Microstructural and magnetic properties of the X₂YZ, namely Fe₂MnSi and Fe₂MnAl, Heusler alloys have been studied from the viewpoint of technology for their production and for the Z element effect. First, arc melting was applied to produce button-type ingots from which samples in a form of 500 µm thick discs were cut. Second, planar flow casting technology yielded samples in a ribbon-form 2 mm wide and 20 μm thick. The checked area chemical compositions were in agreement with the nominal ones. Nevertheless, the darker square objects and smaller bright objects observed at the wheel side of the Fe₂MnSi ribbon sample yielded higher Mn content at the expense of Fe. The X-ray diffraction patterns of all samples have indicated L2₁ structure with lattice parameters, 0.567 (1) nm for Fe₂MnSi and 0.584 (1) nm for Fe₂MnAl, being within an experimental error independent of production technology. On the other hand, the technology has markedly influenced the microstructure clearly pointing to the larger size of grains and grain boundaries in the disc samples. From the magnetic viewpoint, both alloys are paramagnetic at room temperature without visible influence of their production. On the contrary, the low-temperature behavior of the microscopic hyperfine parameters and the macroscopic magnetic parameters exhibits differences affected by both chemical composition and microstructure.
Keywords: Curie temperature; Heusler alloys; L21 phase; arc melting; hyperfine parameters; microstructure; planar flow casting; temperature of re-orientation.