Investigation of phase selection hierarchy in Mn–Al alloys

2019-12-01
Genc, Ayse Merve
Acar, Ozgun
Turan, Servet
Kalay, Ilkay
Savacı, Umut
Kalay, Yunus Eren
Primarily attributed to the formation of the ferromagnetic τ-phase, near equiatomic composition of Mn–Al have recently received much attention in permanent magnet industry. Several mechanisms have been proposed in literature for the τ-phase formation but controversy still arises regarding the dominating mode. In the current work, MnAl-based alloys having different compositions in a range between Mn50.5Al49.5 and Mn57Al43 have been studied by means of in-situ high energy X-ray diffraction, differential scanning calorimetry (DSC) and magnetic measurements. Synchrotron and DSC experiments showed the dependence of the τ-MnAl on the intermediate disordered ε0-phase. Alloys having 53.4 at% or less Mn (S1, S2) followed a transformation route of εþε’→τ→βþγ2 upon annealing. Alloys having more than 53.4 at% of Mn had only ε-phase. High energy X-ray diffraction pat-terns showed that ε-phase directly transformed into stable phases in the absence of ε0-phase. It is observed that ε0not only promoted the ferromagnetic τ-phase but also stabilized it by delaying the nucleation of stable phases

Suggestions

The investigation of electronic, anisotropic elastic and lattice dynamical properties of MAB phase nanolaminated ternary borides: M 2 AlB 2 ( M = Mn , Fe and Co ) under spin effects
Surucu, Gokhan; YILDIZ, BUĞRA; Erkisi, Aytac; Wang, Xiaotian; Surucu, Ozge (Elsevier BV, 2020-10-01)
In the present study, the structural, electronic, magnetic, anisotropic elastic and lattice dynamic properties of the ternary metal borides (, and ) known as MAB phases have been investigated by density functional theory. The obtained results from the structural optimizations show that all these compounds have negative formation enthalpy implying the thermodynamic stability and synthesizability. The spin effects on the phases have been studied with the plotted energy-volume curves for different magnetic pha...
The role of amorphous precursor in phase selection hierarchy in marginal metallic glasses
YILDIRIM, CİHAN; KUTSAL, M.; OTT, R. T.; BESSER, M. F.; KRAMER, M. J.; Kalay, Yunus Eren (Elsevier BV, 2016-12-15)
The solid state amorphous structure and devitrification products of Al90Tb10 alloys produced by Cu block meltspinning and magnetron sputtering were investigated by a combined study of differential scanning calorimetry, in-situ X-ray diffraction and conventional transmission electron microscopy. The as-prepared specimens were found to be fully amorphous according to the electron and X-ray diffraction. The thermal analysis and in-situ XRD analyses of the amorphous samples having the same chemistry but differe...
A study of phase stability and mechanical properties of hydroxylapatite-nanosize alpha-alumina composites
Evis, Zafer (Elsevier BV, 2007-04-01)
Hydroxylapatite (HA)-nanosize alumina composites were synthesized to study their phase stability and mechanical properties. To make these composites, nanosize alpha-Al2O3 powder was used because of its better sinterability and densification as compared to nanosize gamma-Al2O3. The composites were air sintered without pressure and hot pressed in vacuum at 1100 degrees C and 1200 degrees C. In the composites, HA decomposed to tricalcium phosphate faster after the air sintering than hot pressing. Moreover, hex...
The structural and electronic properties of BN and BP compounds and BNxP1-x alloys
Mohammad, Rezek; Katırcıoğlu, Şenay (Elsevier BV, 2009-06-10)
The structural and electronic properties of BN and BP compounds and BNxP1-x alloys have been investigated by full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The total energies and electronic band structures of these compounds have been calculated for different approximations of exchange-correlation energy. The comparative study has showed that the Perdew-Wang-generalized gradient approximation (PW-GGA) is the best one to produce the measured structur...
Production of in situ aluminum-titanium diboride master alloy formed by slag-metal reaction
CHANGIZI, Ahmad; Kalkanlı, Ali; SEVINC, NACİ (Elsevier BV, 2011-01-12)
Al-TiB(2) master alloys have received much attention in recent years owing to their potential as efficient grain refiners for aluminum foundry alloys. In this study, the process of production of master alloys was investigated to develop a low cost method, namely, slag-metal reaction. This method can be used to fabricate Al-TiB2 master alloy in situ from the TiO(2)-H(3)BO(3)-Na(3)AlF(6) and Al system. Since the price of the raw materials is low and the technology is simple, the processing technique appears t...
Citation Formats
A. M. Genc, O. Acar, S. Turan, I. Kalay, U. Savacı, and Y. E. Kalay, “Investigation of phase selection hierarchy in Mn–Al alloys,” Intermetallics, pp. 0–0, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36880.