The early stage of fatigue crack initiation in a 12%Cr martensitic steel

Stability of fatigue cracks at 350 °C in air and in liquid metal in T91 martensitic steel

“…Annihilation can explain the softening and since it is a bulk effect, there is no reason why the presence of LBE should modify the response. Though martensitic steels have a multi-scaled microstructure, cyclic plasticity results in slip bands emergence at the external surface and in the formation of intrusion-extrusion pairs [18,19]. Extrusions form first, and then intrusions at interfaces of the microstructure [18].…”

“…Though martensitic steels have a multi-scaled microstructure, cyclic plasticity results in slip bands emergence at the external surface and in the formation of intrusion-extrusion pairs [18,19]. Extrusions form first, and then intrusions at interfaces of the microstructure [18]. The latter are preferential sites for short crack initiation and their developments are sensitive to the presence of the environment.…”

Effect of initial microstructure on surface relief and fatigue crack initiation in AISI 410 ferritic‐martensitic steel

“…This produces a decrease of the applied stress until its stabilization and the final rupture of the specimen. 10 There are very few reported studies 11,12 dealing with the application of the electron back-scattered diffraction (EBSD) technique to describe the initiation of microstructurally short fatigue cracks in ferritic-martensitic stainless steels. After a certain number of cycles, the lines intensified and turned into bands.…”

Investigation of microstructure and mechanical properties of A131 EH36 steel additively manufactured by selective laser melting and direct laser deposition

“…More elaboration is needed for harder martensitic structure as it was reported slippery bands were not possible for brittle martensitic steel [209]. However this type of slip feature was found in 12%Cr martensitic steel along the vicinity of lath boundaries which has been explained by Seidameova et al in a few mechanisms like vacancy diffusion induced redistribution of matter, grain boundary sliding, plane slipping and soft phase of retained austenite located at lath boundaries [204]. Similar slip markings were observed in SLMed SS630 [120].…”

“…The early crack propagation along longitudinal lath/block is observed from the fractured path of the fatigue sample SS200 tested at 400 MPa as shown in Figure 5-13. Fourthly, the effect of retained austenite on crack initiation/propagation is more argued, which may contribute to fatigue behavior in certain aspects [204]. A lowered fatigue strength of welded EH36 steel than TMCPed one is probably due to the welding defect, increased brittleness and hydrogen embrittlement where hydrogen is inevitably introduced into welding process.…”