非晶合金多重剪切带形成与演化动力学研究

项目名称： 非晶合金多重剪切带形成与演化动力学研究

项目编号： No.11202221

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 陈艳

作者单位： 中国科学院力学研究所

项目金额： 28万元

中文摘要： 非晶合金作为新型结构材料已在国防、空天等众多高新技术领域显示出广阔的应用前景。然而，该材料在室温下极易形成纳米尺度的剪切带，并迅速诱导材料断裂，伴随极低的宏观塑性，极大地限制了它作为结构材料的应用。近年来，研究发现，通过引入残余应力、优化设计材料成分、加入纳微米尺度的非均质等，可以促进非晶合金内部剪切带的相互交割和多重化，从而大大提高该材料的室温塑性。然而，对于非晶合金多重剪切带行为的认知目前还十分匮乏，其中的关键问题是多重剪切带的形成与演化动力学及其内在机理。为此，本项目拟通过实验研究、数值模拟和理论分析相结合，系统深入地研究非晶合金多重剪切带形成机制及演化动力学过程，定量表征多重剪切带形貌演化及考察其内在规律；并建立新的本构模型数值模拟剪切带多重化过程；揭示多重剪切带群体演化行为的控制机理。本项目的研究将有助于深入理解非晶合金的塑性变形机制，为改善非晶合金的室温塑性提供有益指导。

中文关键词： 非晶合金；多重剪切带；演化动力学；能量耗散；塑性机理

英文摘要： Metallic glasses (MGs) have shown wide potential applications as advanced materials in fields such as defense applications, space projects, etc. However, plastic deformation in MGs at room temperature is prone to be localized into nanoscale shear bands and leads to catastrophic failure, accompanied with very limited plasticity. This greatly impedes their structural applications. Lately, the room-temperature plasticity in MGs have been greatly developed by triggering the interaction and multiplication of shear bands, via the introducation of the residual stress, the optimum design of material composites,and the presence of nanoscale or microscale heterogeneities. Nevertheless, the understanding of the behavior of multiple shear bands in MGs is still lacking, and the key proplem is the formation and evolution dynamics of multiple shear bands and their underlying mechanisms. Therefore, this research is aimed to investigate the formation mechanism and dynamic evolution process of multiple shear bands, via systematical experiments, numerical simulation, and theoretical analyses. The evolution of the shear band patterns will be characterized quantitatively and the inherent laws will be uncovered. Then, a new constitutive model of MGs will be established and the whole process of shear band multiplication will be numeri

英文关键词： Metallic glasses；Multiple shear banding；Evolution dynamics；Energy dissipation；Plastic mechanisms