In this study, the influence of high temperature exposure on mechanical properties as well as on the microstructures of two Al-Cu alloys, has been investigated. Driven by an industrial will to use structural aluminium at higher temperature than usually stated, this work is focused on the characterization of the evolution of two commercial alloys, the 2219-T851 and the 2050-T84, induced by an ageing treatment of 1000 hours at 200°C. Careful TEM observations confirm the importance of the nanoscale precipitation and that the precipitate size and distribution strongly influence the mechanical properties of the studied alloys. Results unexpectedly show that the ${\theta }^{\prime }-A{l}_{2}Cu$ precipitates are more stable in time than the $T_1-A{l}_{2}CuLi$ precipitates at this temperature. Regarding the mechanical properties related to ageing, it follows that the 2219-T851 alloy presents a reduced drop with time of its tensile test curves compared to the 2050-T84, thus a limited, and at least less pronounced, temperature dependence. For an industrial application on structural part, 2219-T851 alloy then appears to be a good candidate for long-term structural applications at intermediate temperatures.

在这项研究中，研究了高温暴露对两种 Al-Cu 合金的机械性能和微观结构的影响。在比通常所说的温度更高的温度下使用结构铝的工业意愿的驱动下，这项工作的重点是表征两种商业合金 2219-T851 和 2050-T84，它们是由 1000 小时的时效处理引起的。 200°C。仔细的 TEM 观察证实了纳米级沉淀的重要性，并且沉淀的尺寸和分布强烈影响所研究合金的机械性能。结果出人意料地表明，${\theta }^{\prime }-\mathrm{一种}{升}_{2}C你$ 沉淀物在时间上比沉淀物更稳定 ${吨}_1-\mathrm{一种}{升}_{2}C你升\mathrm{一世}$在此温度下沉淀。关于与时效相关的机械性能，与 2050-T84 相比，2219-T851 合金的拉伸测试曲线随时间的下降减少，因此温度依赖性有限，至少不太明显。对于结构部件的工业应用，2219-T851 合金似乎是中等温度下长期结构应用的良好候选材料。