First-Principle Calculations of the MgYA_4(A=Co and Ni)Phase with AuBe_5-Type Structure

• 作 者: Na Wang Wei-Bing Zhang Bi-Yu Tang En-Jie He Mao-Lian Zhang
• 机 构: College of Electrical and Electronic Engineering,Anhui Science and Technology University,School of P
• 出 处: Acta Metallurgica Sinica(English Letters)
• 发表日期: 2015年11期
• 关键词: modulus ductility Poisson magnetism plasticity have trigonal cohesive cubic fitt

First-principles calculations have been performed to study the structural,mechanical and magnetic properties of the MgYCo_4 and MgYNi_4 phases in AuBe_5-type structure.The obtained values of cohesive energy as well as formation energy prove that the MgYCo_4 and MgYNi_4 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 MgYCo_4 phase is 19.06 μ_B per unit cell mainly owed to the 3d state of Co atom,and the MgYNi_4 phase exhibits no magnetism.Both the trigonal shear constant C_(44) and the shear modulus G of the Mg YNi_4 phase are larger than those of the MgYCo_4 phase.Plasticity of alloys has been estimated by the C_(11)-C_(12) and Young’s modulus E,and C_(12)-C_(44),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 MgYCo_4 phase has better plasticity as well as ductility,compared with the MgYNi_4 phase.

First-principles calculations have been performed to study the structural, mechanical and magnetic properties of the MgYCo_4 and MgYNi_4 phases in AuBe_5-type structure. The resulting values ​​of cohesive energy as well as formation energy prove that the MgYCo_4 and MgNi_4 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 MgYCo_4 phase is 19.06 μ_B per unit cell mainly owed to the 3d state of Co atom, and the MgYNi_4 phase exhibits no magnetism. Both the trigonal shear constant C_ (44) and the shear modulus G of the Mg YNi_4 phase are larger than those of the MgYCo_4 phase. Plasticity of alloys has been estimated by the C_ (11) -C_ (12) and Young’s modulus E, and C_ (12) - C_ (44), the shear to bulk modulus ratio G / B and Poisson’s ratio v have been studied to predict the ductility of the alloys. According to calculated results, the MgYCo_4 phase has better plasticity as well as ductility, com pared with the MgYNi_4 phase.