摘要
非晶合金力学行为与其微观结构非均匀性之间本征关联,是固体力学研究领域至今未能很好解决的重要科学问题之一.单一力学激励形式并不能有效地描述非晶合金微观结构非均匀性,特别是结构与动力学的关联.如何探索非晶合金结构信息,须将诸多因素综合,在不同力学激励下研究非晶合金微观结构非均匀性与变形机理.本研究以La_(62)Cu_(12)Ni_(12)Al_(14)非晶合金为模型体系,利用动态力学分析仪研究非晶合金动态弛豫行为.基于准点缺陷模型,对模型合金体系α弛豫和β弛豫进行了分离.借助于拉伸应变率跳实验,探索非晶合金高温流变行为.确定非晶合金塑性流变过程中弹性、滞弹性以及塑性变形的贡献.本研究从非晶合金动态力学弛豫行为和宏观塑性流变行为出发,尝试揭示微观非均匀性对非晶合金在不同激励形式中缺陷的激活、扩展和融合的物理本质.
The intrinsic structural heterogeneity of amorphous alloy is closely related to the thermodynamics and dynamical behavior,such as relaxation/crystallization,glass transition and plastic deformation.However,the structural information is submerged into the meta-stable disordered long-range structure,which makes it very difficult to explore the structural heterogeneity of amorphous alloy.A mechanical excitation factor is insufficient to effectively describe the heterogeneity of the microstructure in amorphous alloy,particularly the correlation between structure and dynamics.To explore the essence of the structure in amorphous alloy,it is necessary to consider the different mechanical stimuli.La_(62)Cu_(12)Ni_(12)Al_(14) amorphous alloy is selected as the model system,dynamic mechanical process is probed by dynamic mechanical analyzer(DMA).The contributions ofαrelaxation process andβrelaxation process are described in the framework of the quasi-point defect theory.Based on the quasi-point defect theory,theα-relaxation andβ-relaxation in the La-based amorphous alloy are separated.Tensile strain rate jump measurements are conducted to study the high temperature rheological behavior of amorphous alloy.The contributions of elasticity,anelasticity,and plastic deformation during the homogeneous flow of amorphous alloy are determined within the framework of quasi-point defect theory.The present work aims to reveal the structural heterogeneities of amorphous alloys under the action of dynamics on various temporal scales.The physical background of the activation,propagation and coalescence of defects in amorphous alloy under different mechanical stimuli are reviewed.
作者
张剑
郝奇
张浪渟
乔吉超
Zhang Jian;Hao Qi;Zhang Lang-Ting;Qiao Ji-Chao(School of Mechanics,Civil Engineering and Architecture,Northwestern Polytechnical University,Xi’an 710072,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第4期224-234,共11页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51971178,52271153)
陕西省杰出青年基金(批准号:2021JC-12)资助的课题.
关键词
非晶合金
微观结构非均匀性
动力学弛豫
高温变形
准点缺陷模型
amorphous alloys
microstructural heterogeneity
dynamic mechanical relaxation
high-temperature flow
quasi-point defects theory
