Short crack nucleation and growth in lean duplex stainless steels fatigued at room temperature

The room temperature cyclic behaviors of Lean Duplex stainless steels (LDSSs) LDX 2101 (UNS S3210) and AL 2003 (UNS S32003) were investigated. In both stainless steels an initial cyclic hardening followed by cyclic softening characterizes the fatigue behavior. The lower stress levels and the more rapid dislocation structure evolution observed in LDX 2101 in comparison with AL 2003 is explained by a solid solution hardening mechanism due to molybdenum in AL 2003. Short cracks initiate along extrusions in ferrite grains and austenite presents an effectiveness barrier to crack propagation.