High temperature abrasion behaviour of Al/SiCP composites

In this study, high temperature wear behaviour of commercially pure Al matrix and Al-8 wt.% Mg alloy matrix composites reinforced with 60 vol.% SiCp were compared. Composites were produced by pressure infiltration technique and their tribological performance were examined by abrasive wear tests at various temperatures up to 500 °C. Wear tests were carried out under normal stress of 0.7 N/mm2 by rubbing on 125 µm Al2O3 abrasive grains bonded to belts. At all testing temperatures, the Al-8 wt.% Mg alloy matrix composite exhibited lower wear rate than that of pure Al matrix composite. Wear rates of the composites were almost independent from test temperatures up to 200 °C. At temperatures higher than 200 °C, the wear rate of both composites increased dramatically with increasing test temperature

The effect of alloying elements (Si and Mg) on microstructure and mechanical properties of Al-60 % SiC composites produced by gas pressure infiltration technique

TMS, Mater. Proces. and Manufact. Div. Solidific. Commit.;TMS, Struct. Mater. Div. Composite Mater. Commitee2006 TMS Annual Meeting -- 12 March 2006 through 16 March 2006 -- San Antonio, TX -- 67288This study provides a brief overview of effects of alloying elements (Mg and Si) on the microstructures and mechanical properties of Al-60 % SiC composites, produced by gas pressure inflitration technigue. Upon addition of Mg and Si, the matrix hardness increases due to precipitation of intermetalics such as Al4C3, Si and Mg2Si. As an alloying element, the contribution of Mg to overall mechanical properties of the composite is higher than that of Si. If toughness is considered along with strength, the Mg content of the matrix should be less than 2 %, to obtain optimum mechanical properties from the 60%SiC particle reinforced Al matrix composites

Effect of the particle size on the mechanical properties of 60 vol. % SiCp reinforced Al matrix composites

WOS: 000175664000013The effect of the reinforcing particle size on the mechanical properties of 60 vol.% SiC reinforced aluminium matrix composites produced by the pressure infiltration technique was examined by compression, impact and wear tests. The compression strength and the impact resistance decreased with increasing reinforcing particle size. The composites exhibited different abrasion behaviour depending on the size of abrasive Al2O3 grains. On fine abrasive Al2O3 grains (85 mum), the abrasion resistance increased with increasing reinforcing SiC particle size. The contrary result was obtained on coarse abrasive Al2O3 grains (250 mum). The wear tests conducted on M2 quality tool steel revealed that reinforcing of aluminium with coarse SiC particles has a very beneficial effect on the wear resistance with respect to fine reinforcing SiC particles

Abrasive wear behavior and mechanical properties of Al-Si/SiC composites

In this study, the effect of Si addition up to 8% Si on the abrasive wear and mechanical properties of Al-Si/60 vol.% SiC composites produced by pressure infiltration technique has been investigated. Optimum properties in terms of improved strength and abrasion resistance without significant loss in toughness were obtained when the matrix alloy contained 1% Si. At Si contents higher than 1%, dramatic decrease of toughness was accompanied a reduction in strength and abrasion resistance. © 2004 Elsevier B.V. All rights reserved

Mechanical properties of Al-60 pct SiCp composites alloyed with Mg

In the present work, the effect of an Mg addition on the mechanical properties of the Al-60 vol pct SiCp composites were investigated by uniaxial compression, three-point bending, impact and wear tests (composite-metal and composite-abrasive types). The composites were produced by the pressure-infiltration technique. The composition of the Al matrix was varied between 0 and 8 pct Mg. The mean diameter of the SiC particles was 23 µm. Upon addition of Mg, Mg 2 Si precipitated in the matrix and the amount of the porosity dramatically decreased. Mg-alloyed-matrix composites exhibited higher strength, lower toughness, and higher wear resistance than pure-Al-matrix composites. During composite-metal wear testing, wear progressed in two sequential periods (running-in and steady state). Weight loss during wear testing decreased with increasing Mg content of the matrix. The degree of improvement of abrasive resistance depended on the abrasive-grain size. Above 200 °C, the composite-abrasive wear resistance decreased with increasing test temperature for all materials

Abrasive wear behaviour of Al-SiC composites produced by pressure infiltration technique

In this study, abrasive wear behaviours of compacts produced by pressure infiltration technique were investigated. Pure aluminum and SiC particles having 13 and 37 µm mean diameters were used in the infiltration process. The volume fraction of the SiC particles was 60% in the compacts. Abrasive wear tests were carried out under the normal load of 28 N, by rubbing the compacts to abrasive Al2O3 grains with diameters in the range of 85-250 µm. Wear tests revealed that, the effect of the size of SiC particles on the wear resistance of compacts, depends on the size of the Al2O3 abrasive grains being rubbed. The compact which had 13 µm SiC particles exhibited higher wear rate than the compact having 37 µm SiC particles when rubbed on fine abrasive Al2O3 grains (<150 µm). Wear tests performed on Al2O3 abrasive grains having diameters higher than 150 µm revealed that, the compact reinforced with 37 µm SiC particles had higher wear rate than the compact reinforced with 13 µm SiC particles

