Effect of applied potential on fatigue crack propagation behavior of Fe24Mn steel in seawater

High cycle fatigue and fatigue crack propagation behaviors of β-annealed Ti-6Al-4V alloy

“…For the β-annealed Ti64 specimen, large transgranular cleavage facets were observed in near-threshold ΔK regime. Considering the size of each facet it was suggested that both colony boundaries and β grain boundaries affected the FCP behavior of β-annealed Ti64 specimen (Kim et al 2011;Jeong et al 2015b;Jeong et al 2014). With increasing ΔK, quasicleavage faceting became dominant for the β-annealed specimen.…”

Comparative studies on near-threshold fatigue crack propagation behavior of high manganese steels at room and cryogenic temperatures

“…4(c) were obtained from stress-strain curves and may have typical range of error in measurement. These graphs clearly indicate that the nearthreshold FCP behavior of high-Mn steels cannot be understood by tensile properties, unlike the S-N fatigue behavior which shows a strong dependency on tensile strength [2,[21][22][23][24]. No direct correlation was observed between the ΔKth values and yield strength, tensile strength and elastic modulus in the FCP-tested high-Mn steels.…”

“…The previous studies on the fractographic observation of FCP-tested high-Mn steels showed that the near-threshold FCP behavior of single phase austenitic steels was greatly influenced by the degree of slip planarity [2,23,24]. High slip planarity would encourage the reversibility of slip at the tip of a crack under fatigue loading, decreasing the FCP rates by reducing the accumulation of fatigue damage [25,26].…”

“…It has been proposed that the slip planarity of austenitic single phase steels is largely determined by the stacking fault energy (SFE), as well as the grain size [27][28][29]. The slip reversibility for the fatigued specimen with cleavage faceting as dominant fracture mode may roughly be expressed by the ratio between cleavage facet size and grain size [2,[22][23][24]. considerable difference in ΔKth values, the fracture mode of transgranular cleavage faceting was similar for the austenitic steels, including high-Mn and STS304 steels.…”

“…It was therefore hypothesized that different mechanisms play a role in improving the near-threshold FCP behavior of high-Mn steels, other than the martensitic transformation. Previously, it was proposed that the improvement in the near-threshold FCP resistance in high-Mn steels down to 173 K was largely related to the thermally activated process in light of a dislocation dynamics model [2,23,27,31]. At the tip of the crack, the thermally activated energy available to move the dislocation over the barriers decreases with decreasing temperature, thereby resulting in the increase in intrinsic FCP resistance of high-Mn steels at cryogenic temperature.…”