Distinct fatigue crack propagation limit of new precipitation-hardened aluminium alloy

New aluminium alloys were developed by adding excess Mg to the ordinary precipitation-hardened aluminium alloy, JIS 6061-T6. By analyzing the results of the fatigue tests and the coaxing effect test, the existence of a distinct fatigue crack propagation limit in these new aluminium alloys was confirmed using a small-holed specimen. Moreover, by comparing the fatigue process with that of the 6061 alloy, the possibility of generating the fatigue limit in face-centred cubic metals, which has been considered to be absent, was discussed.