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1

Tribological and surface morphological characteristics of titanium alloys: a review

Gupta Munish Kumar, Etri Hamza El, Korkmaz Mehmet Erdi, Ross Nimel Sworna, Krolczyk Grzegorz M., Gawlik Józef, Yaşar Nafiz, Pimenov Danil Yu.

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e72, 1--23

EN

Being easily fabricated, welded, biocompatible, having a high strength-to-weight ratio, withstanding comparatively high temperatures up to 800°C and low modulus of elasticity make grade titanium and its alloys an important choice for automotive, biomedical and aerospace industries. In contempt of the different pleasant assets of Ti-6Al-4V alloy, the operation of this alloy is restricted especially when it comes to tribological and surface morphological characteristics. Enhancing these properties is important, for this purpose, a diversity of attempts and studies have been conducted. This paper mounts a review of morphological and tribological behaviors of titanium alloys including Ti-6Al-4V against different materials counting with carbide tools and other types of materials under dry and lubricated sliding conditions. The surface morphological, wear, and other properties have been discussed in this review article.

2

Effect of h-BN solid nano lubricant on the dry sliding wear behaviour of Al-B4C nanocomposites

Harichandran R., Selvakumar N.

Archives of Materials Science and Engineering

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2016

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Vol. 77, nr 1

5--11

EN

Purpose: In this paper, three composites with different B4C content and fixed h-BN nanoparticles reinforced aluminium composites were fabricated through ultrasonic cavitation assisted casting. The role of the B4C and h-BN nanoparticles content on the mechanical and tribological properties of the aluminium composites was evaluated. This study presents the report on characterizion and evaluation of mechanical properties of h-BN and B4C nanoparticles reinforced aluminium composites. Design/methodology/approach: Al-B4C-h-BN composites are fabricated using stir and ultrasonic cavitation-assisted casting processes. The prepared composites are characterized using X-ray diffraction, Scanning Electron Microscopy and Energy Dispersive Spectroscopy. The dry sliding wear behaviour of the Al-B4C-h-BN composites are investigated using pin-on-disc wear test. Findings: The results of microstructural study reveal that uniform distribution, grain refinement and low porosity in composite specimens. The wear properties of the hybrid nanocomposites, containing 4 wt% B4C and 2 wt. % h-BN, exhibit the superior wear resistance properties as compared to unreinforced aluminium matrix. Practical implications: The interest in use of hexagonal boron nitride nanoparticles (h-BN) as solid nano lubricant for aluminium has been growing considerably due to its self lubricating properties.

3

Wear mechanisms of fibre reinforced composite materials based on 2024 and 7075 aluminum alloys

Naplocha K., Kaczmar J. W.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

180--187

EN

Purpose: Determination of fibre reinforcement influence on wear rate and wear mechanisms were examined. Moreover, effect of fibre orientation and specimen pressure on the counterpart were analyzed. Design/methodology/approach: Composite materials based on 2024 and 7075 aluminium alloys were reinforced with 10-20 vol. % of alumina Saffil fibres and additionally choosen specimens with graphite fibres. Wear tests were carried out on pin-on-disc device where the specimens were pressed to the cast iron counterpart with forces corresponding to pressures of 0.8, 1.2 and 1.5 MPa. Findings: Wear mass loss for composite materials reinforced only with Saffil Al2O3 fibres decreased with increase of fibre content in the matrix. The largest wear rate in relation to the unreinforced alloy exhibited composites containing 20 vol. % of Saffil Al2O3 fibres, tested under the largest applied pressure of 1.5 MPa. The graphite fibres enhance the wear resistance of composite materials under all applied pressures. The lubricant medium originated form worn graphite fibres prevented composite from seizure and adhesive wear. Research limitations/implications: Fragmented alumina fibres acting as loose debris can enhance the wear rate both composite and iron counterpart. At high volume of graphite fibres produced preform possess low strength caused by weak joints between fibres. Practical implications: Composite 2024 and 7075 materials reinforced with hybrid preforms produced from alumina and graphite fibres exhibit good wear resistance. Originality/value: Manufactured composite materials will be considered as the friction materials for the high duty brakes.

4

Własności trybologiczne materiałów kompozytowych na osnowie stopu aluminium 7075 umacnianych włóknami Al2O3

Naplocha K., Kaczmar J. W.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 2 spec.

