Effect of cobalt content on mechanical properties of 7%Al bronzes

Abstract

The tensile properties of three aluminium bronzes with 0, O·5, and 1·0%Co have been determined for a wide range of aging treatments. The proofstress and UTS of the as-quenched alloys increased in proportion to the cobalt content, demonstrating a considerable solid-solution hardening by cobalt. The cobalt-free alloy was largely unaffected by aging although some changes in the percentage elongation were measured. The cobalt-containing alloys were found to exhibit a substantial age-hardening effect giving useful increases in proof stress and UTS. The maximum proofstress of 290MN ^m-2 obtained in the 1·0%Co alloy is over twice that of the cobalt-free alloy. The tensile properties indicated that there is substantial latitude for further improvement in yield strength without entailing an unacceptably low ductility.