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Title: Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles

Authors:
; ; ; ; ; ; ; ; ; ; ; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1397652
Grant/Contract Number:
AR0000188
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Alloys and Compounds
Additional Journal Information:
Journal Volume: 712; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 21:34:12; Journal ID: ISSN 0925-8388
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Law, J. Y., Rial, J., Villanueva, M., López, N., Camarero, J., Marshall, L. G., Blázquez, J. S., Borrego, J. M., Franco, V., Conde, A., Lewis, L. H., and Bollero, A. Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles. Netherlands: N. p., 2017. Web. doi:10.1016/j.jallcom.2017.04.038.
Law, J. Y., Rial, J., Villanueva, M., López, N., Camarero, J., Marshall, L. G., Blázquez, J. S., Borrego, J. M., Franco, V., Conde, A., Lewis, L. H., & Bollero, A. Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles. Netherlands. doi:10.1016/j.jallcom.2017.04.038.
Law, J. Y., Rial, J., Villanueva, M., López, N., Camarero, J., Marshall, L. G., Blázquez, J. S., Borrego, J. M., Franco, V., Conde, A., Lewis, L. H., and Bollero, A. Sat . "Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles". Netherlands. doi:10.1016/j.jallcom.2017.04.038.
@article{osti_1397652,
title = {Study of phases evolution in high-coercive MnAl powders obtained through short milling time of gas-atomized particles},
author = {Law, J. Y. and Rial, J. and Villanueva, M. and López, N. and Camarero, J. and Marshall, L. G. and Blázquez, J. S. and Borrego, J. M. and Franco, V. and Conde, A. and Lewis, L. H. and Bollero, A.},
abstractNote = {},
doi = {10.1016/j.jallcom.2017.04.038},
journal = {Journal of Alloys and Compounds},
number = C,
volume = 712,
place = {Netherlands},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.jallcom.2017.04.038

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

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  • Ni-based bulk metallic glasses (BMGs) with a large size were fabricated by spark plasma sintering (SPS) of a gas-atomized Ni{sub 52.5}Nb{sub 10}Zr{sub 15}Ti{sub 15}Pt{sub 7.5} glassy alloy powder. The structure and thermal stability of the sintered specimens as well as the interface characteristics between powder particles were investigated. The sintered glassy specimens with nearly 100% relative density were obtained by the SPS process at a sintering temperature of 773 K with a loading pressure of 600 MPa. It was achieved using relatively low sintering temperature, short holding time, and rapid cooling during the SPS process. The results suggest that themore » BMGs fabricated by the SPS process opens possibilities of application as structural materials offering excellent properties and satisfying large-size requirements.« less
  • The solid state reactions and the microstructural evolution during high-energy ball milling of Al-Ni powder mixtures in the composition rate 25--75 at.% Al have been investigated. Experimental observations have shown that the microscopic mechanism underlying the alloying process in this system is the diffusion of Ni atoms in the Al-rich layers and that an important role is played by the oxygen contamination. An amorphous Al-rich phase containing a few at.% oxygen and with a Ni content not exceeding approximately 50 at.% has been detected in the equiatomic and Ni-rich samples milled for a few hours. This phase upon further millingmore » transforms to a Ni-rich fcc solid solution thus allowing one to by-pass the nucleation of Al{sub 3}Ni in these samples. The self-sustaining high-temperature synthesis of the AlNi B2 phase has been found to occur over the 40--60 at.% range of Al concentration after about 3 h of milling. The same reaction has been observed in the Differential Scanning Calorimeter if equiatomic samples premilled for about 3 h (unreacted) are heated at a sufficiently high heating rate.« less
  • Structural changes in mechanically treated CaF{sub 2} powders have been studied by X-ray diffraction, transmission electron microscopy, thermal analysis, {sup 19}F and {sup 1}H MAS Nuclear Magnetic Resonance and Electron Paramagnetic Resonance methods. Applying the same methods, the results could be compared with those of mechanochemically synthesized CaF{sub 2} samples, prepared for the first time in this study by high-energy ball milling. The applied methods indicate that the mechanically treated samples become, under the applied conditions, nanocrystalline. Unexpectedly, the mechanochemically synthesized samples show the same effects, i.e., nanocrystalline samples were formed. In contrast to many oxide compounds, a weak amorphizationmore » takes place only after a strong mechanical impact, and essentially in grain boundaries of spherical particles. Observed effects after the application of mechanical impact like broadening of XRD reflections, broadening of {sup 19}F resonances, or the decreasing ability for H {sup {center_dot}} trapping at ambient temperature, are mainly due to decreasing particle sizes as well as very small structural changes in the bulk of the particles. Surprisingly, the spin relaxation of both nuclear spins ({sup 19}F) and electron spins (H {sup {center_dot}}) appears to be the most sensitive tool for the investigation of mechanically and chemically induced changes indicating the increasing surface to bulk ratio with increasing mechanical impact.« less
  • The metastable tetragonal τ-phase has been directly obtained from casting Mn{sub 0.54}Al{sub 0.46} and (Mn{sub 0.55}Al{sub 0.45}){sub 100}C{sub 2} using the drop synthesis method. The as-casted samples were ball milled to decrease the particle size and relaxed at 500 °C for 1 h. The phase composition, crystallographic parameters, magnetic properties and microstructure were systematically studied. The results reveal that the τ-phase could be directly obtained from drop synthesis. The highest M{sub s} of 117 emu/g was achieved in the (Mn{sub 0.55}Al{sub 0.45}){sub 100}C{sub 2} where the τ-phase was stabilized by doping with carbon. Carbon doping increased the c/a ratio ofmore » the τ-phase as it occupies specific interstitial positions (½, ½, 0) in the structure. Furthermore, ball milling increases the coercivity (H{sub c}) at the expense of a decrease in magnetic saturation (M{sub s}). The increase in coercivity is explained by a decrease of grain size in conjunction with domain wall pinning due to defects introduced during the ball milling process. - Graphical abstract: The tetragonal τ-phase has been directly obtained from casting Mn{sub 0.54}Al{sub 0.46} and (Mn{sub 0.55}Al{sub 0.45}){sub 100}C{sub 2} using the drop synthesis method. The phase composition, crystallographic parameters, magnetic properties and microstructure were systematically studied. The highest M{sub s} of 117 emu/g was achieved for (Mn{sub 0.55}Al{sub 0.45}){sub 100}C{sub 2} ball milling increases the coercivity (H{sub c}) at the expense of a decrease in magnetic saturation (M{sub s}). - Highlights: • The ferromagnetic τ-phase has been directly obtained from casting. • The highest M{sub s} of 117 emu/g was achieved for (Mn{sub 0.55}Al{sub 0.45}){sub 100}C{sub 2}. • Ball milling increases the coercivity but decreases the magnetic saturation.« less