Wear mechanisms in a hypereutectic aluminium silicon alloy sliding against steel

A study of wear mechanisms in an Al--17Si as-cast alloy is reported. Test specimens were rubbed against a hardened EN 24 steel surface (55 HRC) at 0.5 m/s for a sliding distance of 0.9 km. The pressure range was 1-30 MPa. The wear rate--pressure characteristics have a transition point. Post-transition wear is controlled by unstable material behavior in hump-shaped pockets of the near-surface regime. Room temperature compression tests over a range of strain rates from 0.1-100/s showed that, beyond a strain rate of 1/s, the stress--strain curve fluctuates with strain. At a strain rate of 100/s, the curve shows flow softening beyond a strain of 0.25. Graphs, Photomicrographs. 4 ref.--M.W.C.(UK/US).