2. Analytical Procedure
2. 1 Molecular dynamics (MD) simulation
MD simulation is one of the most efective methods
of treating atomic structure evolutions in various materi-
als. Its range of application is rapidly expanding with the support of the recent progress of computer performance. Because the movements of each atom can be traced, MD simulation is very powerful even for the analysis of amor- phous materials in which direct observations of atomic
structures are extremely difcult. Thus it has been applied
to a variety of research on amorphous structures(10) - (15).
In this study, we employed the Parrinello-Rahman al- gorithm(16), (17) to control the external stress. However, when the Parrinello-Rahman algorithm is used, we can- not use velocity Verlet's method, which is a second-order symplectic integrator, without convergent calculation, be- cause velocity terms appear in the calculation of accelera- tion. Therefore, the first-order symplectic integrator(9) was used in this study. We used the velocity scaling method for temperature control. Moreover, we employed the block separation method and link-cell method to reduce the cal- culation costs; the domain decomposition method was also used for parallel calculation. The three-dimensional peri- odic boundary condition was applied in all calculations.
2. 2 Interatomic potential
Although numerous highly accurate interatomic po- tentials have been developed(18), none of these can en- ssure the accuracy required for an amorphous structure and multi-element systems. In this paper, the constituent elements are not specified, and the common mechani- cal properties and strengthening mechanism of amorphous metal with dispersed nanocrystalline particles are studied
using the modified Lennard-Jones potential MLJ.