(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(shì)和廣義梯度近似的第一性原理和特殊準(zhǔn)隨機(jī)結(jié)構(gòu)模型計(jì)算FCC結(jié)構(gòu)Fe-25Cu、Fe-31.25Cu、Fe-3.125Ni-25Cu和Fe-3.125Ni-31.25Cu無序固溶體的基態(tài)性質(zhì)、彈性常數(shù)以及電子結(jié)構(gòu)，其中無序固溶體晶胞結(jié)構(gòu)建立在由特殊準(zhǔn)隨機(jī)結(jié)構(gòu)方法所產(chǎn)生的結(jié)構(gòu)模型基礎(chǔ)上。計(jì)算結(jié)果表明：FCC 結(jié)構(gòu)Fe-Ni-Cu無序固溶體存在無磁性與鐵磁性兩種狀態(tài)，其中鐵磁性Fe-Cu和Fe-Ni-Cu無序固溶體的能量相對(duì)較低；鐵磁性Fe-25Cu和Fe-3.125Ni-25Cu無序固溶體不滿足Born彈性穩(wěn)定性準(zhǔn)則，而Fe-31.25Cu和Fe-3.125Ni-31.25Cu無序固溶體滿足Born彈性穩(wěn)定性準(zhǔn)則，以亞穩(wěn)態(tài)形式存在，合金元素Ni的加入顯著提高了鐵磁性FCC結(jié)構(gòu)Fe-31.25Cu無序固溶體的結(jié)構(gòu)穩(wěn)定性。
關(guān)鍵字: Fe-Cu無序固溶體；特殊準(zhǔn)隨機(jī)結(jié)構(gòu)；合金化；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 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
