Hot-forming Quenching (HFQ) can lead to significant changes in microstructure of high-strength aluminum alloys for car body sheet. Furthermore, through effective control, desired performance of the alloys can be achieved. Three designed processes, HFQ + Natural Aging (NA) + Simulate Baking (SB), HFQ + Pre-aging (PA) + SB and HFQ + Peak-aging (T6) were applied in this work, and the evolution of precipitated phases was systematically studied using High Resolution Transmission Electron Microscopy-Selected Area Electron Diffraction (HRTEM-SAED). The results revealed the precipitation nature of η phase in 7055 aluminum alloys is that GP zone I evolves into GP zone II, on which η’ phases directly nucleate and multiply, resulting in the transformation from η’ phases into η phases. By comparing the three processes, it is found that HFQ + PA + SB has high-density and finely distributed η’ phases, and grain boundary precipitates are small and discontinuously distributed. By adjusting the pre-aging temperature and time, it can provides a large amount of precipitation nucleation basis for the baking stage and ensure that η’ phase formation with high quantity density. The end product has a tensile strength of 660.1 MPa and a yield strength of 639.4 MPa, which is the most promising sheet material for future car body application.

热成型淬火 (HFQ) 会导致车身板用高强度铝合金的显微组织发生显着变化。此外，通过有效的控制，可以实现合金的理想性能。三种设计工艺，HFQ +自然老化（NA）+模拟烘烤（SB），HFQ +预老化（PA）+ SB和HFQ +峰值老化（T6）被应用在这项工作中，沉淀相的演变是使用高分辨率透射电子显微镜-选区电子衍射 (HRTEM-SAED) 系统地研究。结果表明7055铝合金中η相的析出性质为GP区Ⅰ向GP区Ⅱ演化，η'相在GP区直接形核增殖，导致η'相向η相转变。通过比较这三个过程，发现HFQ + PA + SB的η'相密度高且分布较细，晶界析出物数量少且呈不连续分布。通过调整预时效温度和时间，为焙烧阶段提供大量的析出形核基础，保证高量密度的η'相形成。最终产品的抗拉强度为660.1 MPa，屈服强度为639.4 MPa，是未来汽车车身应用最有前景的板材。