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An ultrasonic device was designed to fabricate relatively small (about 0.7 kg) vacuum chill castings of FeAl-based alloys with improved microstructure. The influence of ultrasound on the solidification microstructure of the Fe-40 at.% Al based castings was investigated. The subsequent hot-rolling of such an as-cast alloy was made using a special stainless steel bandage of the casting. This effectively prevents fraying and cracking caused by the thermal shock arising at the surface of the hot casting, when it comes in contact with a cold roller. The efficiency of ultrasonic vacuum casting, based on the influence of the acoustic cavitation on the solidification of the melt, is manifested by a refined microstructure of the prepared iron aluminides Fe-40 at.% Al with addition of C or Zr and B. First results of improved mechanical properties of these alloys are presented and discussed.

An experimental study based on specific heat, thermal expansion, magnetisation and neutron diffraction measurements on polycrystal and single crystal of the orthorhombic TmCu, compound is presented. The results are satisfactorily interpreted within a model involving the crystal and molecular field acting on the Tm3+ ions. The energy spectrum of the ground-state multiplet 3H6 of Tm3+ with the isolated split lowest quasi-doublet (A, = 5 k 1 K, A2 = 68 -t 3 K) is proposed. The appropriate sets of crystal-field parameters V y are obtained and discussed.

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