As-cast aluminum–magnesium alloys with 3, 5, and 10 wt% Mg are subjected to high-pressure torsion (HPT) at room temperature: 5 GPa, five turns with rotation speed of 1 rpm. HPT leads to the strong grain refinement for both (Al) solid solution and intermetallic β-phase. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) are used to characterize the phase transitions under heating of the HPT-treated alloys. The decomposition of the solid solution in the ultrafine-grained Al–10 wt% Mg alloy obtained by HPT does not follow the equilibrium diagram. The results of DSC, XRD, and TEM show that the Mg-rich intermetallic phases appear during heating in the following sequence: GP zones → β → ε → β → γ → β. The (Al)/(Al) grain boundaries (GBs) in the fine-grained Al–10 wt% Mg alloy after HPT and annealing up to 400 °C (i.e., in the solid solution area, far from solvus and solidus lines) contain the Mg-rich areas. This can be the result of possible GB phase transitions with the formation of Mg-rich GB phases. The GBs in the binary AlMg can contain the thin layers of a GB phase far away from the solvus line.

中文翻译：

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高压扭转驱动的铝镁合金相变

含 3、5 和 10 wt% Mg 的铸态铝镁合金在室温下经受高压扭转 (HPT)：5 GPa，旋转五圈，转速为 1 rpm。HPT 导致 (Al) 固溶体和金属间 β 相的强烈晶粒细化。透射电子显微镜 (TEM)、差示扫描量热法 (DSC) 和 X 射线衍射 (XRD) 用于表征 HPT 处理合金在加热下的相变。通过 HPT 获得的超细晶 Al-10 wt% Mg 合金中的固溶体分解不遵循平衡图。DSC、XRD和TEM结果表明，在加热过程中富镁金属间相的出现顺序为：GP区→β→ε→β→γ→β。HPT 和退火至 400 °C 后细晶 Al-10 wt% Mg 合金中的 (Al)/(Al) 晶界 (GBs)（即，在固溶区，远离固溶线和固相线）含富镁区。这可能是由于形成富含镁的 GB 相而可能发生 GB 相变的结果。二进制 Al 中的 GB Mg 可以包含远离固溶线的 GB 相薄层。