We employ density functional theory to study the mechanical, electronic and thermodynamic properties of the cubic NiTi in a prssure range of 0 -40 GPa. The calculated lattice parameters are well in agreement with expe...We employ density functional theory to study the mechanical, electronic and thermodynamic properties of the cubic NiTi in a prssure range of 0 -40 GPa. The calculated lattice parameters are well in agreement with experimental values and other calculated results, showing that the B2 NiTi is mechanically stable and no phase transformation occurs with pressure go-ing up to 40 GPa. The bulk modulus B, shear modulus G, Young＇s modulus E and B /G of B2 NiTi improve linearly with in-creasing pressure, implying that the volume change resistance, shear deformation resistance and elastic stiffness could also be strengthened by pressure. The pressure could also have an influence on the ductility of NiTi. The density of state （DOS） of Ni-Ti indicates that the bonding nature of B2 NiTi is metallic combining with covalent bonding, and pressure has no significant in-fluence on the electronic properties in a pressure range of 0 - 40 GPa. In addition, the dependences of temperature and pressure on Debye temperature ⊙D ,heat capacity Cv and Cp are further studied to figure out the thermodynamic properties of B2 NiTi.All above are especially useful to further study the properties of NiTi.展开更多
基金National Natural Science Foundation of China(Nos.U1610123,51674226,51574207,51574206)International Cooperation Project of the Ministry of Science and Technology of China(No.2014DFA50320)+3 种基金Science and Technology Major Project of Shanxi Province(No.MC2016-06)International Science and Technology Cooperation Project of Shanxi Province(No.2015081041)Research Project Supported by Shanxi Scholarship Council of China(No.2016-Key 2)Transformation of Scientific and Technological Achievements Special Guide Project of Shanxi Province(No.201604D131029)
文摘We employ density functional theory to study the mechanical, electronic and thermodynamic properties of the cubic NiTi in a prssure range of 0 -40 GPa. The calculated lattice parameters are well in agreement with experimental values and other calculated results, showing that the B2 NiTi is mechanically stable and no phase transformation occurs with pressure go-ing up to 40 GPa. The bulk modulus B, shear modulus G, Young＇s modulus E and B /G of B2 NiTi improve linearly with in-creasing pressure, implying that the volume change resistance, shear deformation resistance and elastic stiffness could also be strengthened by pressure. The pressure could also have an influence on the ductility of NiTi. The density of state （DOS） of Ni-Ti indicates that the bonding nature of B2 NiTi is metallic combining with covalent bonding, and pressure has no significant in-fluence on the electronic properties in a pressure range of 0 - 40 GPa. In addition, the dependences of temperature and pressure on Debye temperature ⊙D ,heat capacity Cv and Cp are further studied to figure out the thermodynamic properties of B2 NiTi.All above are especially useful to further study the properties of NiTi.
