WEAR AND WEAR MECHANISMS OF AL-22-PERCENT-SI AL2O3F COMPOSITE/

The influence of FP-type alumina fibers on the wear characteristics of a cast Al-22%Si alloy, produced by the squeeze casting technique, has been assessed using a pin-on-ring dry wear test. Pin specimens of 8 m m diameter and 12 mm in length, were machined from Al-22%Si and Al-22% Si containing 26 vol% of alumina fibers, which were rubbed against rot ating steel ring (SAE 1045), at a sliding speed of 1 m s(-1) over the load range from 40 to 350 N. It was found that the addition of fibers increases the transition load for severe wear of this alloy by more th an three times and decreases the coefficient of friction. The mechanis m of wear does not change by the addition of fibers; there are still t hree regimes of wear; namely, oxidation induced delamination, high str ain induced delamination, and sub-surface delamination (microgrooving) . In both the matrix and the composite, the transition from mild to se vere wear takes place at the same wear rate, about 3.9 X 10(-3) mm(3) m(-1), although the transition load is completely different.