Effect of cooling rate and Al content on solidification characteristics of AZ magnesium alloys using cooling curve thermal analysis

摘要

The solidification behavior of AZ Magnesium alloys in various cooling conditions was investigated using a computer-aided cooling curve thermal analysis method. In each case, the cooling curve and its first and second derivative curves have been plotted using accurate thermal analysis equipment and solidification characteristics were recognized from these curves. The cooling rates used in the present study range from 0.22 to 8.13 A degrees C s(-1). The results of thermal analysis show that the solidification parameters of AZ alloys such as nucleation temperature (T (N,alpha)), nucleation undercooling (a dagger T (N,alpha)), recalescence undercooling (a dagger T (R,alpha)), range of solidification temperature (a dagger T (S)) and total solidification time (t (f)) are influenced by variation of cooling rate. Also, the effect of Al content on these parameters was studied. Microstructural evaluation was carried out to determine the correlation between the cooling rate and secondary dendrite arm spacing.