Thermodynamics And Dynamics Research On Improvement Of Magnesium Purity Using Alloy Elements

Energy and green manufacturing have become increasingly prominent problems in the 21 st century. As a green engineering material, magnesium alloys have a broader application prospects in the field of aerospace, defense, electronics, automotive and transportations. However the performance of currently used magnesium alloys can not meet the requirements for industrial field of high-end manufacturing. The purification of magnesium alloys is one of the important methods to improve the ir mechanical properties, thus improving the purity of magnesium alloys is crucial factor and must be explored during research on magnesium al oys.So far, the preparations of high purity magnesium alloy mainly use high purity magnesium which is expensive and thus limits its application on industrial scale. The use of alloy elements in preparation process to purify the melt is a technique to realize magnesium self-purification which should be promoted. However, related scientific research issues are rather lacking. Threrfore, to carry out the effect of alloying elements on the self-purification of molten magnesium, not only provides the purification process design basis for the optimization of alloy elements, but also provides an important theoretical basis to research and develop ment of new magnesium alloy material with low cast, high purity and good comprehensive performance of the internal purified mechanism preliminarily.In order to reduce the main impurity elements(Fe, Si) content with low cost, Pandat thermodynamics calculation software is used to establish the relevant multiple magnesium phase diagram containing trace of Fe, Si, to study the effect of the solubility of impurity elements in magnesium alloy. It figures out the present forms of impurity elements in the melt and the relationship between the corresponding content and temperature, reaction time and the type of alloying elements. Furthermore, Stocks formula is used to determine the kinetic process and factors affecting the impurity rising or precipitating.On the basis of the above theoretical analysis, alloying element Mn is selected to verify the results of thermodynamic and kinetic calculations, which showed that the experimental results are in consistent with the calculated results. As verification experimental materials Mg-Mn master alloy and commercially pure magnesium are used to study the impact of Mn content, setting temperature and time on the purity of the magnesium melt, and the thermodynamic and kinetic calculations results using Pandat and Stocks formula. Experiental research shows that the impurities in bottom of the alloy was increased with the Mn content increased, the setting temperature decreased and under a certain setting time; the bottom contain impurities of Mn and Fe, Si combined with large density of particles; the purification effect is better when the Mn content is 2.5wt.% with setting 30 min at 655?.