Abstract The precipitation behavior of β0 particles in the α2 lamellae of a β-solidifying multiple-phase γ-TiAl alloy, i.e., Ti-42.05Al-3.96Nb-1.01Mo-0.21B (at.%) alloys, was investigated using conventional transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It has been found that β0 phase can precipitate in α2 lamellae when aging-treated at 950–1150 °C for 6 h. This is a process controlled by diffusion of Mo element. The β0 precipitates nucleate initially at the α2/γ lamellar interfaces and grow firstly along the α2 lamellar width direction then along the length direction. The lamellar spacing of α2 lamella and growth stage of β0 precipitates codetermined the morphologies of β0 precipitates. All β0 phases precipitated from α2 matrix follow the Burgers OR: 101 β 0 / / 0001 α 2 , 1 ¯ 11 β 0 / / 11 2 ¯ 0 α 2 , and the interface dislocations between α2/β0 interfaces are commanded to accommodate the lattice misfit. Besides, the decomposition of α2 → γ also occurs during the aging treatments. The α2/γ interface ledges promote the nucleation of β0 phase, but the precipitated β0 particles at the α2/γ ledges impede the α2 → γ transformation. The coordination of α2 → β0 and α2 → γ transformations is influenced by the aging temperature. When the aging temperature is 1150 °C, the amount of β0 precipitation in α2 lamellae up to the maximum.

中文翻译：

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β凝固多相γ-TiAl合金α2片晶中的βo析出

摘要 β0 粒子在 β 凝固多相 γ-TiAl 合金，即 Ti-42.05Al-3.96Nb-1.01Mo-0.21B (at.%) 合金的 α2 片晶中的析出行为，使用常规方法进行了研究。透射电子显微镜 (TEM) 和高分辨率透射电子显微镜 (HRTEM)。已经发现，当在 950-1150°C 下时效处理 6 小时时，β0 相可以在 α2 片晶中沉淀。这是一个由钼元素扩散控制的过程。β0 析出物最初在 α2/γ 层状界面成核，先沿 α2 层状宽度方向生长，然后沿长度方向生长。α2 片层的层间距和 β0 沉淀物的生长阶段共同决定了 β0 沉淀物的形貌。从 α2 基体中析出的所有 β0 相都遵循 Burgers OR: 101 β 0 // 0001 α 2 , 1 ¯ 11 β 0 // 11 2 ¯ 0 α 2 ，α2/β0 界面之间的界面位错被命令以适应晶格失配。此外，α2→γ的分解也在时效处理过程中发生。α2/γ 界面边缘促进了 β0 相的成核，但 α2/γ 边缘处沉淀的 β0 粒子阻碍了 α2 → γ 转变。α2 → β0 和 α2 → γ 转变的协调受时效温度的影响。当时效温度为1150℃时，α2片晶中β0的析出量最大。但在 α2/γ 边缘沉淀的 β0 粒子阻碍了 α2 → γ 的转变。α2 → β0 和 α2 → γ 转变的协调受时效温度的影响。当时效温度为1150℃时，α2片晶中β0的析出量最大。但在 α2/γ 边缘沉淀的 β0 粒子阻碍了 α2 → γ 的转变。α2 → β0 和 α2 → γ 转变的协调受时效温度的影响。当时效温度为1150℃时，α2片晶中β0的析出量最大。