铝单晶力学稳定性的EAM势

Mechanical Stability of Crystal Lattice of Metal Al

用嵌入原子势（ＥＡＭ）表达的晶体结构力学稳定性判据肯定了ＡＶｏｔｅｒ等人给出的铝原子的嵌入原子势的可靠性，计算了铝单晶体的力学性质，铝单晶沿［１００］方向受单轴外力作用，当外力为压应力时，其结构发生转变，产生两个不稳定的新结构相ＢＣＣ和ＢＣＴ；外力为张应力时，铝单晶产生均匀形变，其形变达１４．４２％时材料断裂，相应的理论拉伸强度为０．６４×１０４ＭＰａ。由计算结果确定了与铝原子ＥＡＭ势的适用范围相对应的ａ１取值范围为０．３５８～０．４７３ｎｍ。

A mechanical stability criteria is used to investigate the mechanical propoties of metal Al.The method is applied to calculate the tension strength of Al crystal by the EAM potential proposed by A Voter et al when the crystal is subjected to an uniaxial tension or compression along[100] direction.Under compression the crystal structure is transformed from FCC into BCC and then from BCC into BCT.The BCC and BCT structures are unstable.Under tension the crystal is destroyed,when the thoeretical strain arrives at 14.42% and the corresponding theoretical strength is 0.64×104 MPa.From above calculations it is obtained that when the strain of the deformed crystal is out of the range from-11.56% to 14.42%,the EAM potential is not suitible to describe the mechanical properties of metal Al.