve the safety, reliability weight and productivity. A hybrid MMC was produced for the chamber liner of cutting-edge diesel motors. Dry sliding wear testing equipment, employing a pin-on-disc wear tester, is used to examine the wear properties of casted hybrid metal matrix composites. The examination shows that the wear opposition of Al-6061 is expanded while adding the chicken bone ash and graphite as support content. Within the current work, effort has been made to survey the tribological properties of aluminium as-projected combination test for Al amalgam and unadulterated aluminium. The operational boundaries were a typical load and sliding velocity of the pin concerning rotating disk at temperature. The medium utilized was dry and wet greasing. The amount of mileage has been decreased altogether in aluminium alloy similar to unadulterated aluminium. Dry condition testing showed huge loads of noise and a similarly more measure of mileage for both aluminium and aluminium alloy. The coefficient of contact for aluminium alloy in wet conditions was roughly steady up to the applied load and then diminished with additional utilization of load while the coefficient of friction for unadulterated aluminium was rising persistently with the load. Evaluation of the corrosion conduct of the aluminium MMC is achieved by the usage of the salt spray method or immersion test and the results are considered.

Influence of oxides on the formation of self-lubricating layer and anti-wear performance during sliding

Oxides are the key roles on the formation of self-lubricating layer (SLL) with anti-wear performance. In present study, dry sliding wear tests of 00Cr13Ni4Mo steel were performed to investigate the influence of oxides on SLL. The formation of SLL with different oxides was comparatively analyzed by the cross-sectional and surface morphologies. Mechanism of oxides on the integrity of SLL and anti-wear performance is discussed. It is confirmed that Cr-oxide, Fe3O4 and suitable SiO2 are the key to endow SLL with good self-lubricating performance while FeO, Fe2O3 and excessive SiO2 are opposite, good integrity of SLL is the prerequisite for anti-wear.

Hardness and Dry Sliding Wear Characterization of Functionally Graded Materials Employing Centrifugal

In this work, functionally graded materials were synthesized by centrifugal technique at different volume fractions (0, 0.5, 1, 1.5, and 2% Vf) with different rotational speed of (0, 600, 800, 1000 and 1200) r.p.m and different rotational time (0, 1, 2, 3 and 4) min. The hardness and tribological properties were characterized to study the graded and non-graded nanocomposites and the pure epoxy material. Using a pin-on-disc machine, sliding wear tests are conducted with the following parameters: rotation speed (400 rpm), normal load (30 N), filler content (0–2% Vf), and sliding distance (0.15 km). The hardness and wear parameters of graded composites were investigated and compared to those of epoxy composites with homogeneous filling. This work demonstrates that incorporating Al2O3 nanoparticles improves graded composites' hardness and sliding wear resistance. Epoxy–Al2O3 epoxy composites with a volume fraction of 2 had the lowest specific wear rate of all samples. The FGMs had superior sliding wear performance compared to homogenous composites. The maximum difference in hardness and coefficient of friction occurred at (FGM), which is loaded from the rich side of the nanoalumina at (Vf = 2%, N = 1200 r.p.m and T = 6 min), where the maximum value was 168% and 78 % as compared with neat epoxy, respectively. The wear rate of the functionally graded samples was enhanced by (87.7%) compared with neat epoxy if loaded from the alumina-rich side.

Wear behavior of materials for additive manufacturing after simulated occlusion of deciduous dentition