153--158

PL

Badano odporność na zużycie ścierne materiałów kompozytowych na osnowie stopu aluminium 7075 umacnianych włóknami Al2O3 Saffil. Pomiary przeprowadzono metodą pin-on-disc w warunkach tarcia suchego dociskając próbki do obracającej się żeliwnej tarczy. Określono wpływ ciśnienia wywieranego przez próbki oraz ukierunkowania włókien, w stosunku do powierzchni ścieranej na stopień zużycia. Materiały wytwarzano metodą prasowania w stanie ciekłym nasycając stopem aluminium 7075 kształtki ceramiczne z włókien Saffil o porowatości 80-90%. Odporność na zużycie materiałów kompozytowych, w stosunku do nieumocnionego stopu 7075, była nieznacznie gorsza przy mniejszym ciśnieniu 0,8MPa wywieranym przez próbkę z kompozytu na żeliwną tarczę. Pod większym ciśnieniem 1,2 MPa odporność stopu nieumocnionego była jeszcze lepsza, a ukierunkowanie włókien w materiałach kompozytowych nie miało większego znaczenia na zużycie. Zaobserwowano również znaczne zużycie przeciwpróbki, gdyż zużyty materiał kompozytowy wraz z rozdrobnionymi włóknami Al2O3 pełnił rolę ścierniwa. Wzrost odporności na ścieranie materiałów kompozytowych na osnowie stopu 7075 uzyskano po zastosowaniu umocnienia zawierającego oprócz włókien Al2O3 również włókna C.

EN

Wear resistance of 7075 aluminium alloy based composite materials reinforced with Al2O3 Saffil fibres was investigated. The measurements of wear were performed applying the pin-on-disc method at dry friction conditions with the gray iron counterpart. The effects of pressure of composite samples on the counterpart made of gray iron and the orientation of fibers in relation to the friction surface on wear rate were determined. The materials were produced by squeeze casting method where 80-90% porous ceramic preform were infiltrated. After T6 heat treatment hardness increased about 50-60% both for unreinforced alloy and composites containing strengthening Saffil fibres. Wear resistance of composite materials in relation to the unreinforced 7075 alloy was slightly worse at lower pressure of 0.8 MPa. Under higher pressure of 1.2 MPa wear resistance of unreinforced 7075 alloy was even better whereas no effect of orientation of fibers on wear in composite materials was observed. Additionally, significant wear of counterface in the presence of debris with fragmented Al2O3 fibres as abrasives was observed. Wear resistance improvement of composite materials was obtained when with alumina Saffil fibres Carbon C fibres in the preforms were applied.

5

Tribological properties of thixocasted and heat-treated hypoeutectic Al-Si alloy A356

Vencl A.

Scientific Problems of Machines Operation and Maintenance

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2009

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Vol. 44, nr 3

15-23

EN

This paper presents results of structural, mechanical and tribological tests of thixocasted and heat-treated hypoeutectic Al-Si alloy A356 (EN-Al Si7Mg0.3). The results of tribological tests were analysed and compared with the results of grey cast iron, which was choose as a standard material for cylinder blocks. The pin-on-disc tribometer was used to carry out tribological tests under dry and lubricated sliding conditions at different loads and speeds. The results showed that thixocasted and heat-treated Al-Si alloy under dry sliding conditions, for applied loads interval, could not be satisfactorily used since plastic flow of the material occurs. However, under lubricated sliding conditions tested material showed a low coefficient of friction without any plastic deformation.

PL

Przedstawiono wyniki badań strukturalnych, mechanicznych i tribologicznych stopu hipoeutektycznego Al-Si A356 (EN-AlSi7 Mg0.3). Wyniki testów tribologicznych zostały porównane z rezultatami uzyskanymi dla żeliwa szarego. W testach użyto stanowiska badawczego typu trzpień-tarcza. Badania obejmowały styk smarowany i niesmarowany dla szeregu wartości obciążenia i prędkości. Stwierdzono, że bez smarowania badany stop nie wykazuje pozytywnych własności z powodu występujących odkształceń plastycznych. W styku smarowanym badany stop wykazał niski współczynnik tarcia i brak odkształceń plastycznych.

6

Zużycie i struktura powierzchni po współpracy w warunkach tarcia technicznego suchego w kompozytach AK12-cząstki ceramiczne

Wieczorek J., Śleziona J., Myalski J., Dolata-Grosz A., Dyzia M.

