Tribological properties of A356 Al-Si alloy composites under dry sliding conditions

2014 ◽  
Vol 66 (1) ◽  
pp. 66-74 ◽  
Author(s):  
Aleksandar Vencl ◽  
Ilija Bobic ◽  
Blaza Stojanovic
Keyword(s):  
Aluminium Alloy ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Aluminium Alloys ◽  
Dry Sliding ◽  
Tribological Behaviour ◽  
Ceramic Particles ◽  
Content Type ◽  
Graphite Content ◽  
Graphite Particles

Purpose – Aluminium alloys are frequently applied in automotive and other industries, since they provide mass reduction. Besides positive effects, aluminium alloys have their shortcomings reflected, first of all, in inappropriate tribological properties of these materials. The aim of this research was to enable the production of cheap aluminium alloy matrix composite with favourable combination of structural, mechanical and tribological properties, focusing on the tribological behaviour. Design/methodology/approach – The A356 Al-Si alloy was used as a matrix for producing metal matrix composites in compocasting process. Three different materials, in form of particles, were added to the matrix (Al2O3, SiC and graphite). Hardness and tribological properties (wear, friction and wear mechanism) of heat-treated (T6) samples were examined and compared. Tribological tests were carried out on ball-on-block tribometer under dry sliding conditions. Sliding was linear (reciprocating). Counter body was alumina ball. Average velocity was 0.038 m/s (max. 0.06 m/s), sliding distance was 500 m and normal load was 1 N. Findings – The effect of two different ceramic particles and graphite particles on tribological properties of obtained composites was evaluated. Wear resistance of composites reinforced with SiC particles was higher and coefficient of friction was lower compared to the composite reinforced with Al2O3 particles. A dual hybrid composite (with SiC and graphite particles) showed the lowest value of wear rate and friction coefficient. Dominant wear mechanism for all tested material was adhesion. Research limitations/implications – It seems useful to continue the work on developing hybrid composites containing soft graphite particles with A356 Al-Si alloy as matrix. The major task should be to improve particles distribution (especially with higher graphite content) and to explore tribological behaviour in diverse working conditions. Originality/value – Particulate composites with A356 aluminium alloy as a matrix produced in compocasting process using ceramic particles (Al2O3, SiC) were investigated in many researches, but there are only few detailed analyses of dual composites (with the addition of ceramic and graphite particles). In some previous studies, it was shown that compocasting process, as relatively cheap technology, can obtain good structural and mechanical characteristics of composites. In this study, it was shown that even a low graphite content, under specified conditions, can improve tribological properties.

Tribological properties of Fe-Cr-B alloy for sliding boot in coal mining machine under dry sliding condition

2017 ◽  
Vol 69 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Hongbin Xuan ◽  
Gongjun Cui
Keyword(s):  
Coal Mining ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Normal Load ◽  
Mining Machine ◽  
Dry Sliding ◽  
Wear Resistant ◽  
Content Type ◽  
Wear Rates ◽  
1045 Steel

Purpose To improve the wear resistance of the sliding boot, the wear-resistant Fe-21 Wt.% Cr-5 Wt.% B alloy is prepared, and the wear mechanism is studied under dry sliding condition. Design/methodology/approach The anti-wear Fe-21 Wt.% Cr-5 Wt.% B alloy is prepared by powder metallurgy technique. The tribological behavior of Fe-Cr-B alloy sliding against ASTM 1045 steel pin is studied at 30-60 N and 0.03-0.12 m/s using a reciprocating pin-on-disk tribometer under dry sliding condition. Meanwhile, the ASTM 5140 and 3316 steel are studied as compared samples. Findings The friction coefficients of tested specimens increase with the increasing normal load. However, this effect is the opposite in case of different sliding speeds. The specific wear rates increase as the sliding speed and normal load increase. The Fe-Cr-B alloy shows the best tribological properties under the dry sliding condition and the wear mechanism is mainly ploughing. Originality/value This wear-resistant Fe-21 Wt.% Cr-5 Wt.% B alloy can replace the traditional materials to process the sliding shoes and improve the service life of coal mining machine.

