103 Investigation of micro-defect effect on material properties of single crystal silicon based on molecular dynamics simulation

Molecular dynamics (MD) simulation can play a significant role in addressing a number of machining problems at the atomic scale. This simulation, unlike other simulation techniques, can provide new data and insights on nanometric machining; which cannot be obtained readily in any other theory or experiment. In this paper, some fundamental problems of mechanism are investigated in the nanometric cutting with the aid of molecular dynamics simulation, and the single-crystal silicon is chosen as the material. The study showed that the purely elastic deformation took place in a very narrow range in the initial stage of process of nanometric cutting. Shortly after that, dislocation appeared. And then, amorphous silicon came into being under high hydrostatic pressure. Significant change of volume of silicon specimen is observed, and it is considered that the change occur attribute to phase transition from a diamond silicon to a body-centered tetragonal silicon. The study also indicated that the temperature distributing of silicon in nanometric machining exhibited similarity to conventional machining.

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A Study on the Nanoindentation Behaviour of Single Crystal Silicon Using Hybrid MD-FE Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.32.259 ◽

2008 ◽

Vol 32 ◽

pp. 259-262 ◽

Cited By ~ 18

Author(s):

Akbar Afaghi Khatibi ◽

Bohayra Mortazavi

Keyword(s):

Molecular Dynamics ◽

Finite Element ◽

Single Crystal ◽

Material Properties ◽

Single Crystal Silicon ◽

Dynamics Simulation ◽

Fe Method ◽

Crystal Silicon ◽

Element Analysis ◽

Nano Scale

Developing new techniques for the prediction of materials behaviors in nano-scales has been an attractive and challenging area for many researches. Molecular Dynamics (MD) is the popular method that is usually used to simulate the behavior of nano-scale material. Considering high computational costs of MD, however, has made this technique inapplicable as well as inflexible in various situations. To overcome these difficulties, alternative procedures are thought. Considering its capabilities, Finite Element Analysis (FEA) seems to be the most appropriate substitute for MD simulations in most cases. But since the material properties in nano, micro, and macro scales are different, therefore to use FEA methods in nano-scale modeling one must use material properties appropriate to that scale. To this end, a previously developed Hybrid Molecular Dynamics-Finite Element (HMDFE) approach was used to investigate the nanoindentation behavior of single crystal silicon with Berkovich indenter. In this study, a FEA model was developed based on the material properties extracted from molecular dynamics simulation of uniaxial tension test on single crystal Silicon. Eventually, by comparison of FEA results with experimental data, the validity of this new technique for the prediction of nanoindentation behavior of Silicon was concluded.

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