TY - JOUR
T1 - Strengthening in Metal/Graphene Composites
T2 - Capturing the Transition from Interface to Precipitate Hardening
AU - Shuang, Fei
AU - Dai, Zhaohe
AU - Aifantis, Katerina E.
N1 - Funding Information:
Authors K.E.A. and F.S. are grateful for the support of the U.S. Department of Energy, Office of Basic Energy Sciences under grant DE-SC0017715, which made this work possible. Author Z.D. acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 886028.
Publisher Copyright:
©
PY - 2021/6/9
Y1 - 2021/6/9
N2 - A promising materials engineering method for improving the strength of crystalline materials is to add obstacles to dislocation motion that induce interface hardening (IH) or precipitate hardening (PH). In this study, molecular dynamics simulations are performed for Ni/graphene composites, revealing for the first time that graphene can strengthen the Ni matrix not only strictly via IH or PH but also through a continuous transition between the two. When graphene behaves like an interface, dislocation pileups form, whereas when it behaves as a precipitate, complex Orowan looping occurs by dislocation cross-slip. IH transitions to PH when the integrity of the graphene-dislocation configuration (GDC) deteriorates, leading to a reduced strengthening effect. Furthermore, the deformation of graphene is found to be an effective signature to indicate the real-time strengthening. This observation relates the graphene strengthening effect on metals to a combination of parameters, such as the GDC integrity, graphene deformation, and dislocation evolution, opening an avenue to tune the mechanical properties by controlling the dislocation movements and manipulating the dislocation-obstacle interaction mechanisms.
AB - A promising materials engineering method for improving the strength of crystalline materials is to add obstacles to dislocation motion that induce interface hardening (IH) or precipitate hardening (PH). In this study, molecular dynamics simulations are performed for Ni/graphene composites, revealing for the first time that graphene can strengthen the Ni matrix not only strictly via IH or PH but also through a continuous transition between the two. When graphene behaves like an interface, dislocation pileups form, whereas when it behaves as a precipitate, complex Orowan looping occurs by dislocation cross-slip. IH transitions to PH when the integrity of the graphene-dislocation configuration (GDC) deteriorates, leading to a reduced strengthening effect. Furthermore, the deformation of graphene is found to be an effective signature to indicate the real-time strengthening. This observation relates the graphene strengthening effect on metals to a combination of parameters, such as the GDC integrity, graphene deformation, and dislocation evolution, opening an avenue to tune the mechanical properties by controlling the dislocation movements and manipulating the dislocation-obstacle interaction mechanisms.
KW - graphene
KW - interface
KW - molecular dynamics
KW - precipitate
KW - strengthening transition
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U2 - 10.1021/acsami.1c05129
DO - 10.1021/acsami.1c05129
M3 - Article
C2 - 34038072
AN - SCOPUS:85108021219
SN - 1944-8244
VL - 13
SP - 26610
EP - 26620
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 22
ER -