(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(jì)算方法計(jì)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(jì)算。能量計(jì)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(shí)，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(shí)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
