双相钛合金界面调控塑性变形机理的原子尺度研究

界面调控是改善金属结构材料使役性能的重要途径。虽然界面调控在工程合金中已经广泛应用，但仍然面临原子尺度界面调控机理不清的问题。作为典型工程合金，片层组织双相钛合金因包含高密度相界面而具备优异的损伤容限。本项目将通过铸造和增材制造等方法，制备具有α/β、α′/β以及α/界面层/β三类界面的全片层Ti-6Al-4V合金；利用球差校正透射电子显微学技术，研究以上三类界面的原子尺度界面结构特征；利用球差校正及原位电子显微学技术在原子尺度揭示三类界面与位错滑移、孪生等微观变形方式之间的作用机理，建立三类界面与合金强塑性之间的对应关系。项目通过对α/β、α′/β以及α/界面层/β三类界面的对比研究，完善原子尺度界面结构对全片层Ti-6Al-4V微观变形行为及其强塑性的影响机理，建立可以调控材料变形行为、改善材料强塑性的原子尺度界面模型。

Interface engineering is an important way to improve the properties of metallic structural materials. Although interface regulation has been widely used in complex engineering alloys, the mechanism of atomic scale interface regulation still is unclear. As a typical engineering alloy, the lamellar dual-phase titanium alloys have excellent damage tolerance because they contain high-density interfaces. In this project, full-layered Ti-6Al-4V alloys with three types of interfaces, α / β, α ′ / β, and α / interface layer / β, will be prepared by methods such as casting and additive manufacturing; the atomic scale interface structure characteristics of the above three types of interfaces will be studied by spherical aberration corrected transmission electron microscopy; the effects of the three types of interfaces on microscopic deformation mechanisms such as dislocation slip and twinning will be revealed at the atomic scale using spherical aberration corrected and in-situ electron microscopy, and the correspondence between the three types of interfaces and the alloy's strength-plasticity will be established. Finally, through the comparative study of α / β, α ′ / β and α / interface layer / β interfaces, the understanding of the influence of the atomic scale interface structure on the deformation behavior and strength-plasticity of the full-layered Ti-6Al-4V will be improved, and an atomic scale interface model that can regulate the deformation behavior of the material and improve the material's strength-plasticity will be created.