Wear Resistance Values Research Articles

Complex electron-ion-plasma surface modification of high-alloy stainless steel

The work is devoted to identification and analysis of patterns of change in the elemental and phase composition, defective substructure, mecha­nical (microhardness) and tribological (wear resistance and friction coefficient) properties of stainless high-chromium steel subjected to complex processing, combining vacuum irradiation of the samples surface layer with an intense pulsed electron beam of submillisecond exposure duration and subsequent nitriding under electron-ionic heating conditions. High-chromium steel AISI 310S, which in the initial state is a polycrystalline aggregate based on γ-iron, was used as the research material. Pulsed electron beam treatment of steel was carried out on a “SOLO” installation equipped with an electron source with a plasma cathode based on a low-pressure pulsed arc discharge with grid stabilization of the cathode plasma boundary and an open anode plasma boundary. Steel nitriding was carried out on a “TRIO” installation with a chamber size of 600×600×600 mm, equipped with a switching unit to implement the electron-ionic processing mode. Nitriding was carried out at 723, 793, and 873 K temperatures for 1, 3 and 5 h. It was found that electron-ionic nitriding of the samples pre-irradiated with an electron beam (10 J/cm2, 200 μs, 3 pulses at 723 and 793 K for 3 h) is accompanied by the formation of a ceramic layer containing only iron and chromium nitrides. The highest values of steel wear resistance after electron-ionic nitriding, exceeding the wear resistance of the initial steel by more than 700 times, are observed at nitriding parameters of 793 K, 3 h.

STRENGTHENING OF THE SURFACE BY FRICTION

The study is devoted to the application of the method of surface hardening by friction Object of study - the process of surface hardening by friction.Subject of study - samples of 65G steel the method allows achieving high values of hardness, strength and wear resistance of materials in a short time and at much lower cost compared to other processing methods. The aim and objectives of the study are to investigate the nature of surface hardening of steel samples by friction. To achieve this goal, the following tasks are envisaged: manufacturing samples from 65G steel in the form of plates, preliminary heat treatment of samples for their maximum thermal hardening, hardening of the surface of samples by friction, analysis of the microstructure and microhardness of each sample, comparison of the microstructure, microhardness and depth of hardening of these samples, conclusions on the influence of processing factors on the hardening result. Based on the experimental data obtained, we constructed graphs of microhardness changes in the cross-section of the samples and studied the microstructures. It can be seen that after friction treatment, a layer with a modified structure is formed in the surface of the samples. The microhardness of the surface is significantly higher (approximately 2 times) than the microhardness of the main part in the samples. Metallographic analysis has shown that the layer formed in the samples has a martensitic structure characterized by a higher degree of dispersion and microhardness compared to the martensitic structure obtained during the previous heat treatment. Changes in the microstructure and microhardness of the samples that were surface hardened using different processing modes were compared. Certain differences in the characteristics of their hardened «white» layers were found. It is also shown that the hardened «white» layer is located along the entire length of the surface in the samples and is continuous and homogeneous.

Prediction and Verification of Wear Resistance of In-situ Inorganic Compounds Reinforced Zinc Matrix Composites

The wear resistance of zinc matrix composites reinforced by inorganic compounds in situ and the prediction of wear resistance by neural network were studied. The inorganic compound is Mg2Sn phase. The results show that Mg2Sn phase is a strengthening phase, and its uniform distribution in the matrix can improve the hardness and wear resistance of zinc matrix composites. When the amount of tin and magnesium respectively reach 10%, the wear resistance value at load 80N is 4.0, while the wear resistance value at 40N is 4.5. The influence of Mg and Sn elements on the hardness and wear resistance of the zinc matrix composite was predicted by neural network, and the experimental results showed that when the content of Mg and Sn elements exceeded 10%, the hardness and wear resistance of the material would decrease, which was related to the aggregation of Mg2Sn and the cleavage of the matrix, which reduced the toughness of the material.

