| As one kind of light alloy, Mg alloy has such significant features as low density, high strength and rigidity, high damping prosperity, better shock absorption and electrical and magnetric shield perfoarmance, and also easily retrived. In areas where die-casting parts are widely used such as aviation and spaceflight, transportation and 3C production, Mg alloy can be found, especially in auto industries.Mg alloy has better mechanical performance under normal temperature. When temperature is higher than 120℃, it has worse mechanical performance, especially its anti- performance under high tempertature. The mechanical performance of Mg alloy has close relation with the size of crystalline grain. Through lessening the size of crastalline grain, it can enhnace the comprehensive prosperity of Mg alloy. To add changing sustance is one kind of main method. Currently, some reserachers added alkaline earth metal into the meting Mg alloy, small quantity of Sr can increase its heat resistance greatly. Yet, Sr has active chemical characteristics, if it is added into the alloy diretly, Sr can be damaged seriously and be harmful to the enviroment. If it is added as middle alloy, there will be unnecessary third of fourth substance. All these become bottle neck inhibiting the development of Mg alloy and needs to be resolved.Based on comparing two methods to produce Mg alloy, one of which is blending method, the other is melting, immersing and retiriving method, this study applies economical and enviomenal "melting salt electrolysis method " to produce Mg-Al-Sr alloy. In this study, the density differnce of Mg alloy and Sr salt are further considered.So the structure of electrolysis will be determined from the study of low density mixed melting salt which contains Sr. And also through adjusting parameters as electrolysis temperaturre, electrical current density, etc to analyze the change of electrical current, this study aims to find the optimal electrolysis technology condition. This study uses Mg-Al as negative pole, blending melting salt comprised of SrCl2-LiCl as electrolyte and analyze the experimental results using such tessting method as OM, SEM and XRD.The study showed that: 1) Using appropriate quantity ratio Mg-Al alloy as negative pole can make the meting salt electrolyte have larger choosing scope.The SrCl2-LiCl blending melting salt can suspend above the Mg-Al liquid. The alloy obtained in experiment is even in tissue and pure; 2) During the electrolysis process, due to the low density of metal Li , it will floating above the upper part of the liquid, it will cause the damage of Li, so the quantity of Li in alloy is low; while the density of Sr is much higher than that of Mg-Al alloy, so the metal Sr will spred and sink down ; 3) The alloy tissue of Mg-Al-Sr is comprized of tiny branch likeα-Mg, bar shape and flake shape tissue within common crystal. the constitutional sustances includeα-Mg, common crystal compoiunds Mg17Sr2, Mg12Al17 and Mg-Al-Sr compounds; 4) In Mg-Al-Sr compounds, there exists small quantity of Sr in first crystalized branch and crystal boundary as Al4Sr-α(Mg) layer , with the decrease of Sr, the volume of Al4Sr will decrease consequently, and the surpersaturation of crystalized Mg-Al will increase, at same time there will be Mg17Al12 . Using SEM to observe, there appeared specific bacilliform phase in Mg-9Al-Sr(0.2%Sr) alloy that contained very small quantity of Sr.
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