The Preparation Of Al-Ti-B-Re The New Kinds Of Master Alloy And The Research About Grain Refining Property

The article contrapose the phenomenon that the refiner used widely has the lacuna when it refines the pure aluminum (The second phases aggregate and deposit easily in the refiner; With time becoming long the declining capability of the refining effect is increased; Poisoning because the Zr, Cr), On the basis of research of Al-Ti-B we add the rear-earth and prepare the new kinds of refiner. We hope to improve the capability of the refiner and prepare the refiner that has batter refining effect, longer refining effect ,lower cost.During the course of experimentation the order of charging,the superheating temperature of aluminum melt,the temperature of holding,stirring and etc will be researched, who will affect the absorptivity of the elements in the master alloy Al-Ti-B-Re, and who will affect the shape,size and the distribution of the second phase; It will also be researched that the effect of the rear-earth to the declining of refiner,to the remelting property and to the refining property.Some experimental methods is used, such as metallographic examination,analyse by scanning electron microscope ,analyse by X-ray, analyse by electron probe microanalyzer and analyse by IGP. The results show that mixed addition is in favor of absorption of elements, and the refiner can has better microstructure; Casting of middle and low temperature(about 820°C) is in favor of improving property of the refiner; The stirring,the superheating temperature of aluminum melt and the temperature of holding will bring effect to the master alloy Al-Ti-B-Re, such as the shape of phase TiAl₃, TiB₂, AlTiRe, the size and distribution.During the experiment of refining,remelting of the refiner and the refining after remelting, the results can be educed that: Although with the time becoming long the grain refining property becomes badly( the additional quantity of the Ti is 0.01%, the contacting temperature is 750"C), the best result is that the size of the grain is 60.2 μ m, and grain refining property however is better, and the master alloy Al-Ti-B-Re has better refining property after it was remelted by different temperature and several times.The grain refining mechanism of Al-Ti-B master alloy was discussed elementarily by analyse about nucleus of pure aluminum and the existing theories.