First-principles Study Of Graphene Reinforced Titanium Matrix Composites

The rapid development of aviation industry puts forward higher requirements for the lightweight,high specific strength and high temperature resistance of engine and structural materials.Using the first principle method,the adsorption properties of graphene / titanium and the interfacial bonding strength are studied from atomic scale.The adsorption,interface structure and interfacial bonding are deeply analyzed.The microstructure of the interface of graphene reinforced titanium matrix composites and the nature of the performance of the interface are revealed.Firstly,the adsorption mechanism of single titanium atom on the surface of intrinsic graphene,vacant graphene and nitrogen doped graphene film is studied.The adsorption energy,electron density and differential charge density of each adsorption system have been calculated.It is shown that the electron orbital hybridization is produced between the three adsorption systems and the adsorption properties of graphene are slightly enhanced,while the adsorption energy of the vacant graphene is 4 times as high as that of the intrinsic graphene,and the localization of the electronic state near the Fermi level is the largest and the chemical adsorption effect is the best.Secondly,the interface structure and properties of the titanium cornerstone composite were studied.A single interface model of graphene / titanium(GR/Ti)and a double interface model(Ti/GR/Ti)were established.The binding energy of the stable interface,the density of the electronic state,the Mulliken distribution and the radial distribution function were calculated.The results show that the binding energy of the double interface model is 2.3 times as much as the single interface model,and the interaction is stronger.The surface of the graphene in the two models is interacted with the most adjacent two layers of titanium atoms,the most adjacent Ti layer is strongly hybrid with the C atom,the d orbit of Ti atom contributes the most,the charge transfer quantity of the Ti/GR/Ti model is more and the covalent effect is stronger,and the interfacial bonding characteristics are determined.The metal bond and covalent bond,the crystal structure and electronic properties of the Ti/GR/Ti double interface model are smooth transition at the interface.The atoms of each layer are closer together and the structure is more stable.Finally,using the ab initio molecular dynamics method to simulate the temperature effect of the interface model of graphene / titanium composites,the atomic structure,binding energy and radial distribution function of the graphene / titanium interface at different temperatures(300~2500 K)were calculated.The results show that with the increase of temperature,the titanium atoms are close to the graphene film.When the temperature reaches 1100 K,the most close atomic structure and the corresponding binding energy are the most,and the interfacial bonding is the best.When the temperature reaches 2000 K,the interfacial binding energy decreases rapidly,and the surface titanium begins to melt,and the interface effect begins to weaken.