A STUDY OF THE LIQUIDUS IN ALUMINUM-URANIUM ALLOYS

Liquidus temperatures in the aluminum -uranium system have been redetermined for alloys containing 13 to 50 wt. % uranium. Thermal analysis, electricalresistance measurements, and metallography were employed in the investigation. The binary aluminumuranium alloys studied and, their corresponding liquidus temperatures are as follows: 17 wt. % uranium, 755 deg C; 17.5 wt. % uranium, 780 deg C; 24.5 wt. % uranium, 954 deg C; 30.9 wt. % uranium, 1068 deg C; 41.6 wt. % uranium, 1190 deg C; 51.2 wt. % uranium, 1265 deg C. Eutectic and peritectic temperatures were determined to be at 640 and 732 deg C, respectively. Binary alloys containing ternary addition of up to 1 wt. % silicon and up to 0.5 wt. % magnesium were studied also. Neither silicon nor magnesium were found to have any effect on the liquidus temperatures. However, silicon lowered the peritectic temperature from 732 to 700 deg C and among alloys coataining less than 30 wt. % uranium had a refining effect on eutectic UAl/sub 4/ particles. The only effect that could be attributed to the magnesium addition was a tendency toward coarsening the UAl/sub 4/ particles in alloys containing less than 30 wt. % uranium. (auth)