About the order-disorder transition in arc melted Fe3SiAlx soft alloys

Joint Event on 2^nd Edition of Graphene & Semiconductors | Diamond Graphite & Carbon Materials Conference & 6^th Edition of Smart Materials & Structures Conference

April 16-17, 2018 Las Vegas, Nevada, USA

A Boulouma, A. Drici and A. K. Gangopadhahay

ESTI of Annaba, Algeria
University of Annaba, Algeria
Washington University in St Louis, USA

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

There is an increasing interest in soft magnetic Fe-Si-Al alloys due to their promising properties for applications in various fields; however, all these structural and magnetic properties depend on the structure of the composition alloys The Fe-rich side of the phase diagram of the Fe-Al, Fe-Si and Fe-Al-Si systems presents the same structures; at room temperature, Fe-Al system is characterized by a wide range of ferromagnetic disordered body centered cubic solid solution (A2) up to 22 at.% Al at room temperature. On increasing the Al content, the first intermetallic structure is Fe3Al with D03 cubic structure and it exists over the 1832 at.% Al range. The other stable intermetallic structure is FeAl, which is also cubic with B2 structure (CsCl) and it exists over the range 32-50 at.% Al. The magnetic behavior of ordered Fe-Al alloys is complex in the 27 to 32 at.% Al region where the magnetization actually decreases with decreasing temperature. It was found that partial substitution of Al by Si leads to significantly improved D03 structural stability against ordered B2 structure and disordered A2 structure. Moreover, there have been extensive studies, both experimentally and theoretically, of order-disorder transitions of Fe-rich ternary alloys. Mutual solid solubility between Fe3Al and Fe3Si is well-established. The solid solubility and the magnetic behavior of Fe3(Al,Si) was correlated with the ratio of electron-atom . Polishchuk and Katsnel�´son studied the existence of the ordered phases �±1 (Fe3Al and Fe3Si which have D03 or BiF3 type order) and �±2 (FeAl and FeSi which have B2 or CsCl type order) along the Fe3Al-Fe3Si section by means of high temperature X-ray diffraction and recording the disappearance of D03 superlattice (111) and (200) reflections as a function of temperature and composition. In this work, alloys of nominal compositions of sendust Fe3SiAlX (X =1, 0.75, 0.5, 0.25). The phase purities of the arc-melted ingots were studied by x-ray diffraction using a Rigaku D-MaxB X-ray diffractometer with Cu-K�± radiation. It was found that decreasing Al leads to more disorder in the alloy by the formation of �±-Fe solid solution. However, the addition of Al influences both of the lattice parameter and crystallite size of the Fe3Si phase. Results show that the presence of �±1-Al0.3Fe3Si0.7 with a (422) preferred orientation has been noticed over the 70 at% Fe range. bouloumaa@gmail.com