Experimental study on the effect of load and rotation speed on dry sliding of silicon nitride

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhishuang Wang ◽  
Songhua Li ◽  
Jian Sun ◽  
Junhai Wang ◽  
Yonghua Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Silicon Nitride ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Wear Mechanism ◽  
Rotation Speed ◽  
Friction Pair ◽  
Test Method ◽  
Dry Sliding ◽  
Content Type

Purpose The purpose of this study is to investigate the effects of load and rotation speed on dry sliding of silicon nitride, including a series of tribological behaviors (friction coefficient, wear rate, temperature rise, etc.) and wear mechanism. Through the analysis of the above characteristics, the influence law of load and speed on them and the internal relationship between them are determined, and then the best comprehensive performance parameters of silicon nitride full-ceramic spherical plain bearings in dry sliding are predicted, which can provide guidance for the operation condition of silicon nitride full-ceramic spherical plain bearings in dry sliding. Design/methodology/approach The experimental study of different loads and rotation speeds under dry friction conditions was carried out by the using ball-disk sliding test method. Findings With the increase of load, the friction coefficient of silicon nitride friction pair and the wear rate of silicon nitride ball decrease continuously. With the increase of rotation speed, the friction coefficient of silicon nitride friction pair first increases and then decreases, and the wear of silicon nitride ball first increases and then decreases. With the increase of load and rotation speed, the wear mechanism eventually changes to adhesive wear. Originality/value Because of the low timeliness and inefficiency of bearing experiments, this work adopts a simple ball-disk model to comprehensively explore the influence rules of different conditions, which provides a theoretical basis for the subsequent practical application of silicon nitride full-ceramic spherical plain bearings.

High-Speed Dry Tribological Behaviors of CrNiMo Steel in Nitrogen and Oxygen Atmospheres

2011 ◽  
Vol 704-705 ◽  
pp. 877-885
Author(s):  
San Ming Du ◽  
Yong Zhen Zhang ◽  
Bao Shangguan
Keyword(s):  
Abrasive Wear ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Wear Mechanisms ◽  
High Speed ◽  
Normal Load ◽  
Dry Sliding ◽  
Tribological Behaviors ◽  
Electron Dispersion ◽  
Worn Surface

Abstract: In this article, the high-speed dry sliding tribological behaviors of CrNiMo steel against brass in nitrogen and oxygen atmospheres are investigated using a pin-on-disc tribometer. The worn surface is characterized by scanning electron microscopy and electron dispersion spectrums analysis. The wear mechanisms of CrNiMo steel are also analyzed. The results indicate that the tribological properties of CrNiMo steel are coincidental with the law of dry sliding of metal, where the friction coefficients decreases with an increase in sliding speed and with normal load. However, the atmosphere has obvious effects on the tribological properties of CrNiMo steel. In the sliding process, friction heat plays an important role on the tribological properties of materials in high-speed dry friction. The high-speed wear mechanism of CrNiMo steel varies at different atmospheres. In a nitrogen atmosphere, the wear mechanism of CrNiMo steel is mainly characterized by adhesion at a lower speed and load. When the speed and load are increased, melting trace is found in the worn surface accompanied by an abrasive wear. In an oxygen atmosphere, the mechanism is characterized by adhesion at a lower speed and load; with an increase in speed and load, it gradually transformed into oxidation wear and abrasive wear. The difference of the wear mechanisms in the different atmospheres and test parameters is primarily due to the transfer films formed on the contact surfaces of the sliding pairs. In our experimental conditions, the surface film is mainly the metal film in nitrogen, whereas, it is the oxide film in oxygen.

Study on the influence of round pits arrangement patterns on tribological properties of journal bearings

2019 ◽  
Vol 71 (7) ◽  
pp. 931-941 ◽  
Author(s):  
Yazhou Mao ◽  
Yang Jianxi ◽  
Xu Wenjing ◽  
Liu Yonggang
Keyword(s):  
Friction Coefficient ◽  
Markov Model ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Friction And Wear ◽  
Journal Bearing ◽  
Energy Dispersive ◽  
Content Type ◽  
Tribological Behaviors ◽  
Bearing Contact

Purpose The purpose of this paper is to investigate the effect of round pits arrangement patterns on tribological properties of journal bearing. In this paper, the tribological behaviors of journal bearing with different arrangement patterns under lubrication condition were studied based on M-2000 friction and wear tester. Design/methodology/approach The friction and wear of journal bearing contact surface were simulated by ANSYS. The wear mechanism of bearing contact surfaces was investigated by the means of energy dispersive spectrum analysis on the surface morphology and friction and wear status of the journal bearing specimens by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). Besides, the wearing capacity of the textured bearing was predicted by using the GM (1,1) and Grey–Markov model. Findings As the loads increase, the friction coefficient of journal bearing specimens decrease first and then increase slowly. The higher rotation speed, the lower friction coefficient and the faster temperature build-up. The main friction method of the bearing sample is three-body friction. The existence of texture can effectively reduce friction and wear. In many arrangement patterns, the best is 4# bearing with round pits cross-arrangement pattern. Its texturing diameters are 60 µm and 125 µm, and the spacing and depth are 200 µm and 25 µm, respectively. In addition, the Grey–Markov model prediction result is more accurate and fit the experimental value better. Originality/value The friction and wear mechanism is helpful for scientific research and engineers to understand the tribological behaviors and engineering applications of textured bearing. The wear capacity of textured bearing is predicted by using the Grey–Markov model, which provides technical help and theoretical guidance for the service life and reliability of textured bearing.

