I wonder if necking can occur during strain-controlled low-cycle fatigue deformation (R=-1)? I found that the fracture area is smaller than the initial area after low-cycle fatigue deformation in a polycrystalline superalloy. Can this be called necking? What is the mechanism of necking if the total strain amplitude is controlled?
The fracture surface is as follows. The area is about 27.5 mm2, which is smaller than the initial area (33.18 mm2 ).