Friction and wear characteristics of Al–Cu/C composites synthesized using partial liquid phase casting process
✍ Scribed by S.C Lim; M Gupta; W.B Ng
- Publisher
- Elsevier Science
- Year
- 1997
- Weight
- 342 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0261-3069
No coin nor oath required. For personal study only.
✦ Synopsis
During the sliding of aluminium alloys dispersed with graphite particulates, a layer of graphite is usually present at the sliding interface. This tribo-layer significantly reduces the amount of direct metal-to-metal contact, giving rise to low friction and a low rate of wear, making these composites useful candidate materials for anti-friction applications. Such self-lubricating composites are commonly fabricated via the squeeze casting, slurry casting or powder metallurgy route. These processes are expensive while the less-expensive conventional casting route is limited by the agglomeration of graphite particles in the composites, giving rise to poor mechanical properties. In this work, graphite ( particulate-reinforced Al᎐4.5 wt.% Cu composites with two effective graphite contents Al᎐4.5 Cu / 4.2 ) wt.% C and Al᎐4.5 Cu / 6.8 wt.% C were synthesized through an innovative partial liquid phase ( ) casting rheocasting technique, which is a modification of the conventional casting process. Unlubri-( ) cated without the use of conventional liquid lubrication friction and wear performance of these composites as well as the un-reinforced aluminium alloy was determined using a pin-on-disk tester. The results revealed that the graphite-reinforced composites have a higher wear rate than the un-reinforced matrix alloy while their frictional characteristics are very similar within the range of testing conditions. Combining these with the information gathered from worn-surface examinations and wear-debris analysis, it is suggested that there exists a certain threshold for the amount and size of graphite particulates in these composites to enable them to have improved tribological properties.