An experimental study on the formability of intermetallic nickel aluminide

In this paper, the formability of ductile intermetallic Ni₃Al and limiting strains at room temperature are presented. Uniaxial tensile tests are carried out to identify uniform elongation, work hardening behavior, and fracture character. Forming limit diagrams are determined and the effect of biaxial deformation on limiting strains and failure modes are shown. The bulk formability is investigated by cold upset testing on continuous cast and extruded bars. Forming limit diagrams, both for bars and sheets, do not show a significant effect of thermomechanical processing and sheet thickness at the range of 0.30-0.46 mm. These observations are in agreement with common ductile metals where larger deformations are obtained in biaxial modes. Microcrack initiation at grain boundaries is shown to contribute to lower limiting strains in the plane strain region during sheet metal stretching and compression of intermetallic nickel aluminide.