Microstructure-induced anisotropic tribological properties of Sc-Zr modified Al–Mg alloy (Scalmalloy®) produced via laser powder bed fusion process

AbstractIn this study, the correlation between the microstructure and tribological performance of Sc and Zr-modified Al–Mg alloy (Scalmalloy®) samples produced via laser powder bed fusion process was evaluated via a dry sliding Pin-on-Disc wear test under different planes, directions, and various normal applied loads. The results revealed a remarkable dependency of wear properties on the as-built microstructure so that different behaviors were observed along the scanning and building planes. The microstructural examination indicated the presence of bi-modal grains and finely shaped equiaxed grains observed in the building and scanning planes, respectively. Increasing the applied loads from 20 to 40 N led to a significant increase in the coefficient of friction (COF) while increasing the load from 40 to 60 N, slightly decreasing the COF for the studied samples. No dependency was found between the COF and the corresponding microstructure at the highest applied load. The anisotropic wear resistance and COF values were predominant at the lowest applied load. Due to tailored as-built microstructural features and different microhardness values, lower wear rates were noticed along the scanning plane for all applied loads. Under the 20 N applied load, however, the worn surface of the scanning plane showed a clearer and smoother surface compared to the building plane surfaces. Ultra-fine equiaxed grains along the scanning plane and columnar grains along the building plane were determined as the main factors creating anisotropic tribological behavior. The outcomes of this study can pave the way toward producing more wear-resistant surfaces and developing components for critical wear applications in as-built conditions with no need for expensive and time-consuming surface treatments.

Effect of Varying the Volume Fractions of Ledeburitic Cementite and Graphite on the Tribological Properties of Commercially Used Cast Irons

The types and volume fractions of the carbonaceous phases present in the microstructures of cast irons strongly influence their properties. In the case of materials used commercially for tools, an important parameter with regard to their use is the resistance to abrasion wear. Cementite is the main reinforcing phase in cast irons and is present in significant quantities. In addition, cast irons contain graphite precipitates, which also affect wear by interacting with the matrix of the alloys. In this study, abrasive wear tests were carried out on a group of cast irons with different chemical compositions and, consequently, different microstructural morphologies. Due to the wide scatter of the results and the commercial rather than laboratory nature of the alloys studied, it was decided to use analysis of variance (ANOVA) to determine whether there was a statistically significant difference between the volume fractions of the carbonaceous phases. The volume fractions of graphite and ledeburite were then related to the results of the tribological tests. Statistical analysis confirmed significant differences in the results obtained for the alloys tested. A continuous increase in the volume fractions of both graphite and ledeburitic cementite is unfavourable in terms of the wear resistance and friction coefficient values. Optimum results can be obtained by balancing the volume fractions of the two phases observed. In addition, the phase composition of the material matrix plays an important role in wear, as the differences in the matrix of the tested alloys modify the nature of the influence of cementite and graphite on the wear.

Development of technology for obtaining functional coatings from Kh15Yu5 steel powders

The paper presents the results of research on the development of technology for the application of functional coatings with high values of adhesion strength, microhardness and wear resistance using the method of supersonic cold gas dynamic spraying. Oxidized powder from X15Yu5 steel was used as a starting material for obtaining such coatings.

Study of the Cement Additives Effect on the Physical and Mechanical Characteristics of Rubber Material

The materials of the article are devoted to obtaining the material based on a mixture of natural rubber with the refractory cement filler in a certain proportion and the study of its physical and mechanical characteristics. The samples with different cement contents were formed to determine the optimal proportion of cement additives in the mixture. The resulting analysis showed that the material with a cement proportion of 15 (pphr) has the best characteristics, in which an increase in the values of the maximum tensile pressure (8.98 MPa) was achieved, a decrease in the values of elongation, while an increase in the value of hardness and wear resistance, and minimum level of absorption was observed when the samples were immersed in technical oil - by 1.29%.

