大塑性铁基块体金属玻璃拉伸性能及变形破坏机理

Owing to the combination of excellent magetic, mechanical, and chemical properties, Fe-based bulk metallic glasses are one of promising materials. However, the poor tensile plasticity is the short slab in overall performance, thus the research and improvement of plasticity, the exploration of their tensile performance and deformation-failure mechanism are important issues, and the preparation of the “dumbbell-shaped” tensile specimen is the key technology in this field. In this project, “dumbbell-shaped” quartz tubes will be prefabricated, and the Fe-based bulk metallic glasses tensile specimens will be prepared by water quenching the molten alloys in them, and the tensile properties and the deformation-failure mechanism will be studied and disclosed. The atomic structure, composition distributions and atomic bonding characteristics in Fe-based bulk metallic glasses with high strength and large plasticity will be systematically investigated by three dimensional atom probes, X-ray photoelectron spectroscopy and so on; the microstructure will be characterized and analyzed, the microstructure units of shear and instability in Fe-based bulk metallic glasses under tensile stress will be explored, and the physical mechanism from local instability to macroscopic fracture will be revealed; moreover, the relationship among the composition, the microstructures and the tensile and compressive macroscopic mechanical properties will be established, and the theory and methods concerning of plasticity tailoring will be explored comprehensively. This project has important scientific significance and practical value in understanding the deformation and failure mechanism of Fe-based bulk metallic glasses, the improvement of advancement of damage-fracture theory as well as the instruction of plasticity tailoring of Fe-based bulk metallic glasses.

铁基块体金属玻璃具有优异的磁学、力学与化学性能，应用前景广阔，但拉伸塑性是其综合性能的短板。改善铁基块体金属玻璃的拉伸塑性、揭示其变形破坏机理是该领域科研人员孜孜以求的梦想，而拉伸试样的制备是该课题的难点与关键。本项目通过预制“哑铃状”石英管，水淬其内高温熔体制备“哑铃状”铁基块体金属玻璃拉伸试样，研究并揭示大压缩塑性铁基金属玻璃的拉伸性能及变形破坏机理。利用三维原子探针、X射线光电子能谱等研究大塑性铁基金属玻璃的原子结构、成分分布及键合特征；表征铁基金属玻璃的微观结构，探索影响铁基金属玻璃拉应力条件下剪切、失稳的微观结构单元，揭示其从局域失稳演变为宏观断裂的物理机制；建立铁基金属玻璃组元与微观结构及宏观拉伸、压缩力学性能的关系，探索其塑性调控理论及方法。该项目对于深入理解铁基金属玻璃变形破坏机理、促进金属玻璃断裂损伤理论发展、指导金属玻璃拉伸塑性调控具有重要的科学意义和实践价值。

铁基块体金属玻璃是一类新型亚稳态金属材料，具有优异的磁学、力学与化学性能，应用前景广阔，但缺乏塑性变形能力是制约其大规模应用的瓶颈之一。因此，揭示铁基块体金属玻璃变形破坏机理、改善其塑性变形能力是该领域科研人员孜孜以求的梦想。该项目研究并揭示了Fe-Ni-P-C铁基块体金属玻璃体系具大塑性的机理，利用“哑铃状”石英管，水淬其内高温熔体制备出了“哑铃状”Fe-Ni-P-C铁基块体金属玻璃拉伸试样，并研究了其拉伸力学性能；利用三维原子探针、X射线光电子能谱等研究了Fe50Ni30P13C7大塑性铁基金属玻璃的原子结构、成分分布及键合特征；研究探索了影响铁基金属玻璃剪切、失稳的微观结构单元，通过有限元模拟揭示了其从局域失稳演变为宏观断裂的物理机制，发现了残余应力对铁基块体金属玻璃压缩塑性起到关键作用；建立了铁基金属玻璃组元与微观结构及力学性能的关系，探索出了通过增加残余应力梯度制备新型大塑性铁基块体金属玻璃的方法。利用该方法大大改善了典型脆性Fe74Mo4P13C7铁基金属玻璃的的塑性变形能力。该项目对于深入理解铁基金属玻璃变形破坏机理、促进金属玻璃断裂损伤理论发展具有重要的科学意义和实践价值。