Research on Microstructure Evolution in Al-9.8Zn-2.0Mg-1.8Cu Alloy during Solution Treatment

Abstract:

The microstructure of as-extruded Al-9.8Zn-2.0Mg-1.8Cu aluminum alloy and its evolution during solution treatment were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), differential scanning calorimetry (DSC) analysis and electron back-scatter diffraction (EBSD). The results indicated that second phase of the as-extruded alloy mainly consisted of Mg (Zn, Cu, Al)₂ and Fe-rich phases. After solution treated at 475°C for 4h, Mg (Zn, Cu, Al)₂ phases were dissolved into the matrix, while Fe-rich phases still existed. Fe-rich phases cannot dissolve by prolonging solution time. The room temperature tensile strength gradually increased by prolonging solution time at 475^oC. The ultimate tensile strength of the alloy reached 700MPa after both single and two-step solution treatments.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 2336-2341
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.2336
• Online since: November 2016
• Authors: Bai Qing Xiong*, Kai Wen, Yong An Zhang, Xi Wu Li, Zhi Hui Li, Shu Hui Huang, Hong Wei Liu, Hong Wei Yan
• Keywords: Aluminum Alloy, Mechanical Properties, Microstructure, Solution Treatment

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