Determination of Optimum Ratio of Selected Carbonaceous Materials on Mechanical and Corrosion Behavior of Carburized Mild Steel

This work is centred on the determination of optimum ratio of selected carbonaceous materials of A(40% Snail shell + 40% Animal bone), B(60% Snail shell + 20% Animal Bone), C(20% Snail shell + 60% Animal bone), D(50 Snail shell + 30 Animal bone) and E(30 Snail shell + 50% Animal bone), the mechanical properties and corrosion behaviour of carburized mild steel. Which were carburized at single austenitic temperatures of 1000°C, soaked at single carburizing time of 5hr, at the treatment temperature and samples were then quenched in water. Before the carburization process, standard test specimens were prepared from the received sample for testing hardness, tensile strength, wear, and microstructure analysis. After the carburization process, the test samples are subjected to standard testing to generate data on the ultimate tensile strength and wear rate of the carburized samples. Research shows that the mechanical properties of mild steel are strongly influenced by each of the mixed ratios of the carbonaceous material (Such as Snail shell and Animal Bone). An improved hardness values in all the samples were observed, with sample A having the highest hardness value of 59.05 RHC while sample B and sample C have the highest wear resistance value of 0.090. The samples were immersed in 0.3M H2SO4 solution for potentiodynamic studies. There results show that sample E had the least corrosion rate of 8.1809 mpy hence is less prone to corrosion attack in acidic environment than others. These samples are found to be useful in automobile industry.

Synthesis and Characterization of a Novel Two-Dimensional Copper p-Aminophenol Metal-Organic Framework and Investigation of Its Tribological Properties.

Here, a novel copper p-aminophenol metal-organic framework (Cu(PAP)2) is first reported. Powder X-ray diffraction (PXRD), infrared spectra (FTIR), Raman spectra, transmission electron microscopy (TEM) and X-ray photoemission spectroscopy (XPS), in combination with a structure simulation, indicated that Cu(PAP)2 is a two-dimensional (2D) material with a staggered structure analogous to that of graphite. Based on its 2D graphite-like layer structure, Cu(PAP)2 was expected to exhibit preferable tribological behaviors as an additive in liquid lubricants, and the tribological properties of Cu(PAP)2 as a lubricating additive in hydrogenated polydecene (PAO6) or deionized water were investigated. Compared to PAO6 or deionized water, the results indicated that deionized water-based Cu(PAP)2 showed much better friction reduction and anti-wear behavior than PAO6-based Cu(PAP)2 did, which was due to Cu(PAP)2 penetrating the interface between friction pairs in deionized water, but not in PAO6, thus producing lower friction and wear resistance values.

Effect of Fe addition on phase evolution, microstructure and properties of Ti50Ni50-X Fe X alloy

The work aims to study the effect of the Fe content on the properties of Ti50 Ni(50−X) Fe X alloy (where X = 0, 2, 4, 6, 8, and 10 at.-%) sintered at 1050°C and 1150°C using the conventional sintering technique. The microstructure, chemical composition and phase evolution of the sample were analysed by SEM, EDS, and XRD, respectively, along with various properties. It was observed that the sintered sample microstructure consists of (Ni, Fe)-rich, and Ti-rich phases. Here, the porosity decreases, whereas density, hardness, and wear resistance increase with the increasing temperature. The 8at.-%Fe sample shows lower porosity and higher wear resistance, relative density and hardness value than other Fe content samples. The 2at.-%Fe sample sintered at 1050°C shows a higher shape recovery value compared to other compositions sintered at various temperatures.

Effect of rare earth oxide (Y2O3) addition on wear characteristic of TiB2 ceramic reinforced Mo-based composite coating fabricated by Argon shielded Arc cladding

