Abstract We studied the crystallographic characteristics of the Al18Mg3Ti2 intermetallic phase in a solution-treated Al–7.6Zn–2.6Mg–2.0Cu–0.1Zr–0.07Ti (wt.%) alloy utilizing transmission electron microscopy (TEM). Cubic spinel Al18Mg3Ti2 intermetallic phase features { 111 } faceted interfaces with the Al matrix. Selected-area electron diffraction pattern, stereographic projection, and atomic projection studies indicated four possible orientation relationships between the Al18Mg3Ti2 phase and the Al matrix, which are categorized by a misorientation angle (θ) at { 111 } planes of each phase (i.e., θ = ± m, 70.5°±m, where m = 12–14°). High resolution TEM analyses confirmed that the growth of the Al18Mg3Ti2 intermetallic phase is based on the ledge mechanism on the { 111 } interfaces along with multiple { 111 } twinning. This growth mechanism of the Al18Mg3Ti2 phase contributes to the formation of faceted morphologies with { 111 } interfaces. The interface between the Al18Mg3Ti2 phase and Al matrix provides a heterogeneous nucleation site for the L12-precipitate and a Zn-rich phase.

中文翻译：

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Al-Zn-Mg-Cu-Zr-Ti合金中Al18Mg3Ti2金属间相的晶体学表征

摘要 我们利用透射电子显微镜 (TEM) 研究了固溶处理的 Al-7.6Zn-2.6Mg-2.0Cu-0.1Zr-0.07Ti (wt.%) 合金中 Al18Mg3Ti2 金属间相的晶体学特征。立方尖晶石 Al18Mg3Ti2 金属间相具有 {111} 面与 Al 基体的界面。选区电子衍射图、立体投影和原子投影研究表明 Al18Mg3Ti2 相和 Al 基体之间存在四种可能的取向关系，这些关系按每个相的 {111} 平面（即 θ = ± m，70.5°±m，其中 m = 12–14°）。高分辨率 TEM 分析证实，Al18Mg3Ti2 金属间相的生长基于 {111} 界面上的边缘机制以及多个 {111} 孪晶。Al18Mg3Ti2 相的这种生长机制有助于形成具有 {111} 界面的多面形貌。Al18Mg3Ti2 相和 Al 基体之间的界面为 L12 沉淀物和富锌相提供了异质成核位点。