An investigation of short fatigue crack growth in Ti–6Al–4V with colony microstructures

This paper presents the results of an experimental study of the growth of two-dimensional, short fatigue cracks, in Ti–6Al–4V with well-controlled colony microstructures. The underlying crack/microstructure interactions associated with anomalous short fatigue crack growth behavior are elucidated for three colony microstructures with controlled α lath dimensions and β volume fractions. The fatigue fracture modes in the short crack regime are shown to be similar to those in the long crack growth near-threshold regime in the same microstructural conditions. However, unlike long cracks in the near-threshold regime, no evidence of closure contact-induced debris is observed on the fracture surfaces of the short fatigue cracks.