This study focuses on the high temperature characteristics of thermo-mechanically processed AA7075 alloy. An integrated die forming process that combines solution heat treatment and hot forming at different temperatures was employed to process the AA7075 alloy. Low die temperature resulted in the fabrication of parts with higher strength, similar to that of T6 condition, while forming this alloy in the hot die led to the fabrication of more ductile parts. Isothermal uniaxial tensile tests in the temperature range of 200–400 °C and at strain rates ranging from 0.001–0.1 s⁻¹ were performed on the as-received material, and on both the solution heat-treated and the thermo-mechanically processed parts to explore the impacts of deformation parameters on the mechanical behavior at elevated temperatures. Flow stress levels of AA7075 alloy in all processing states were shown to be strongly temperature- and strain-rate dependent. Results imply that thermo-mechanical parameters are very influential on the mechanical properties of the AA7075 alloy formed at elevated temperatures. Microstructural studies were conducted by utilizing optical microscopy and a scanning electron microscope to reveal the dominant softening mechanism and the level of grain growth at elevated temperatures.

中文翻译：

---

高温下热机械加工AA7075合金的性能-从微观结构到力学性能

这项研究的重点是热机械加工AA7075合金的高温特性。结合了固溶热处理和在不同温度下的热成型的集成式模具成型工艺用于加工AA7075合金。较低的模具温度导致制造出具有更高强度的零件，与T6条件相似，而在热模具中形成这种合金导致制造出了更具延展性的零件。等温单轴拉伸试验，温度范围为200–400°C，应变率范围为0.001–0.1 s ^-1对收到的材料，热处理的溶液和热机械加工的零件都进行了研究，以探讨变形参数对高温下机械性能的影响。在所有加工状态下，AA7075合金的流变应力水平都与温度和应变率密切相关。结果表明，热机械参数对在高温下形成的AA7075合金的机械性能有很大的影响。利用光学显微镜和扫描电子显微镜进行了微观结构研究，以揭示主要的软化机理和高温下晶粒的生长水平。