Research On The Preparation And Refining Performance Of Al-5Ti-1B Master Alloy

Al-5Ti-1B master alloy was fabricated by hybrid element reaction method. The grain refinement was studied among the Al-5Ti-1B refiners prepared by own lab, domestic and imported.The effects of additive sequence, holding time and melting temperature on microstructure of grain refiner were analyzed when Al-Ti-B master alloy was fabricated. The KBF4and Titanium sponge were added individually or simultaneously, holding time was separately in20min,40min and80min, melting temperature was750℃,800℃and850℃.The results indicate that when KBF4and Titanium sponge were added together, microstructure and phase distribution will be fine and homogeneous. Also the average particle size of TiAl3and TiB2are15.38μm and9.35μm, respectively. The proper holding time is20min and melting temperature is850℃.The effects of the amount of addition, holding temperature and holding time of modification on the pure aluminum microstructure were discussed by using the above three Al-Ti-B refiners. The additional amount of Al-5Ti-1B master alloy selected0.1wt%,0.2wt%,0.3wt%,0.4wt%, and0.8wt%. Different holding temperatures were670℃,700℃,730℃,760℃. Holding time of modification selected5min,10min,20min and40min. The results show that the grain refinement performance can be improved obviously when the grain refiner increased from0.1wt%to0.2wt%, and the grain size decreased from291μm to212μm. So0.2wt%is proper.Also the grain size of aluminum is minimum at730℃of holding temperature and the three grain refiners could refine commercial pure aluminum when the holding time is10-20min.However when the time is more than20min, the grain size of aluminum increased obviously. So the best holding time is20min. When the grain refiner increased from0.2wt%to0.6wt%, tensile strength and elongation rate were increased obviously. When the additional amount was0.6wt%, the tensile strength reached at72.78MPa and the elongation is30.16%.