| Abstract Scope |
Binary Al-Ce alloys have impressive high-temperature mechanical properties due to the presence of the thermally-stable Al11Ce3 intermetallic that forms upon eutectic solidification. However, the aluminum solid-solution channels are still susceptible to easier plastic deformation at high temperatures. Addition of Er, Sc and Zr enables the formation of high-number-density, coarsening-resistant, L12-ordered precipitates within these channels following specific aging regimens. This study focuses on the thermo-mechanical stability of these L12 precipitates and their effects on the strengthening mechanisms observed. Quasi-static tensile tests are conducted on peak-aged samples at room temperature, 200°C and 300°C, to determine the tensile strength, yield strength, and elongation. Furthermore, long-term tensile creep tests are carried out on peak-aged samples at constant temperature. Post-failure microstructural changes are analyzed in both quasi-static and creep samples using SEM and TEM imaging. This study reveals the failure mechanisms associated with these tests and the roles played by the Al11Ce3 and Al3(Er,Sc,Zr) phases. |