Strain Rate Induced Amorphization in Metallic Nanowires
Using molecular dynamics simulations with a many-body force field,
we studied the deformation of single crystal Ni and NiCu random
alloy nanowires subjected to uniform strain rates but kept at 300 K.
For all strain rates, the Ni nanowire is elastic up
to 7.5% strain with a yield stress of 5.5 GPa, far above that of
bulk Ni. At high strain rates, we find that for both systems the
transforms continuously to an amorphous phase,
exhibiting a dramatic
change in atomic short-range order and a near
vanishing of the tetragonal
shear elastic constant perpendicular to the tensile direction.
This amorphization which occurs directly from the homogeneous,
elastically deformed system with no chemical or structural
inhomogeneities exhibits a new mode of amorphization.
- Hideyuki Ikeda,2 Yue Qi,1 Tahir Çagin,1
Konrad Samwer,2 William L. Johnson,2 and William A. Goddard III1
- 1Materials and Process Simulation Center, California
Institute of Technology, Pasadena, California 91125
2Keck Laboratory of Engineering Materials, California Institute of Technology,
Pasadena, California 91125
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