Abstract Hydrogen uptake in titanium alloys leads to the formation of hydride phases, which in-turn cause severe embrittlement upon further deformation. The embrittlement micro-mechanisms are complicated by the distinct hydrogen diffusion and solution characteristics of the α and β phases, which arise from their different crystal structures. To improve the fundamental understanding of the room temperature interplay among hydrogen, the present phases and the hydride that is formed at their interface, we investigated the hydride formation process in Ti–6Al–4V alloy by in situ scanning electron microscopy and electron backscatter diffraction analyses during hydrogen charging, and post-mortem synchrotron diffraction tests. These investigations reveal that the lattice expansion of the hydrogenated β phase introduces a localized stress field near the phase boundary, which, in turn, induces hydrogen confinement therein, eventually facilitating the hydride growth along the boundary. The volumetric expansion of the α-to-hydride transformation extends the local stress field, influencing the work-hardening and damage evolution in the alloy. We discuss these findings and the overall damage initiation and propagation taking place in the hydrogenated alloy, based on the interplay among the present phases and hydrogen.

中文翻译：

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氢化引起的晶格膨胀及其对 Ti-6Al-4V 中氢扩散和损伤的影响

摘要 钛合金中的吸氢导致氢化物相的形成，进而在进一步变形时引起严重的脆化。由于 α 和 β 相不同的晶体结构，它们具有不同的氢扩散和溶液特性，使脆化微观机制变得复杂。为了更好地了解氢、现相和在它们界面处形成的氢化物之间的室温相互作用，我们通过原位扫描电子显微镜和电子背散射衍射分析研究了 Ti-6Al-4V 合金中的氢化物形成过程在充氢和验尸同步加速器衍射测试期间。这些研究表明，氢化 β 相的晶格膨胀在相边界附近引入了局部应力场，这反过来又在其中引起了氢的限制，最终促进了沿边界的氢化物生长。α-氢化物转变的体积膨胀扩展了局部应力场，影响合金的加工硬化和损伤演变。我们讨论了这些发现以及氢化合金中发生的整体损伤开始和扩展，基于当前相和氢之间的相互作用。影响合金的加工硬化和损伤演变。我们讨论了这些发现以及氢化合金中发生的整体损伤开始和扩展，基于当前相和氢之间的相互作用。影响合金的加工硬化和损伤演变。我们讨论了这些发现以及氢化合金中发生的整体损伤开始和扩展，基于当前相和氢之间的相互作用。