Adhesive Wear Mechanism Research Articles

Influence of Oxynitriding on Antifriction Properties of Ti–6Al–4V Titanium Alloy

The wear resistance of a plate–screw tribo pair used to fix bone fractures was investigated using the pin-on-plate configuration under conditions of dry friction and friction in Ringer’s solution. The nitrided and oxynitrided plates of Ti–6Al–4V titanium alloy in friction pairs with Fe–18Cr–10Ni–1Ti stainless steel were used. It was determined that under dry friction conditions, regardless of load, the nitrided Ti–6Al–4V titanium alloy provides a lower friction coefficient than the oxynitrided one; friction is implemented according to the adhesive wear mechanism. The use of Ringer’s solution during friction tests leads to an adhesive–oxidative wear mechanism that decreases the friction coefficient in friction pairs of nitrided (oxynitrided) Ti–6Al–4V titanium alloy–Fe–18Cr–10Ni–1Ti stainless steel. In addition, the oxidative portion in the wear mechanism for an oxynitrided surface is greater, which decreases the adhesive wear in such a friction pair.

Microstructure evolution and mechanical performance of Cr-N/Al-Cr multilayer coatings produced by plasma nitriding Cr-coated Al alloy

A two-step treatment was proposed to strengthen the surface mechanical performance of 2024 Al alloys. Nano-scale Cr film was firstly deposited by using magnetron sputtering, then Al alloys deposited with Cr film were plasma nitrided at different temperatures (400-480 °C). Results showed that nitriding treatment transformed the Cr film to Cr(N) and CrN phase. With increasing temperature, the nitride surfaces became denser and the nitrogen content (at. %) increased from 17% to 40% at 480 °C. Low temperature nitriding obtained only single Cr-N layer on the surface of Al substrate. High temperature nitriding stimulated surface Cr-N reaction and inner Cr-Al reaction simultaneously to generate multilayer coatings consisting of outmost Cr-N layer and inner Al-Cr intermetallic layers (Al4Cr and Al18Cr2Mg3). The surface hardness of as-prepared coatings reached the maximum value of 9.21 GPa, which significantly enhanced the Al alloy surface (1.57 GPa). The friction coefficient of Al alloy (0.72) was decreased to 0.51 for samples with multilayer coatings. The multilayer coatings showed a mixture wear mechanism of adhesive wear and abrasive wear, accompanied by oxidative wear.

Examination of Wear and Rockwell-C adhesion Properties of Nitronic 50 Steel Coated with Pack Boriding Method

The Nitronic 50 steel is a nitrogen containing stainless steel, which has a high corrosion resistance, and high strength but its surface resistance against wear is low, making it extremely limited to use in areas subject to wear. In this study, in order to improve the material surface and to investigate its effect on tribological properties, boronizing process was carried out by used pack boriding method at 850 ° C, 900 ° C and 950 ° C for 4 hours. As a result of coating process, the boride layer has a smooth and flat structure in SEM investigations, the coating thickness varies between 9 µm and 36 µm and the boride layer thickness increases with increasing temperature. While the hardness of the uncoated material was around 250 HV0.05, the surface hardness of the material reached up to 1.712 HV0.05 with the coating process and increased about 7 times. According to XRD analysis, the surface of the coating layer consisted of phases FeB, CrB, Ni3B, Fe2B, Cr2B and MnB. Wear behavior was performed by ball-on-disk wear test in dry environment. The friction coefficient and wear rate decreases with increasing temperature, while the wear resistance is increased by 20 times compared to unboronized sample. When the wear tracks were examined, the uncoated Nitronic 50 had an adhesive wear mechanism, on the other hand the boronized samples had an adhesive and abrasive wear mechanism together. The Rockwell-C adhesion test was carried out under a load of 1.471 N and the resulting surface damages were evaluated according to the quality map. Boronized steel at 850 °C is defined as HF3 type, at 900 °C and 950 °C at boronized steel it is defined as HF4 type and adhesion is acceptable.

