Intragranular and grain boundary precipitates (GBPs) and precipitate-free zones (PFZ) are critical for regulating the properties of an Al–Zn–Mg–Cu alloy. Herein, an even precipitate dispersion strategy, including microparticle dissolution and grain refinement in a solid solution (SS), was introduced to optimize the microstructure and mechanical properties of the Al–10Zn–3Mg–2.5Cu alloy, with the SS duration being the only variable. The dissolution of microparticles rapidly occurred in the initial stage, reaching stability at 8 min. At this time, numerous grain boundaries were developed through static recrystallization. During the subsequent T6 process, considering the increase in nucleation sites and internal stress via large numbers of grain boundaries, the precipitate's growth was restricted and the transformation activation energy of η′ decreased, promoting the fine size and dispersed distribution of precipitates. These precipitates resulted in excellent ultimate tensile strength of 675 MPa, yield strength of 645 MPa, and elongation of 5.0% for the component. The sizes of the GBP and PFZ were weakened. Overall, this study provides new insights into the action of grain boundaries during SS to the subsequent aging precipitates. Furthermore, a cost-effective SS scheme with short-duration was proposed to adapt the online rapid manufacturing.

中文翻译：

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固溶时间对Al-10.0Zn-3.0Mg-2.5Cu合金显微组织和力学性能的影响

晶内和晶界析出物 (GBP) 以及无析出物区 (PFZ) 对于调节 Al-Zn-Mg-Cu 合金的性能至关重要。在此，引入了均匀析出物分散策略，包括固溶体（SS）中的微粒溶解和晶粒细化，以优化 Al-10Zn-3Mg-2.5Cu 合金的显微组织和机械性能，其中 SS 持续时间是唯一的多变的。微粒在初始阶段迅速溶解，8 min 时达到稳定。此时，通过静态再结晶，形成大量晶界。在随后的T6过程中，由于大量晶界增加了形核位点和内应力，限制了析出物的生长，降低了η'相变活化能，促进了析出物尺寸细化和弥散分布。这些析出物使部件具有优异的极限拉伸强度（675 MPa）、屈服强度（645 MPa）和伸长率（5.0%）。英镑和 PFZ 的规模被削弱。总体而言，这项研究为 SS 期间晶界对随后时效析出物的作用提供了新的见解。此外，还提出了一种具有成本效益的短周期SS方案来适应在线快速制造。