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MA: Fachverband Magnetismus
MA 56: Bulk Materials: Soft and hard permanent magnets
MA 56.6: Talk
Thursday, March 23, 2017, 16:15–16:30, HSZ 403
Producing two different L10 phases in ternary MnAlGa alloys — •Torsten Mix1,2, Florian Bittner1,3, Karl-Hartmut Müller1, Ludwig Schultz1,2,3, and Thomas George Woodcock1 — 1IFW Dresden, Institute for Metallic Materials, PO Box 270116, 01171 Dresden, Germany — 2Department of Physics, TU Dresden, Dresden, Germany — 3Institute for Materials Science, TU Dresden, Dresden, Germany
The L10 phases in the binary MnAl and MnGa systems are interesting candidates for rare earth free permanent magnets. The main drawbacks, are the high price of Ga and the poor resistance to decomposition at evelated temperature of the metastable L10 phase in binary MnAl. As the L10 phase in MnGa is thermodynamically stable, the formation of a ternary MnAlGa alloy is a promising approach to overcome these difficulties. Ternary alloys of the form Mn55Al45−xGax have been produced in the range 0 < x < 45. In alloys with 5 < x ≤ 9 after appropriate heat treatments, two different phases with the L10 structure can be made to coexist. One is stable as in the binary MnGa system, the other metastable as in binary MnAl. The magnetic properties of the ternary alloys are superior to those of the binary analogues. The thermal stability of the metastable phase is greatly improved by the addition of the small amount of Ga. Up to 700∘C, the decomposition of the metastable phase is strongly suppressed. This allows longer processing time at higher temperatures, thus enabling new routes to produce rare earth free MnAl-based magnets to be envisaged.