High‐Cycle Fatigue Behavior of an Ultrafine‐Grained Ti–6Al–4V Alloy Processed by ECAP and Extrusion

This work is focused on an investigation of the high‐cycle fatigue behavior of a Ti–6Al–4V alloy subjected to a combination of equal‐channel angular pressing and extrusion. Samples with a bimodal microstructure and with an ultrafine‐grained (UFG) structure are tested using a cyclic rotational bending. The fatigue endurance of the UFG alloy is almost 40% higher as compared to the alloy with a bimodal microstructure. The main differences in the fracture surfaces of the UFG and bimodal Ti–6Al–4V alloy are considered. The effect of the UFG structure on the resistance of the alloy to fatigue crack initiation and propagation is also discussed.