Effects of alloying element on stabilities, electronic structures, and mechanical properties of Pd-based superalloys

• 来源期刊: 中国物理B（英文版）
• 关键词: high temperature superalloy first-principles calculations palladium mechanical properties anisotropy
• 年，卷（期）: 2017,（12）
• 页码范围: 420-426
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/12/126202

摘要

The thermodynamic stabilities,electronic structures,and mechanical properties of the Pd-based superalloys are studied by first principles calculations.In this work,we discuss the effect of Pd-based superalloys made from A1,Si,Sc,Ti,V,Cr,Mn,Fe,Cu,Zn,Y,Zr,Nb,Mo,Tc,Hf,Ta,W,Re,Os,Ir and Pt,and we also calculate a face centered cubic (fcc) structure 2 × 2 × 2 superalloy including 31 Pd atoms and one alloying element TM (Pd31 TM).The mixing energies of these Pd-Based superalloys are negative,indicating that all Pd-based superalloys are thermodynamically stable.The Pd31Mn has the lowest mixing energy with a value of-0.97 eV/atom.The electronic structures of the Pd-based superalloys are also studied,the densities of states,elastic constants and moduli of the mechanical properties of the Pd-based superalloys are determined by the stress-strain method and Voigt-Reuss-Hill approximation.It is found that Pd31 TM is mechanically stable,and Pd31Tc has the largest C11,with a value 279.7 GPa.The Pd31Cr has the highest bulk modulus with a value of 299.8 GPa.The Pd31Fe has the largest shear modulus and Young's modulus with the values of 73.8 GPa and 195.2 GPa,respectively.By using the anisotropic index,the anisotropic mechanical properties of the Pd31TM are discussed,and threedimensional (3D) surface contours and the planar projections on (001) and (110) planes are also investigated by the Young modulus.