Influence of various parameters on the determination of the fatigue crack arrest threshold. Discussion

This report presents the results of a round-robin work on the fatigue crack arrest threshold (ΔK t h ) of 2618 aluminium alloy and AISI 316 steel. The main purpose was to develop a method for the determination of ΔK t h , and to examine the influence of various test parameters on this threshold. Among the parameters considered, only the load ratio (R) and the environment (vacuum) appear to have a significant influence on very slow fatigue crack growth rates (FCGR). Moreover, while the results obtained with the 316 steel show a great scatter, the importance of the adopted procedure is pointed out.