| Fe is one of the important factors that deteriorate corrosion resistance ofmagnesium alloys. In this paper, solubility of Fe in magnesium was reduced thoughdecrease temperature, meanwhile Fe was settled into the crucible after stewingreasonable time, by this way magnesium ingots with high properties can be obtained.Appling the principles, AZ81and AZ61alloys were melted in Middle Stage TestWorkshop. After getting the expected effective results, mass productions of Mg alloyswere produced in ShengMei magnesium industry co., LTD. The results are following:The Mg-Fe binary alloy phase diagrams show that Fe does not react with Mg andthe solubility of Fe in magnesium decreases with the decrease of temperature.According to this principle, the Vary-temperature Measurements of Melt decreased thesolubility of Fe, though stewing reasonable time, Fe settled into the bottom of cruciblein the form of atoms. The content of second phases decrease and the species of thesecond phase do not change after Vary-temperature Measurements of Melt.Under the same holding time, the content of Fe presents a tendency of decreasewith the decrease of temperature. When the temperature decreases to630℃, the contentof Fe stay the same level and does not change with the holding time. Under the samestewing time, the content of Fe keeps decreasing with the decrease of temperature. Withthe stewing temperature and time are650℃and120min, the content of Fe is lowest(0.001%).The yield strength σy、tensile strength σband elongation δ improve obviously afterthe Vary-temperature Measurements of Melt. The fracture of squeeze-cast alloyspresents mixed characteristics of ductile and quasi-cleavage fractures. TheVary-temperature Measurements of Melt does not change the fracture morphologies andfracture modes. Though comparing electrochemical potentiodynamic polarizationcurves of Magnesium alloy, the corrosion potential shift negatively and corrosionelectricity decreases are researched after the Vary-temperature Measurements of Melt.Due to the decrease of content of Fe, the probability of contact corrosion is reduced, thefunction of the local cell of Mg is weakened and the resistance of hydrogen evolutionreaction increases.In the stewing process of magnesium alloy melt, the atom of Fe moves in a laminarflow state, at this time Re≤0.6,Cd24Reis used, the equation of velocity of Fe atoms and the sedimentation distance with time are kexp(2tAk)1andThe primary magnesium was adopted as raw material in this subject, compare tomagnesium alloy produced by high purity magnesium, the alloys after Vary-temperatureMeasurements of Melt present the advantages of low cost and simple productionprocesses, meanwhile, the content of Fe in casting is relatively more stable than that inhigh purity magnesium. It is obvious that mechanical properties of magnesium alloyafter Vary-temperature Measurements of Melt stay the same with alloy produced byhigh purity magnesium, and the corrosion resistance increases obviously. Therefore,Vary-temperature Measurements of Melt has effect on purifying magnesium alloy andimproving quality of casting, and has significant importance to simplify productionprocess and save cost. |
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