Molecular Dynamic Simulation On Solid-liquid Compound Of Copper And Aluminum Two-phase Materials

In this paper, the molecular dynamics(MD) method is employed to simulate the preparation process of copper-aluminum composite material by solid-liquid composite method. We investigate how heat preservation time regulates the thickness of composite material’s transition layer and the elastic mechanical properties of copper-aluminum composite material with different thickness of transition layer. In addition, the details of the formation process of transition layer and the influence of transition layer on the mechanical properties are analyzed.The results indicate that heat preservation time has a strong impact on the thickness of transition layer under the same heating and cooling conditions. As the heat preservation time becomes longer, the transition layer becomes thicker. But the thickening rate becomes slower. Similarly, the thickness of transition layer influences the mechanical properties of materials deeply. Young’s modulus, elastic limit, yield limit and ultimate strength decrease with thickening transition layer. But, the rate of decrease becomes slower.In the solid-liquid composite process of copper and aluminum, aluminum atoms in the liquid state are more active than copper atoms in solid state. The main diffusion mechanism is that solid copper atoms break away and diffuse with liquid aluminum atoms. On the other hand, some aluminum atoms enter solid copper.The transition layer is made up with intermetallic compounds and atomic groups, which are the main factor in reducing the strength of the material. The thicker the transition layer is, the more the type and quantity of intermetallic compounds are. And they become more disordered. These are all the factors that break the integrity of metal bond.