Cu adding effect upon the cellular structure and magnetic properties for the (Mn55Al45-xCux)100C2 (x = 0,1,2,3) permanent magnetic alloy

Fang, Hailiang; Liu, J.; Huang, P.W.; Li, M.Y.

doi:10.1016/j.jallcom.2022.165988

Cited by 3 publications

(4 citation statements)

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“…Most of the work done on the impact of Cu on formation and properties of the τ-phase has been focused on the high Mn content with composition of Mn55Al45 (Saravanan et al 2015, Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022, with only two papers exploring the addition of Cu at nearer-to-equiatomic composition of Mn51Al49 (Sugihara 1963, Muller et al 1997. It was reported that the addition of Cu to MnAl did not impact the phase formation of the τ-phase in ingots of both as cast and homogenized samples but did reduce the Ms of the τ-phase (Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022. There are conflicting reports with some papers seeing a drop in Tc and some showing no reduction on Tc of the τ-phase (Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022.…”

Section: Mnalcu Literature Overviewmentioning

confidence: 99%

“…It was reported that the addition of Cu to MnAl did not impact the phase formation of the τ-phase in ingots of both as cast and homogenized samples but did reduce the Ms of the τ-phase (Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022. There are conflicting reports with some papers seeing a drop in Tc and some showing no reduction on Tc of the τ-phase (Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022.…”

Section: Mnalcu Literature Overviewmentioning

confidence: 99%

“…A copper-rich intergranular phase was reported to exist between τ-phase crystals in Cumodified-MnAl (Saravanan et al 2015, Jurries et al 2020, Fang et al 2022 ). The intragranular phase was reported to be the к-phase, found in specimens of greater than 6 at.% Cu (Jurries et al 2020).…”

Section: Mnalcu Literature Overviewmentioning

confidence: 99%

“…The к-phase is a ferromagnetic chemically ordered B2 (CsCl prototype structure) phase with composition region of к is 25 ≤ at.% Mn ≤ 45, 37.5 ≤ at.% Al ≤ 50, and 12.5 ≤ at.% Cu ≤ 25 and low Tc in the range of 70 o C to 190 o C (Tsuboya 1951). They reported it was possible to create pure ε-phase material when quenching MnAlCu ingots in water after homogenization at high temperature (Su et al 2018, Zhao et al 2019, Jurries et al 2020, Fang et al 2022. There is disagreement in the literature Mn51Al45Cu4 composition.…”

Section: Mnalcu Literature Overviewmentioning

confidence: 99%

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Towards efficient and sustainable magnets: controlling L10 ordering in the MnAl system through elemental addition

Baldino

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Permanent magnets have become an integral part of our society, with a wide range of applications from simple toys to complex medical equipment as well as their essential use in the generation of electricity in wind turbines and hydropower. However, the production of modern strong permanent magnets requires the use of rare-earth elements whose unpredictable supply underscores the importance of developing high-performance rare-earth-free magnets. A promising alternative is the L10 structured compound consisting only of abundant Fe and Ni; however, it remains extraordinarily challenging to synthesize this compound due to its extremely sluggish formation. Nevertheless, the ferromagnetic proxy system of L10-type MnAl serves as a good testbed for investigating and identifying factors that control L10 ordering. The metastable L10 phase of MnAl, known as the τ-phase, is formed by annealing the high-temperature, A3 structure, ε-phase which is retained by high quenching rates from the melt. In this thesis, the structure, magnetism, and phase stability of MnAl alloys both with and without a small amount of Cu were investigated to understand the effect the ternary element on the formation of the L10 phase.This objective was investigated through the study of alloys of composition Mn51Al49 ("MnAl") and Mn51Al45Cu4 ("MnAlCu") synthesized by conventional cooling using arc-melting as well as by rapid solidification via melt-spinning. Arc-melting donated a cooling rate of 100 o C/second, while melt-spinning provided a quench rate of 10 6 o C/second. The changes in crystal structure, microstructure, and magnetic properties arising from adding Cu were characterized by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. While the unmodified MnAl composition adopted the metastable hexagonal ε-phase structure upon meltspinning, the MnAlCu composition directly formed phase-pure L10 irrespective of quench rate.Adding Cu changes the microstructure and magnetic domain structure of the MnAl L10_phase, transitioning them from isotropic grains exhibiting spherical magnetic domain patterns to that of iv poly-twinned crystallographic plates with a pronounced striped magnetic domain pattern. The results of this work provide insight into how Cu alters the nature of the solidification pathway of MnAl to directly form the L10 structure and may have implications in other L10-containing systems such as FeNi.

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