Study On The Al-Ti-B-Re Master Alloys

The article contraposes the phenomenon that the refiner used widely has the lacuna when it refines the pure aluminum (The refining phases aggregate and deposit easily in the refiner; With time becoming long the declining capability of the refining effect is increased; Poisoning because of 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 better refining effect, longer refining effect, and 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, which will affect the absorptive of the elements in the master alloy Al-Ti-B-Re, and which 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 are used, such as metallographic examination, scanning electron microscope, X-ray, electron probe microanalyzer and ICP. 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 800°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 phases TiAl₃, TiB₂,AlTiRe, the size and distribution.During the experiment of refining, the results show that Al5Ti1BRe has stronger refining performance and long time efficiency than Al5Ti1B. The best result is that the size of the grain is 60μm; the effective duration is eight hours.We discuss the reason that the refiner has stronger refining performance and long time efficiency by adding rare earth. AlTiRe has more lattice planes matching with aluminum than TiAl₃, which provides AlTiRe with strong ability of resisting the decline of refinement. Besides AlTiRe decomposes and dissolves at a higher temperature and a lower speed than TiAl₃, the viscosity increase of aluminum melt resulting from the release of rare earth from AlTiRe is also responsible for the long time efficiency of Al5Ti1BRe.