中程尺度类晶体结构决定非晶合金慢二次弛豫
Medium-range imperfect order determining the slow β-relaxation in metallic glasses
罗强 1邵里良 2薛琳 3崔静贤 1杨芊姿 1王俊鹏 1柯海波 4沈宝龙 1汪卫华5
作者信息
- 1. School of Materials Science and Engineering,Jiangsu Key Laboratory of Advanced Metallic Materials,Southeast University,Nanjing 211189,China
- 2. School of Materials Science and Engineering,Jiangsu Key Laboratory of Advanced Metallic Materials,Southeast University,Nanjing 211189,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China
- 3. College of Mechanics and Materials,Hohai University,Nanjing 211100,China
- 4. Songshan Lake Materials Laboratory,Dongguan 523808,China
- 5. Songshan Lake Materials Laboratory,Dongguan 523808,China;Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China
- 折叠
摘要
二次弛豫特别是慢β弛豫和结构不均匀性是非晶合金悬而未决的关键问题.尽管经历了几十年的深入研究,慢β弛豫与结构不均匀性之间的本征关联及其成分依赖性尚未建立.本文以镝基块体非晶合金为载体,通过微量掺杂不同类金属元素包括硼、碳、氮和硅,实现了β弛豫的有效调控,并且揭示了其原子尺度结构起源.通过对比研究混合焓、弹性不均匀度、相互作用强度和不完美序结构(或类晶体结构)对β弛豫的影响,发现β弛豫强度与中程类晶体结构的含量密切相关(与混合焓没有显著的对应关系),这表明原子的链状协同运动发生在含有类晶体结构的中程序软区.此外,镝元素和类金属元素之间的相互作用强度对于类晶体结构的形成至关重要.本工作对于理解β弛豫的原子结构起源和调控非晶合金性能具有重要意义.
Abstract
Secondary(slow β)relaxation and structural heterogeneity are crucial in several critical unresolved issues in metallic glasses(MGs).However,their intrinsic correlations and composition dependence are not established despite ex-tensive work for decades.In this work,we modulated the secondary relaxation and structural heterogeneity of Dy-based bulk MGs by microalloying different metalloids(B,C,N,and Si)and demonstrated the atomic-scale mechanism.We shed light on the effects of enthalpy of mixing,degree of elastic heterogeneity on the micrometer scale,intensity of interac-tion,and imperfect orders(IPOs)on β-relaxation dynamics.We revealed that both the obviousness/intensity of the shoulder and the activation energy for β-relaxation are closely associated with the fraction of medium-range IPO.This shows that the cooperative string-like atomic rearrangements con-sidered as the structural origin in terms of the first-order transition theory probably occur in soft medium-range structures(or defects)with IPO.In addition,the intensity of interaction between Dy and metalloid elements is found to play a crucial role in the formation of medium-range IPO.This work offers new insights into the longstanding mystery regarding the atomic mechanism of β-relaxation and shows significance for tuning the properties of MGs.
关键词
β-relaxation/structural heterogeneity/metallic glass/imperfect orderKey words
β-relaxation/structural heterogeneity/metallic glass/imperfect order引用本文复制引用
基金项目
国家自然科学基金(51971061)
国家自然科学基金(52231005)
国家自然科学基金(52301212)
国家自然科学基金(52101193)
出版年
2024
NETL
NSTL
万方数据