Papers by Author: Artur Hanc

Abstract: Magnetic properties of the Fe76.2Nb5.7B13.3Gd4.8, Fe69.6Nb5.2B12.2Gd13, Fe76.2Nb5.7B13.3Y4.8, Fe69.6Nb5.2B12.2Y13 bulk nanocrystalline alloys (mould casting technique) are presented and discussed. Measurements were carried out by the means of SQUID magnetometer (temperature range 2 K – 400 K, field up to 7 T) and magnetic balance (temperatures up to 1100 K). Microstructure was studied by the Mössbauer spectroscopy at room temperature. It was shown that the samples are nonocrystalline with α-Fe and different Fe-B, Y/Gd-Fe or Y/Gd-Fe-B compounds. The preparation method as well as the Gd addition causes a magnetic hardening of the studied alloys.

Abstract: This work presents the results of investigations using Mössbauer spectroscopy technique and XRD, and their interpretation concerning precipitations and transformation of iron carbides and retained austenite stabilization. It also discusses changes in hardened matrix during tempering in relation to previously conducted dilatometric, microscopic and mechanical examinations. This research was carried out using a new high-carbon alloy 120MnCrMoV8-6-4-2 steel, which was designed in 1998, in Phase Transformations Research Group at the AGH UST. The influence of the tempering time on the mechanical and chemical stability of retained austenite and on the products of its transformation, nucleation and solubility of iron carbides and cementite nucleation and growth, was determined.

Abstract: The systematic studies of non-stoichiometric phases from Fe-Al system obtained by selfpropagating high-temperature synthesis (SHS) were the aim of the present work. Investigations were performed using 57Fe transmission Mössbauer spectroscopy. The presence of nonsteichiomertic FeAl, FeAl2 and Fe2Al5 phases was found. It is can be concluded that the studied powder material is in non-equilibrium state. As the result of milling process the contents of FeAl phase increase whereas of FeAl2 and Fe2Al5 ones decrease. The determined crystal structure parameters and the hyperfine interaction parameters are presented and discussed.

Abstract: The Fe-Al-X and Fe-Al-Ni-X (X = Fe,Ni,Cu,Cr) metallic powders obtained by the selfdecomposition method and next intensive grinding in an electro-magneto-mechanical mill were examined by X-ray powder diffraction (XRD). Morphology of powders was determined by scanning electron microscopy (SEM) whereas energy dispersive spectroscopy (EDS) was applied to identify the composition of phases. The FeAlX and FeAlNiX phases both of B2 type structure were found besides small amounts of Al(OH)3 and rest of metallic additions.