Shocking of metallic glass to induce microstructure heterogeneity: A molecular dynamics study

Surface severe plastic deformation (SSPD) has been demonstrated to improve the ductility of metallic glass. The physical interpretation, however, remains on the phenomenological level. In this study, a molecular dynamics (MD) simulation is carried out to elucidate the molecular mechanisms underlying...

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Bibliographic Details
Published inJournal of applied physics Vol. 122; no. 9
Main Authors Ma, Chi, Wang, Guo-Xiang, Ye, Chang, Dong, Yalin
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 07.09.2017
Subjects
Amorphous materials
Applied physics
Compressive properties
Deformation mechanisms
Ductility
Edge dislocations
Metallic glasses
Microstructure
Molecular dynamics
Plastic deformation
Shear bands
Shock waves
Stress concentration
Stress distribution
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Summary:Surface severe plastic deformation (SSPD) has been demonstrated to improve the ductility of metallic glass. The physical interpretation, however, remains on the phenomenological level. In this study, a molecular dynamics (MD) simulation is carried out to elucidate the molecular mechanisms underlying the improvement in ductility. MD simulation reveals that shock waves resulting from SSPD can induce pre-deformed atoms, which are randomly embedded in the matrix of the metallic glass. The pre-deformed atoms have similar stress distribution and short-order structure as the matrix atoms, but with a larger atomic volume. When subjected to tensile or compressive stress, more shear bands are promoted by the pre-deformed atoms in the shock-treated sample as compared to the untreated one. The randomly distributed shear bands were found to experience more interactions, which delayed the catastrophic fracture, leading to increased ductility.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.5000366