| With the development of research technology,a growing number of alloys which are superior to traditional metal materials have been found.Alloys have excellent physical properties and play an important role in chemical industry.Nowadays,most of the research focuses on the experimental method to make high performance Aluminum alloys RT2Al20,including rare earth elements?RE?,actinides and calcium of alloys.But other properties are rarely studied,such as elastic properties,the electronic structure and thermodynamic properties,etc.In this paper,the first-principles calculations were performed,which based on the density functional theory?DFT?to explore physical properties of CaT2Al20?T=Ti,V,Cr,Nb,Mo,Ta?,GdT2Al20?T=Ti,V,Cr?and ThT2Al20?T=Ti,V,Cr?.The three kinds of crystal materials have structural stability can be obtained by phonon frequencies and formation enthalpy.Based on the mechanical properties,elastic modulus B,the elastic constant Cij,the shear modulus G,the Young's modulus E,the ductility and brittleness?B/G?,the hardness Hv are obtained,indicating that CaT2Al20,GdT2Al200 and ThT2Al200 intermetallics possess the better elastic properties than pure Al.In addition,the orbital hybridization and occupation number of atomic orbital in the crystal are analyzed by the density of electronic states.These compounds show the better elastic properties of than those of pure aluminum,which are attributed to the bond strength of Ca/Gd/Th-Al bond,Ca/Gd/Th-T bond and T-Al metallic bonds.According to the optical properties curve,reflection spectrum,the energy loss function,absorption spectrum and dielectric function of calcium metal compound CaT2Al200 are analyzed.Finally,By mean of using data of F?V,T?-V data,we fit them to EOS and obtained the related thermodynamic parameters,such as Gibbs free energy,bulk modulus,thermal expansion coefficients and entropy.At high temperature,this kind of crystal material shows better thermodynamic properties than pure aluminum. |
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