In this study, Mo-based composite coatings with 1 wt.% of rare Earth oxide (Y2O3) contents were successfully manufactured on AISI SS304 (stainless steel) by argon shielded arc (ASAC) cladding method. The effect of Y2O3 on phase composition, microstructure, mechanical and tribological properties of Mo-based coatings were investigated by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) with energy dispersive x-ray spectrometer (EDS), micro-Vickers hardness apparatus and pin-on-disc type wear tester. The result demonstrates that the upper surface of composite coating with and without addition of Y2O3 were mainly comprised of TiB2, Ni3Ti, Fe3Mo, MoNi4, NiTi, Mo2B, Y2TiO7, Cr2Ti, Fe3B, Y2O3, and MoNi4 appeared. The constituent phase components in the coated layer were found to be beneficial for the enhancement of the microhardness and wear resistance. The maximum value of average micro-hardness and wear resistance was observed in samples having 1 wt.% of Y2O3 as a precursor. The average microhardness of Mo-based coatings with Y2O3 addition was in the range of 1599 to 2170.4 HV0.1 and wear resistance increases from 1.41 to 6.36 × 10−8 g/N-m. The pronounced effect of Y2O3 addition on microhardness and wear resistance of coatings were consistent with the calculation results of applied multivariate statistical analysis. Thus, it can be concluded that the addition of Y2O3 is effective and achievable way to solidate hardness and wear resistance of Mo-based coatings.

Dependence of Arc Ion plating process on properties of CrAl coating for ATF cladding: Effect of bias voltage and targets

After the Fukushima accident, studies on accident tolerant fuel cladding focusing to prevent hydrogen explosions have been actively performed. Many researchers have been working on modifications of commercial cladding, especially direct coating on the cladding surface. In this work, a CrAl binary alloy system and an arc ion plating method were selected to grow a film on commercial Zircaloy-4 claddings. CrAl coating layers were systematically deposited on the cladding surface under various voltage conditions using targets manufactured in different ways. Microstructural characterizations and the evaluations of the mechanical properties showed that a robust coating layer can be achieved by controlling the deposition parameters. Surface roughness values satisfying required manufacturing criteria were achieved and wear resistance values of coated claddings also notably improved. These results suggest that CrAl films on Zircaloy-4 cladding are promising candidates for future ATF cladding.

Структура и свойства покрытий WC-10Co4Cr, полученных высокоскоростным плазменным напылением

Introduction. Carbon steel is often used for the manufacture of various machine parts, but its operation in aggressive conditions (operation of steel parts under conditions of wear, high temperatures and aggressive corrosive environments) contributes to an extreme decline in properties, up to failure. To solve this problem the modification of the working surfaces of steel parts can be used. It increases its wear resistance, corrosion resistance, and service life. Metal-ceramic coatings based on WC are often used to improve the hardness, wear resistance and corrosion resistance of steel parts. The work purpose is to study the effect of high velocity atmospheric plasma spraying (HV-APS) modes on the structure, phase composition and properties of WC-Co coatings. Materials and methods. 86% WC-10% Co-4% Cr coatings were deposited on a mild steel substrate with help of the HV-APS method. The structure and phase composition of the coatings were analyzed using optical microscopy, scanning electron microscopy, and X-ray phase analysis. In addition, the results of measurements of porosity, microhardness, wear resistance, as well as a qualitative assessment of the adhesion are shown in this paper. Results and discussion. It is shown that all coatings are characterized by high density, absence of cracks and oxide films. Using the SEM and XRD methods, it is found that the coatings contain WC and W2C particles uniformly distributed in the metal matrix. The matrix is an amorphous or nanocrystalline supersaturated Co(W,C) solid solution. The maximum amount of carbides (49%) is observed in coatings obtained by deposition from a distance of 170 mm, arc current — 140 A; the minimum (25%) is observed in coatings obtained by deposition from a distance of 250 mm, arc current — 200 A. The coatings with the maximum amount of carbides have the maximum values of microhardness (1,284 HV0.1) and wear resistance. It is established that all coatings are characterized by high adhesion.

