This study investigated the effect of melt hydrogenation on the as-cast microstructure, deformed microstructure evolution and deformation induced phase transformation of Ti2AlN/Ti46Al4Nb1Mo composites, and the corresponding mechanism was revealed. Results of as-cast microstructure showed hydrogen increased the length of Ti2AlN from 5 to 13 to 11–18 μm, which resulted in the decreased heterogeneous nucleation sites, thus the size of α2/γ lamellar colony increased from 27 to 33 μm. With the deforming temperature increasing from 1100 to 1200 °C and strain rates of 0.01 s−1/0.001 s−1, trace addition of hydrogen significantly reduced the peak stress and improved the hot workability. Additionally, the initial bending α2/γ lamellae decomposed, and hydrogen facilitated the lamellae decomposition as well as the phase transformation from γ to α2 phase. Hydrogen accelerated the diffusion of solute atoms and improved the mobility of dislocations, which promoted the dynamic recrystallization (DRX) of both α2 and γ phase. The enhanced atomic diffusion, especially the excess Ti atoms, reduced the barrier for the phase transformation from γ to α2 phase, and higher content of DRX for both α2 and γ phase facilitated the α2/γ lamellae decomposition. These above factors induced higher hot workability and more uniform deformed microstructure of Ti2AlN/Ti46Al4Nb1Mo composites.

中文翻译：

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氢对 Ti2AlN/Ti46Al4Nb1Mo 复合材料变形诱导相变和热加工性的影响


本研究研究了熔融加氢对 Ti2AlN/Ti46Al4Nb1Mo 复合材料铸态微观结构、变形微观结构演变和变形诱导的相变的影响，并揭示了相应的机制。铸态微观结构结果表明，氢将 Ti2AlN 的长度从 5 增加到 13 到 11-18 μm，这导致异质成核位点减少，因此 α2/γ 层状集落的大小从 27 μm 增加到 33 μm。随着变形温度从 1100 °C 升高到 1200 °C，应变速率为 0.01 s−1/0.001 s−1，微量氢的添加显著降低了峰值应力并提高了热加工性。此外，初始弯曲的 α2/γ 薄片分解，氢促进了薄片分解以及从 γ 相到 α2 相的相变。氢加速了溶质原子的扩散并提高了位错的迁移率，从而促进了 α2 和 γ 相的动态再结晶 （DRX）。增强的原子扩散，尤其是过量的 Ti 原子，降低了从 γ 相转变为 α2 相的障碍，α2 和 γ 相的 DRX 含量较高，促进了 α2/γ 薄片分解。上述因素导致 Ti2AlN/Ti46Al4Nb1Mo 复合材料具有更高的热加工性和更均匀的变形微观结构。