Influence of Microscale Sc and Zr on Squeeze Casting Solidification Structure of 7055 Aluminum Alloy

摘要

Two kinds of aluminum alloy, 7055 and 7055-Zr-Sc (mass traction, %), were prepared by melting method. Direct squeeze casting technology was applied to melt for molding to study the influence of microscale Sc and Zr on the microstructure and property of 7055 aluminum alloy. The result shows that, there is certain refining function on 7055 alloy ingot by adding microscale of Sc or Zr; during the process of solidification, compound addition of 0. 10% Sc+ 0. 20% Zr firstly forms large numbers of dispersed primary Al3 (Sc, Zr) particles that are coherent with α (Al), which can refine solidification structure as the nucleation nucleus of α (Al). When the additive amounts of Sc and Zr reach to 0.30% and 0.18% respectively, the average grain size of ingot casting can reach to 0-15μm; so Al3 (Sc, Zr) particles play the function of heterogeneous crystal nucleus refining grain on 7055 alloy.