原位研究Ti基大块非晶合金拉伸过程多尺度应变及剪切带特征

Due to the unique atomic configuration and thus excellent performance, bulk metallic glasses (BMGs) have been triggered a flood of interests from materials science community. However, the room temperature brittleness of BMGs seriously hinders their engineering applications as high performance structural materials. To explore the formation mechanism of shear bands and the evolution of strain and atomic structure upon loading will be helpful for the development of BMGs with high strength and high plasticity. This has important theoretical and practical significance for the promotion of the industrial application of this material. This project will select a Ti-based BMG with excellent glass forming ability as model materials. Synchrotron X-ray diffraction and high-resolution scanning electron microscope, combined with the finite element simulation, will be used to study in-depth the macro/microscopic tensile deformation behaviors of Ti-based BMG. The underlying correlation between the multi-scale strain evolution and the formation mechanism of shear bands will be established. This project will focus on the physical nature of shear band formation at atomic level, which will provide a better understanding of deformation and fracture mechanism of BMGs. It is expected that this study will lay the solid foundation for the industrial applications of high performance BMGs.

大块非晶合金因其独特的微观结构特征以及优异的综合性能而引起人们的广泛关注，然而，该材料的室温脆性极大地阻碍了其作为高性能结构材料的应用。理解非晶合金变形过程中剪切带形成的机理以及应变与原子结构演变规律，从而开发具有高强度与高塑性的非晶合金，这对于促进其工程化应用具有重要的理论与实际意义。本项目拟以具有优异玻璃形成能力的Ti基大块非晶合金为研究对象，采用同步辐射高能X射线与高分辨扫描电子显微镜这两种原位研究手段，并结合有限元模拟，通过理论分析、实验研究以及数值模拟，深入研究该合金的宏/微观拉伸力学行为，揭示非晶合金在拉伸过程中多尺度应变演变与结构演变规律和剪切带形成机理之间的内在关系，并研究自由体积对剪切带形核与扩展的影响规律，从原子层面深入揭示剪切带形成的物理本质，从而加深对非晶合金变形与断裂机理的认识，为推进高性能非晶合金在实际工程领域的应用提供重要的理论依据和技术支持。

大块非晶合金因其独特的微观结构特征以及优异的综合性能而引起人们的广泛关注，然而，该材料的室温脆性极大地阻碍了其作为高性能结构材料的应用，理解非晶合金变形过程中剪切带形成的机理以及应变与原子结构演变规律，从而开发具有高强度与高韧性的非晶合金，这对于促进其工程化应用具有重要的理论与实际意义。本项目以具有优异玻璃形成能力的Ti基及Zr基大块非晶合金为对象，采用同步辐射高能X射线与高分辨扫描电子显微镜这两种原位研究手段，并结合有限元模拟，通过理论分析、实验研究以及数值模拟，深入研究了该合金的宏/微观拉伸力学行为，揭示了非晶合金在拉伸过程中多尺度应变演变规律和剪切带形成机理之间的内在关系，从原子层面深入揭示剪切带形成的物理本质，从而加深对非晶合金变形与断裂机理的认识，为推进高性能非晶合金在实际工程领域的应用提供重要的理论依据和技术支持。本项目在研期间，在International Journal of Plasticity, Applied Physics Letters及Scripta Materialia等国际重要学术期刊上发表SCI论文15篇；申请并授权国家发明专利2项。