(上海交通大學(xué) 材料科學(xué)與工程學(xué)院，上海 200240)
摘 要: 采用基于投影綴加波贗勢和廣義梯度近似的第一性原理計算方法計算FCC 結(jié)構(gòu)Fe以及3種Fe-Cu無序固溶體合金(Cu原子摩爾分?jǐn)?shù)分別為25%、37.5%和50%)的基態(tài)性質(zhì)、彈性常數(shù)以及電子結(jié)構(gòu)，其中Fe-Cu無序固溶體合金采用特殊準(zhǔn)隨機(jī)結(jié)構(gòu)模型進(jìn)行計算。能量計算結(jié)果表明：FCC結(jié)構(gòu)Fe存在無磁、低鐵磁以及高鐵磁性3種狀態(tài)，而FCC 結(jié)構(gòu)Fe-Cu無序固溶體合金只存在無磁與高鐵磁性兩種狀態(tài)。高鐵磁性FCC 結(jié)構(gòu)Fe不滿足Born彈性穩(wěn)定性準(zhǔn)則，鐵磁性FCC 結(jié)構(gòu)Fe-Cu無序固溶體合金的彈性穩(wěn)定性隨著Cu 含量的增加而增加；當(dāng)Cu 原子的摩爾分?jǐn)?shù)不低于37.5%時，F(xiàn)e-Cu無序固溶體合金滿足Born彈性穩(wěn)定性準(zhǔn)則，此時合金以亞穩(wěn)態(tài)形式存在。
關(guān)鍵字: Fe-Cu無序固溶體合金；特殊準(zhǔn)隨機(jī)結(jié)構(gòu)；彈性性質(zhì)；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 structure of face-centered cubic (FCC) Fe and Fe-Cu random solid solution alloys with Cu contents of 25%, 37.5% and 50% (mole fraction). The special quasirandom structure (SQS) models were selected as the computational models for FCC Fe-Cu random solid solution alloys. The calculated total energies show that a nonmagnetic, a low ferromagnetic and a high ferromagnetic state are obtained in the FCC Fe, whereas a nonmagnetic state and a high ferromagnetic state exist in the ferromagnetic FCC Fe-Cu random solid solution alloys. The high ferromagnetic FCC Fe does not satisfy Born’s criterion of elastic stability. The elastic stability of ferromagnetic FCC Fe-Cu random solid solution alloys increases with increasing the Cu content. When the Cu content is not less than 37.5%(mole fraction), the ferromagnetic FCC Fe-Cu random solid solution alloys satisfy Born’s criterion of elastic stability, and can exist as the metastable phases.
Key words: Fe-Cu random solid solution alloy; special quasirandom structure; elastic property; first-principles
