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The mechanical properties and intrinsic hardness of the α-Ga boron phase(α-Ga-B) are studied by using the combination of first-principles calculations and a semiempirical macroscopic hardness model.It is found that α-Ga-B is mechanically stable and possesses higher bulk/shear modulus as compared with γ-B_(28),a newly discovered high-pressure boron phase.The theoretical hardness of α-Ga-B is estimated to be 45 GPa,which is much higher than 38 GPa for γ-B_(28).The results strongly indicate that α-Ga-B is a potential superhard boron phase.To further obtain insight into the superhard nature of α-Ga-B,we simulate stress-strain curves under tensile and shear deformation.Meanwhile,the microscopic mechanism driving the tensile and shear deformation modes inα-Ga-B is discussed in detail.
The mechanical properties and intrinsic hardness of the α-Ga boron phase (α-Ga-B) are studied by using the combination of first-principles calculations and a semiempirical macroscopic hardness model. It is found that α-Ga-B is mechanically stable and possesses higher bulk / shear modulus as compared to γ-B_ (28), a newly discovered high-pressure boron phase. The theoretical hardness of α-Ga-B is estimated to be 45 GPa, which is much higher than 38 GPa for γ-B_ (28). The results of an explicit indication that α-Ga-B is a potential superhard boron phase. To obtain insight into the superhard nature of α-Ga-B, we simulate stress-strain curves under tensile and shear deformation .Meanwhile, the microscopic mechanism driving the tensile and shear deformation modes in α-Ga-B is discussed in detail.