Microstructure and Mechanical Properties of As-cast 5182 Aluminum alloy Modified with Al-RE and Al-5Ti-1B Master Alloys

The modification effects of Al-RE (rare earth) and Al-5Ti-1B master alloys on the microstructure and mechanical properties of as-cast 5182 aluminum alloys were studied. Experimental results show that both of the modifications refine the α-Al grains and the Mg2Si and (FeMn)Al6 eutectics. The Mg2Al3 phases exist in the forms of thin flake (β′-Mg2Al3) and small granule (β-Mg2Al3) for the unmodified 5182 aluminum alloy. Modifications with 0.1 wt% Al-5Ti-1B and 0.2 wt% Al-RE yield longer flakes of β′-Mg2Al3 and small amounts of β-Mg2Al3 granules. The other contents of the modifiers reduce the longer flakes of β′-Mg2Al3 but facilitate formation of the particles and islands of β-Mg2Al3. The 0.2 wt% of Al-RE modification yields the finest microstructure and the largest ductility; the 0.2 wt% of Al-5Ti-1B modification has better microstructure and the highest tensile strength