Microstructure and Mechanical Properties of Purity Aluminum Refined with Salt Containing Ti and B Elements

The microstructure and mechanical properties of purity aluminum refined with salt containing Ti and B elements have been studied in detail with Optical Microscope and MTS (Mechanical Testing and Simulation). The salt containing weight ratio of 22.2 Ti : 1 B has the most refining effect on the purity aluminum with the finest structure and the best mechanical properties, meanwhile it also possesses the advantages of short reacting time (within 5 minutes) and long fading time (more than 20 hours). The refining effect of the salt increases with the content of Ti and B in the melting and the refining mechanism is mainly contributed to the heterogeneous nuclei of more fine TiAl3 particles dispersed in the melting, which come from the reaction between the salt and aluminum. Purity B contained salt has little or no directly refining effect, However, B contained salt has indirect refining effect on the purity aluminum when it is added simultaneously with Ti contained salt, this may be due to that the dispersive and fine boride (TiB2) could be taken as the heterogeneous nuclei for TiAl3 particle, and then prevents the coarsening of the TiAl3 particle.