Strain-Life of Shot Peening AA2017-T4

In the present work the effect of shot peening time on strain life of aluminum alloy AA2017-T4 was investigated. Tensile, fatigue and SEM tests were performed before and after shot peening at different times (3, 5, 10, 15, and 25 min). This alloy maintained its biliner behavior before and after shotting at all shotting time. The strain hardening exponent (n) and strength coefficient (k) increased at 15 min, while the values of fatigue strength exponent (b) and fatigue ductility exponent (c) were within the range of metallic materials. The NT was increased until reached to its higher value at 15 min shotting time. All shot peening times reveal improvement in the strain life in both elastic and plastic strain as compared with as received material. The fine size of dimples and microvide coalescence at fracture surface can be observed. This feature is an indication to the plastic deformation.