Experimental and empirical model analysis of microsurface texturing on 316 L press-fit joints fabricated by selective laser melting

In this study, selective laser melting (SLM) was investigated for the manufacturing of 316L stainless steel press-fit joints. The accuracy of selective laser melting technique in fabrication of texture profile in shape, pitch and height of microsurface texturing was examined. The resulting insertion and removal forces achieved from the produced textured pins for cold-formed high-end fixation applications were studied. The experimental results showed that the shape, pitch and height of the texture, as well as the resultant bonding strength of the joints, can be effectively set via control of the SLM processing parameters. While trapezoidal and triangular shapes of the texture lead to stronger bonding compared with oval-shaped texture profiles, the texture height was found to have a predominant effect on bond strength. To a much lower extent, larger pitch distances also resulted in higher bond strengths. A combination of abrasive and adhesive wear mechanisms was detected via examination of the inner surface of the hub into which the press fit was inserted. Along with a process map of design of the microsurface texture geometry of metal interference fit joints, this paper also presents the underlying mechanics for their bonding. The SLM process is shown to present a useful one-step method for the manufacturing of knurl metallic interference fit pins of customisable and definable texture and ensuing bond strength.

Enhancement of the hardness and wear-resistance of aluminum-silicon alloy using atmospheric plasma-sprayed ZrO2, Al2O3-ZrO2 multilayer, and Al2O3/ZrO2 composite coatings

The present study aims to improve the hardness and wear resistance of aluminum-silicon alloys using atmospheric plasma-sprayed ZrO2, Al2O3-ZrO2 multilayer and Al2O3/ZrO2 composite coatings. The fabricated coatings were characterized to explore their morphological changes, surface hardness, phase composition, surface roughness, friction and wear. Friction and wear resistance against cast iron were determined under dry-sliding conditions at the load of 15 N in room temperature. The micro structural studies revealed the morphological changes of the various coatings fabricated on aluminum-silicon alloys. The Al2O3/ZrO2 composite coating contained equiaxed grains due to differences in the melting points of the two particles. The formation of equiaxed grains increased the hardness of the aluminum-silicon alloy from 55 HV0.3 to 1168 HV0.3 after the deposition of the Al2O3/ZrO2 composite. X-ray diffraction analysis confirmed the formation of intermetallic phases in the various deposits. Low surface roughness of 2.51 μm was exhibited for ZrO2 deposit compared to 3.02 μm of Al2O3/ZrO2 composite and 3.90 μm of Al2O3-ZrO2 multilayer deposit. Al2O3/ZrO2 composite coating achieved better tribological performance than the ZrO2 and Al2O3-ZrO2 multi-layer coatings. Hardened tribofilm reduced the wear rate to 9.5 × 10−5 gm−1 for Al2O3/ZrO2 composite from the wear rate of 4.53 × 10−4 gm−1 of Al-Si alloy. Though the wear resistance is improved for the composite deposit, the COF was increased to 0.55 compared to the other deposit. The delamination, adhesive, abrasive and Grain pull-out wear mechanism occurred during the sliding of Al-Si alloy, ZrO2 and Al2O3-ZrO2 multilayer against the cast iron had been reduced considerably after the Al2O3/ZrO2 composite.

Microstructure and mechanical properties of titanium alloy / zirconia functionally graded materials prepared by laser additive manufacturing

The titanium alloy/zirconia functionally graded materials can greatly improve the hardness and wear resistance of titanium alloy, thus greatly enhance work life of titanium alloy. In this paper, the titanium alloy (Ti6Al4V)/zirconia functionally graded and non-functionally graded block were prepared by laser additive manufacturing to compare the microstructure evolution, elements distribution. The results indicated that the Ti6Al4V microstructure in the functionally graded block present the fine lath with the zirconia increasing. Compared to element distribution in the non-functionally graded block, the microstructure distribution in the functionally graded block altered from smooth and linear to nonlinear, and the elements transition is more stable and uniform. Microhardness in the functionally graded block increases with the zirconia increasing, and its variation trend agreed with the lever principle of composite mechanical properties. The wear loss was reduced with the zirconia increasing, and it was well conformed to the fitted function 1.09 × 10−2x-0.082. Also, the wear mechanism was mainly abrasive wear as the zirconia content rises in the functionally graded block, this was not like the mechanism of both abrasive wear and adhesive wear in the non-functionally graded block.

