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The excellent performance of magnesium alloy and industrialization, market prospects to become recognized as a 21st century green engineering materials, will have an important role in the establishment of a resource-saving and environment-friendly low-carbon society. Mg-Mn-based alloy having excellent extrusion characteristics, good weldability and corrosion resistance can be widely applied, wherein the Mn as the basic element of the Mg-Mn-based alloy is generally added to the intermediate alloy in the form, but the actual production of Mg greater degree of solid solution and the melting point of the difference of the Mn is extremely small, and therefore very difficult Preparation of Mg-Mn intermediate alloy, commercial Mg-Mn intermediate alloy Mn content is not more than 3 wt%, and seriously affect the efficiency of its use. Therefore, the development of high content of Mn content Mg-Mn master alloy has become one of the bottleneck in the development of magnesium alloy. Firstly, using electromagnetic stirring casting prepared Mn content 10wt% and 12 wt% with high Mn content Mg-Mn master alloy by orthogonal experiment, Mn powder particle size, cooling, stirring time and stirring power of Mn content and Mn uniformity to determine the best preparation process; then Mg-15 wt% Mn master alloy was prepared by powder metallurgy technology and methods by orthogonal experiment of Mn powder particle size, to suppress the temperature, to suppress pressure and binder pressure green strength and ductility, to determine the optimal preparation; by homemade solid-liquid diffusion couples studied theoretically in the 963K, 983K, 1003K solid-state Mn dissolved in the liquid magnesium and magnesium alloys diffusion behavior; Four, the middle of the home-made alloy used to smelt growth rates of M1A, AZ91 and ZM21 magnesium alloys, and chemical composition, microstructure and mechanical properties of three national standards with the corresponding grades contrast, in order to evaluate the application of homemade intermediate alloy. The study found that: ① electromagnetic stirring casting Preparation of Mg-10 wt% Mn master alloy smelting process: Mn powder of particle size 150 to 68μm, cooling, cooled copper mold, stirring time 45min, stirring power 12.5kW; MG-12 wt% master alloy best smelting process: Mn powder of particle size from 150 to 68μm, cooling method, cooled copper mold, stirring time 45min, stirring power of 10kW. ② prepared by powder metallurgy Mg-15 wt% master alloy process: Mn powder particle size of 150 to 68μm, to suppress the temperature is room temperature, pressing pressure 125MPa, without the addition of a binder. (3) the use of Fick's second law and Boltzmann-Matano method, 963K, 983K, 1003K under solid-state Mn average diffusion coefficient in the liquid magnesium were 1.72 × 10-14m2 / s, 4.07 × 10-14m2 / s, 6.91 × 10-14m2 / s, the average dissolving rate of 9.393 x 10-10m / s, 2.219 x 10-9 m / s, 3.771 x 10-9 m / s; the solid Mn average diffusion coefficient in the liquid AZ91 were 8.10 × 10-15m2 / s, 8.29 × 10-15m2 / s, 2.27 × 10-14m2 / s, the average dissolution rate were 4.419 × 10-10m / s, 4.522 × 10-10 m / s, 1.473 × 10-9 m / s; Solid Mn average diffusion coefficient in the liquid ZM21 were 1.24 x 10-14m2 / s, 2.92 × 10-14m2 / s, 4.17 × 10-14m2 / s, the average dissolution rate of 6.747 × 10-10m / s, 1.593 × 10-9m / s, 2.273 × 10-9m / s. According to the Arrhenius equation to calculate the the solid Mn dissolved in the liquid magnesium, liquid of AZ91 and liquid ZM21 diffusion activation energy, respectively: 266.1 kJ / mol, 202.8kJ/mol 232.33kJ/mol. In order to save energy and improve the the intermediate alloy recovery rate, the rate of diffusion activation energy and dissolved results obtained melting M1a, the AZ91 and ZM21 heating, power in accordance with PAZ91 LT; PZM21 lt; PM1a, holding time can follow TM1A lt; tZM21 the lt; tAZ91 the law to determine the the intermediate alloy smelting process applications. ④ the homemade Mg-Mn intermediate alloy can be prepared M1A, AZ91 and ZM21, compared to the chemical composition and microstructure of the cast and the corresponding gold standard is not much difference in terms of mechanical properties, electromagnetic casting was stirred prepared The intermediate alloy melting the M1A, AZ91 and ZM21 mechanical properties up to standard, and master alloy prepared by powder metallurgy smelting ZM21 up to standard, and the melting M1A and AZ91 did not meet national standards.
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