Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50-nNbn alloys (n=1, 3, 5, 7, and 9 at%)

Date

2016-05-10

Author

Yıldırım, Mehmet
Akdeniz, Mahmut Vedat
Mehrabov, Amdulla

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The microstructural evolution and room-temperature mechanical properties of Fe50Al50-nNbn alloys (n=1, 3, 5, 7, and 9 at%) were investigated after solidification and subsequent heat treatment. For all the compositions, the (Fe, Al)(2)Nb Laves phase formed because of the incomplete solid solubility of Nb in the Fe-Al-based phases and tended to develop an eutectic mixture with the Fe-Al-based phase. According to the results of EDS analysis and microstructural investigations, the Nb concentration of the eutectic composition was 9 at%, and the solid solubility of Nb in the B2-type Fe-Al-based phase was 3 at%. In addition, the eutectic phase transition temperature was approximately 1265 degrees C. Compared with the as cast state, all the heat-treated alloys exhibited ultrahigh compressive strength and considerably increased compressive fracture strains. The heat-treated hypoeutectic Fe50Al42Nb3 alloy exhibited the highest compressive strength and fracture strain of 3.02 GPa and 33.1%, respectively, and the eutectic Fe(50)oAl(41)Nb(9) alloy exhibited the lowest compressive strength and fracture strain of 2.66 GPa and 21.8%, respectively, because of the absence of the comparably softer Fe-Al-based primary dendrites. The superior mechanical properties of the heat-treated alloys were attributed to the bimodal distribution of the microstructure, structural incoherency between the crystalline phases, and elimination of solidification artifacts and lattice defects.

Subject Keywords

Iron aluminides (based on FeAl), Microstructure, Mechanical properties at ambient temperatures, Compressive properties

URI

https://hdl.handle.net/11511/49283

Journal

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

DOI

https://doi.org/10.1016/j.msea.2016.03.128

Collections

Department of Metallurgical and Materials Engineering, Article

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Citation Formats

M. Yıldırım, M. V. Akdeniz, and A. Mehrabov, “Microstructural evolution and room-temperature mechanical properties of as-cast and heat-treated Fe50Al50-nNbn alloys (n=1, 3, 5, 7, and 9 at%),” MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, pp. 17–25, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49283.