INFLUENCE OF Al ON DUCTILITY IMPROVEMENT BY B IN Ni_3 Al ALLOYS
Ni3Al中Al含量对硼韧化作用的影响

The "order-disorder" model was adopted to calculate the lattice vacancy relatedto the composition change in Ni_3Al alloys. A great deal of vacancies, i. e., the non-stoichiome-tric vacancies, may exist in the Ni_3Al alloys containing Al over stoichiometry, saying, 25 at.-%.This was confirmed by the positron annihilation technique. Therefore, the influence of Al con-tent on the bettering behaviour of B towards the ductility of Ni_3Al alloys can be understoodthrough the interaction of non-stoichiometric vacancy and B atom.