Papers by Keyword: MEAM

Abstract: In this paper, Modified Embedded Atom Method (MEAM) method, one of the molecular dynamic (MD) methods, was utilized to investigate the wettability of Sn droplet on the copper plate to simulate the wetting and spreading phenomena of the solder process. And the experiment of spreading and wetting process of Sn droplet on the copper plate was performed by sessile-drop as well to get the contact angles. The results show that the MEAM method is fit to simulate the soldering process. Keywords: Wettability; Soldering; MEAM; Sessile-drop; Molecular dynamic

Abstract: The self-diffusion coefficient of Cu in Sn-1.5wt.%Cu and Sn-2wt.%Cu lead-free solders was investigated using molecular dynamics simulations based on a modified embedded-atom method from 503 K to 773 K. Then the viscosity of the solders was calculated using the selfdiffusion coefficient values, and the results were in good agreement with the experimental data. Two segments, a low-temperature zone and a high-temperature zone, were found on both η–T and lnη–1/T plots, where η is the viscosity and T is the absolute temperature. Through analysis, we infer that the viscosity mutation was attributed to the remarkable structure transition.

Abstract: In the present study molecular dynamics simulations were carried out to investigate the deformation of pure FCC aluminum and diamond cubic silicon interfaces under shear stress. A second nearest-neighbor modified embedded atom method was used to describe the interactions between Al-Al, Si-Si and Al-Si atoms. The critical shear stress (CSS) was determined for various Al/Si and Al/Al interfaces with different alignments and orientations. Structural analyses show that the deformation is localized at approximately 10 Å thickness of the interface in Al. The critical shear stress of Al/Si interface was found to be significantly lower than the critical tensile stress due to the partial stick-slip in sliding. In addition, it has been proven that there is no explicit relationship between shear and tensile critical stresses, which is fundamentally different from isotropic materials, where the shear stress is about half of the tensile stress. The misorientation has a dramatic effect in reducing shear stress at Al/Al interfaces, but has no effect on CSS in Al/Si. As a result, it was shown that introducing Si improves the strength of the interface (and the composite material in general) for different grain orientations.