Regular Article

Phase-field-crystal study on shear-induced coupled evolution of intragranular crack and grain boundary in nanoscale bicrystal system

¹ College of Civil Aviation Safety Engineering, Civil Aviation Flight University of China, Guanghan 618307, P.R. China
² School of Automotive Engineering, Chengdu Industry and Trade College, Chengdu 611731, P.R. China

^a e-mail: hshi@mail.ustc.edu.cn

Received: 11 July 2020
Received in final form: 6 September 2020
Accepted: 24 September 2020
Published online: 18 November 2020

Abstract

Shear-induced coupled evolution behavior of intragranular crack and grain boundary (GB) in nanoscale bicrystal system is studied by using phase-field-crystal method. Evolution process of system with different crack sizes and grain boundary misorientations (GBMs) is analyzed. Instead of normally extending under applied strain, intragranular crack can partially heal and even disappear under shear strain. This healing process is realized by compression stress field provided by GB migration. Increasing GBM and decreasing crack size can both facilitate crack healing. Besides, with the existence of intragranular crack, centripetal GB migration can be accelerated. The acceleration effect will be decreased by large GBM and small crack size. Low GBM is a prerequisite, but decreasing crack size can only make this effect not obvious. Increasing GBM or crack size has opposite effects on crack healing and centripetal GB migration.