This research program addresses the high temperature deformation of boron-doped nickel aluminide. Fundamental mechanisms responsible for high temperature creep and superplastic deformation will be studied. The unusual temperature dependence of the yield strength of this material, i.e., an increasing yield strength with increasing temperature up to a maximum, makes it a particularly interesting material for high temperature applications. Mechanisms causing creep and superplastic behavior are not well understood. The nature of the ordered lattice, including anisotropy of antiphase boundary energy and details of the cross- slip process, make the creep properties quite different from those observed in solid solution alloys. This project will investigate the rate-controlling micromechanisms of elevated temperature deformation in this ordered alloy.
