Grain Refinement of Commercial EC Grade 1370 Aluminium Alloy for Electrical Applications

Abstract

The purpose of the present study was to investigate the effect of different grain refiners’ additions on structure and electrical conductivity of commercially electrically conductive (EC) grade 1370 aluminium alloy. A series of controlled lab scale experiments were carried out by addition of 0.1 wt. percentage Al-5Ti-1B, Al-3Ti-1B, OPTIFINE, TiBloy, and Al-3Ti-0.15C, grain refiners to molten aluminium at 730 ± 5 °C. The macro structural analysis showed that 0.1 Wt % of TiBloy, Al-5Ti-1B, Al-3Ti-1B, and OPTIFINE did not grain refine commercial EC grade aluminium. The Al-3Ti-0.15C master alloy showed, however, good grain refining performance, giving an equiaxed structure. Fading effect was observed in the samples grain-refined by Al-3Ti-0.15C master alloy. The electrical conductivity of all the grain-refined samples decreased between 0.02-0.75 ± 0.3 % IACS, compared to the reference samples of commercial pure aluminium. However, the electrical conductivity increased slightly by holding the melt, after the addition of the grain refiners, for 90 minutes, that might be due to settling of the particles by grain refiner additions.