Mechanical and electronic structural properties of intermetallic compounds CuBe and CuBe2
Purposes—To provide an intuitive and profound understanding of the mechanical strengthening mechanism of Cu-Be binary alloys by fully investigating the mechanical behavior and e-lectronic structure characteristics of intermetallic compounds CuBe and CuBe2.Methods—First-princi-ples of density functional theory(DFT)and the"strain-stress"methods were employed in the investi-gation.Results—The calculated lattice parameters of CuBe and CuBe2 are in agreement with available experimental data.The obtained crystal elastic constants showed that both intermetallics meet the cu-bic elastic stability criterion.The excellent mechanical properties of CuBe2 was mainly attributed to the Be tripyramids composed of strong Be-Be covalent bonds.The obtained findings further reveal that both CuBe and CuBe2 intermetallics possess a complex bonding characteristics including metallic,ionic and covalent bonds.Conclusions—The increase in Be content can effectively improve the tensile and shear strengths of such two intermetallics,but it will weaken the toughness and ductility of the alloy.
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