Estimation of the Mechanical Properties of Amorphous Metal with a Dispersed Nano-crystalline Particle by Molecular Dynamics Simulation

• Published in: Computer modeling in engineering & sciences 2005-12, Vol.10 (3), p.187-198
• Main Authors: Matsumoto, R, Nakagaki, M
• Format: Article
• Language: English
• ISSN: 1526-1492; 1526-1506

Large-scale molecular dynamics simulations of tensile deformation of amorphous metals containing a nano-crystalline particle were performed in order to clarify the effects of particle size and crystal volume fraction on the deformation mechanism and strength. It became clear that particle size has very little effect, while crystal volume fraction has a substantial influence. Elastic modulus and flow stress intensify as crystal volume fraction increases. Furthermore, the stress in the crystal phase continues to increase, even after yielding in the amorphous phase. Consequently, work-hardening effects appear, preventing localization of plastic deformation. Thus, the dispersed nano-crystalline particles improve the amount of tensile elongation in amorphous metal. When the crystal volume fraction is high, there is a strong interaction between particles. Therefore the particles undergo plastic deformation even with small global deformations. Flow stress decreases after yielding of the crystal particles because defects are introduced into the crystal. There is probably an optimum crystal volume fraction for obtaining maximum ductility. Debonding at the amorphous-crystal interface was not observed while the material underwent large deformation. The Lennard-Jones potential, modified to enforce the continuity at the cut-off distance, was used as an interatomic potential. The potential parameters were defined based on Inoue's three basic principles.