Aluminum base bearing alloy and method of producing same

Abstract

The invention provides an aluminum base bearing alloy which is excellent in both lubricating capability and fatigue resistance and is useful, e.g. in automotive engines. The bearing alloy consists essentially of at least one lubricating element such as Pb and/or Sn the total amount of which is more than 0.04 and not more than 0.07 by sectional area ratio to the aluminum matrix, Si the amount of which is in the range from 0.01 to 0.17 by sectional area ratio to the aluminum matrix, 0.2-5.0 wt % of at least one reinforcing element such as Cu and/or Cr, 0-3.0 wt % of at least one refining element such as Ti and/or B and the balance of Al. The grain size of the lubricating element(s) is not larger than 8 .mu.m, and the grain size of Si is not larger than 12 .mu.m and preferably not smaller than 6 .mu.m. The bearing alloy is produced by preparing a raw material alloy powder mixture in which Si grains are grown to the desired size by heat treatment, compacting the alloy powder mixture into a billet and extruding the billet at an extrusion ratio not lower than 10.