Effect of Mo addition on microstructure, ordering, and room-temperature mechanical properties of Fe-50Al
(1. Department of Metallurgical and Materials Engineering, Selcuk University, Konya 42130, Turkey;
2. Novel Alloys Design and Development Laboratory (NOVALAB), Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey)
2. Novel Alloys Design and Development Laboratory (NOVALAB), Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey)
Abstract: The effects of Mo addition on microstructures, phase relationships, order–disorder phase-transition temperatures and room-temperature mechanical properties of Fe50Al50-nMon alloys (n=1, 3, 5, 7, and 9, mole fraction, %) were investigated after solidification and heat treatment. Structural characterization of the samples was performed via X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry. Room-temperature mechanical properties were investigated by conducting compression and microhardness tests. Mo3Al particles precipitated in all alloys because of the limited solid solubility of Mo in the Fe-Al-based phases. The as-cast Fe50Al50-nMon alloys exhibited brittle behavior with high yield strength and limited fracture strain at room temperature. Compared with the as-cast alloys, all the heat-treated alloys except for the Fe50Al41Mo9 alloy exhibited enhanced mechanical properties at room temperature. The heat-treated Fe50Al43Mo7 alloy exhibited the highest fracture strain and compressive strength of 25.4% and 2.3 GPa, respectively.
Key words: iron aluminides; microstructure; order–disorder phase transformation; compressive properties