Al-Mn-Fe-Si strips were fabricated via both the twin-roll casting (TRC) and the more conventional route, direct-chill casting (DC). The two types of strips prepared were subjected to thermal exposure at a series of temperatures. Uniaxial tensile tests after the thermal exposure showed that while the DC strip presented a ∼74% decrease in the yield strength and ∼35% decrease in the ultimate tensile strength (UTS) after being exposed to 350 °C for 12 h, the TRC strip, in contrast, maintained its strength at temperatures up to ∼460 °C for the same duration. Systematic microstructure characterization revealed that the different thermal stability in the strength of the two types of strips arised from their distinct evolution in grain morphology and second phase particles during the thermal exposure. The calculation based on Cahn-Lücke-Stüwe (CLS) model suggested that due to the highly supersaturated solute atoms, at the beginning of the thermal exposure, the TRC strip experienced a strong solute drag which reduced the grain boundary migrating velocity to a value that is orders of magnitude smaller than that in the DC strip. With the progress of the thermal exposure, the solute atoms precipitated out, forming densely distributed second phase particles. For one thing, these particles stabilized the grain structure by inducing Zener pinning pressure which could be ten times higher than that in the DC strip, depending on the temperature. For another, they acted as dislocation obstacles and compensated for the strength loss owing to decreasing solution hardening. Both effects contributed to the TRC strip's fairly stable strength regarding thermal exposure below 460 °C. The present work could guide the direct application of the TRC strips in the industry. The results should also be helpful for the development of a fundamental framework for designing advanced TRC Al strips with improved mechanical properties at elevated temperatures.

Al-Mn-Fe-Si 带材是通过双辊铸造 (TRC) 和更传统的路线，直冷铸造 (DC)。制备的两种类型的条在一系列温度下经受热暴露。热暴露后的单轴拉伸试验表明，虽然 DC 条在暴露于 350°C 12 小时后屈服强度下降了约 74%，极限拉伸强度 (UTS) 下降了约 35%，但 TRC 带相比之下，在相同的持续时间内，它在高达 460°C 的温度下保持其强度。系统的微观结构表征表明，两种类型的带材强度的不同热稳定性源于它们在热暴露过程中晶粒形态和第二相颗粒的不同演变。基于 Cahn-Lücke-Stüwe (CLS) 模型的计算表明，由于溶质原子高度过饱和，在热暴露开始时，TRC 条带经历了强烈的溶质阻力，使晶界迁移速度降低到一个值比直流条小几个数量级。随着热暴露的进行，溶质原子析出，形成密集分布的第二相粒子。一方面，这些颗粒通过诱导齐纳钉扎压力稳定了晶粒结构，齐纳钉扎压力可能比直流带中的钉扎压力高十倍，具体取决于温度。另一方面，它们充当位错障碍并补偿由于降低固溶硬化而导致的强度损失。两种效应都促成了 TRC 带' 在 460 °C 以下的热暴露下具有相当稳定的强度。目前的工作可以指导TRC带在工业中的直接应用。结果也应该有助于开发一个基本框架，用于设计在高温下具有改进机械性能的先进 TRC 铝带。