Abstract

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 m1/2. The thermal expansion coefficient varies from 14 × 10−6/K (at 100 °C) to 32 × 10−6/K (at 600 °C). Al11Ce3 oxidation kinetics follow a parabolic law, with rates at/below 500 °C slow enough to enable long-term testing in air. Plastic creep deformation is extensive at 500 °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 °C). The creep resistance of Al11Ce3 at 500 °C is similar to that of L12-Al3Sc.

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