Abstract High temperature tensile test over the temperature range from 100 °C to 250 °C of die forged Al-5.87Zn-2.07Mg-2.42Cu alloy were carried out and the effect of aging treatment on microstructures and mechanical properties of alloy were studied. The strength of alloys processed with peak aged (T6), over aged (T73) and retrogression and re-aging (RRA) treatment suffered from different extent of decreasing for the increase of the stretching temperature. Among them, the RRA alloy has the most obvious drop in tensile strength, which has dropped from 615 MPa to 268 MPa with temperature rising from room temperature to 250 °C. While T6 and T73 alloys drop by 338 MPa and 333 MPa, respectively. With the increase of test temperature, the coarsening rate of precipitates in RRA sample is faster than that of T6 and T73, resulting in more significant decrease in the high temperature strength. The T73 sample exhibits good stability of high temperature mechanical properties, due to the slowing coarsen rate of precipitates.

中文翻译：

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不同时效处理对模锻Al-5.87Zn-2.07Mg-2.42Cu合金高温性能的影响

摘要 对模锻Al-5.87Zn-2.07Mg-2.42Cu合金进行100～250℃高温拉伸试验，研究时效处理对合金组织和力学性能的影响。经峰值时效（T6）、过时效（T73）和回归再时效（RRA）处理的合金强度随着拉伸温度的升高而出现不同程度的下降。其中，RRA合金的抗拉强度下降最为明显，随着温度从室温上升到250℃，从615 MPa下降到268 MPa。而 T6 和 T73 合金分别下降 338 MPa 和 333 MPa。随着试验温度的升高，RRA试样中析出物的粗化速度比T6和T73快，导致高温强度下降更为显着。由于析出物粗化速度减慢，T73 样品表现出良好的高温机械性能稳定性。