Investigation of mechanical, tribological and magnetic properties after plasma nitriding of AISI 316L stainless steel produced with different orientations angles by selective laser melting

In this study, AISI 316L stainless steel samples were produced with different orientations (0°, 45°, and 90°) using selective laser melting (SLM). In addition, plasma nitriding of the samples produced with SLM was performed at 400 °C for 4 h. The effect of different orientation on the structural, mechanical, tribological, and magnetic properties of 316L stainless steel was investigated. The same measurements also were made after the plasma nitriding process. The results showed that the phase composition and microstructure of the non-nitriding and nitridied samples were affected from the built orientation. Especially the XRD peaks shifted to the left with a decrease in the orientation angle. It was obtained that the highest modified layer thickness was measured from the samples produced with an angle of 0°. It was observed that the surface hardness, residual stress, wear resistance and antimagnetization tendency values of nitridied samples were higher than the non-nitriding samples. Furthermore, these values tended to increase with the decrease in build orientation angles.

Mechanical and Tribological Properties of Al2024/Al2O3 Functionally Graded Spur Gears Synthesized by Centrifugal Casting Process

The mechanical and tribological properties of spur gears are important because they can affect the efficiency and wear life of these gears. Thus, this study's primary goal is to use functionally graded material (FGM) to enhance the properties of Al2024 aluminium alloy spur gears. The mechanical and tribological properties of aluminium alloy Al2024 with graded Al2O3 reinforcement particles spur gears synthesized by the vertical centrifugal casting (VCC) process were investigated experimentally. Different weight percentages were used for the reinforcement particles, including 0, 2, 5, and 10 wt.% of Al2O3. Microstructural and mechanical properties were determined by SEM, EDS, and hardness tests. The Al2024/Al2O3 FGM spur gears were subjected also to dry sliding wear conditions. It was seen that hardness, strength, and wear resistance values increased by adding Al2O3 reinforcement particles to the Al2024 base material. In addition, the wear rate of FGM gears decreased by increasing the Al2O3 reinforcement particles in Al2024 alloy.

Investigation of microstructure and mechanical properties of SiC and FeCrC reinforced components fabricated with plasma wire arc additive manufacturing (P-WAAM)

In wire arc additive manufacturing, components are generally fabricated using commercial wires. In this study, the mechanical and microstructural properties of the material were improved by adding the powder to the feedstock wire. The effects of powder reinforcement on microstructure, tensile strength, wear behavior, and hardness have been investigated. In experimental studies, composite parts in the form of walls were successfully fabricated using AISI 304 wire material, SiC, and FeCrC powder-reinforced wires. According to the results, the powder reinforcement increased the hardness and wear resistance, but the tensile strength of the SiC-reinforced component did not increase sufficiently. On the other hand, the tensile strength, hardness, and wear resistance of the FeCrC-reinforced component increased compared to the W304 component. The microstructures of the components were generally determined as columnar dendrites in the bottom layers and equiaxed dendrites in the top layers. The best tensile strength was obtained in the FeCrC-reinforced horizontal sample (979 ± 45 MPa). The best wear resistance and hardness values were obtained in the SiC-reinforced component.

Service life assessment of yttria stabilized zirconia (YSZ) based thermal barrier coating through wear behaviour

Countless research has suggested Yttria-stabilized Zirconia (YSZ) to be a top candidate for being implemented as thermal barrier coatings (TBC). However, when exposed to prolonged service, temperature and stress variations succeed in initiating a catastrophic phase transformation from tetragonal to monoclinic structure in Zirconia. Hence, the estimation of endurance for YSZ-based TBC is necessary to minimize failure in such situations. The main purpose of this research was to determine the relationship between tribological investigations and the estimated lifespan of YSZ coatings accurately. The study used various methods such as wear resistance testing, optical profilometry, specific wear rate, and coefficient of friction to estimate the maximum durability of TBCs. The research also provided insights into the composition and microstructure of the TBC system and found the optimized concentration of Yttrium doping to be 3.5 wt %. The study discovered that erosion was the main cause of roughness depreciation from SN to S1000. The estimation of the service life was primarily made based on optical profilometry, specific wear rate (SWR), coefficient of friction (COF) and wear resistance values which were further supported by the results of chemical characterization of the samples through electron dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS) and X-Ray Diffraction (XRD) analysis. The results were reliable and accurate and suggested future areas of investigation, such as 3D profilometry for surface roughness and thermal conductivity evaluation using laser-assisted infrared thermometers.

