Effects of Zr additions on structure and tensile properties of an Al-4.5Cu-0.3Mg-0.05Ti (wt.%) alloy

The effects of different Zr additions (0.05wt.%-0.5wt.%) on the structure and tensile properties an Al-4.5Cu-0.3Mg-0.05Ti (wt.%) alloy solidified under a high cooling rate (18 °C·s-1), in as-cast T6 heat-treated conditions were studied. consists equiaxed grains α-Al with average size 64 μm which is unaffected by additions, indicating ineffectiveness grain refinement alloy. Scanning electron microscopy, along X-ray diffraction analysis revealed presence elongated θ-Al2Cu at boundaries; addition, coarse Al3Zr particles exist intergranular regions 0.5wt.% Zr-containing After heat treatment, θ fragmented; however, remained unchanged microstructure. Also, formation fine β′-Al3Zr θ″-Al3Cu/θ′-Al2Cu phases during treatment was transmission microscopy. results tests showed that increase strength both conditions, but reduce its elongation, especially addition. 0.3wt.% Zr-added condition has highest quality index value (249 MPa). Fractography fracture surfaces alloys ductile mode including dimples cracked intermetallic conditions.