Effect of Heat Treatment Hardening on the Dry Sliding Wear Behaviour of Mild Steel

Abstract:Mild steel offers a variety of properties for various applications at lower costs giving the alloy a large application base in industry. However, the increasing complexity and severity of service environments has shifted the focus of many industries to structure modification techniques, like heat treatment, to improve material properties and performance. The focus of this paper was to therefore investigate the effect of heat treatment induced hardness on the sliding wear behaviour of mild steel. The results showed that resistance to dry sliding wear increased with increasing hardness of the mild steel samples. Both abrasive and adhesive wear mechanisms were observed to occur on the samples, however abrasive wear was predominant.

High temperature tribological behaviors of aluminum matrix composites reinforced with solid lubricant particles

Abstract The AA6061−10wt.%B4C mono composite, AA6061−10wt.%B4C−Gr (Gr: graphite) hybrid composites containing 2.5, 5, and 7.5 wt.% Gr particles, and AA6061−10wt.%B4C−MoS2 hybrid composites containing 2.5, 5, and 7.5 wt.% MoS2 particles were fabricated through stir casting. The dry sliding tribological behaviors of the mono composite and hybrid composites were studied as a function of temperature on high temperature pin-on-disc tribotester against EN 31 counterface. The wear rate and friction coefficient of the Gr-reinforced and MoS2-reinforced hybrid composites decreased in the temperature range of 30−100 °C due to the combined lubrication offered by the wear protective layer and its solid lubricant phase. Scanning electron microscopy (SEM) observation of the worn pin surface revealed severe adhesion, delamination, and abrasion wear mechanisms at temperatures of 150, 200, and 250 °C, respectively. At 150 °C, transmission electron microscopy (TEM) observation of the hybrid composites revealed the formation of deformation bands due to severe plastic deformation and fine crystalline structure due to dynamic recrystallization.

Machinability investigations on high-speed drilling of aluminum reinforced with silicon carbide metal matrix composites

In this work, the research efforts have been made to investigate the effect of important drilling parameters such as spindle speed and feed rate on effectiveness of process and quality of holes during drilling of difficult-to-machine Al/SiC metal matrix composite using diamond-coated cemented carbide tool. Thrust force, hole diameter, delamination factor, surface roughness, tool wear, and chip analysis of the drilled holes were investigated at different spindle speeds (3000–9000 rpm) as well as feed rates (0.05–0.2 mm/rev), respectively. The outcomes of this study reveal that thrust force varies directly with the feed rate, but inversely with the spindle speed. Both the hole diameter and the delamination factor shows a rough proportionality with the feed rate, although the rates of variation are slow at the high spindle speed combined with a high feed rate. Similarly, the hole surface roughness increases with the feed rate, while the moderate spindle speeds produce better surface roughness. Smaller chips were found for all spindle speed. Adhesive and abrasive wear mechanisms are prominent on drill bit and drill wear occurs on both drill tip and secondary cutting edge. Drilling at moderate spindle speeds of 5000 rpm and 7000 rpm is the most suitable for the hole drilling in the Al/SiC metal matrix composites.

Dry Sliding Wear Behavior of Boron-Doped 205 Manganese Steels

In the present study, the wear properties of 205 manganese steels produced by a casting process with different boron contents (0.0023-0.0182 wt.%) were investigated, using a pin-on-disc tribometer under dry sliding conditions. The friction coefficient of 205 manganese steel by boron addition (at 0.0076 wt.%) reduced from 0.28 to 0.18. The addition of boron to 205 manganese steel led to a decrease in the friction coefficient due to the lubricating effect of boron. X-ray diffraction showed that the boron addition to 205 manganese steel increased lattice parameters of the samples. The wear test results at 5 and 10 N loads showed that the wear amount of 205 manganese steels decreased with boron addition. Thus, the wear results showed that the wear resistance of 205 manganese steel is increased with the addition of small amounts of boron. Furthermore, scanning electron microscopy images indicated that the characteristic wear mechanisms for the boron-doped samples on the worn surfaces were abrasive, and it was plastic deformation, mild abrasive, and adhesive wear mechanism in the undoped 205 manganese steel.

