Observations on diffuse scattering in a Ti50Ni48Fe2 alloy by energy-filtering TEM

Modulated structure in the parent phase of a Ti₅₀Ni₄₈Fe₂ alloy, which appeared prior to the R-phase transformation, was studied by transmission electron microscopy with a recently developed omega-type energy-filter. Some differences in characters were observed between diffuse scattering in the parent phase and superlattice reflections in the R-phase, such as in the peak positions and extinction rules etc. It was speculated that a modulated structure, which showed a distinct crystal structure from the R-phase, was formed in the parent phase before the R-phase transformation.