Wpływ obróbki cieplnej na korozje stopów AA6063 zawierajacych Al.₃Ti

The purpose of this study is to analyse the microstructure and corrosion properties of homogenised and aged AA 6063 aluminium alloys, containing up to 2% Ti, after the conventional casting technique. The microstructure of the homogenised and aged alloys was examined using an optic microscope, and scanning electron microscope. The micro-hardness test was used for the hardness measurements of the investigated alloys. Corrosion tests were performed by suspending samples of certain sizes into 30 gr/l NaCl + 10 ml/l HCl solutions, measuring the mass loss; potentiodynamic polarisation measurements were carried out in the same solution. The microstructure characterization of the investigated alloys shows the Al (matrix), non-shaped dark globular grey-coloured phase and rod-shaped phases formed at the grain boundaries. The non-shaped dark grey-coloured phase is Mg2Si. The rod-shaped phase, formed in the microstructure of the Ti-added AA 6063 alloys, is Al3Ti. The Ti content of the alloy increases, the Al3Ti phase tends to elongate and become plated. The results of the corrosion tests proved that the corrosion rate decreased in alloys containing less than 1% Ti, and the rate of corrosion increased in alloys containing more than 1% Ti, regardless of whether the alloys were homogenised and aged. Another observation was that aging heat treatment improved corrosion resistance.Celem niniejszej pracy jest analiza mikrostruktury i właściwości korozyjnych poddanych obróbce cieplnej stopów aluminium AA 6063, zawierających do 2% Ti, po odlewaniu konwencjonalnym. Mikrostrukturę homogenizowanych stopów zbadano za pomocą mikroskopii optycznej i skaningowej mikroskopii elektronowej. Test mikrotwardości zastosowano do pomiaru twardości badanych stopów. Badania korozyjne przeprowadzono poprzez zawieszenie próbki o określonych rozmiarach w roztworze 30 gr/l NaCl + 10 ml/l HCl i pomiar ubytku masy; pomiary potencjo-dynamicznej polaryzacji zostały przeprowadzone w tym samym roztworze. Charakterystyka mikrostruktury badanych stopów pokazuje matryce Al; ciemnoszare, nieregularne wydzielenia fazy Mg2Si; oraz na granicach ziaren pręcikowe wydzielenia fazy Al3Ti, obecne w mikrostrukturze stopów AA 6063 z dodatkiem Ti. Ze wzrostem zawartości Ti, wydzielenia fazy Al2Ti stają się wydłużone i płytkowe. Wyniki testów korozyjnych wykazały, że szybkość korozji spadła w stopach zawierających mniej niż 1% Ti, a wzrosła w stopach zawierających więcej niż 1% Ti, niezależnie od tego, czy stopy były homogenizowane i starzone. Zaobserwowano, że obróbka cieplna podwyższa odporność stopów na korozję

Effect of magnesium addition on wear behaviour of Al-70 vol.-%Al2O3p composites

WOS: 000184340800017In this study, dry sliding and abrasive wear behaviour of Al - 70 vol.-%Al2O3 particulate composite alloyed with Mg was examined. The composites were produced by a pressure infiltration casting technique. The composition of the matrix varied between 0 and 8 wt-%Mg, and the diameter of the Al2O3 particulates was 60 mum. Dry sliding wear tests were carried out on an unlubricated M2 quality high speed tool steel disc by a pin on disc type wear tester. Abrasive wear tests were run by rubbing the composites on abrasive Al2O3 grains. The results of the wear tests revealed that, both dry sliding and abrasive wear resistance of the composites increased with increasing Mg content in the matrix. MST/5421 Mr Ahlatci. Mr Karakas and Professor Dr Cimenoglu are in the Department of Metallurgical and Materials Engineering, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey ([email protected]). Associate Professor Candan is in the Technical Education Faculty, Division of Metal Casting, Zonguldak Karaehnas University 78100 Karabuk, Turkey. Manuscript received 4 February 2002: accepted 27 August 2002. (C) 2003 IOM Communications Ltd. Published by Maney, for the Institute of Materials, Minerals and Mining

Dry sliding wear behaviour of Fe-0.4C-25Cr-XNi cast steels

The effect of composition and heat treatment (solutionizing at 1200 °C and aging at 750 °C) on the room temperature mechanical properties (hardness and impact toughness) and dry sliding wear resistance of Fe-0.4C-25Cr-XNi steels (where nominal Ni contents were 4, 12 and 20 wt.%) have been investigated. The steel containing 4 wt.% Ni had ferritic and others (12 and 20 wt.% Ni) had austenitic matrixes along with M23C6 type chromium carbides. The applied heat treatment resulted in precipitation of sigma phase in austenitic matrix, which was accompanied by an improvement in hardness and a decrease in impact toughness. Ferritic matrix steel exhibited higher hardness and lower impact toughness than austenitic matrix steels. The results of the wear tests conducted on an unlubricated M2 quality tool steel disc revealed that at test pressures lower than 2.2 N/mm2, the dominant wear mechanism was mild wear. However, at high test pressures (>2.2 N/mm2) severe wear mechanism was operative. Increase of hardness and decrease of toughness resulted in a decrease in wear resistance under mild wear conditions. However, these mechanical properties were not effective on wear resistance under severe wear testing conditions. © 2005 Elsevier B.V. All rights reserved

Effect of magnesium addition on wear behaviour of Al - 70 vol.-% Al2O3p composites

In this study, dry sliding and abrasive wear behaviour of Al - 70 vol.-%Al2O3 particulate composite alloyed with Mg was examined. The composites were produced by a pressure infiltration casting technique. The composition of the matrix varied between 0 and 8 wt-%Mg, and the diameter of the Al2O3 particulates was 60 µm. Dry sliding wear tests were carried out on an unlubricated M2 quality high speed tool steel disc by a pin on disc type wear tester. Abrasive wear tests were run by rubbing the composites on abrasive Al2O3 grains. The results of the wear tests revealed that, both dry sliding and abrasive wear resistance of the composites increased with increasing Mg content in the matrix. © 2003 IoM Communications Ltd. Published by Maney for the Institute of Materials, Minerals and Mining