Deformation Modes of the Intermediate Phase NiAl

The deformation modes of single crystal NiAl deformed in compression in the range 77 to 1000 °K were found to be dependent on orientation and temperature. The preferred slip direction was confirmed as 〈001〉, but this may be constrained geometrically to allow kinking, or slip in 〈111〉 or 〈011〉 directions, depending on temperature. When 〈001〉 slip occurred, the slip plane was invariably {110} at 77 °K but was dependent on orientation at higher temperatures. The slip planes were also sensitive to temperature when slip occurred in other directions. The von Mises criterion for polycrystalline ductility can be satisfied by combinations of the observed slip systems.