First-Principle Calculations of the MgYA4 （A = Co and Ni） Phase with AuBe5-Type Structure

• Published in: 金属学报：英文版 no. 11; pp. 1326 - 1331
• Main Author: Na Wang Wei-Bing Zhang Bi-Yu Tang En-Jie He Mao-Lian Zhang
• Format: Journal Article
• Language: English
• Published: 2015
• Subjects: bes型; 剪切模量; 合金化; 第一性原理计算; 结构相; 结构稳定性
• ISSN: 1006-7191; 2194-1289

First-principles calculations have been performed to study the structural, mechanical and magnetic properties of the MgYCo4 and MgYNi4 phases in AuBes-type structure. The obtained values of cohesive energy as well as formation energy prove that the MgYCo4 and MgYNi4 phases have a good combination of structural stability and alloying ability, which is also supported by electronic structure. It is found that the magnetic moment of the MgYCo4 phase is 19.06 ktB per unit cell mainly owed to the 3d state of Co atom, and the MgYNi4 phase exhibits no magnetism. Both the trigonal shear constant C44 and the shear modulus G of the MgYNi4 phase are larger than those of the MgYCo4 phase. Plasticity of alloys has been estimated by the C11-C12 and Young＇s modulus E, and C12-C44, shear to bulk modulus ratio G/B and Poisson＇s ratio v have been studied to predict the ductility of alloys. According to the calculated results, the MgYCo4 phase has better plasticity as well as ductility, compared with the MgYNi4 phase.