The different influences of the two incorporation sites of B atoms on the mechanical and thermodynamic properties of B2–ZrCu compounds: a first-principle calculation

Abstract

We applied a first-principle calculation to investigate the different influences of the two incorporation sites of B atoms on the mechanical and thermodynamic properties of the near-equiatomic B2–ZrCu compound. The alloying B atoms have two possible incorporation sites, namely, octahedral interstices and Cu sites. When the concentration of B atoms is lower than 5.882 at.%, interstitial B atoms will be effective at improving the bulk modulus (B), shear modulus (G) and Young’s modulus (E) of the B2–ZrCu parent. When the concentration of the substitutional B atoms is lower than 12.5 at.%, the ductility of the parent will be strengthened. The interstitial B atoms that are located at octahedral interstices in the 〈110〉 direction can remarkably improve the Debye temperature (Θ_D) of the substituted Zr₈Cu_8−zB_z phase. The prediction for the melting point shows that the high-temperature stability is strengthened with the increase of the B concentration. Interstitial B atoms are beneficial to the minimum thermal conductivity. Finally, the electronic properties are discussed in detail to further understand the mechanical properties.

Keywords:

• First-principle calculation
• high-temperature shape memory alloy
• thermodynamic properties
• mechanical properties
• ZrCu-based alloy