Microstructure-property evolution of mechanically alloyed Al-20 wt% Si matrix powders and sintered composites reinforced withTiB2 particulates

Microstructural, physical and mechanical properties of Al–20 wt% Si matrix alloy powders and those reinforced with TiB2 and their sintered composites were investigated in relation to TiB2 content and mechanical alloying (MA) durations. Al–20 wt% Si matrix alloy powders and those containing 5 and 10 wt% TiB2 reinforcing particles were MA’d for 1, 2, 4, and 8 h followed by consolidation and sintering at 843 K. Si solubility in a-Al matrix increased with increasing MA duration. Increasing the TiB2 content, on the other hand, resulted in a systematic drop in Si solubility over the same MA period. Scanning electron micrographs of the sintered samples revealed sub-micron-sized, rod-shaped Si and spherical Al9Si phase particles. With increasing TiB2 content and MA durations, the microhardness of the Al20Si/TiB2 composites improved. The wear resistances of TiB2 reinforced composites better by 5 to 8 times than that of the as-blended and 1 h MA’d AlSi matrix alloy. Due to the presence of the Al3Ti intermetallic phase, sintered composite samples containing 10 wt% TiB2 particles MA'd for 8 h had the maximum hardness value and lower wear resistance values than those of the Al–20 wt% Si/5 wt% TiB2 composites.

Increasing the erosion resistance of compressor blades of gas turbine engine and gas pumping unit by applying vacuum-plasma coatings

A test for resistance to gas-abrasive wear of several variants of multilayer vacuum-plasma coatings based on titanium and vanadium nitrides of various thicknesses and number of layers was carried out. Erosion curves are given, areas of accelerated wear are determined, and comparative values of wear resistance are calculated. Based on the conducted microscopic studies, a mechanism of layer-by-layer wear of the studied multilayer coatings is proposed. It is shown that due to the creation of a special layered coating structure, including the alternation of highly hard nitride and relatively softer Ti and V layers, the resistance to gas-abrasive wear of parts of gas turbine engines made of titanium alloys is greatly increased.

ВЛИЯНИЕ ЛАЗЕРНОЙ МОДИФИКАЦИИ ПОВЕРХНОСТИ НА ФИЗИКО-МЕХАНИЧЕСКИЕ И ТРИБОЛОГИЧЕСКИЕ СВОЙСТВА ШТАМПОВОЙ СТАЛИ

The effect of laser modification of the surface on the value of the coefficient of elasticity, hardness, coefficient of friction and the amount of wear of the counterbody when testing pro­ducts made of tool die steel H12MF was investigated. The SVAROG-1-5DR laser complex (Russia) was used for laser processing. When setting different modes of laser processing, the power of laser radiation, the speed of movement of the laser beam relative to the treated surface and the focal length were varied. The measurement of Vickers hardness and wear resistance indicators was carried out using the MicroCombiTester and Tribometer units of the firm CSM Instruments (Switzerland). Rockwell hardness was measured using a TN 301 hardness tester from Time Group (China). The alloy structure was studied by metallography and X-ray diffractometry. It was found that the indicators of hardness and wear resistance of the surface layers of steel H12MF strongly depend on the laser treatment modes. These dependencies are extreme in nature, have maximums and minimums. The paper presents quantitative values of hardness and wear resistance indicators before and after laser treatment of the surface of this steel according to different modes. The reasons for the change in the hardness and wear resistance of the surface layers of steel H12MF after laser treatment according to various modes have been established. The results of the work were used to optimize the modes of laser surface treatment of steel H12MF in order to obtain maximum values of hardness and wear resistance. It has been shown that laser treatment of steel H12MF without melting is promising in terms of increasing hardness and reducing friction. The mode of laser modification of the SVAROG-1-5DR complex was obtained, which allows increasing the hardness by 55.5% while reducing the coefficient of friction by 12.9% and reducing wear by 27.3%.