Molecular Dynamics Simulation Of The Aluminum Crack Propagation Behavior

Aluminum alloy will appear microcracks, voids and other defects in manufacturing and using process. This defects gradually evolved, will lead to material failure. Therefore master the evolving law of those defects has a positive role in the proper use of material. As a very important method in computational approaches, the molecular dynamics simulation plays an important role in many fields, especially in describing the details of the micro-level. According to this simulation technology, a series of crack propagation behavior have been studied by the initial model respectively without void and void in this paper.In this paper, the research status of molecular dynamics simulation has been summarized about the crack initiation and propagation and the evolution behavior of the holes. The basic principle of molecular dynamics simulation are been systematically introduced. And the detailed descriptions are given to the four steps of molecular dynamics simulation.The crack propagation behavior is studied by molecular dynamics method with the speed loading for model without void and void model. For the model without void, the special moment of crack propagation map is drawn. The change of crack propagation is observed clearly, such as crack tip blunted, generation of sub-crack, formation and growth processing of void and collection of crack and void. Evolution process of the system is described in detail from energy evolution map. Crack propagation behavior of the system is discussed by loading speed, initial crack length, size of the model and initial temperature. The results show that the time of system completely open is shortened with increasing loading speed. And atomic motion is intensified. The longer the initial crack length, the less details of the atomic motion are show up. The details of the crack propagation are observed difficultly and crack propagation rule become more complex for the larger or smaller model. With the increase of temperature, the degree of atoms thermal vibration is becoming bigger in the crystal lattice equilibrium position and atomic lattice restructuring become easily.Crack propagation behavior of the special moment is described in detail and explained by energy evolution figure for model with void. Crack propagation behavior of model with void is discussed by size of the void, loading speed and initial temperature. The results show that the bigger the void, the shorter the time of system completely open. The details of the atomic motion are not easy to show up around the void. At the same period time, the time of system completely open is obviously shortened with increasing loading speed. The details of the atomic motion are difficult to show up. The edge shape is more complicated after system open. The higher initial temperature, the law of crack propagation and void evolution become more complex. And atomic motion is intensified.