Study about improving mechanism of electrical conductivity of AA1070Al treated by a novel composite boron treatment with trace Ti

Abstract In this paper, a novel titanium (Ti) assistant composite boron (B) treatment (TBT) was done to improve the electrical conductivity (EC) of AA1070Al and the effects of Ti addition, holding time and stirring on EC of AA1070Al were studied in detail. Results show that the EC of AA1070Al firstly increased and then decreased with the increase of Ti addition, and the optimal addition of Ti is 0.05 wt.%, promoting more transition metal (TM) elements dope into composite borides. Furthermore, composite borides can fully sink down at the bottom of Al melts with the extension of holding time, and the optimum holding time of TBT is shorted to 20 min from 90 min (conventional boron treatment). Through TBT and stirring, more TM elements further react with the unreacted B of conventional borides center, thus achieving high boron treatment efficiency and EC. Correspondingly, the content of excessive B is neutralized to 66 ppm from 266 ppm, reduced by 75.2%. At last, the EC of AA1070Al can reach 66.9% International Annealed Copper Standard (IACS), improved by 7.2% compared with without any treatment (62.4% IACS). Based on this, a schematic diagram is drawn to analyze the complex mechanism of a novel composite boron treatment and provide theoretical guidance for Al melt treatment.