Sliding wear behavior of the WC/FeAl-B intermetallic matrix composites at high temperatures

In this research, the sliding wear of sintered WC/40vol% (FeAl-B) composites was studied at high temperatures. It is expected that the wear behavior of WC/FeAl can be improved in the presence of boron at high temperatures. The composites contained different amounts of boron and alumina was chosen as the counter body material in the wear tests. The tests were carried out at temperatures ranging from ambient to 600°C so that the effect of boron and temperature on wear resistance could be specified. The results showed that while hardness slightly decreased with increasing the boron content to 500ppm in the FeAl-B matrix, the fracture toughness increased significantly. The maximum wear resistance of the WC/FeAl-500ppm B composite was recorded at all the temperatures examined. Investigations of the wear surfaces showed that while the wear mechanism of the WC/FeAl-B composites was an abrasive one at room temperature and 300°C, a more adhesive wear mechanism was detected at 400°C and a matrix oxidation mechanism was observed at 600°C.

Evaluation of physical indicators and tool wear during grooving of spheroidal cast iron with a novel WCCo/cBN (BNDCC) inserts

The WCCo/cBN (Boron Nitride Dispersed Cemented Carbide – BNDCC) cutting inserts fabricated by PPS (pulse plasma sintering) method constitute the novel tool materials with advantages of cemented carbide and cubic boron nitride tools. However, the cutting properties of these materials are not yet recognized. Therefore, this work is focused on the identification of BNDCC tools cutting performance during the grooving process of a hard-to-cut N-GJLA-XNiCuCr 15-6-2 spheroidal cast iron. The conducted studies involved the evaluation of a fundamental cutting process physical indicators, as cutting forces, vibrations and average coefficient of friction on the rake face. The tool wear mechanisms and tool life of the uncoated and coated (with TiN and TiAlN coatings) BNDDC inserts were identified and compared with ones obtained during cutting with a coated and uncoated cemented carbide (H3 and H10) tools. The obtained results showed that the adhesion wear mechanism of the coated and uncoated BNDCC inserts was dominant throughout the entire range of cutting speed. The application of the novel BNDCC inserts during grooving of spheroidal cast iron is more advantageous in terms of tool life, comparing to the coated cemented carbide inserts.

Friction and tribological behavior of bare nitrided, TiAlN and AlCrN coated MDC-K hot work tool steel

TiAlN and AlCrN coating has been deposited on MDC-K hot work tool steel by PVD technique. The microstructure, elemental composition, nanomechanical and wear properties of bare nitrided and coated surface were evaluated using XRD, Raman spectroscopy, FE-SEM along with EDS, nanoindentation and nanoscratch test. AFM have showed improvement in surface with reduction in friction coefficient by ∼47.62% and ∼45.71% with TiAlN and AlCrN coating respectively. The mechanical properties of MDC-K tool steel substrate such as hardness, elastic modulus and strain hardening exponent got improved post coating wherein TiAlN coating had exhibited higher wear resistance (H/E), improved plastics deformation resistance (H3/E2), high scratch hardness and lower specific wear rate compared to AlCrN coating. This led to lower pile up and plastic deformation in TiAlN coating. In addition to this, wear behavior of bare nitrided, TiAlN and AlCrN coated surface were evaluated under different tribological conditions. Bare nitrided surface worn out due to abrasive wear mechanism whereas AlCrN coating exhibited both smooth and rough surface due to adhesive and abrasive wear mechanism. Furthermore, TiAlN coated surface exhibited lower specific wear rate and superior micro-hardness compare to bare nitrided and AlCrN coated surface post tribotests.

Effect of the Outer Layer of Al Coatings Deposited by Cold Gas Spray on the Microstructure, Mechanical Properties and Corrosion Resistance of the AA 7075-T6 Aluminum Alloy

