Microstructure and thermomechanical properties of Al11Ce3

This study investigates the microstructure and thermomechanical properties of the intermetallic compound Al11Ce3, which strengthens Al-Ce based eutectic alloys. Arc-melted bulk Al11Ce3, consisting of coarse, elongated grains oriented along the solidifying direction with internal twins, is hard and brittle at ambient temperature, with a microhardness of 4.3 +/- 0.3 GPa and indentation fracture toughness of 0.70 +/- 0.09 MPa m(1/2). The thermal expansion coefficient varies from 14 x 10(-6) /K (at 100 degrees C) to 32 x 10(-6) /K (at 600 degrees C). Al11Ce3 oxidation kinetics follow a parabolic law, with rates at/below 500 degrees C slow enough to enable long-term testing in air. Plastic creep deformation is extensive at 500 degrees C under uniaxial compressive loads; the strain rates follow a power-law with respect to stress with a stress exponent of 5.6, indicative of dislocation-controlled creep deformation, and with an activation energy of 276 +/- 29 kJ/mol (measured between 450 and 600 degrees C). The creep resistance of Al11Ce3 at 500 degrees C is similar to that of L1(2)-Al3Sc.

Automated summary

This study investigates the microstructure and thermomechanical properties of Al11Ce3, an intermetallic compound that strengthens Al-Ce based eutectic alloys. The results show that Al11Ce3 is hard and brittle, with coarse and elongated grains and internal twins. The thermal expansion coefficient and oxidation kinetics of Al11Ce3 vary with temperature. At 500 degrees C, Al11Ce3 exhibits extensive plastic creep deformation. The study also found that the creep resistance of Al11Ce3 at 500 degrees C is similar to that of L1(2)-Al3Sc.