摘要
金属玻璃作为一种典型的无序合金,其微观结构短程有序而长程无序并展现出独特的物理和力学特性.机械加载会导致金属玻璃结构的过度老化或年轻化,而热力耦合作用下过度老化行为的物理机制尚不明确.本研究采用Zr_(50)Cu_(40)Al_(10)金属玻璃,结合黏弹性力学实验和分子动力学模拟,研究了应力作用下金属玻璃的弛豫时间、力学性能、固有结构势能、老化速率和原子激活能的演化,并分析了应力导致过度老化的物理机制.结果表明,应力松弛过程中固有结构势能相较等温退火状态呈现出更快的衰减趋势,应力作用下,金属玻璃的原子激活能整体减小,证实应力作用降低金属玻璃原子激活能垒的物理图像.随着温度的降低和应变的增大,金属玻璃的激活体积相应增大,表明应力和温度对金属玻璃局部弛豫事件具有相似的影响.本研究有助于加深对应力松弛过程及局部弛豫事件的理解,并且为通过机械调控制备稳定玻璃提供了理论依据.
Metallic glass(MG)is an amorphous alloy formed by rapid cooling,characterized by short-range order and unique physical and mechanical properties.Mechanical loading can lead to either overaging or rejuvenation.However,the physical mechanisms driving overaging under thermo-mechanical coupling remain poorly understood.This study focuses on the Zr_(50)Cu_(40)Al_(10)MG,employing viscoelastic mechanical experiments and molecular dynamics simulations.It explores the evolution of relaxation time,mechanical properties,inherent structural potential energy,aging rate,and atomic activation energy under mechanical loading,aiming to elucidate the physical mechanisms underlying overaging.The findings indicate that during stress relaxation,the inherent structural potential energy decays more rapidly than under isothermal annealing.Applied stress decreases the atomic activation energy of the MG,supporting the notion that stress reduces the energy barriers for atomic rearrangements.Additionally,as temperature decreases and strain increases,the activation volume of the MG grows,suggesting that stress and temperature exert similar effects on local relaxation events.This study advances the understanding of stress relaxation processes and local relaxation events,offering theoretical guidance for producing super-stable glasses via mechanical loading.
作者
邢光辉
赵思瑾
吕国建
王兵
乔吉超
XING GuangHui;ZHAO SiJin;LYU GuoJian;WANG Bing;QIAO JiChao(School of Mechanics and Civil Engineering and Architecture,Northwestern Polytechnical University,Xi’an 710072,China;School of Physical Science and Technology,Northwestern Polytechnical University,Xi’an 710072,China)
出处
《中国科学:物理学、力学、天文学》
北大核心
2025年第8期230-243,共14页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(编号:52271153,12472069)
陕西省杰出青年基金(编号:2021JC-12)资助项目。
关键词
金属玻璃
过度老化
应力松弛
分子动力学模拟
metallic glass
overaging
stress relaxation
molecular dynamics simulation
