Microstructures and Mechanical Properties of a Squeeze-Casted Al-Zn-Mg-Cu Alloy after Heat Treatment

Abstract:

The effects of heat treatment on the microstructures and mechanical properties of a squeeze-casted Al-6.8%Zn-2.7%Mg-2.0%Cu alloy were studied by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It is found that squeeze casting can refine the microstructure of the alloy markedly accelerates the diffusion process of solute atoms during solution heat treatment. After solution heat treatment at 470°C for 10h and artificial aging at 130°C for 24h, the tensile strength and the elongation of the squeeze-casted alloy reach 590MPa and 5.0%, respectively, which are almost equal to those of the wrought alloy, and are significantly higher than those of the gravity-casted alloy (435MPa and 1.3%). Based on the experimental results, the mechanism of microstructural evolution and the effect of squeeze casting on the kinetics of solute diffusion and aging precipitation of the squeeze-casted Al-Zn-Mg-Cu alloy were discussed.

• Periodical: Materials Science Forum (Volume 788)
• Pages: 187-192
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.788.187
• Online since: April 2014
• Authors: Lei Lu*, Da Tong Zhang, Yuan Yuan Li
• Keywords: Al-Zn-Mg-Cu Alloy, Heat Treatment, Mechanical Property, Microstructure, Squeeze Casting

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