Method of Changing the Structure of Cast Fe–Al Alloys By Inputting Titanium-containing Modifiers


Iron–aluminum alloys with a high (more than 10 wt.%) aluminum content are alloys with sufficiently high heat resistance and can be considered as an alternative to expensive superalloys containing nickel and chromium. A method is proposed for obtaining an equiaxial structure in cast alloys of Fe- (12–14 wt.%) Al. Alloys were smelted in an open mid-frequency induction furnace by introducing titanium-containing modifiers, which can act as crystallization centers during melt solidification when they are introduced into a liquid metal, helping to obtain an optimal grain structure of the solid metal. Several modifications were used: FeTi30, FeTi30 with the addition of metallic zirconium and the complex microcrystalline modifier “Insteel 7”. All modifiers contained varying amounts of titanium. They were introduced into the melt of Fe–Al alloys 5 minutes before the metal was drained. The purpose of this study was to obtain an equiaxed grain structure of the alloys in the solid state. The desired grain shapes were achieved by introducing the FeTi30 modifier when the total titanium content in the ingot was more than 1.2% by weight. Another way to obtain the optimal structure was the introduction of FeTi30 with the addition of metallic zirconium (1.83 wt.% Ti and 0.3% Zr in the ingot). The use of the Insteel 7 modifier, consisting of Ca, Ba, Fe, Ti, Ce, and La in the form of complex silicides, is impractical because its use does not allow obtaining an equiaxial or close to equiaxial granular structure of cast Fe–Al alloys.

Keywords: cast Fe–Al alloys, an open mid-frequency induction furnace, FeTi30 modifier, zirconium, Insteel 7 complex modifier, grain structure, rare earth metals silicide

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