Journal
APPLIED SURFACE SCIENCE
Volume 417, Issue -, Pages 54-63Publisher
ELSEVIER
DOI: 10.1016/j.apsusc.2017.02.030
Keywords
Laser processing of metal surfaces; Surface nanocrystallization; Molecular dynamics simulations; Laser processing in liquid; Spatial confinement; Laser melting and resolidification
Categories
Funding
- National Science Foundation (NSF) [CMMI-1301298, CMMI-1436775]
- NSF through the Extreme Science and Engineering Discovery Environment [TG-DMR110090]
- Austrian Science Fund (FWF) through the Lise Meitner Programme [M 1984]
- Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Germany
- Oak Ridge Leadership Computing Facility (INCITE) [MAT130]
- Austrian Science Fund (FWF) [M1984] Funding Source: Austrian Science Fund (FWF)
- Austrian Science Fund (FWF) [M 1984] Funding Source: researchfish
- Div Of Civil, Mechanical, & Manufact Inn
- Directorate For Engineering [1301298, 1436775] Funding Source: National Science Foundation
Ask authors/readers for more resources
The effect of spatial confinement by a solid or liquid overlayer on short pulse laser-induced surface microstructure modification is investigated in a series of large-scale atomistic simulations performed for Ag targets irradiated in the regime of melting and resolidification, below the thresholds for laser spallation and ablation. For Ag targets with free surfaces, the formation of a nanocrystalline region with random crystallographic grain orientation is observed under irradiation conditions leading to the generation of numerous sub-surface voids that slow down the solidification process. When no voids are generated, the resolidification produces grains misoriented with respect to the bulk of the target by just several degrees and separated from each other by low angle grain boundaries or dislocation walls. The presence of a liquid or solid overlayer suppresses nucleation of sub-surface voids, provides an additional pathway for cooling through the heat conduction to the overlayer, and facilitates the formation of nanocrystalline structure in a region of the metal target adjacent to the overlayer. Moreover, the stabilizing effect of the solid overlayer may result in an incomplete melting of metal in the vicinity of the interface, making it possible for grains growing from the interface to retain memory of the target orientation and to produce nanocrystalline interfacial region with small misorientation of grains with respect to the bulk of the target. In all simulations, the nanocrystalline layers generated by laser processing of single crystal Ag targets are characterized by a high density of stacking faults, twin boundaries, and point defects produced in the course of the rapid resolidification. (C) 2017 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available