非晶合金微观非均匀结构及其与变形行为联系研究

Metallic glasses (MGs) exhibit many excellent physical, chemical and mechanical properties, which have attracted considerable attentions from academia and industry. However, many basic problems remain unsolved, such as the deformation mechanism, characterization and construction of heterogeneous structure. Therefore, this proposal plans to characterize the heterogeneous structure of MGs utilizing atom force microscope(AFM), and to systematically study the deformation behavior employing nanoindentation, in-situ AFM loading and other methods. Through comparative analysis of the heterogeneous and uniform structure of ordinary and ultrastable MGs, the interface between the loosely packed and densely packed atom regions will be pinpointed, the features of heterogeneous structure will be characterized；Afterwards, the characteristics of different MGs will be studied, the physical origin of different heterogeneous structure will be elucidated from the viewpoint of chemical and topological viewpoints; In the end, based on the measurement of mechanical parameters of the heterogeneous structure and in-situ observation of the structural evolution during tension, direct correlation between the heterogeneous structure and deformation behavior will be established, and deformation mechanism will be elaborated. The study will improve our understanding about the heterogeneous structure and deformation mechanism of MGs, and will provide guidance for the alloy design and mechanical performance optimization for MGs.

非晶合金具有优异的物理、化学和力学性能，引起了科学界和工业界的广泛关注，然而其中一些基础问题迄今仍未得到明确解答,如对非晶合金非均匀结构的构建以及对变形机理的理解。因此，本项目拟采用高分辨率原子力显微镜对不同非均匀度非晶合金进行微观结构表征，同时借助纳米压痕和原子力显微镜原位加载等手段对其变形行为进行系统研究。通过对比超均匀密排非晶合金和非均匀非晶合金结构明确非均匀区域边界，表征非均匀结构特征；基于此，剖析不同体系非晶合金非均匀结构差异，从化学和拓扑角度揭示结构差异的物理本源；进而，测量非均匀结构微区力学参数，实时观察拉伸过程非均匀结构演化，构建非均匀结构和变形行为之间直接联系，阐述非晶合金变形机理。项目的开展将促进人们对非晶合金非均匀结构的全面认识，加深对其变形机理的理解，为非晶合金结构设计和性能优化提供指引。

非晶合金具有优异的物理、化学和力学性能，引起了科学界和工业界的广泛关注，然而其中一些基础问题迄今仍未得到明确解答,如对非晶合金非均匀结构的构建以及对变形机理的理解。项目提出采用高分辨率原子力显微镜等新手段对非晶合金非均匀结构进行表征，并研究结构变化对其力学性能的影响规律，揭示非晶合金的变形机理。项目通过三种方法来改变非晶合金的非均匀结构：一是铸造过程冷却速度调整，二是块体非晶合金后处理回春，三是非晶体系多组元合金晶化，结构的改变带来性能的改善，通过研究揭示了非晶合金的变形机理。发表SCI学术论文5篇，其中Top期刊1篇；申请国际专利1项，已经通过国际检索；申请国内专利3项，目前授权1项。项目期间培养研究生两人，参加学术会议4次。项目基本按照研究计划进行。