Friction and Wear Properties of Aluminum-Silicon Alloy Impregnated Graphite Composite (ALGR-MMC) under Lubricated Sliding Conditions

• Published in: Tribology transactions 2009-05, Vol.52 (3), p.331-345
• Main Authors: Goto, Hozumi, Suciu, Claudiu V., Inokuchi, Takahiro
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Aluminum-Silicon Alloy; Applied sciences; Composite; Contact of materials. Friction. Wear; Exact sciences and technology; Friction; Friction and Wear; Friction, wear, lubrication; Graphite; Lubricants & lubrication; Machine components; Mechanical engineering. Machine design; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Oil Lubrication; Tribology; Wear
• ISSN: 1040-2004; 1547-397X
• DOI: 10.1080/10402000802475353

In this work, friction and wear properties of aluminum-silicon alloy-impregnated graphite composite (ALGR-MMC) and its component matrices, graphite and aluminum-silicon alloy, in contact with bearing steel are investigated under lubricated sliding conditions. Pin-on-disk type wear experiments are conducted under "dry" sliding; i.e., in moist air with a relative humidity of 50% at 24°C; drop-feed lubrication; i.e., an oil drop with a certain volume selected in the range of 0.005-1 cm 3 is deposited on the disk surface before commencing the wear tests; and immersion lubrication; i.e., the pin-on-disk contact is submerged in a 90-cm 3 oil bath. Changes in friction and wear are continuously monitored. Tests revealed a reduction of the friction coefficient and wear rate for pins made in graphite with augmentation of the oil-drop volume. For aluminum-silicon alloy, breakdown of the oil film occurred below 0.03 cm 3 volume of the drop, and since this was accompanied by a drastic rise of the friction and wear, damage of the counter surface was observed. Oppositely, a gradual decrease of the friction and wear with augmentation of the oil-drop volume was found for ALGR-MMC, without the breakdown of the oil film and/or damage of the counter surface. All tested materials reached the minimum friction and wear under immersion lubrication; however, graphite showed the worst and ALGR-MMC the best anti-friction properties. Since the friction coefficient and the wear rate of ALGR-MMC were much lower than those of the component matrices under all lubrication conditions, one concludes that the proposed composite material can be successfully used under both partially and fully lubricated sliding conditions.