Effect of thermomechanical processing on mechanical properties and the microstructure of ternary Al-Ce-Mg alloy
摘要
Al-Ce alloys are known to retain a large fraction of their room temperature properties at elevated temperatures and after exposure to temperature for extended periods. Here we work with the ternary close-to-eutectic alloy Al-10Ce-4Mg and explore the effect of extrusion on its microstructure and mechanical properties. Extrusion produces a highly refined microstructure with texture exhibiting a twofold increase in strength (tensile strength of 390 MPa at room temperature) and fourfold increase in failure strain relative to the as cast state. After exposure to 300 °C for 100 h the alloy retains 82% and 88% of the room temperature strength in the as-cast and extruded states, respectively. The ratio of the strength at 300 °C to the strength at room temperature is 0.4, below the corresponding ratio for the Al-10Ce binary alloy (ratio 0.7) but higher than that of AA2618 (ratio 0.1). The extruded Al-10Ce-4Mg has fracture toughness of 23 kJ/m2, which is retained in proportion of 97.6% after exposure to 300 °C for 100 h. The material exhibits negative strain rate sensitivity at room temperature and in the range of strain rates