(1. 中国航发上海商用航空发动机制造有限责任公司，上海 201306；
2. 上海工程技术大学 材料工程学院，上海 201620；
3. 上海市激光先进制造技术协同创新中心，上海 201620；
4. 上海交通大学 材料科学与工程学院，上海 200240)
摘 要: 采用基于密度泛函理论的第一性原理平面波赝势计算方法，计算了Ni-M(B、Si、Zr和Hf)二元共晶沉淀相(Ni2B、Ni3B、Ni3B2、Ni23B6、Ni3Si、Ni5Zr和Ni5Hf)的相稳定性、弹性常数、硬度及相应的电子结构。相稳定性计算结果表明，二元共晶沉淀相结构稳定性变化趋势由高到低的顺序为Ni3Si、Ni5Zr、Ni2B、Ni5Hf、Ni3B、Ni3B2、Ni23B6，这意味着降熔元素Si形成的Ni3Si沉淀相稳定性强于降熔元素B、Zr和Hf形成的沉淀相。弹性力学计算表明，Ni3B2表现为很强的各向异性，Ni2B、Ni3B和Ni3Si表现出一定的各向异性，而Ni23B6、Ni5Zr和Ni5Hf则表现为较强的各向同性。二元共晶沉淀相B/G值均大于1.75，这意味着它们为延性相。硬度计算的由小到大的小趋势为Ni3B2、Ni3B、Ni23B6、Ni2B、Ni5Zr、Ni3Si、Ni5Hf，其与各相中Ni 3d与B 2p，Si 3p，Zr 4d和Hf 5d的原子轨道杂化强度密切相关。
关键字: 二元共晶沉淀相；相稳定性；弹性常数；硬度；电子结构；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
