“As‐cast” microstructure investigation of two iron aluminides

Abstract

The “as‐cast” microstructure of Fe–30Al–6Cr and Fe–30Al–10Ti high purity alloys was investigated using Electron Backscatter Diffraction. The first alloy is characterized by a highly textured columnar grain microstructure with large grains, while the second is characterized by an equiaxed grain microstructure with small grains and a random texture. These differences are discussed with regard to the higher reactivity of Ti compared with Cr, leading to nanometric nitride or oxide, which may act as sites for heterogeneous nucleation, and the ordered state of the BCC phase in equilibrium with the liquid during solidification and its effect upon dendrite growth kinetics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Characterization of the texture evolution during thermomechanical processing of an Fe–30at% Al–6at% Cr alloy

“…This points to a very low nucleation frequency of solid nuclei in the melt [23]. This is certainly affected by the absence of inoculants and refining agents, due to the selection of a very pure alloy, and also due to a steep directional temperature gradient imposed by the copper mold.…”

“…The rolled strips have been analyzed in the LeS orientation and the sample was ground at least 1 mm so that the results correspond to the bulk of the strip and not to its surface. Texture analysis of the AC sample was subject of a recent publication by two of the present authors [23] and will not be reproduced here. The main conclusions of this work, however, are that the ingot presents a strong h100i fiber texture parallel to the radial direction of the ingot.…”