Friction of Thin Electroless NiP and NiP-SiO2 Coatings on Aluminium Alloy Substrate

2012 ◽  
Vol 527 ◽  
pp. 92-97 ◽  
Author(s):  
Nikolai K. Myshkin ◽  
Andrei Ya. Grigoriev ◽  
Dzmitry M. Gutsev
Keyword(s):  
Aluminum Alloy ◽  
Chemical Composition ◽  
Friction Coefficient ◽  
Aluminium Alloy ◽  
Tribological Properties ◽  
Contact Geometry ◽  
Secondary Structures ◽  
Dry Sliding ◽  
Tribochemical Processes ◽  
Friction Surfaces

Thin NiP and NiP+SiO2 coatings were deposited by electroless techniques on aluminum alloy plates. Dry sliding tests against Al2O3 counterbody with the ball on plate contact geometry and reciprocal moving were carried out. The results of tribological tests showed that the friction coefficient of the modified coating at loads above 500 mN by 3-4 times, and wear 1.4-2 times lower than for original NiP coatings. It was found that during friction of NiP and NiP+SiO2 coatings different tribochemical processes are realized. These processes lead to the formation of different by chemical composition of P, Ni and O of secondary structures on the friction surfaces and as result to different tribological properties of the investigated coatings.

Effect of load on the tribological properties of Si3N4-hBN composite ceramics sliding against Si3N4

2018 ◽  
Vol 70 (9) ◽  
pp. 1699-1705
Author(s):  
Dong Qiang Gao ◽  
Rui Wang ◽  
Wei Chen
Keyword(s):  
Abrasive Wear ◽  
Tribological Properties ◽  
Wear Mechanism ◽  
Friction And Wear ◽  
Water Lubrication ◽  
Content Type ◽  
Lubrication Film ◽  
Pin On Disc ◽  
Lubrication Condition ◽  
Worn Surface

Purpose The effect of the load on the tribological properties of Si3N4-hBN sliding against Si3N4 were investigated under dry and water lubrication condition. Design/methodology/approach Using a MMU-5G type pin-on-disc friction and wear tester. Findings Under the dry friction, the wear mechanism was dominated by ploughing and abrasive wear, and the contact status was elastic contact under the load less than 25 N. With the increase of the load, the friction coefficient decreased; the main wear mechanism was fatigue fracture, and the contact status turned into plastic contact. Under water lubrication, effective lubrication film could be produced on the worn surface, and it had a function of fluid lubrication under the load less than 15 N. With the increase of the load, the pin and the disc came into direct contact, and the friction and wear of the pairs were aggravated; the wear mechanism changed from chemical wear into abrasive wear and brittle spalling. Originality/value The study on the effect of the load on the tribological properties of Si3N4-hBN sliding against Si3N4 was investigated under dry and water lubrication condition in the way of contact stress.

Influence of anodic coatings on stress corrosion behaviour of 7017 aluminium alloy

2013 ◽  
Vol 61 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Panagiotis Spathis
Keyword(s):  
Sodium Chloride ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Corrosion Potential ◽  
Nacl Solution ◽  
Free Corrosion Potential ◽  
Content Type ◽  
Dry Air

Purpose – The purpose of this work was to study the cracking susceptibility of a 7017 aluminium alloy, after anodising under various conditions. Design/methodology/approach – Slow strain tests in dry air, laboratory air and sodium chloride solution were employed. Anodic oxide films were produced with various applied current densities and thicknesses, in horizontal or vertical orientation of the coatings, at the free corrosion potential and also at various anodic or cathodic potentials. For the interpretation of the results, a metallographic study of the specimens before and after straining to failure was carried out using a scanning electron microscope. Findings – The behaviour of anodic coatings was found to depend very much on the anodising conditions. The coatings reduced the ductility of the alloy in dry air but can actually increase the ductility in laboratory air and in 3.5 per cent sodium chloride solution. In most cases, the ductility of coated specimens was greater in 3.5 per cent NaCl solution than in dry air, possibly due to crack blunting by the aggressive environment. Anodic coatings moved the free corrosion potential of the alloy in the noble direction and both the anodised and the bare alloy generally suffered a reduction in ductility at potentials anodic or cathodic to the free corrosion potential, the fall being more rapid for the anodised alloy. Research limitations/implications – The mechanism causing the increased ductility of coated specimens in 3.5 per cent NaCl solution than in dry air remains yet to be confirmed. Practical implications – The selection of suitable anodic coatings for the protection of aluminium alloys against stress corrosion cracking depends on the anodising conditions. Originality/value – The paper provides information regarding the influence of anodising conditions on the anticorrosive properties of electrolytically prepared anodic coatings on aluminium alloys.