ObjectivesTo evaluate wear characteristics of materials for additive manufacturing (AM) after a simulated occlusal test in primary teeth. Wear was simulated by means of impacting - sliding wear testing (ISWT) between specimens prepared from materials for AM against enamel derived from deciduous teeth. MethodsThe prepared hemispherical upper specimens were subjected to impacting-sliding wear test (ISWT) machine against the flattened enamel of deciduous molars on lower specimens. The samples were subjected to 20,000 load cycles using a contact force of 30 N between the opposing surfaces under controlled conditions. In the upper specimens, five groups (n=9): four types of additively manufactured materials Dima, Zenith, Detax, Veltz and a deciduous enamel groups were tested in this study. The enamel-to-enamel group was used as the control. Wear characteristics comprised wear surface area, wear depth, wear volumetric loss, and surface roughness were measured with a confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Data obtained were statistically analyzed by Kruskal-Wallis test and Dunn’s test with Bonferroni correction (p < 0.05). ResultsDima showed significantly higher worn surface area (p = 0.009, 0.001, and < 0.001 for Zenith, Detax, and control enamel, respectively), volumetric loss (p = 0.027, 0.007, and < 0.001 for Zenith, Detax, and control enamel, respectively), and damaged opposing enamel (p = 0.002, 0.001, and 0.01 for Detax, Veltz, and control enamel, respectively). There was no significant difference among the volumetric loss in Zenith and Detax. However, SEM revealed that Zenith showed rough worn surfaces and chipping, Detax showed rather a smooth circular worn surface. The worn area of Veltz was smaller than Detax and Zenith at 5,000 cycles, but higher at 15,000 and 20,000 cycles, and SEM showed detachment. ConclusionWear behavior was different among different materials for AM. In the upper specimens, DM and VZ showed large wear. In the lower specimens, DM caused largest enamel wear and damage. In contrast, ZT and DX showed lower wear and caused less damage to the antagonistic primary enamel. SEM image of ZT showed large losses due to chipping, whereas DX showed the rather smooth. DX was confirmed to have lowest wear and caused least damage to the opposing deciduous enamel, which might be applicable as restorative treatments in deciduous dentition. SignificanceAdditive manufactured dental materials could be considered as a treatment modality in deciduous teeth.

Evaluation of in-situ synthesised titania-zirconia-boron carbide composite cladding on Ti6Al4V substrate using continuous wave fibre laser

In this work, titanium metal matrix composite (TiC, TiB2, TiO2, ZrB2) cladding was synthesised by irradiating a fibre laser beam on a mixture of Ti6Al4V alloy, ZrO2, B4C powders pre-placed on Ti6Al4V alloy plate. The effect of varying wt.% of B4C on the microstructure, hardness, erosion, and wear properties of the composite cladding were investigated using XRD, XPS, EBSD, FESEM with EDAX, nano-indentation, and wear tests. Under the exposure of fibre laser on a mixture of preplaced powders, the in-situ formation of TiC, TiB2, TiO2, and ZrB2 ceramic particles have taken place and get uniformly dispersed in the molten titanium alloy matrix. The volume fraction of these phases increases with the increasing percentage of B4C. A black willow-shaped structure (TiB2) is observed in sample BM3 (30 wt% of B4C), along with grey cellular dendrites (TiC) dispersed uniformly in the matrix. The average microhardness of the claddings increases with the increase of B4C contents. The average weight loss of the cladding samples in dry sliding wear tests decreases with increasing the B4C content. The maximum microhardness of 1582.4HV300 is recorded in BM3 cladding, which is almost four times higher than the substrate material. The decrease in the average value of maximum nano-indentation depth with an increase in the content of B4C is in good agreement with the results of microhardness tests. The hardening of the cladding is also accompanied by increased values of parameters H/E (hardness(H)/Young's modulus (E)) and H3/E2(0.133), indicating better resistance to crack formation during indentation even at higher loads showing the cladding is hard as well as tough. The grain size variation and volume fraction of TiC–TiB2 obtained from electron backscatter diffraction test results agrees with cladding having these properties. The coefficient of friction (0.15–0.25) is found to be lower than the substrate material (∼0.3). The claddings also show good erosion resistance at ambient, 250 °C, 350 °C and 750 °C.

Effect of nano-Y2O3 on the microstructure and wear behaviour of TIG cladded TiC-Co-nY2O3 coating

To improve the mechanical performance of Ti-6Al-4V alloy, TiC-Co-nY2O3 clad layer was deposited on Ti-6Al-4V alloy plate through TIG cladding route. Nano-Y2O3 powder in different weight percentages (n) was mixed with TiC-Co powder blend, and used as precursor. The microstructural analysis of the clad cross-section revealed the formation of uniform coating for incorporating nano-Y2O3. With the addition of nano-Y2O3, the melting efficiency of the precursor augmented, which utterly melted the TiC particles and transformed it into elongated dendrite during solidification. A marginal improvement in the average micro-hardness, along with significant reduction in the wear and coefficient of friction (COF) was observed for the addition of nano-Y2O3. Almost, four times lesser wear was recorded for TiC-Co-2%Y2O3 coating as compared to TiC-Co coating. The addition of nano-Y2O3 effectively refined the grain structure of the clad material, and improved the fracture toughness and ductility of the coating. Subsequently, the brittle cracking and extraction of TiC particles restrained during the sliding wear test, and augmented the absolute wear resistance of the cladding.

