Effect of structural vacancies on lattice vibration,mechanical, electronic,and thermodynamic properties of Cr5BSi3

In recent years, transition metal silicides have become the potential high temperature materials. The ternary silicide has attracted the attention of scientists and researchers. But their inherent brittle behaviors hinder their wide applications. In this work, we use the first-principles method to design four vacancy defects and discuss the effects of vacancy defects on the structural stability, mechanical properties, electronic and thermodynamic properties of hexagonal Cr₅BSi₃ silicide. The data of lattice vibration and thermodynamic parameters indicate that the Cr₅BSi₃ with different atomic vacancies can possess the structural stabilities. The different atomic vacancies change the mechanical properties and induce the Cr₅BSi₃ to implement the brittle-to-ductile transition. The shear deformation resistance and volume deformation resistance of Cr₅BSi₃ are weakened by different vacancy defects. But the brittleness behavior is remarkably improved. The structural stability and brittle-to-ductile transition of Cr₅BSi₃ with different vacancies are explored by the electronic structures. Moreover, the thermal parameters indicate that the Cr₅BSi₃ with vacancies exhibit different thermodynamic properties with temperature rising.