scholarly journals Some aspects regarding the influence of the anisotropy of an AA2021-T351 rolled thick plate on its tribological behaviour

2019 ◽  
Vol 20 (6) ◽  
pp. 610
Author(s):  
Elisabeta Pirva ◽  
Andrei Tudor ◽  
Adinel Gavrus ◽  
Nicolae Stoica ◽  
Sorin Cananau
Keyword(s):  
Aluminium Alloy ◽  
Tribological Properties ◽  
Thick Plate ◽  
Normal Force ◽  
Rolling Direction ◽  
Scientific Paper ◽  
Local Motion ◽  
Tribological Behaviour ◽  
Normal Forces ◽  
Numerical Studies

This scientific paper aims to study the influence of the anisotropy of an aluminium AA2024-T251 rolled thick plate on the surface tribological properties based on previous experimental and numerical studies concerning bulk and surface mechanical behaviour. Experimental friction tests have been made on the aluminium alloy thick plate surface using sliding of an ultra-high-molecular-weight polyethylene (UHMWPE) cylindrical pin. The used tribological test involves the generation of local motion along specified trajectories with different orientations under the action of a constant normal force and a constant slip velocity. Three different normal forces (3N, 5N, 7N) have been applied using five different sliding speeds (0.005, 0.05, 0.5, 1 and 5mm/s) along a linear trajectory of 3 mm length. In order to analyze the influence of the aluminium alloy anisotropy, the tests have been performed along three directions: a longitudinal one, corresponding to the rolling direction of the sample (0°), a transverse one, perpendicular to the rolling direction (90°), and a median direction (45°). Taking into account the observed bulk and surface anisotropy, especially concerning a fractal nature of the surface topography, an investigation was performed in order to determine its influence on the anisotropic tribological properties. In this purpose, fractal friction characteristics have been determined for the sliding process using a constant normal force Fn = 7N and the above five sliding speeds.

scholarly journals Effect of Addition of Graphite on Tribological Behaviour of Sic and Fly Ash Reinforced Copper Based Self-Lubricating Composites

2019 ◽  
Vol 8 (4S2) ◽  
pp. 976-978
Keyword(s):  
Fly Ash ◽  
Powder Metallurgy ◽  
Tribological Properties ◽  
Wear Behaviour ◽  
Loading Conditions ◽  
Tribological Behaviour ◽  
Graphite Content ◽  
Powder Metallurgy Process ◽  
Metallurgy Process ◽  
Self Lubricating Composites

In the present study 4 different combinations of composites are prepared with varying proportions of graphite content by keeping the same proportion of copper, SiC and Fly ash through powder metallurgy process. hardness, Microstructure and tribological properties are studied with varying sliding velocities(1, 2 & 3m/s) and loading conditions (10, 30 and 50N). The addition of graphite reduces the hardness, but the wear behaviour is enhanced with its addition.

scholarly journals MODIFICATION OF THE T-17 TESTER HOLDER TO ENABLE TRIBOLOGICAL TESTS TO BE CARRIED OUT IN A ROLLER-PLATE COUPLE

Tribologia ◽  
2018 ◽  
Vol 280 (4) ◽  
pp. 5-12
Author(s):  
Marek BARA
Keyword(s):  
Aluminium Alloy ◽  
Tribological Properties ◽  
Aluminium Alloys ◽  
Flat Surface ◽  
Test Stand ◽  
Alloy Surface ◽  
Surface Material ◽  
Tribological Tests ◽  
Rolling Elements ◽  
Anodised Aluminium

The aim of this paper is to propose a solution that will make it possible to perform tribological tests of materials intended for rolling elements (e.g., rollers) interacting with a flat surface (e.g., sliding door guide). Tribological tests were carried out on a T-17 test stand, which was equipped with a holder that made it possible to perform tests in the roller-plate couple. The paper presents the results of tribological tests of a typical polymer PA 6 used in sliding door systems interacting with anodised and non-anodised aluminium alloys. The analysis of the tribological tests was supplemented by stereometric studies. The studies showed the possibility of performing tests for the roller-plate couple with the use of a T-17 test stand. The influence of the modification of the aluminium alloy surface (material of the sliding door guide) on tribological properties of the examined friction node was also shown.

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