Molecular Dynamics Simulation Of The Interfacial Mechanical Properties Of SiC/Al Composites

This work mainly study the mechanical properties and interfacial structure of SiC/Al composite materials by using molecular dynamics method. Through-simulate the tensile, compress and shear properties of the double membrane structure of SiC/Al composites, the interfacial structure, interfacial mechanical properties, the factors of influence, the plastic deformation mechanism and tensile fracture mechanism have been obtained and discussed.After study different kinds of interfaces, we found that when the carbon atoms situate in the interface, the carbon atoms is more disorder than that silicon atoms in the interface. Due to the interfacial lattice mismatch, there are some misfit dislocations on the interface near to the aluminum after relaxation.Through to stretch (100)Al|| (100si)Sic structure of SiC/Al, we conclude that the micro-layer composite laminate structure of the SiC/Al composite has a higher tensile strength than that the double membrane structure of the SiC/Al composite, and both their strengths are similar to that of single crystal Al; The simulated results shown that plastic deformation and fracture mechanism are the dislocation launch from the interface and move to the internal Al, and then reflected when meets the interface. After that, it take place slipping, rotation and crystal refactoring, then generate holes. Finally, they produce cracks and fracture.The tensile strength of SiC/Al increases with tensile strain rate, but reducing with the temperature increase. Both the tensile strength of micro-layer composite laminate structure and the double membrane structure of the SiC/Al composite can’t be improved compared with that of single crystal Al. The mechanical properties of the composite board or double layer structure of SiC/Al are mainly determined by the mechanical properties of Al, and when the SiC crystal orientation is different, the mechanical properties of SiC/Al shown difference. When the silicon atoms combine with aluminum atoms in the interface, the yield strength and tensile strength of SiC/Al composites are higher than that of Al-C bonding’s strength.The mechanism of (100)Al|| (110si)Sic structure of SiC/Al from elastic deformation to plastic deformation under compression is that:the intrinsic stacking fault launching from the interface near to Al along the [111] crystal on the surface of the (111), and reflect when meet to interface, and stop when meet to other stacking faults. The new fault lanuch constantly until stacking fault density reaches a certain value.