Although fine equiaxed structure benefits both strength and ductility in titanium alloys, it is often considered incompatible with high toughness, for its insufficient ability to deflect propagating cracks compared to coarse lamellar structure. This work reports an excellent combination of standard Charpy impact toughness (∼100 J) and yield strength (∼820 MPa) in a powder metallurgy titanium alloy with fine equiaxed structure (∼1.5 μm), wherein the β matrix exists as equiaxed nodules and fine ligaments for globularization of α grains. The impact curve divided with the “compliance changing rate” (CCR) method indicates that the energy consumed by crack propagation is dominant (∼82%) during the impact process. Fractographic and structural examinations indicate that multiple micro-voids nucleation near boundaries between fine β ligaments and α grains mitigates local stress concentration, and that coordinated deformation between equiaxed β nodules and α grains hinders crack propagation, which together enable the excellent combination of yield strength and impact toughness. Our work provides a new pathway for designing impact-resistant titanium alloys.

中文翻译：

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粉末冶金制备的具有精细等轴结构的抗冲击钛合金


尽管精细的等轴结构对钛合金的强度和延展性都有好处，但它通常被认为与高韧性不相容，因为与粗层状结构相比，它无法偏转扩展的裂纹。这项工作报道了在具有精细等轴结构 （∼1.5 μm） 的粉末冶金钛合金中标准夏比冲击韧性 （∼100 J） 和屈服强度 （∼820 MPa） 的完美组合，其中β基体以等轴结节和细韧带的形式存在，用于α晶粒的球状化。用“柔度变化率”（CCR） 方法除以的冲击曲线表明，在冲击过程中，裂纹扩展消耗的能量占主导地位 （∼82%）。压裂学和结构检查表明，细β韧带和α晶粒之间边界附近的多个微空隙形核减轻了局部应力集中，并且等轴β结节和α晶粒之间的协调变形阻碍了裂纹扩展，这共同实现了屈服强度和冲击韧性的完美结合。我们的工作为设计抗冲击钛合金提供了一条新的途径。