Effects of contact pressure and surface roughness on fretting fatigue characteristics of a high workable Ti-4.5%Al-3%V-2%Mo-2%Fe alloy

The effects of contact pressure and surface roughness on fretting fatigue strength of Ti-4.5Al-3V-2Mo-2Fe conducted with annealing at 1123K were investigated in this study. Fretting fatigue tests in the low and high cycle fatigue life region of the alloy annealed at 1123K were carried out at each contact pressure of 10, 15, 30, 45, 75, 105 and 153 MPa. The fretting fatigue crack initiation mechanism is changed by contact pressure. At a contact pressure of 15 MPa, fretting fatigue life tends to be very low in each fatigue life region. The tangential force tends to increase with increasing contact pressure in each fatigue life region. Contrary to this trend, the tangential force coefficient tends to decrease with increasing contact pressure in each fatigue life region. The fretting fatigue life of the alloy buff-polished to produce mirror surface tends to increase about 20% and 10% in the low and high cycle fatigue life region, respectively as compared with the alloy wet-polished by water-proof emery paper up to #1000.