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The influence of heating rate during sintering on mechanical properties of Fe40Al sinters at room temperature DOI:10.15199/28.2016.5.11

  The results of a uniaxial compression test of Fe40Al (at. %) sintered powders are presented. Compression yield stress Rc0.2, ultimate strength Rcm, permanent deformation, and true compression strength at the maximum force point were determined. All Fe40Al sinters behaved like a plastic material; they were not brittle, and the sample after the compression test did not fall apart and was barrel-shaped. Observations of the microstructure revealed plastically-deformed grains. The obtained sinters were characterized by very high ultimate compressive strength (ok. 2700÷2800 MPa) and low yield stress (Rc0.2 approx. 280 MPa). This paper presents also XRD analyses, microstructure, and density of Fe40Al sinters. Key words: intermetallic alloys, iron aluminides, reaction synthesis, compression test, plasticity.1. INTRODUCTION Despite its obvious advantages, such as low density, good corrosion and oxidation resistance, and high strength at both room and elevated temperature [1÷3], the FeAl-based alloys are still only potentially used as replacements for expensive alloy steels; this is primarily due to their ductility and inherently low toughness, especially at ambient temperature [4]. It is generally known that the mechanical properties of iron aluminides are very sensitive to many factors, including aluminium content, order, heat treatment, the test temperature, alloying additions, environment, microstructure, and defects [5]. Due to the fragility of Fe-Al alloys, which increases with increasing aluminium content, alloys with an aluminium content of 40% are the most frequently analysed. FeAl alloys of 40% Al are characterized by high strength properties at an acceptable ductility. Due to the potential embrittlement of sintered FeAl powders, it is tested mostly by the compression test. Literature sources indicate that the yield stress of Fe40Al at ambient temperature ranges from 380 to 820 MPa [4, 6÷9]. The strain obtained during testing strength[...]

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