Intermetallics ( IF 4.4 ) Pub Date : 2022-06-21 , DOI: 10.1016/j.intermet.2022.107636 Tiffany Wu , David C. Dunand
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.
中文翻译:
Al11Ce3的显微组织和热机械性能
本研究研究了金属间化合物 Al 11 Ce 3的微观结构和热机械性能,它可以强化 Al-Ce 基共晶合金。电弧熔体Al 11 Ce 3由沿凝固方向取向的粗大细长晶粒组成,内部孪晶,在环境温度下硬而脆,显微硬度为4.3±0.3 GPa,压痕断裂韧性为0.70±0.09 MPa·m 1/2。热膨胀系数从 14 × 10 -6 /K(在 100 °C)到 32 × 10 -6 /K(在 600 °C)不等。铝11铈3氧化动力学遵循抛物线规律,在 500 °C/以下的速率足够慢,可以在空气中进行长期测试。塑性蠕变变形在 500 °C 时在单轴压缩载荷下广泛;应变率遵循关于应力的幂律,应力指数为 5.6,表示位错控制的蠕变变形,活化能为 276 ± 29 kJ/mol(在 450 和 600 °C 之间测量)。Al 11 Ce 3在500℃下的抗蠕变性与L1 2 -Al 3 Sc 相似。