Fe-Al materials obtained from powder substrates
Stefan Szczepanik*, Elżbieta Godlewska**, Ryszard Mania** *Akademia Górniczo-Hutnicza, Wydział Metalurgii i Inżynierii Materiałowej, ul. Reymonta 23, 30-059 Kraków **Akademia Górniczo-Hutnicza, Wydział Inżynierii Materiałowej i Ceramiki, ul. Reymonta 23, 30-059 Kraków
Annals 2 No. 4, 2002 pages 242-247
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abstract The paper presents the results of investigations on mechanical properties (bending strength and hardness) of Fe-Al intermetallics. The materials were obtained by hot forming of compacted blocks, received from the self-propagating high- -temperature synthesis (SHS). It has been shown that the properties of SHS products can be markedly improved by hot processing. The hot-forming parameters strongly affect final density, mechanical properties (Table 1) and structure (Figs 3, 5-9) of Fe-Al intermetallics. Moreover, deformability of these materials is temperature dependent. For FeAl, deformation attained at 850oC is 65% and as much as 83% at 1080oC. For Fe3Al, deformation attained at 1060oC is 78% with the preserved sample integrity. Bending strength of FeAl is the highest when the material is strongly deformed, e.g. 1967 MPa for the processing parameters ε = 83%, T = 1080oC. Fe3Al deformed at the same temperature with ε = 73% has a lower bending strength, i.e. 1263 MPa. Hardness has also been found to depend on deformation parameters. After the bending test the features of brittle fracture are observed in the case of FeAl samples processed at 850oC with ε = 56% or at 1060oC with ε = 42%, whereas the samples processed at 1060oC with ε = 60% or 80% undergo plastic deformation prior to failure (Figs 7 and 9). Fine alumina dispersions encountered in the fractured samples do not seem to have any significant effect on the properties of the investigated materials. The intermetallic phases, FeAl and Fe3Al, obtained from powder substrates according to the technology developed by the authors of the present paper, exhibit good ductility combined with high bending strength, which are unattainable by means of other known manufacturing methods.