Development of novel Fe-based bulk metallic glasses with excellent wear and corrosion resistance by adjusting the Cr and Mo contents

In this work, a series of novel Fe80–x–yCrxMoyP10C7B3 (x = 0, y = 0; x = 0, y = 4; x = 5, y = 4; x = 15, y = 4; x = 20, y = 4; x = 15, y = 8 in at.%; denoted as CrxMoy) bulk metallic glasses (BMGs) with critical diameters in the range 1.0–2.5 mm were fabricated. The effect of Cr and Mo contents on the glass forming ability (GFA), thermal stability, mechanical properties, corrosion behavior, and wear performance of the these Fe-based BMGs were systematically investigated. A partial substitution of Fe by Cr and Mo was found to enhance the GFA of the Fe-based BMGs. The sample Cr15Mo4 exhibited the maximum critical diameter (2.5 mm), maximum temperature range of the supercooled liquid phase (55 K), and highest activation energy for the primary crystallization process (184 kJ·mol−1). Uniaxial compression and microhardness tests revealed that the compressive strength and Vickers microhardness of the Fe-based BMGs were in the range 3.0–3.7 GPa and 794–958 HV0.1, respectively, and increased with increasing Cr/Mo content. Electrochemical tests in a 3.5 wt.% NaCl solution showed that the Fe-based BMGs exhibited a significantly higher corrosion resistance than 316L stainless steel (316L SS) and 304L stainless steel (304L SS). The corrosion resistance of the Fe-based BMGs generally improved with increasing Cr/Mo content. The sample Cr15Mo4 exhibited the highest corrosion resistance with a self-corrosion and passivation current density ∼10−8 A·cm−2 and ∼10−6 A·cm−2, respectively. X-ray photoelectron spectroscopy of the samples revealed that compared to Cr15Mo4, there was a higher proportion of defective high-valence metal cation (Fe3+, Cr6+, and Mo6+) oxides and a lower proportion of stable low-valence metal cation (Fe2+, Cr3+, and Mo4+) oxides in the passive films of Cr20Mo4 and Cr15Mo8. This explains the reason why adding more than 15 at.% Cr and 4 at.% Mo degrades the corrosion resistance of the Fe-based BMGs. The dry sliding wear test demonstrated that the Fe-based BMGs exhibited significantly better wear performance than 316L SS and 304L SS. The wear rate and coefficient of friction of the Fe-based BMGs decreased with increasing Cr/Mo content. The sample Cr15Mo8 exhibited the lowest wear rate and coefficient of friction of 0.98 × 10−5 mm3·N−1·m−1 and 0.38, respectively. The Fe-based BMGs synthesized in this work, especially Fe61Cr15Mo4P10C7B3, exhibited a high GFA and excellent corrosion and wear resistance. Therefore, they have immense potential for various engineering applications.

Effect of spray angle and substrate material on formation mechanisms and properties of HVAF sprayed coatings

Thermally sprayed coatings are often used to enhance the surface properties (wear resistance, corrosion resistance, etc.) of engineering components in order to extend their performance and service lifetime. Typically, the industrial components to be coated possess complex geometries and are fabricated using different materials, which can influence the deposited coating's microstructure and performance. High-velocity air fuel (HVAF) process is a relatively new thermal spray processing technique that has shown tremendous potential to deposit high performance coatings for durable industrial components. However, no detailed studies have been reported on HVAF sprayed coating formation mechanisms so far in relation to the spray angle and substrate properties, and the influence of coating material on the above. The objective of this work was to study the influence of spray angles and substrate materials on splat characteristics, coating microstructure evolution, properties and performance for two distinct coating materials.In this study, one cermet (WC-CoCr) and one metallic (Inconel 625) feedstock were deposited onto three different substrates (aluminium alloy, carbon steel and Hastelloy-X) utilising different spray angles (40°, 60° and 90°). The coating evolution was analysed utilising SEM/EDS, image analysis, and micro-indentation. To determine the tribological performance, coatings were subjected to dry sliding wear test utilising alumina ball as counter surface and specific wear rates were obtained.The results showed that initial splat characteristics were substantially altered on changing the substrate and the spray angle. However, the final coating properties were not affected significantly even though the deposition rate was reduced significantly at lower spray angle, suggesting the versatility of the HVAF process.

