Microstructural Evolution During Homogenization Heat Treatment for an Al–0.92Mg–0.78Si–0.60Zn–0.20Cu–0.12Zr Alloy
Homogenization heat treatment on an Al–0.92Mg–0.78Si–0.60Zn–0.20Cu–0.12Zr alloy was investigated by OM (optical microscopy), DSC (differential scanning calorimetry), energy dispersive X-ray diffractometry (EDX), and SEM (scanning electron microscopy) in the present work. The results indicated that with homogenization temperature increasing, the grains enlarged and the secondary phases dissolved into matrix gradually. The residual phase was Fe-rich particle after the alloy homogenized at 550 °C for 24 h and Zr-containing particle with larger size precipitated. While grains of the alloy with almost no change were observed after double-stage homogenization treatment, and the phases dissolved into matrix completely and Zr-containing particle with smaller size precipitated. Meanwhile the size of Zr-containing particle changed little with prolongation of second-stage time. The ideal homogenization process for the alloy was to homogenized at 430 °C for 10 h, subsequently followed by 550 °C for 24 h.
KeywordsAl–Mg–Si alloy Homogenization treatment Microstructural evolution
This study was financially supported by the National Key and Development Program of China (No. 2016YFB0300802).
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