Sc and Sc-Zr effects on microstructure and mechanical properties of Be-Al alloy

Herein, we investigated the effects of Sc and Sc-Zr on the microstructure and mechanical properties of Be-Al alloy, showing that Sc alloying resulted in Be grain refinement and reduced the secondary dendritic arm spacing (SDAS) of these grains by 1/3, whereas Sc-Zr alloying further decreased the SDAS to 7.5 mu m and afforded equiaxed/cellular-like morphology with further refined Be grains. The above alloying resulted in the formation of intermetallic compounds (Be13Sc, Be13Zr, and Al-3(Sc1-xZrx)), increasing the macrohardness of the Be-Al alloy, with the microhardness and elastic modulus of the Be phase increasing to a larger extent than those of Al. Importantly, Sc-Zr alloying resulted in better microstructure modification and mechanical reinforcement than Sc alloying.