The Solid-Solution Alloying Effects of Ti on the High-Temperature Deformation Behavior of NiAl Single Crystals

Abstract

ABSTRACTWe have investigated the high-temperature deformation behavior of the solid-solution strengthened alloy Ni-47.5Al-2.5Ti. Single crystals were deformed in compression in the “hard” <001> and “soft” <111> orientations, at temperatures between 900°C and 1200°C. The results show that Ti has a very powerful solute strengthening effect in NiAl. The creep rates for the solid-solution alloy were observed to be three to four orders of magnitude lower than for the stoichiometric material. We discuss our efforts to understand this solid-solution strengthening effect. We have studied high-temperature deformation transients in an effort to determine whether solute drag effects contribute to the creep resistance of this solid solution. In addition, we have examined the solute size effect of Ti as it replaces Al on the Al sub-lattice. We discuss the probable mechanism of creep of this alloy in light of TEM observations of the dislocation structures in creep-deformed crystals.