TY - JOUR

T1 - Real-time atomic-resolution observation of coherent twin boundary migration in CrN

AU - Chen, Zhuo

AU - Zheng, Yong Hui

AU - Löfler, Lukas

AU - Bartosik, Matthias

AU - Sheng, Huaping

AU - Gammer, Christoph

AU - Holec, David

AU - Zhang, Zaoli

PY - 2021/2/11

Y1 - 2021/2/11

N2 - Although coherent twin boundary (CTB) migration in fcc metals has been widely studied, little is known about the CTB migration behavior in the binary transition-metal nitrides system (e.g. rock-salt CrN). Using in-situ atomic-resolution electron microscopy, we report two different twin boundary defect (TD) nucleation and CTB migration modes at the CTB/ITB (incoherent twin boundary) and CTB/surface junctions. A new twin defect nucleation and CTB migration mode are observed from the CTB/surface junction. We show that such CTB migration is associated with a boundary structure alternating from an N-terminated to Cr-terminated, involving Cr and N atom respective motion, i.e., asynchronous CTB migration. We further reveal the dynamic and thermodynamic mechanism of such asynchronous migration through strain analysis and DFT simulations. Our findings uncover an atomic-scale dynamic process of defect nucleation and CTB migration in a binary system, which provides new insight into the atomic-scale deformation mechanism in complex materials.

AB - Although coherent twin boundary (CTB) migration in fcc metals has been widely studied, little is known about the CTB migration behavior in the binary transition-metal nitrides system (e.g. rock-salt CrN). Using in-situ atomic-resolution electron microscopy, we report two different twin boundary defect (TD) nucleation and CTB migration modes at the CTB/ITB (incoherent twin boundary) and CTB/surface junctions. A new twin defect nucleation and CTB migration mode are observed from the CTB/surface junction. We show that such CTB migration is associated with a boundary structure alternating from an N-terminated to Cr-terminated, involving Cr and N atom respective motion, i.e., asynchronous CTB migration. We further reveal the dynamic and thermodynamic mechanism of such asynchronous migration through strain analysis and DFT simulations. Our findings uncover an atomic-scale dynamic process of defect nucleation and CTB migration in a binary system, which provides new insight into the atomic-scale deformation mechanism in complex materials.

UR - http://www.scopus.com/inward/record.url?scp=85101764213&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2021.116732

DO - 10.1016/j.actamat.2021.116732

M3 - Article

VL - 208.2021

JO - Acta materialia

JF - Acta materialia

SN - 1359-6454

IS - 15 April

M1 - 116732

ER -