The Effect of Hot Rolling on Room Temperature Ductility of a NiAl Intermetallic Compound
A Ni57Fe18Al25 alloy is produced by vacuum induction melting under an argon atmosphere and gravity cast into a copper chill mould. Ingots of 2 x 10 x 50 mm are re-heated at 1100 °C for 24 hours and hot rolled until a 25 % reduction is reached. Immediately, hot rolled plates are heat treated at 1100 °C for 1 hour and water cooled to room temperature. Microstructures of as cast, hot rolled and hot rolled plus heat treated specimens are characterized using scanning and transmission electron microscopy and x-ray diffraction. Specimens in the as-cast and hot rolled conditions show the presence of equiaxial and partially elongated β-grains, respectively, with the presence of a thin γ-phase decorating the grain boundaries. Hot rolled plus heat treated specimens have partially recrystallized β-grains with γ-phase and (Ni,Fe)3Al at the grain boundaries. The hot rolled specimens have a room temperature ductility of approximately 5 % in tensile testing. This enhancement in ductility is attributed to the modification of the β-grains by coexistence with a γ- phase along the grain boundaries.
H. Balmori-Ramírez, M. Brito, J.G. Cabañas-Moreno, H.A. Calderón-Benavides, K. Ishizaki and A. Salinas-Rodríguez
S. Garcia-Galan et al., "The Effect of Hot Rolling on Room Temperature Ductility of a NiAl Intermetallic Compound", Materials Science Forum, Vol. 509, pp. 69-74, 2006