Research Article Open Access

The Synergistic Effect of La And Yb on the Microstructure and Mechanical Properties of Al-Cu-Mg Alloy

Abstract

The Al-4.6Cu-1.6Mg alloys with different contents of La and Yb were fabricated by ultrasonic assisted casting in this study. The synergistic effect of La and Yb additions on the microstructure and mechanical properties of Al-4.6Cu-1.6Mg alloys was systematically studied. The results showed that adding La and Yb into Al-4.6Cu-1.6Mg alloys had an obvious grain refining effect and could form new two phases of Al₆Cu₆La and Al_7.4Cu_9.6Yb₂. The Al-4.6Cu-1.6Mg-0.6 (La+Yb) alloy exhibited the optimal microstructure and mechanical properties. Compared to Al-4.6Cu-1.6Mg alloy, the grain was obviously refined. According to the calculated results, the grain refining effect was attributed to the heterogeneous nucleation and compositional undercooling. Additionally, the yield strength, ultimate tensile strength and elongation of Al-4.6Cu-1.6Mg-0.6 (La+Yb) alloy were 181.2 MPa, 264.5 MPa and 6.3%, which were 41.2%, 45.1% and 75.0% higher than those of the unmodified alloy, respectively. The strength mechanisms of Al-4.6Cu-1.6Mg-0.6 (La+Yb) alloy were ascribed to the refinement strengthening, solid solution strengthening and second phase strengthening, in which the refinement strengthening was the main strength mechanism.

Xiuliang Zou1,2, Lanjian Yu1,2, Zijian Cheng1,2, Hong Yan1,2*

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