Deformation Microstructures of Two-Phase Intermetallic Alloy Composed of Ni3Al and Ni3V in Single Crystalline Form

Two-phase single-crystal intermetallic alloys composed of Ni3Al (L12) and Ni3V (D022) with some orientations were compressed at various temperatures, and their deformation microstructures were observed by transmission electron microscopy (TEM). The deformation at room temperature was governed by the glide motion of dislocations in the primary Ni3Al precipitates and the activation of the microtwins in the Ni3V variant structures in the channel regions. The interfaces between the primary Ni3Al precipitates and the Ni3V variant structures are suggested to work as the barriers to the dislocation motion. While, at temperature above the peak temperature (873 K), the deformation microstructures of the two-phase intermetallic alloy exhibited the ribbon-like deformation microstructures penetrating the constituent phases i.e. through the interfaces between primary Ni3Al precipitates and the Ni3V variant structures in the channel regions. It was also suggested that the superior strength in the two-phase intermetallic alloys is due to the high flow strength of the Ni3V phases and to the interfacial hardening receiving when the dislocations activated in the primary Ni3Al precipitates propagate to the channel regions.