In:
Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 43, No. 1 ( 1994), p. 154-
Abstract:
The microdefects and electronic structure have been studied by measuring the positron lifetime spectra of mono- and polycrystalline Ni3Al alloys with B content ranging from 0.00 to 2.22at%,The experimental results show that the opening space of the defect on grain boundary is larger than that of a monovacancy in polycry-stalline Ni3Al alloy. More valence electrons participate in Ni-Ni and Ni-Al bondings in bulk corresponding to stronger cohesion, while less valence electrons parti-cipate in those on grain boundaries corresponding to weaker cohesion. When B atoms segregate to defects, they form strong covalent bondings with Ni and A1 atoms and strengthen the bonding cohesion in those locations. The interaction of B atoms which occupy interstitial sites,with Ni and Al atoms in bulk leads to the increase of the density of valence electrons, thus increases the bonding cohesion in the bulk.
Type of Medium:
Online Resource
ISSN:
1000-3290
,
1000-3290
Language:
Unknown
Publisher:
Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
Publication Date:
1994