Comparison of fatigue performance of HVOF spray coated and conventional roll bonded aluminium bearing alloys

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Description/Abstract

A comparative study on fatigue resistance of thin aluminium bearing linings (supported by harder backing steel layers) produced by high velocity oxyfuel (HVOF) spray coating and conventional roll bonding (RB) processes has shown that the former is superior to the latter with similar lining composition (Al-20%Sn-1%Cu-0.25%Mn) when compared on the basis of oscillating lining surface strains under a three point bend test condition. In terms of the integrity of the multi-layered bearing systems under oscillating stresses, the HVOF lining appeared to show worse fatigue resistance due to a poor/brittle bond between the lining and the backing steel layer resulting in the detachment of the lining from the backing layer. The newly developed RB alloy with reduced Sn content (Al-6.5%Sn-2.5%Si-1%Ni-1%Cu-0.25%Mn) and scattered intermetallics showed higher fatigue resistance than the HVOF and previous RB systems. This was linked to delayed initiation of short cracks leading to a longer overall lifetime compared to all other systems.