Influence of Sc and Zr additions on microstructure and properties evolution of Al–Zn–Mg alloy

• Published in: Journal of materials science Vol. 57; no. 3; pp. 2208 - 2228
• Main Authors: Jiang, Ke-Da, Zhang, Zhen, Zhu, Wen-Bo, Pan, Qing-Lin, Deng, Yun-Lai, Guo, Xiao-Bin
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2022; Springer; Springer Nature B.V
• Subjects: Alloys; Aluminum base alloys; Characterization and Evaluation of Materials; Charge transfer; Chemistry and Materials Science; Classical Mechanics; Corrosion; Corrosion and anti-corrosives; Corrosion currents; Corrosion resistance; Corrosion resistant alloys; crystallization; Crystallography and Scattering Methods; dielectric spectroscopy; Electrochemical impedance spectroscopy; Fracture toughness; Grain structure; Impact strength; Magnesium; Materials Science; Mechanical properties; Metals & Corrosion; microstructure; Pitting (corrosion); Polymer Sciences; Precipitation hardening; Recrystallization; Scandium; Solid Mechanics; Specialty metals industry; Strengthening; Stress corrosion cracking; Tensile properties; Tensile strength; Zinc; Zinc compounds; Zirconium; Zirconium compounds
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-021-06692-6

In this study, the effects of different Sc + Zr compound addition on the tensile properties, impact toughness, stress corrosion cracking (SCC) properties, polarization curves, electrochemical impedance spectroscopy (EIS), and pitting corrosion (PC) of Al–Zn–Mg alloys are investigated. The results show that the Sc + Zr co-addition significantly inhibits the recrystallization behavior, refines the grain structure, and improves the tensile properties and impact toughness of the studied alloys. In fact, 0.43 wt% Sc + Zr-containing alloy achieves the maximum tensile properties, the tensile strength and yield strength are increased by 60.4 and 71.5 MPa, respectively. The impact toughness of 0.30 wt% Sc + Zr-containing alloy is 36.5 J/cm 2 , which is increased by 6.4 J/cm 2 . The Sc + Zr co-addition significantly reduces the SCC sensitivity, increases the charge transfer resistance, decreases the corrosion current density, and improves the PC resistance of Al–Zn–Mg alloys. The results of the strengthening model show that the main strength mechanism of Al–Zn–Mg alloys is precipitation strengthening of conventional η′ phases. The high toughness and corrosion resistance of alloys with Sc + Zr co-addition associated with the recrystallization resistance and the grain structures yielded by coherent Al 3 Sc x Zr 1- x particles. Graphical Abstract