(1. 中國航發(fā)上海商用航空發(fā)動機制造有限責任公司，上海 201306；
2. 上海工程技術大學 材料工程學院，上海 201620；
3. 上海市激光先進制造技術協(xié)同創(chuàng)新中心，上海 201620；
4. 上海交通大學 材料科學與工程學院，上海 200240)
摘 要: 采用基于密度泛函理論的第一性原理平面波贗勢計算方法，計算了Ni-M(B、Si、Zr和Hf)二元共晶沉淀相(Ni2B、Ni3B、Ni3B2、Ni23B6、Ni3Si、Ni5Zr和Ni5Hf)的相穩(wěn)定性、彈性常數(shù)、硬度及相應的電子結構。相穩(wěn)定性計算結果表明，二元共晶沉淀相結構穩(wěn)定性變化趨勢由高到低的順序為Ni3Si、Ni5Zr、Ni2B、Ni5Hf、Ni3B、Ni3B2、Ni23B6，這意味著降熔元素Si形成的Ni3Si沉淀相穩(wěn)定性強于降熔元素B、Zr和Hf形成的沉淀相。彈性力學計算表明，Ni3B2表現(xiàn)為很強的各向異性，Ni2B、Ni3B和Ni3Si表現(xiàn)出一定的各向異性，而Ni23B6、Ni5Zr和Ni5Hf則表現(xiàn)為較強的各向同性。二元共晶沉淀相B/G值均大于1.75，這意味著它們?yōu)檠有韵唷Ｓ捕扔嬎愕挠尚〉酱蟮男≮厔轂镹i3B2、Ni3B、Ni23B6、Ni2B、Ni5Zr、Ni3Si、Ni5Hf，其與各相中Ni 3d與B 2p，Si 3p，Zr 4d和Hf 5d的原子軌道雜化強度密切相關。
關鍵字: 二元共晶沉淀相；相穩(wěn)定性；彈性常數(shù)；硬度；電子結構；第一性原理
（1. AECC Shanghai Commercial Aircraft Engine manufacturing Co., Ltd., Shanghai 201306, China;
2. School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201602, China;
3. Shanghai Collaborative Innovation Center of Laser Advanced Manufacturing Technology, Shanghai 201620, China;
4. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:A systematic investigation concerned with phase stability, elastic properties, hardness and relevant electronic structure of Ni-M binary eutectic precipitates (Ni2B, Ni3B, Ni3B2, Ni23B6, Ni3Si, Ni5Zr and Ni5Hf) was carried out using first principles calculations. The calculated results show that the change trend of the structural stability follows Ni3Si＞Ni5Zr＞Ni2B＞Ni5Hf＞Ni3B＞Ni3B2＞Ni23B6, indicating that the stability of Ni3Si phase using Si as melting-point depressant is stronger than that using B, Zr and Hf as melting-point depressants. The calculated elastic constants indicate that Ni3B2 is significantly anisotropic, and Ni2B, Ni3B and Ni3Si exhibit some anisotropy, while Ni23B6, Ni5Zr and Ni5Hfshow a relatively isotropic character. The ratios of bulk modulus (B) to shear modulus (G) are more than 1.75 for all the Ni-M binary eutectic precipitates in this research, indicating their ductile nature. The trend of Vickers hardness of these Ni-M binary eutectic precipitates is as Ni3B2＜Ni3B＜Ni23B6＜Ni2B＜Ni5Zr＜Ni3Si＜Ni5Hf, and the strength of Ni 3d, B 2p, Si 3p, Zr 4d and Hf 5d hybrid orbitals were found to play important roles in the hardness of these compounds.
Key words: binary eutectic precipitates; phase stability; elastic constant; hardness; electronic structure; first principles
