Influences of stress amplitude on the transient current behavior for LY12CZ aluminum alloy during corrosion fatigue

Influences of stress amplitude on the transient current behavior during corrosion fatigue for LY12CZ aluminum alloy in 3.5% NaCl at constant potential under the load control condition have been studied. The results indicated that as the cycling processed the transient current amplitude the number of the current peak will change, which could provide valuable information of the damage at different stages of corrosion fatigue. At the high stress amplitude there are two current peaks in each fatigue cycle during the whole cycling. However at the low stress amplitude there is only one current peak in each fatigue cycle at the saturated stage and the high crack propagation stage although there are two peaks at the crack initiation stage. The Questar Remote Measurement System (QRMS) observations show that there are more cracks on the surface at high stress amplitude as comparison to low stress amplitude, which agrees well with the higher current density and amplitude at relatively high stress amplitude recorded during corrosion fatigue.