2011•The Chinese Journal of Nonferrous MetalsRequires access
Effect of melt superheating treatment on solidification microstructure of AZ31 magnesium alloy
Fusheng Pan
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Abstract
The effect of different overheating temperatures on the solidification microstructure of AZ31 magnesium alloy was investigated.The overheating temperatures of 750,800,850,900 and 950 ℃ were applied.The secondary dendrite spacing of AZ31 magnesium alloy at different overheating temperatures was quantitatively investigated through the optical microstructures.A method was developed to analyze the mass fraction of Mg,Al and Zn elements in each region of a dendrite cell by scanning electron microscope with energy spectrum,which was used to assess the component homogenization of the solidification microstructures at different overheating temperatures.The results show that with the increase of overheating temperature from 750 to 900 ℃,the chemical composition segregation is reduced,the secondary dendrite spacing is decreased from 13 to 9 μm,and the average value of multi-point random microhardness is increased from 36.5 HV to 42.6 HV.The better melt overheating temperature of AZ31 magnesium alloy is 900 ℃.