Original Article

Effects of Mn and Zr microalloying on the organization and high-temperature mechanical properties of twin roll casting 6061 aluminum alloy sheet

¹ School of Material and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, PR China
² Key Laboratory for Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, PR China

^* e-mail: ustlxuzhen@126.com

Received: 9 February 2025
Accepted: 14 May 2025

Abstract

In this work, Thermo-calc thermodynamic calculations, Castep first principles calculations and other calculations were used to design the alloy compositions, four Mn, Zr composite microalloyed cast 6061 aluminum alloys were prepared using horizontal twin roll casting. At the same time, with the help of Optical Microscope (OM), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Tensile Testing Machine and other testing equipment, the microstructure and mechanical properties of the sheets were be characterized. The effects of Mn, Zr composite microalloying on the organization and high-temperature mechanical properties of 6061 aluminum alloy cast-rolled sheets were discussed. The results showed that Mn, Zr composite microalloying has effectively improved the uneven organization in the alloy, defected such as partial aggregation of iron-containing phases, while promoted the generation of α-AlFeMnSi phase, β^″ phase and Al₃Zr-L1₂ phase, significantly strengthened the sheet. The β^″ phase and Al₃Zr phase are thermally stable and can improve the high-temperature mechanical properties of the alloy. The cast-rolled sheets with co-addition of Mn and Zr had better overall mechanical properties. Compared with the original sheet, the yield strength and tensile strength of the sheet increased by 67.25% and 27.97%, respectively, and the high-temperature yield strength increased by 25.91% compared with that at room temperature.