双相共晶高熵合金中迥异的同/异相界面行为  

Divergent interfacial behaviors of homo-/hetero-phase boundaries in a dual-phase eutectic high-entropy alloy

作　　者：代乾宁 谢碧君 任少飞 余朕翔 徐斌 孙明月 Qianning Dai;Bijun Xie;Shaofei Ren;Zhenxiang Yu;Bin Xu;Mingyue Sun(Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China

出　　处：《Science China Materials》2023年第6期2454-2466,共13页中国科学（材料科学（英文版）

基　　金：supported by the National Key Research and Development Program(2018YFA0702900);the National Natural Science Foundation of China(52173305,52101061,52233017,and 52203384);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC04000000);China Postdoctoral Science Foundation(2020M681004,2021M703276,and 2022T150662);the IMR Innovation Foundation(2022-PY12);LingChuang Research Project of China National Nuclear Corporation;the Youth Innovation Promotion Association,Chinese Academy of Sciences。

摘　　要：界面的结构和行为对材料的性能具有重要的影响.本文旨在研究复杂成分多相体系材料中这些独特的界面结构和行为.我们报道了通过连接AlCoCrFeNi_(2.1)共晶高熵合金所获得的L1_(2)-L1_(2),B2-B2,L1_(2)-B2三种界面迥异的界面行为.具体是,由于热-应变诱导的晶界演化,在L1_(2)-L1_(2)界面附近出现了明显的界面动态再结晶.相反,由于极少的界面应变,B2-B2界面几乎没有发生动态再结晶,其连接可能是由于扩散引起的.由于L1_(2)相和B2相本征的结构差异,在L1_(2)-B2界面处只在L1_(2)相侧发生了动态再结晶.这类异质界面的连接是由于界面元素的扩散.另外,由于高熵合金高的缺陷-析出敏感性,在连接界面附近出现了应变诱导析出的B2_(Ⅱ)相.B2_(Ⅱ)相的析出消耗了基体中的Ni,Al元素,造成了L1_(2)相的无序化.通过定量计算相应晶粒的极限尺寸评估了这些B2_(Ⅱ)相带来的Zener钉扎效应.这种B2_(Ⅱ)相的钉扎作用及元素的缓慢扩散效应可能导致了L1_(2)-L1_(2)界面温度依赖的动态再结晶行为.本研究有助于理解多相高熵合金独特的界面行为,并为多相、复杂成分、界面析出等因素对界面演化的影响提供了新的认识.The interfacial structures and behaviors are critical in determining the material properties.Our study aims to investigate such unique interfacial structures and behaviors in multiphase systems involving complex compositions.Herein,we report the divergent interfacial behaviors of the L1_(2)-L1_(2),B2-B2,and L1_(2)-B2 boundaries prepared via the bonding of AlCoCrFeNi_(2.1)eutectic high-entropy alloys(HEAs).Specifically,interfacial dynamic recrystallization(DRX)occurs in the L1_(2)-L1_(2)boundary owing to the thermostrain-induced grain boundary evolution.In contrast,the bonding of the B2-B2 boundary may be realized by interface diffusion,and no evident DRX occurs owing to the small interfacial shear strain.The DRX grains only developed on the L1_(2)side in the L1_(2)-B2 boundary because of the difference in the intrinsic structural traits between L1_(2)and B2.The diffusion of elements contributed to the bonding of this dissimilar boundary.Moreover,a strain-induced B2_Ⅱprecipitation phenomenon surrounding the bonding interface was revealed because of the high defect-precipitation sensitivity of HEAs.The B2_Ⅱparticle precipitation depleted the Al and Ni within the matrix,leading to L1_(2)disordering.The Zener pinning effect exerted by B2_Ⅱprecipitates was quantitatively evaluated by calculating the corresponding limited grain radius RL=1.8μm.This pinning effect of B2_Ⅱprecipitates and the sluggish diffusion effect may induce temperature-dependent DRX behaviors of the L1_(2)-L1_(2)boundary.This study reveals the understanding of the unique interfacial behaviors of multiphase HEAs and provides new insights into the effects of multiple phases,complex composition,and interfacial precipitation on interfacial evolution.

关 键 词：动态再结晶 极限尺寸 钉扎作用 高熵合金 无序化 共晶 界面行为 双相 

分 类 号：TG139[一般工业技术—材料科学与工程]