Long-Term Thermal Stability of Cerium-Modified B319 Aluminum Alloy

Focused on improving the elevated-temperature performance of the B319 aluminum alloy, this paper investigates, for the first time, the effects that varying Ce additions (i.e., 0.1, 0.3, 0.5, and 1.0 wt% Ce) have on the microstructure, hardness, and tensile properties of the alloy, following a conditioning process. The hardness tests were performed at room temperature before and after exposing the samples to 250 and 300 degrees C for 250 h. It was found that the hardness of the B319 + 0.1%Ce alloy was the highest in all three conditions, showing improvements of 9-11%. For the tensile tests, the cast alloys were tested at room temperature, 250 degrees C before conditioning, and at 250 and 300 degrees C after conditioning at their test temperatures (i.e., 250 and 300 degrees C) for 250 h. In all conditions, the B319 + 0.1%Ce demonstrated the greatest strength during the tensile test and consistently had YS and UTS values 6-10% greater than the unmodified B319 alloy. However, by comparing the YS and UTS values before and after conditioning, it was observed that the Ce additions had little effect on the strength retention, and in some cases (i.e., higher Ce concentrations), the strength retention was worse than for the unmodified B319 alloy.