Influence of Si3N4 on the Dry Sliding Wear Characteristics of Stir-Cast Cu-10Sn/xSi3N4 Metal Matrix Composite for Bearing Applications

Bronze metal matrix composites (MMCs) are futuristic materials that may find applications in automobile, aviation, and marine industries, specifically for propellers in submarines, bearings, and bushings for defence purposes. The present investigation studied the effect of Si3N4 (5, 10, 15 wt%) ceramic particles on the physical, metallurgical, and tribological behaviour of Cu-10Sn/Si3N4 MMCs. Cast rods of three composites and a base alloy were fabricated using the liquid metallurgy route. The microstructural characterisation for the cast samples was conducted using FESEM (Field Emission Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), XRD (X-ray diffraction), and TEM (Transmission Electron Microscope), which revealed that the Cu-10Sn alloy reinforced with 5 wt% of Si3N4 had homogeneous distribution and perfect bonding of the Si3N4 with the bronze MMC. The dry sliding wear test was performed by varying parameters such as the applied load (10, 20, 30 N) and sliding velocity (1, 2, 3 m/s). The specific wear rate (SWR) increased against an increased load. However, the SWR and coefficient of friction decreased and then increased against an increasing sliding velocity due to tribolayer formation. The primary wear mechanism observed at low and high loads was severe delamination. In contrast, the wear mechanism was adhesion wear at high and low velocities. Amongst the researched samples, Cu-10Sn/5 wt% Si3N4 composites revealed the least SWR at a load of 10 N and sliding velocity of 2 m/s and hence can be recommended for manufacturing bearings and bushings in the automobile and defence industry.

Sliding wear performance of novel millet husk reinforced polypropylene composites

The current research aims to investigate the influence of novel millet husk, finger millet husk (FMH), and barnyard millet husk (BMH) as fillers on the sliding wear performance of polypropylene (PP) composites. The composites were prepared with 10 wt% loading of FMH and BMH by the extrusion injection molding (EIM) process. The sliding wear testing was performed at different combinations of sliding velocity (0.5, 1, and 1.5 m/sec), load (10, 20, and 30 N), and sliding distance (300 m) against the 1000-µm silicon carbide abrasive paper as counter surface. It was observed from the micrographs that FMH and BMH established improved adhesion with the PP matrix and lowered the specific wear rate. At higher load and velocity values, tribofilm development was observed, which lowered the rate at which composites wear out. The wear mechanism, bonding behavior, and worn-out surface have also been discussed and supported with surface analysis using a scanning electron microscope.

Microstructure evolution and wear properties of ECAP-treated Al-Zn-Mg alloy: Effect of route, temperature and number of passes

In this study, the effect of severe plastic deformation on Al-Zn-Mg alloy was investigated by ECAP method. The ECAP process parameters were determined using Taguchi experimental design for different routes (A, B C and C), different temperatures (100, 150 and 200 °C) and different number of passes (2, 4 and 8). EBSD and TEM analysis were used for microstructural characterization of the samples and the dry sliding wear test was used to measure the mechanical strength. In the study of microstructural properties, it was determined that there was a direct relationship between the number of passes and temperature. With the increase in the number of passes and the decrease in the temperature, a severe decrease in grain size in the samples was observed. It was observed that the sample subjected to ECAP treatment with 8 passes at 100 °C in the B C route was microstructurally coaxial and had the smallest grain size, and the same sample showed the best wear properties.

