Abstract:

Based on the recent research on fatigue crack initiation life, it is shown that the yield stress of metals has great effects on the fatigue crack initiation （FCI） threshold and life in long life range.Aluminum alloys and high strength steels with higher yield stress display higher FCI threshold and much longer FCI life, especially, in long life range under both constant and variable amplitude loading.Thus, the total fatigue life of metals with higher yield stress is longer.Consequently, the structural alloys with high yield stress should be selected in the design of structure elements. Moreover, the yield stress should be checked during the production of elements.

Key words: yield stress, fatigue crack initiation, life