Microstructure and magnetic properties of Mn–Al–C alloy powders prepared by ball milling

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping byEdström1, Werwiński2, Iuşan3 et al. 2015Phys. Rev. B

“…Recently, however, the availability (and thus price) of the rare-earth elements became rather volatile, calling for development of replacement materials which would use less or none of * Corresponding author: jan.rusz@physics.uu.se the rare-earth elements. Intense research efforts have started worldwide, revisiting previously known materials, such as Fe 2 P [5][6][7], FeNi [8], or Fe 16 N 2 [9], doing computational data mining among the large family of Heusler alloys [10], exploring the effects of strain [11][12][13][14][15][16][17] and doping by interstitial elements [18,19], multilayers such as Fe/W-Re [20] or, as a limiting case of multilayers, the L1 0 family of compounds [21], or promising Mn-based systems [22][23][24][25][26][27], among others.…”

Mechanical alloying and theoretical studies of MnAl(C) magnets

“…On the basis of the reasons given above and taking into account the fact that there is a large difference in melting temperature between Mn and Al, we assume that the quantity of Al missing in the as-milled samples is probably deposited on the surface of the balls or on the wall of the vials. This is opposite to the arc melting method that often vaporizes some amount of Mn under a high temperature arc, resulting in the loss of an amount of manganese [8,19].…”

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

“…Here we report a significant advance in binary MnAl alloys by achieving a coercivity of 4.9 kOe upon only 3 minutes of milling of MnAl gas-atomized particles followed by annealing at 355 ˚C for a short time (10 min). This annealing temperature is lower than the typical range of 400-700 ºC reported in the literature [18,26,28,30,31]. In contrast with previous studies, a side-by-side comparison is provided here of the evolution of morphological, microstructural and magnetic properties with annealing temperature of the powders in the as-atomized and as-milled forms, thereby allowing the effects of milling and of annealing to be identified.…”

“…These results are in agreement with the observed DSC results, which showed a shift to lower temperatures of the nucleation of -phase and indicate that the transformation rate of -phase from its parent -phase is dependent on the -phase grain size [9,21]. The rapid milling process reduces the average crystallite size from above 100 nm (starting as-atomized particles) to <10 nm, promoting the complete  to  transformation at T anneal =365ºC, which is below the transformation temperature of 475ºC in non-milled material and below the typical transformation temperature range of 400-700 ºC reported in the literature [18,30,31]. The diffraction peaks of the β-phase shift to lower angles in comparison to a pure β-Mn phase, and the measured lattice parameter of the cubic β-phase (a=0.6444±0.003 nm) is closer to that of β-Mn 3 Al 2 (a=0.63245 nm, P4 1 32), which has been also reported for 10 h-milled MnAl-based systems [33,34].…”