Influence of rolling temperature on microstructure and mechanical properties of Sc microalloyed Al-3.2Cu-1.5Li alloy

doi:10.13251/j.issn.0254-6051.2025.03.001

Abstract

Abstract: SEM, EBSD, TEM and tensile tests were used to investigate the influences of various rolling temperatures on the microstructure and mechanical properties of Sc microalloyed Al-3.2Cu-1.5Li alloy. The results indicate that the grain structures in hot rolled and T6 treated specimens are primarily composed of substructures. The fine and stable Al₃(Sc, Zr)/Al₃(Li, Sc, Zr) dispersed phases precipitated along dislocations or sub-grain boundaries are the reason that the Sc-containing Al-3.2Cu-1.5Li alloy has higher recrystallization resistance. Meanwhile, the precipitation of nanoscale Al₃(Sc, Zr)/Al₃(Li, Sc, Zr) particles efficiently prevents the growth of recrystallized grain during hot rolling and T6 heat treatment. Furthermore, as the rolling temperature increases, the tensile strength of the alloy first increases and then decreases, while the elongation has a rising tendency and then reaches the stabilizing stage. The alloy rolled at 420 ℃ possesses excellent overall properties, with a tensile strength of 480.4 MPa and an elongation of 13.0%, which can be attributed to the synergistic effects of fine grain, precipitation, dispersion and dislocation strengthening.

Key words: Al-3.2Cu-1.5Li alloy, trace Sc, rolling temperature, microstructure, mechanical properties

CLC Number:

TG146.2

Li Shenao, Chen Siwen, Niu Hongwei, Zhu Hongqian, Kan Yun, Jiang Yan, Wang Jian, Zhao Hongyun. Influence of rolling temperature on microstructure and mechanical properties of Sc microalloyed Al-3.2Cu-1.5Li alloy[J]. Heat Treatment of Metals, 2025, 50(3): 1-8.

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