Microstructure and mechanical properties of die-casting ADC12+x(La+Yb) alloy

Abstract

ABSTRACT Both the mechanical properties and microstructure of die-casting ADC12 + x(La+Yb) alloy (x = 0, 0.3 wt.%, 0.6 wt.%, 0.9 wt.%) were investigated. It was found that the main compounds of the ADC12 matrix die-casting alloy are block-shaped and strip-shaped α-AlFeMnSi phase and net-shaped copper phase which was located at the grain boundary. Mixed rare earth (La+Yb) refined the microstructure and improved the mechanical properties of the alloy. Due to the addition of rare earth, the grain structure of the alloy was refined, the eutectic silicon was modified, and the mechanical properties were improved. At a rare earth addition of 0.6 wt.%, the tensile strength of the alloy increases from 280 MPa to 313 MPa and the elongation increases from 4% to 4.5%, which indicate increases of 12% and 12.5%, respectively. When the rare earth content was further increased, larger-sized rare earth compounds appeared in the alloy, thereby reducing its mechanical properties.