(上海交通大学 材料科学与工程学院，上海 200240)
摘 要: 采用基于投影缀加波赝势和广义梯度近似的第一性原理和特殊准随机结构模型计算FCC结构Fe-25Cu、Fe-31.25Cu、Fe-3.125Ni-25Cu和Fe-3.125Ni-31.25Cu无序固溶体的基态性质、弹性常数以及电子结构，其中无序固溶体晶胞结构建立在由特殊准随机结构方法所产生的结构模型基础上。计算结果表明：FCC 结构Fe-Ni-Cu无序固溶体存在无磁性与铁磁性两种状态，其中铁磁性Fe-Cu和Fe-Ni-Cu无序固溶体的能量相对较低；铁磁性Fe-25Cu和Fe-3.125Ni-25Cu无序固溶体不满足Born弹性稳定性准则，而Fe-31.25Cu和Fe-3.125Ni-31.25Cu无序固溶体满足Born弹性稳定性准则，以亚稳态形式存在，合金元素Ni的加入显著提高了铁磁性FCC结构Fe-31.25Cu无序固溶体的结构稳定性。
关键字: Fe-Cu无序固溶体；特殊准随机结构；合金化；弹性性质；第一性原理
（School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:The first-principles method based on projector augmented wave pseudo-potential and generalized gradient approximation was employed to calculate the ground state properties, elastic constants and electronic structures of FCC structured Fe-25Cu, Fe-31.25Cu, Fe-3.125Ni-25Cu and Fe-3.125Ni-31.25Cu random solid solutions. The cells of the random solid solutions were established based on the special quasirandom structure (SQS) models. The calculated results show that nonmagnetic and ferromagnetic states exist in FCC Fe-Ni-Cu random solid solutions, and Fe-Cu and Fe-Ni-Cu random solid solutions in the ferromagnetic state have lower energy. The ferromagnetic Fe-25Cu and Fe-3.125Ni-25Cu random solid solutions do not satisfy Born criterion of elastic stability, whereas the Fe-31.25Cu and Fe-3.125Ni-31.25Cu random solid solutions satisfy Born criterion of elastic stability and can exist as a metastable phase. The addition of alloying element of nickel can significantly improve the structural stability of FCC Fe-31.25Cu random solid solution.
Key words: Fe-Cu random solid solution; special quasirandom structure; alloying; elastic property; first-principles
