DETERMINATION OF RATES OF SOLUTION OF MASTER ALLOYS IN LIQUID ALUMINIUM BY THERMOELECTRIC POWER MEASUREMENTS

ABSTRACT A reliable, computer controlled procedure has been developped for the determination, via the measurement of thermoelectric power, of rates of true solution of alloying materials used industrially in the making of aluminium alloys. We have investigated the various parameters governing the rate of solution, namely: i) the nature of the alloying element (manganese, iron), ii) the morphology of the input material (powder, splatter, ingot), iii) the target composition. We have established that dissolution time is: i) unaffected by rate of addition, ii) roughly proportionnal either to powder particle size or to splatter thickness. We have developped an elementary model of turbulent forced diffusion. This model can be used to calculate dissolution times. The agreement between theoretical predictions and experimental findings has been found to be better than 20 %.