title: Analysis of internal crack healing mechanism under rolling deformation.
abstract: A new experimental method, called the 'hole filling method', is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion mechanism is used to explain the source of material needed for crack healing. The recrystallisation mechanism is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface.
authors.affiliation: State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, China.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Ai
authors.affiliation: School of Mechanical, Materials & Mechatronic Engineering, University of Wollongong, New South Wales, Australia; School of Mechanical Engineering, Shenyang University, Shenyang, China.
authors.forename: Hailiang
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Liu
mesh_terms: D003460:Crystallization; D066192:Manufacturing Industry; D013232:Steel / Q000737:chemistry*; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D013232:Steel