The corrosion of AA 7075-T6 aluminum alloy is a critical issue for many industries. In this study, aluminum coatings were deposited onto AA 7075-T6 by cold gas spray and the effect of the porous outer layer on different properties of the coating, including corrosion–resistance was investigated. As-prepared and polished samples were used to study the microstructure, morphology, mechanical properties and corrosion resistance of the coating in 3.5 wt.% NaCl solution. Cross-sectional analysis showed a dense structure, low porosity (0.8%) and thickness up to 300 µm (~ 100 µm for the porous outer layer and ~ 200 µm for the compact inner layer). The sliding wear test resulted in a volume loss of 3.2 × 10−4 mm3/Nm with an adhesive wear mechanism. The abrasive wear test showed a wear rate of 1.1 × 10−4 mm3/Nm for the as-prepared coating and 0.8 × 10−4 mm3/Nm for the polished coating. The as-prepared coating pores and interparticle spacing in the outer layer were mostly responsible for the increase in wear rate. For the polished coating immersed in 3.5 wt.% NaCl solution during 900 h, the electrolyte reached some specific points of the substrate as revealed by the cross-sectional analysis. Inspection of the as-prepared coating demonstrated that the coating/substrate interface was completely damaged after long immersion times (~ 900 h).

Dry sliding wear behaviour of Al-5Zn-2Mg alloy processed by severe plastic deformation

Equal channel angular extrusion/pressing (ECAE/P) is an effectual technique to raise the mechanical, physical properties and resistance to wear of the materials. In this research, Al-5Zn-2Mg alloy material was ECAPed in route BC at lowest temperature. Hardness of the test material was increased after ECAE/P due to microstructure refinement. To demonstrate the wear characteristics of the Al-5Zn-2Mg alloy material after ECAE/P, wear tests (in dry sliding condition) were conducted at 2 conditions (condition 1: 19.62 N load and 1 m/s sliding speed, condition 2: 39.24 N load and 2 m/s sliding speed). The wear rate and magnitude of coefficient of friction (µ) were lessened after ECAE/P. Abrasive, adhesive and oxidation wear mechanisms are the predominant wear mechanisms noticed in the ECAE/P processed billets. Along with these mechanisms relocation of iron elements from the counter body (disc) to the test material was noticed.

Wear-resistant boride reinforced steel coatings produced by non-vacuum electron beam cladding

In this work, we present a wear-resistant coating fabricated by non-vacuum electron beam cladding of Fe62Cr10Nb12B16 at.% powder on a mild steel substrate. The protective coating was 1.3 mm thick, dense, and exhibited an α-(Fe,Cr) matrix reinforced by a significant fraction of hard borides formed upon solidification. Micrometric and nanometric borides homogeneously dispersed within the matrix were formed due to the homogeneous melting and the relatively fast cooling to suppress the excessive phase growth. An intimate metallurgically bonded interface between the coating and substrate was characterized by low compositional dilution and a fine eutectic-like transition zone microstructure anchoring the dissimilar materials. The coatings displayed a higher wear resistance compared to the mild steel substrate, showing specific wear rates, κ, about one order of magnitude lower (10−5 against 10−4 mm3/N.m, respectively). The abrasive wear mechanism was dominant for the coating sample when tested at low sliding velocity, 10 cm/s, due to the detachment of hard borides from the surface and their incorporation into the tribosystem. The adhesive wear mechanism was found to be dominant at higher sliding velocities of 20 and 40 cm/s. Dry sand/rubber wheel testing revealed the higher resistance of the coating against abrasive wear compared to the mild steel substrate. Regardless of the wear mechanism, the Fe62Cr10Nb12B16 at.% coatings showed a superior sliding and abrasive wear resistance and represented an interesting protective measure to extend the service of inexpensive mild steel components.

Tribological Studies of Epoxy Composites With UHMWPE and MoS2 Fillers Coated on Bearing Steel: Dry Interface and Grease Lubrication

