The microstructural evolution and relaxation strengthening for nano-grained Ni upon low-temperature annealing  

作　　者：Ze Chai Bo Peng Xukai Ren Kaiyuan Hong Xiaoqi Chen 

机构地区：[1]Shanghai Key Laboratory of Materials Laser Processing and Modification,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai,200240,China [2]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai,201800,China [3]Shaoxing Special Equipment Testing Institute,Shaoxing,312071,China [4]Shien-Ming Wu School of Intelligent Engineering,South China University of Technology,511442,China

出　　处：《Nano Materials Science》2024年第6期726-734,共9页纳米材料科学(英文版)

基　　金：supported by the project funded by China Postdoctoral Science Foundation(grant number 2020M671111).

摘　　要：The microstructural evolution and relaxation strengthening of nano-grained Ni annealed at a temperature range of 493–553 K were studied by in situ X-ray diffraction technique,transmission electron microscopy,and microhardness evaluation.Upon low-temperature annealing,the rather limited variations of anisotropic grain size and root-mean-square strain,conforming to an exponential relaxation model,yield a consistent activation energy of approximately 0.5 eV,which corresponds to the localized,rapid diffusion of excess vacancies on nonequilibrium surfaces/interfaces and/or defective lattice configurations.Microstructure examinations confirm the grain boundary ordering and excess defect reduction.The relaxation-induced strength enhancement can be attributed to the linear strengthening in the regime of small elastic lattice strains.This study provides an in-depth understanding of low-temperature nanostructural relaxation and its relation to strengthening.

关 键 词：Nano-grained metal Microstructure RELAXATION MICROHARDNESS X-ray diffraction 

分 类 号：TG1[金属学及工艺—金属学]