Calculating Study on Properties of Al (111)/6H-SiC (0001) Interfaces

Abstract

The research elaborates on the mechanical properties at the Al (111)/6H-SiC (0001) interface based on the density functional theory. Because of the difference in atom category at the interface of 6H-SiC (0001), it takes the C-terminated interface and Si-terminated interface into account. As indicated by the gross energy computing results at the two interfaces, the C-terminated Al (111)/6H-SiC (0001) interface demonstrates a greater adhesion force than the Si-terminated counterpart. Throughout detailed analysis on the bonding mechanism, surface hybridization and charge transfer at the Al (111)/6H-SiC (0001) reaction interface, the research reveals its strong covalent characteristics. According to the comparative study on the ideal tensile strength and general stacking fault energy at varying cleavage surfaces, a conclusion can be fitly reached that the fracture at the Al (111)/6H-SiC (0001) interface is easily seen in Al-Al bonds in the Al matrix instead of C(Si)-Al bonds at the interface. Despite the greater adhesion energy of the C-Al bond than the Si-Al bond, Al-Al bonds close to the C-terminated Al (111)/6H-SiC (0001) interface easily fracture due to the low ideal tensile strength.

Molecular Dynamics Study of Interfacial Micromechanical Behaviors of 6H-SiC/Al Composites under Uniaxial Tensile Deformation

“…It was observed from Figure 5 a that the stress concentrated on the interface region, where the crack started to nucleate and grow ( Figure 4 c,d). (As a matter of fact, the interface region mentioned here means the specific area two or three atomic layers away from the Si-Al heterogenous bonding interface in the Al matrix [ 34 , 35 , 36 ]. This fracture mode may be attributed to the unique mechanisms of the interface combination mode as mentioned above).…”

Effects of Transition Element Additions on the Interfacial Interaction and Electronic Structure of Al(111)/6H-SiC(0001) Interface: A First-Principles Study

“…The atomic and electronic structures of Al(111)/6H-SiC(0001) interface have been given in detail in our previous studies [ 22 , 23 ]. In order to compare with the results of the following doping interfaces, we further studied the interfacial charge transfer.…”

“…Meanwhile, for interface calculations, the force tolerance of each atom was set as 10 −2 eV/Å. According to previous studies [ 19 , 20 , 21 , 22 , 23 , 27 ], the binding energy of the Al(111)/6H-SiC(0001) is the highest when the C(Si) atom is directly above the Al atom. Therefore, we only studied this configuration here.…”

“…In earlier years, Al/SiC interfaces have been investigated by quantum chemistry methods [ 19 ] and ab-initio calculations [ 20 , 21 ]. Recently, the structural and mechanical properties of the Al(111)/6H-SiC(0001) [ 22 , 23 , 24 ] and Al (100)/6H–SiC(0001) [ 25 ] interfaces have been studied using the first-principles method. All these studies suggest that the strong bonding of SiC/Al interface is attributed to the formation of covalent bonds.…”

Mechanical and Electronic Properties of Al(111)/6H-SiC Interfaces: A DFT Study

“…At the interface between SiC and Al, there are strong covalent bonds between the carbon atoms in SiC and the aluminum atoms in Al. However, in the first few layers of Al, the bonding strength between the Al atoms and the SiC substrate is weaker, as it involves weaker Van der Waals forces and weaker metallic bonds [41,42] system maintain the relative position along the z-direction concerning the new configuration. Then, the atomic positions of the new configuration are entirely relaxed at each displacement step.…”