Kompozyty

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2003

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R. 3, nr 6

131-135

PL

Przedstawiono korelacje pomiędzy strukturalnymi elementami budowy kompozytów a geometrią warstwy wierzchniej tworzonej w warunkach tarcia technicznie suchego. Na podstawie przeprowadzonych badań mikroskopowych i profilografometrycznych struktury powierzchni kompozytów AK12-A12O3 po współpracy opisano zależność pomiędzy wielkością cząstek zbrojących a geometrią warstwy wierzchniej kompozytu. Badania dowiodły możliwość sterowania geometrią powierzchni trących poprzez właściwy dobór geometrii komponentów.

EN

Aluminium-based metal matrix composites are well-known for their high specific strength, stiffness and hardness. They are gaining further importance as their potential for wear resistance becomes established. In general, for sliding against metal and abrasives, many studies have reported that composites exhibit better wear resistance than the unreinforced alloys. Aluminium-based metal-matrix composites have found application in the manufacture of various automotive engine components such as cylinder blocks, pistons and piston insert rings where adhesive wear (or dry sliding wear) is a predominant process. Materials possessing high wear resistance (under dry sliding conditions) are associated with a stable tribolaycr on the wearing surface and the formation of fine equiaxed wear debris. For adhesive wear, the influence of applied load, sliding speed, wearing surface hardness, reinforcement fracture toughness and morphology are critical parameters in relation to the wear regime encountered by the material. Article presents the results of the researches on the surface of composites MMCs reinforced Al2O3 particles after mating in technically dry friction conditions are presented. Investigations were made with the use of Taylor-Hobson profilograph. Tested materials were matrix alloy composites AK12 reinforced Al2O3 particles (10, 25.50 um) (Tab. 1), after collaboration with cast iron. For all samples sliding distance was 5000 m, load 35 N and sliding velocity 0.5 m/s. Abrasion was carried out with the use of tribological tester T-01 pin-on-disc. On the bowies of the investigations it can be stated that: In MMCs reinforced different diameter particles there is proportional dependence between geometry surface parameters and reinforced particles diameter. Friction coefficient value and wear resistance in investigated MMCs layers depend on particle size used as reinforcement. Together with reduction of particles diameter friction coefficient and wear value decrease. In tribological systems working in dry sliding conditions there is a possibility that tribological properties controlled by particle size change surface geometry and particle size decide wear character.

7

The role MoS2 in the mechanical and tribological behavior of super-hard coatings

Lungu C. P., Iwasaki K.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, Spec. is

369-374

EN

A new process for tribo-coatings was developed, where TiN and TiN/MoS2 films of 1~3mm in thickness were deposited by an electron cyclotron resonance - direct current hybrid sputtering system on mirror polished stainless steel or bearing steel flat substrates. Nanoindentation tests showed the increase in hardness from 35 š 5 GPa to 52 š 5GPa by MoS2 inclusion into the TiN matrix. Critical load measured by scratch tests, characterizing the adhesion strength, was found to be 4N and 16N for the TiN and TiN/MoS2 films, respectively. The tribological properties of the films were measured in dry conditions with a CSEM ball-on-disc tribometer and it was found that the super-hard TiN/MoS2 film exhibited lower values of the coefficient of friction than the TiN film. The physical and morphological properties of the films were also analyzed by atomic force microscopy and X-ray diffraction.

8

Zmiany struktury warstwy wierzchniej w procesie tarcia pary poliamid-stal

Polak A., Dryzek J.

Tribologia

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1999

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nr 5

619-624

PL

W obszarze tarcia technicznie suchego o przy smarowaniu smarami stałymi często występuje przenoszenie materiału. Na obu współpracujących powierzchniach tworzy się warstwa ślizgowa mocno przylegająca do podłoża. Struktura tej warstwy jest inna niż struktura materiału z którego powstała. Pomiary czasu życia pozytonów wykazały, że zmiany struktur pod powierzchnia tarcia występują na większej głębokości niż grubość warstwy ślizgowej.

EN

Often in the areas of dry friction and solid lubrication a material occurson both surfaces there is formed a transfer film strongly adhering to the substrate.The structure of this film is different than structure of the virgin material.The positron lifetime measurements revealed that the changes of structure occur deeoer than transfer film thickness.