Dry sliding wear investigation of graphene reinforced copper-silica sand composite by response surface methodology

In the present investigation, Cu-based metal matrix composites (MMCs) have been fabricated through powder metallurgy using silica sand micro-particles and graphene as nano-fillers, and their influence on wear behavior has been studied. The weight fraction of silica sand has been fixed to 5 wt. % and graphene nanoparticles have been varied from 0.1 to 0.3 wt. % in the steps of 0.1 wt. %. The investigated samples have been fabricated by cold pressing at 500 MPa, followed by sintering (750-900 °C × 2 h) in a nitrogen atmosphere. The wear behaviour of all fabricated samples has been done on a pin-on-disc wear tester at ambient conditions. Microstructural characterization such as Optical microscopy, X-ray diffraction (XRD), Energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM), and Raman spectroscopy showed uniform dispersion of both silica and graphene nanoparticles. Relative density, hardness and wear resistance increased with the addition of graphene nanoparticles up to 0.2 wt. %. The electrical conductivity of the samples has been evaluated using four probes setup. Increasing the amount of graphene nanoparticles from 0.1 to 0.3 wt. % resulted in a decrease in the electrical conductivity of the sintered copper silica composite. The wear mechanism of worn surfaces has been analyzed and discussed using scanning electron microscopy. Adhesive wear, abrasive wear and delamination were the dominant wear mechanisms during the dry sliding wear test. Further, Response Surface Methodology (RSM) technique have been employed to investigate the influences of most dominating process parameters on responses like sintered density, hardness and wear loss. Finally, based on error analysis, model-predicted results and experimental data have been compared and found to be satisfactory. The percentage errors during the confirmatory test for sintered density, hardness and wear loss are 1.59, 2.06 and 2 respectively, which justify the worth of present research work.

Influence of Alloying Element and Ageing on Microstructure and Dry Sliding Wear Behaviour of Cu-Zn-xNi Alloy

In this paper, we look at how different nickel concentrations (4, 8, and 12 percent) affect the microstructure, microhardness, and dry sliding wear behaviour of a Cu-Zn-xNi alloy. The alloy was created using a casting technique at 1100°C and a heat treatment method that included solution treatment at 600°C and ageing at 450°C for four hours each. Microstructure studies were performed on the developed alloys using a scanning electron microscope (SEM). To investigate alloy indentation resistance, an ASTM E384 microhardness test was performed. Tribological properties such as friction and wear were investigated using a pin on disc tribometer and a dry sliding wear test according to the ASTM G99 standard. SEM studies revealed α-phase (copper) and solid solution of zinc in cast alloys, while aged alloys revealed a similar structure but with the addition of Cu2NiZn precipitates. The microhardness values improved as the Ni content and ageing increased. The decrease in secondary dendrite arm spacing with increasing Ni content and ageing was attributed to the improvement. The coefficient of friction decreased as the load increased, but increased as the sliding velocity increased. However, as loads and sliding velocities increased, so did the wear rate. For the majority of loads and sliding velocities, the worn surface demonstrated abrasion as the dominant wear mechanism.

Sliding Wear Behavior of Intermetallic Ti-45Al-2Nb-2Mn-(at%)-0.8vol%TiB2 Processed by Centrifugal Casting and Hot Isostatic Pressure: Influence of Microstructure.

Intermetallic alloys such as titanium aluminides (TiAl) are potential materials for aerospace applications at elevated temperatures. TiAl intermetallics have low weight and improved efficiency under aggressive environments. However, there is limited information about wear behavior of these alloys and their microstructure. The present work aims to study the influence of the microstructure in the tribological behavior of TiAl intermetallic alloy (45Al-2Mn-2Nb(at%)-0.8 vol%TiB2). Wear tests were performed on samples manufactured by centrifugal casting (CC) and hot isostatic pressure (HIP). Reciprocating sliding wear test was carried out for TiAl, it was combined with different loads and frequencies. Wear tracks were analyzed through opto-digital microscopy and electron microscopy (SEM). The results obtained reveal that CC intermetallics present the lowest volume wear lost, approximately 20% less than HIP intermetallics. This good behavior could be related to the high hardness material, associated with the main microstructure where CC intermetallic has nearly lamellar microstructure and HIP intermetallics present duplex microstructure.