Mechanical Properties and Fatigue Behavior of Cast/Forged Al–1.2%Mg–1.0%Si–1.0%Cu Aluminum Alloys

抄録

Alloy samples were prepared from Y-block castings. After homogenization treatment, the block samples were held at 195 K, forged using a set of open dies, and then subjected to T6 heat treatment. The tensile specimens were tested to obtain UTS of 420 MPa and an elongation of 12%. After high-cycle fatigue testing, the bare sample exhibited fatigue strength of 117 MPa at 1 × 10⁷ life cycles; and the anodized samples yielded fatigue strength of 110 MPa. The fracture morphologies were observed using SEM and they were used to compute the stress intensity factor for crack initiation (ΔK_init). It was 1.97 MPa√m (at 7.2 × 10⁶ life cycles) for a bare sample fractured at 120 MPa stress amplitude.