Order–disorder effects on the elastic properties of CuMPt6 (M=Cr and Co) compounds
Introduction
The crystal structure represents the deepest and most stable aspect of our understanding of bonding and cohesion, which is critical to material design [1]. Due to this fact, much effort has been invested in the explorations of structure [2], [3]. Particularly, it was reported that the CuMPt6 (M=Cr and Co) exhibited a disordered face-centered cubic (fcc) structure when quenched from 1273 K, while on annealing at temperature below 873 K, they have got an ordered Cu3Au-type structure [4]. It is known that the ordering and disordering process have considerable effects on the physical properties of material. To gain further insight into these new ordered/disordered compounds, their fundamental properties such as order–disorder transition [5], [6], [7], magnetic behavior [8], electrical resistivity [9], and thermal expansion [10] were soon performed. However, the elastic properties, which play important role in evaluating the performance of material, are still not available. Hence, to understand, and especially to guide the ordering treatment effects in the realm of multicomponent alloy systems, it is highly desirable to perform such calculations.
In this paper, the order–disorder effects on the elastic properties for CuMPt6 (M=Cr and Co) are studied using Chen-Möbius lattice inversion embedded-atom method. The elastic constants C11, C12, and C44, bulk modulus B, shear modulus G, Young's modulus Y, Poisson's ratio ν, elastic anisotropy AZ, and Debye temperature θD are calculated. The researches contribute to the development of comprehensive data of the CuMPt6 and may provide some theoretical guidance on the application of Pt-based compounds in engineering.
Section snippets
Methodology
Embedded atom method (EAM) [11], [12] is a common way to describe atomic interactions in metal, which includes many-body interactions by a term that depends on the environment of every atom. The basic equations of EAM arewhere is a pair interaction potential between atoms i and j, F(ρi) is the embedding energy as a function of the host electron density ρi on atom i, f(rij) is the atomic electron density created at site i by other atoms. According to
Structural properties
The crystal structure of CuMPt6 (M=Cr and Co) compounds used in the calculation is made up of 4000 particles arranged on the face-centered cubic (fcc) structure. The compositionally disordered configuration is created by randomly interchanging the Cu, M and Pt atoms in the sites of fcc crystal with the stoichiometry of CuMPt6. In the case of Cu3Au-type structure, all the Pt atoms occupying the face-centered positions, while the Cu and M atoms randomly occupying the corner positions. Defects are
Conclusion
The present work has involved a computational study of the ordering treatment effect on the elastic properties of CuMPt6 (M=Cr and Co) compounds. It is found that the ordered Cu3Au-type structure is energetically more stable than the disordered fcc structure for both compounds. Moreover, the ordering treatment can induce higher hardness but weaker ductile manner.
The utilizing of our method in this study is based on the EAM model and Chen-Möbius inversion. One interesting feature of this
Acknowledgment
This work is supported by the supported by the National Basic Research Program of China (Grant no. 2011CB606401).
References (41)
- et al.
Physica B
(2009) - et al.
J. Alloy Compd.
(2008) - et al.
J. Alloy Compd.
(2009) - et al.
J. Alloy Compd.
(2010) Solid State Phys.
(1964)Acta Metall.
(1960)- et al.
Comput. Mater. Sci.
(2008) J. Phys. Chem. Solids
(1963)- et al.
Phys. Rev. B
(2006) - et al.
Phys. Rev. B
(2012)