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推导出利用embedded-atom method EAM势表达的力学稳定性判据给出了相应的数值方法,并且提出了确定势函数的适用范围的理论判据。根据该理论肯定了A.Voter等给出的镍原子间的EAM势的可靠性,并计算了镍单晶体的力学性质。计算表明:单轴外力沿[100]方向加载在镍单晶体上,在压应力作用下,晶体结构发生转变,产生两个不稳定的新结构相bcc和bct相;在张应力作用下,镍单晶发生均匀形变,当形变量达10.51％时材料断裂,相应的理论拉伸强度值为1.46×10~(11)dyn·cm~(-2)。由这些计算结果确定了镍原子EAM势的适用范围对应α_1的取值范围为0.318—0.389nm。
The numerical method is deduced by using the mechanical stability criterion of embedded-atom method EAM potential expression. The theoretical criterion for determining the applicable range of potential function is also proposed. According to the theory, the reliability of the EAM potential between nickel atoms given by A.Voter et al was affirmed and the mechanical properties of nickel single crystals were calculated. The results show that the uniaxial external force is loaded on the nickel single crystal along the direction of [100]. Under the compressive stress, the crystal structure changes and two unstable new phases bcc and bct are formed. Under the tensile stress, When the deformation amount reaches 10.51%, the material is broken. The corresponding theoretical tensile strength value is 1.46 × 10 ~ (11) dyn · cm ~ (-2). From these calculation results, it is confirmed that the suitable range of the EAM potential of the nickel atom corresponds to the value of α_1 ranging from 0.318 to 0.389 nm.