SUN Y C,CHEN Z F,XU Z,et al．Effect of Mn and Zr composite microalloying on the microstructure and properties of 6061 aluminum alloy cast-rolling plate［J］.Journal of Henan Polytechnic University(Natural Science)，doi:10.16186/j.cnki.1673-9787.2023120081.

doi: 10.16186/j.cnki.1673-9787.2023120081

Received：2023-12-31

Revised：2024-01-22

Online：2024-03-06

Effect of Mn and Zr composite microalloying on the microstructure and properties of 6061 aluminum alloy cast-rolling plate (Online)

SUN Yuchong¹, Chen Zefu¹, XU Zhen¹, TIAN Shuang¹, LIU Zhimin¹, ZHANG Wei¹

(1. Liaoning University of Science and Technology, Anshan 114051, Liaoning,China;2. Liaoning Zhongwang Group Co., Ltd., Liaoyang 111003, Liaoning,China)

Abstract: Objective In order to explore the effect of Mn and Zr composite microalloying on the microstructure and mechanical properties of 6061 aluminum alloy cast-rolling plates, three kinds of 6061 aluminum alloy cast-rolling plates with different compositions were prepared in this work, namely the original 6061 aluminum alloy plate, the 6061-0.4Mn aluminum alloy plate with Mn element added alone and the 6061-0.4Mn-0.3Zr aluminum alloy plate with Mn and Zr composite added. Methods By using EBSD, SEM, room temperature tensile mechanical properties test and tensile fracture analysis, we studied the microstructure and properties of three kinds of 6061 aluminum alloy cast-rolling plates. Ｒesults The research results showed that the Mn element could not only refine the grain structure of 6061 aluminum alloy cast-rolling plate, increase the proportion of small angle grain boundaries, and inhibit the recrystallization, but also promote the transformation of AlFeSi phase to α-AlFeMnSi phase, improve the morphology of AlFeSi phase, reduce the volume fraction of AlFeSi phase, inhibit the aggregation of AlFeSi phase, and promote its dispersion distribution. The results of room temperature tensile mechanical properties test and tensile fracture surface analysis showed that compared with the original 6061 aluminum alloy cast-rolling plate, the strength of 6061 aluminum alloy cast-rolling plate with Mn element added alone was improved, but the plasticity was significantly decreased, and the fracture surface showed brittleness. In contrast, the composite microalloying of Mn and Zr could greatly reduce the proportion of small angle grain boundaries and enhance the inhibition effect on the recrystallization of the microstructure of 6061 aluminum alloy cast-rolling plate. The {100}<001> Cube texture was formed in the microstructure of the cast-rolling plate, which achieved the texture strengthening and further improved the strength and plasticity of the cast-rolling plate. At this time, the fracture surface presented toughness. Conclusion Overall, the comprehensive mechanical properties of the Mn and Zr composite microalloy 6061 aluminum alloy cast-rolling plate were better. Compared with the cast-rolling plate with 0.4 wt.% Mn alone, its tensile strength, yield strength, and elongation were increased by 18.8%, 37.8%, and 59.5%, respectively.

Key words: microalloying; casting and rolling; texture strengthening; microstructure and properties