Excellent dynamic properties are demanded for titanium alloys that operate under shock-loading environments. In this work, we demonstrate that a Ti-8Al-1Mo-1V-0.23C alloy with a low density of 4.36 g/cm³ exhibits superb dynamic compression properties, an excellent dynamic strength of ∼1.72 GPa and a dynamic compressive strain of ∼27.2%, due to the synergic effect associated with deformation induced laminated microstructure and deformation promoted carbon segregation. The low-density Ti-8Al-1Mo-1V-0.23C alloy is composed of nano-ordered Ti₃Al (α₂) particles reinforced equiaxed α phase grains bonded by β phase boundaries. The formation of dual-phase laminated microstructure is attributed to plastic flow stability of α phase grains associated with the geometrical constraint imposed by the relatively hard β phase and the activation of prismatic 〈a〉 and pyramidal 〈c + a〉 dislocations. The heat generated by severe plastic deformation in α phase is dissipated by facilitating carbon segregation along slip traces, thus effectively retarding strain softening associated with dynamic recrystallization. Shear instability is eventually triggered due to plastic deformation incompatibility between α and β phase, resulting in the local rotation of laminated microstructure. Adiabatic shear bands (ASBs) happen in the geometrical shear bands. The severe deformation generated heat promotes dynamic recrystallization and strain softening in the shear bands. Our work offers a strategy for the development of Ti alloys with excellent dynamic response via coupling microstructure engineering and thermodynamic segregation-dissipation mechanisms.

中文翻译：

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与变形诱导的层状微观结构和动态偏析相关的低密度近α钛合金的增强动态压缩性能


在冲击载荷环境下运行的钛合金需要出色的动态性能。在这项工作中，我们证明了具有 4.36 g/cm³ 低密度的 Ti-8Al-1Mo-1V-0.23C 合金表现出优异的动态压缩性能、∼1.72 GPa 的优异动态强度和 ∼27.2% 的动态压缩应变，这是由于与变形诱导的层状微观结构和变形促进碳偏析相关的协同效应。低密度 Ti-8Al-1Mo-1V-0.23C 合金由纳米有序 Ti ₃ Al （α ₂ ） 颗粒组成，这些颗粒由β相边界键合的等轴α相晶粒组成。双相层状微观结构的形成归因于α相晶粒的塑性流动稳定性，这与相对较硬的 β 相施加的几何约束以及棱柱形 〈a〉 和金字塔形 〈c + a〉 位错的激活有关。α相中严重塑性变形产生的热量通过促进沿滑移轨迹的碳偏析而消散，从而有效地延缓了与动态再结晶相关的应变软化。由于 α 相和 β 相之间的塑性变形不相容性，最终会触发剪切不稳定性，从而导致层状微观结构的局部旋转。绝热剪切带 （ASB） 发生在几何剪切带中。产生的严重变形产生的热量促进了剪切带中的动态再结晶和应变软化。我们的工作为通过耦合微观结构工程和热力学偏析耗散机制开发具有出色动态响应的 Ti 合金提供了一种策略。