Home > News > Thermodynamic Analysis and Experiments of Magnesium-Strontium Master Alloy Prepared by Vacuum Reduction of Calcium Carbide

Thermodynamic Analysis and Experiments of Magnesium-Strontium Master Alloy Prepared by Vacuum Reduction of Calcium Carbide

wallpapers News 2021-11-18
Thermodynamic Analysis and Experiments of Magnesium-Strontium Master Alloy Prepared by Vacuum Reduction of Calcium Carbide
Theoretical calculation of the thermodynamics of the reaction thermodynamics of calcium carbide reducing magnesium oxide and strontium oxide. It is determined that at a certain temperature and pressure, it is thermodynamically feasible to prepare an Mg-Sr master alloy from a mixture of calcium carbide reducing magnesium oxide and strontium oxide. Using thermodynamic calculations as a guide, The Mg-Sr master alloy is prepared by vacuum reduction of magnesium oxide and strontium oxide with calcium carbide, and its composition and microstructure are analyzed by advanced testing techniques such as X-ray diffraction analysis, scanning electron microscopy, energy spectrum analysis, and chemical analysis. The analysis results show that The main components of Mg-Sr master alloy are α-Mg and Mg17Sr2, and the mass fraction in the alloy is 18%, and the microstructure is analyzed.
The effect of Mg-9Sr master alloy and its treatment process on the as-cast structure of AZ31 magnesium alloy was studied. The results showed that different states of Mg-9Sr master alloy (conventional as-cast, fast-solidified solid, homogeneous, and dissolved state were added to AZ31 magnesium alloy. Rolled state) has a good grain refining effect on AZ31 magnesium alloy. Among them, the rolled Mg-9Sr master alloy has the best refining effect, followed by a solid solution state, conventional as-cast state, and rapid solidification state. Mg-9Sr master alloy. Under the conditions of 0.1% Sr addition and 80 min melt holding time, the rolled Mg-9Sr master alloy can achieve a minimum average grain size of 62μm for AZ31 magnesium alloy.
The modification effect of Mg-Sr alloy and the heat resistance of Mg-Al-Sr alloy is closely related to its structure. Using the principle of infiltration method, Mg-Sr alloy, and Mg-Al-Sr alloy were successfully prepared, and the metallographic advanced testing techniques such as an optical microscope, electron scanning electron microscope, X-ray diffraction analyzer, etc. carry out in-depth research and analysis of its microstructure. The research results show that the structure of Mg-Sr alloy mainly includes dendritic matrix phase α-Mg and lath, Needle-like eutectic structure (α-Mg+Mg17Sr2); The structure of Mg-Al-Sr alloy is a fine dendritic primary α-Mg phase and strip-like eutectic structure, and its composition includes α-Mg Phase, eutectic compounds Mg17Sr2, Mg12Al17, Al4Sr and Mg-Al-Sr ternary compounds, their microstructure morphology and eutectic structure composition are related to the ratio of Sr/Al.
Thermodynamic analysis of the chemical reaction of the aluminum reducing agent to extract magnesium metal from MgO, 2MgO·B2O3 and 3MgO·B2O3. The effects of the pressure of the agglomeration, the addition of CaF2, the reduction temperature, and the amount of the reducing agent on the reduction rate of magnesium oxide were experimentally studied. Results It shows that appropriately increasing the agglomeration pressure of the reaction material is beneficial to improve the reduction rate of magnesium oxide, but a larger agglomeration pressure will reduce the porosity of the pellets, thereby hindering the release of product Mg vapor and the reduction process of magnesium oxide. The X-ray diffraction analysis of the slag showed that Al2O3 produced by thermite reduction would first be combined with CaO. Adding a small amount of CaF2 is conducive to the reduction of magnesium oxide, and CaF2 combines with the reduced slag to form 11CaO·7Al2O3·CaF2. Add 3% CaF2 to make The mass pressure is 90 MPa, and the reduction rate of magnesium oxide is 85% at 1200°C for 120 min, and the aluminum utilization rate is 74%.
 

Say something
  • All comments(0)
    No comment yet. Please say something!