Effect of heat treatment on microstructure and properties of AZ80 magnesium alloy
TANG Wei; HAN Enhou; XU Yongbo; LIU Lu
Environmental Corrosion Center; Institute of Metal Research; The Chinese Academy of Sciences
Cite this article:
TANG Wei; HAN Enhou; XU Yongbo; LIU Lu. Effect of heat treatment on microstructure and properties of AZ80 magnesium alloy. Acta Metall Sin, 2005, 41(11): 1199-1206 .
Abstract The effect of aging temperature on precipitates in AZ80 magnesium alloy was studied by using environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM). The precipitate/matrix orientation relationships (ORs) were measured, the precipitation mechanism was analyzed and the effect of precipitates on properties of alloy was tested. A new precipitated way of granular β-Mg17Al12 phase was found in aged alloy, which was granular and nucleated at grain boundaries (GBs) and twin boundaries. Plate-like or graunlar-like β-Mg17Al12 precipitated continuously in the alloy aged at higher temperature (310℃). The plates were parallel to the basal plane of matrix, nucleated and grew homogeneously in grains, and had little effect on properties of alloy. Whereas the granular β-phase was harmful for the alloy property. The discontinuous precipitation of β-phase occurred at lower aged temperature (<250℃), which was lamellar structure parallel or perpendicular to the basal plane of matrix, nucleated at grain boundaries and grew into grains. The grain boundaries moved into the grains with the growth of these discontinuous precipitates. The alloy was strengthened by the discontinuous precipitates evidently.
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