Correlation of the Mechanical Properties of Polycrystalline Ni_3Al Alloys with Their Electronic Structure

The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuringthe positron lifetime spectra.The segregation of B atoms to defects could form strong covalentbondings with Ni and Al atoms and make the electronic structure in those locations similar to that inbulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in thecrystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in theincrease of the density of valent electrons,thus increased the bonding cohesion in bulk.The im-provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda-ry effect”and“bulk effect”of B,which correlated with their electronic structure.

Correlation of the Mechanical Properties of Polycrystalline Ni_3Al Alloys with Their Electronic Structure

The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni and Al atoms and make the electronic structure in those locations similar to that in bulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in the crystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in the increase of the density of valent electrons,thus increased the bonding cohesion in bulk.The im- provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda- ry effect”and“bulk effect”of B,which correlated with their electronic structure.