SUS430ステンレス鋼の疲労き裂進展における粒界微細組織の役割

抄録

Roles of grain boundary microstructure in fatigue crack propagation in SUS430 ferritic stainless steel was investigated to obtain a clue to grain boundary engineering for control of high-cycle fatigue fracture in this alloy. The ratio of intergranular fatigue fracture to the overall fracture path became higher when the SUS430 specimen subjected to cyclic deformation at the condition of lower stress intensity factor range ΔK. Fatigue crack was mainly branched when the crack propagated along grain boundaries. The branching of intergranular fatigue crack occurred when the crack tip which propagated along random boundaries reached at triple junction composed of two low-∑ CSL boundaries. The possible grain boundary microstructure for control for fatigue crack propagation in SUS430 stainless steel was discussed on the basis of the obtained observation results.