大尺寸相变韧塑化非晶复合材料的形成机理与动态变形行为

In order to solve the critical challenges for engineering applications of bulk metallic glasses (BMGs), i.e., room-temperature brittleness and insufficient-size, this project aims to develop large sized high-performance BMG composites based on the concept of transformation-induced plasticity (TRIP), and conduct systematic research on the relevant common fundamental scientific problems. Firstly, this project is aimed to scrutinize phase competition mechanism in transformation-mediated bulk metallic glass composites and explore dynamic precipitation behavior of the austenitic reinforcing phase. As such, glass-forming ability of the bulk metallic glass matrix can be promoted and the match of intrinsic mechanical properties between the matrix and reinforcing phase can be manipulated. Secondly, effects of in-situ formed heterogeneous nucleation sites on the precipitation behavior of the reinforcing phase will be studied and large sized bulk metallic glass composites consisting of a single austenitic phase will be developed. Moreover, deformation behavior of the resultant bulk metallic glass composites under high strain rates will be systematically investigated so that the underlying mechanisms can be revealed. The completion of the current project is to develop large sized, transformation mediated bulk metallic glass composites with optimized properties for practical applications, and to establish alloy design principles for this type of glassy materials.

针对目前非晶合金工程应用中所面临的关键挑战：室温脆性和尺寸不足，本项目在引入“相变诱导塑性”概念的基础上，开发大尺寸高性能非晶复合材料，并对相关科学和应用的共性关键基础问题进行研究。本项目首先拟对相变韧塑化非晶复合材料的多相竞争机制展开深入研究，探索奥氏体型增强相的动态原位析出规律，提高基体的非晶形成能力和调控多相的本征性能匹配。其次，研究内生异质形核点对奥氏体型增强相析出的影响规律，研发出大尺寸且奥氏体型增强相均匀弥散分布的非晶复合材料。在此基础上，探索此类非晶复合材料的高速动态变形行为，揭示其高载能应变率条件下的性能特点和其形变形机理。本项目的最终目的是研发出综合性能优异的并可实际工程应用的大尺寸相变韧塑化的非晶复合材料，并为此类材料的合金设计提供理论指导。

针对目前非晶合金工程应用中所面临的关键挑战：室温脆性和尺寸不足，本项目在引入“相变诱导塑性”概念的基础上，开发大尺寸高性能非晶复合材料，并对相关科学和应用的共性关键基础问题进行研究。本项目首先对相变韧塑化非晶复合材料的多相竞争机制展开深入研究，探索奥氏体型增强相的动态原位析出规律，提高基体的非晶形成能力和调控多相的本征性能匹配。其次，研究内生异质形核点对奥氏体型增强相析出的影响规律，研发出大尺寸且奥氏体型增强相均匀弥散分布的非晶复合材料。在此基础上，探索此类非晶复合材料的高速动态变形行为，揭示其高载能应变率条件下的性能特点和其形变形机理。本项目研发出了综合性能优异的并可实际工程应用的大尺寸相变韧塑化的非晶复合材料，并为此类材料的合金设计提供理论指导。本项目发表学术论文70篇；申请发明专利12项；培养博士生6名，硕士生12名，以项目负责人为第一完成人，骨干人员参与获得2018年国家自然科学科学二等奖1项（块体非晶合金的原子结构与强韧化）。