Journal of Materials Science, Vol.30, No.1, 248-252, 1995
A High-Resolution-Electron-Microscopy Study of a Gamma/Gamma’-Alpha Directionally Solidified Eutectic Alloy .1. The as-Solidified State
The microstructure of a gamma/gamma’-alpha directionally solidified (DS) eutectic alloy with a nominal solidified composition of Ni-30.26Mo-6.08Al-1.43V (wt %) was investigated by means of high-resolution electron microscopy (HREM) and analytical electron microscopy. The alpha-fibres exhibited a typical morphology with a rectangular cross-section and they displayed the Bain orientation relationship (OR) with the gamma’/gamma matrix; that is, [0 0 1](alpha)parallel to [0 0 1](gamma), and (1 1 0)(alpha)parallel to(0 1 0)(gamma,). Misfit dislocations and lattice strain fields existed at the alpha/gamma’ interface for different habit planes; that is, (1 1 0)(alpha)parallel to(0 1 0)(gamma,) and (1 0 0)(alpha)parallel to(1 1 0)(gamma,) were analysed. EDAX (Energy dispersive X-ray) analysis showed that the composition of the gamma-phase was approximately Ni-4(Mo, Al, V); it contained 90 degrees rotational domains of Ni-3(Mo, Al, V) with a DO22 structure and Ni-2(Mo, Al, V) with a Pt2Mo structure.
Keywords:MO