非晶合金蜂窝材料强韧性与破坏机理研究

Amorphous alloys have excellent mechanical properties like high strength and hardness, high elastic strain limit and good corrosion resistance etc. And they are good candidates in a wide range of applications in aerospace engineering. By properly applying pores to bulk amorphous alloys, cellular amorphous alloys can not only overcome the shortcoming of brittleness but also become light-weight. A mature understanding of the strengthening-toughening and failure mechanisms of cellular amorphous alloys is of great importance in both scientific research and engineering applications. So far, there is no theoretic model to reveal the relationships between the pores and the mechanical properties of cellular amorphous alloys. A systematic investigation about the effects of pores on the strengthening-toughening mechanisms has yet been reported. In this proposal, large scale molecular dynamics simulations will be carried out to show the deformation mechanisms of cellular amorphous alloys. The key factors and qualitative laws will be elucidated. Furthermore, typical cellular amorphous alloy samples will be prepared by thermoplastic forming method and mechanical experiments will be done to reveal the strengths, plasticity and failure mechanisms. Based on the simulation and experimental results, we will propose theoretical models to predict the relationships between the pores and the mechanical properties. This study will provide a comprehensive understanding for deformation mechanisms of cellular amorphous alloys and give guidance for achieving light-weight cellular amorphous alloys with better mechanical properties.

非晶合金具有高强度和高硬度、大弹性应变极限和良好的抗腐蚀能力等优异的物理力学性能，在航天航空等领域具有广阔的应用前景。通过合理引入孔隙结构，非晶合金蜂窝材料能够克服块体非晶合金脆性的缺点，并实现结构的轻量化，深入研究非晶合金蜂窝材料的强韧性和破坏机制有重要的科学意义和工程应用价值。目前，非晶合金蜂窝材料的强韧性与孔隙结构的关系还缺乏系统深入的研究，没有成熟的理论模型。本项目将通过大规模分子动力学模拟，揭示非晶合金蜂窝材料的微观变形机制，阐明影响强韧性的关键因素和定性规律；通过热塑性成型方法制备典型的非晶合金蜂窝材料，开展力学实验，进一步揭示强度、塑性变形和破坏机制与孔隙结构的关系；依据仿真和实验结果，建立非晶合金蜂窝材料强韧性与孔隙结构之间关系的理论模型。通过本项目的研究，加深对非晶合金蜂窝材料力学行为的认识，为获取具有高强韧性的轻质非晶合金蜂窝材料提供指导。

引入孔隙结构有望克服非晶合金（或金属玻璃）脆断的缺点，本项目完成了非晶合金蜂窝材料强韧性与破坏机制的研究。通过开展大规模分子动力学模拟与分析，揭示了纳米尺度下影响材料强度和塑性的主要因素和影响规律，揭示了不同几何特征非晶合金蜂窝材料的变形和破坏机制。开展了微米尺度下非晶合金蜂窝材料的热塑性成型制备工艺摸索，前后开展4轮试样的制备，揭示了影响制备工艺的主要因素，并成功制备了微米尺度非晶合金蜂窝试样，开展了原位拉伸实验和断口分析。结合模拟和实验结果，开展了非晶合金蜂窝结构的强韧性规律分析，揭示不同尺度下影响非晶蜂窝材料拉伸塑性的主导因素和变化规律。