EFFECT OF WIRE-EDM CUTTING ON FATIGUE STRENGTH OF AZ61 MAGNESIUM ALLOY

Abstract

Effect of wire electrical discharge machining (wire-EDM) cutting on fatigue strength of an extruded AZ61 magnesium alloy at room temperature was investigated. The surface condition of the samples after the wire-EDM cutting process is compared to the samples which have undergone careful polishing on their surfaces. A series of high cycle fatigue tests are performed on both the wireEDM as-cut and polished samples with constant amplitude stress at the frequency of 10 Hz. Fractographic analyses were conducted on the tested samples to identify the mechanism of fatigue fracture. The finding show that the fatigue limit of wireEDM as-cut specimen is 20 MPa lower as compared to smoothly polished specimens. Fatigue cracks are found to initiate and propagate to final failure from a cutting pit on the wire-EDM as-cut specimens.