Abstract Epoxy with ultra-high molecular weight polyethylene (UHMWPE) and MoS2 fillers was coated on a bearing steel (SAE 52100). Frictional and wear properties of the coated samples in sliding contact were investigated on a pin-on-disc tribometer under a normal load of 10 N and a linear sliding speed of 1 m/s against a bearing steel ball. The optimized coating composition (72 wt% Epoxy + 7 wt% hardener + 18 wt% UHMWPE + 3 wt% MoS2) showed highly improved tribological properties compared to pure epoxy and other epoxy-based composites. There was 75% reduction in the coefficient of friction (COF) in the dry interfacial condition (COF reduced from 0.2 to 0.05) over pure epoxy and 80% reduction with grease as the lubricant. The specific wear-rate of the composite was lower by five orders of magnitude over that of pure epoxy. Other mechanical properties such as hardness, tensile strength, and Young's modulus of the composite showed increments of 86%, 121%, and 43%, respectively, with respect to those of pure epoxy. 2–3 wt% of MoS2 had drastic effects on improving strength and reducing friction and wear of the composites. For dry sliding, initial abrasive and adhesive wear mechanisms led to transfer film formation on the steel counterface, and the shearing was mainly within the transfer film. For the grease-lubricated case, a thin layer of grease helped in easy shearing, and the transfer film formation was avoided. This epoxy-based composite will have applications as tribological coatings for journal bearings.

Dry sliding wear behavior of Al 6082 metal matrix composites reinforced with red mud particles

The present study aims at investigating the dry sliding wear behavior of Al-based 6082 metal matrix composites (AMMCs) reinforced with red mud particles by pin-on-disc configuration. AMMCs were fabricated with three different weight fractions of red mud particles ranging from 2 to 6% by using the stir-casting method. The friction coefficients and volumetric wear rates were continuously evaluated under normal loads of 10–30 N and sliding speed of 1.5 m s−1 for the constant sliding distance of 1000 m. Microstructural analysis indicated that red mud particles are more or less uniformly dispersed throughout the Al matrix with minimal agglomeration. Experimental data shows that microhardness and tensile strengths of both the as-cast and heat-treated composites are steadily improved by increasing the amount of reinforced red mud particles but at the cost of ductility. Analysis of worn surfaces revealed that delamination and abrasion are dominant wear mechanisms for the case of the heat-treated composites are whereas the adhesion wear mechanism for the base alloy. The composite containing 4% red mud particles experienced the lowest wear rate at a normal load of 30 N and sliding speed of 1.5 m s−1 as compared to other composites including the base alloy. While the composite with 2% red mud particles shows the lowest friction coefficient, base alloy exhibited the highest friction coefficient.

Tribological Behavior of Cenosphere-Filled Epoxy Syntactic Foams in Dry Sliding Conditions

Abstract The tribological behavior of the 10%, 20%, 30%, and 40% cenosphere-filled epoxy syntactic foams in terms of the wear rate and the friction coefficient of the foams were reported using a pin on disc tribometer in the present study. The influence of the wear parameters like applied pressure, sliding speed, and the sliding distance on the tribological performance of syntactic foams was reported. Syntactic foams with 40% cenosphere volume fraction exhibit better tribological properties over the other syntactic foams. The worn surface examination shows the adhesive dominant wear mechanism and the wear debris with broken cenosphere particles.

Corrosion-wear behavior of AA1050/mischmetal oxides surface nanocomposite fabricated by friction stir processing

Abstract In this study, the wear and corrosion characteristics of six-pass friction stir processed (FSPed) AA1050/mischmetal oxide nanocomposite (6PPA) was compared to six-pass FSPed sample without powder (6 PA) and annealed base metal (BM). Different wear characteristics, such as weight loss, wear rate and coefficient of friction (COF) were studied. In order to evaluate the corrosion resistance of samples, immersion and cyclic polarization tests were performed. In addition, worn and corroded surfaces were investigated by field emission scanning electron microscopy (FESEM). The result of pin on disk dry sliding wear test revealed that wear resistance improved by employing FSP through finer grain structure (6 PA sample) and by incorporation of mischmetal oxides (MMOs) through lubrication and load-bearing action of particles (6PPA sample). At the constant load of 30 N, COF decreased from 0.9 to 0.85 and 0.75, and weight loss from 7.4 to 5.7 and 4.5 mg/m × 10−3 for the BM, 6 PA, and 6PPA samples, respectively. According to FESEM study of the worn surfaces, the BM and 6 PA samples show an adhesive wear mechanism, however the wear mechanism changed to abrasive for 6PPA sample. Based on immersion test results, corrosion rate of BM reduced from 0.41 to 0.36 and 0.29 mpy for the 6 PA and 6PPA samples, respectively. Moreover, the results of cyclic polarization test and FESEM investigation showed improved pitting resistance of 6PPA sample.