Fretting fatigue behavior of shot-peened Ti-6Al-4V

الملخص EN

Fretting fatigue behavior of shot-peened, titanium alloy (Ti–6Al–4V) specimens of two thicknesses was investigated at room temperature.

Fretting fatigue life diagrams were established with and without shot-peening.

Shot-peening improved fretting fatigue life of Ti–6Al–4V.

X-ray diffraction method was used to measure residual compressive stresses from shot-peening before and after fretting fatigue.

Variation in the thickness of shot-peened specimens changed residual stresses at and away from the contact surface, and hence changed the crack initiation location, which was at the contact surface in thicker specimens but below the contact surface in the thinner specimens.

Further, there was relaxation of residual compressive stresses during fretting fatigue.

Finite element analysis of fretting fatigue specimens was also conducted.

Modified shear stress range parameter, a critical plane based fatigue model/criterion, was used to characterize fretting fatigue crack initiation behavior of the shot-peened specimens.

This was found to be an appropriate fatigue parameter that could be used to predict number of cycles to crack initiation, crack initiation location (on fretting surface as well as fracture surface), and initial crack orientation of shot-peened fretting fatigue specimens.