Refining mechanism of salts containing Ti and B elements in purity aluminum

The effect of refiners containing Ti, B elements on the microstructure of purity aluminum has been studied in detail with optical microscopy, scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX). It is shown that salts mixture containing 5Ti1B is the best refiner with the finest α-Al grain and more than 10 h fading time. It is ascertained from the analysis of SEM–EDAX and thermodynamics analysis that the refining mechanism of salts mixture is mainly contributed to the heterogeneous nuclei of more fine TiAl3 particles dispersed in the melting, which come from the reaction between the salts and aluminum. While (Al,Ti)B2 has little or no refining effect, but it will reduce the size of TiAl3 since the TiAl3 nucleates and grows along the (Al,Ti)B2 particle. That is to say, B atom has also refining effect on the purity aluminum when it is added simultaneously with Ti atom.