In this study, Fe-12.50Mn-1.10C-1.70Cr-0.40Mo-0.40Si-0.50(max)P-0.50(max)S (Hadfield alloy) and Fe-28.4Mn-0.86C-1.63Al-0.42Cu-1.80Mo-1.59Si-0.60W (Fermanal alloy) (Wt. %) in the aged condition were compared in terms of its tribological and microstructural properties. The x-ray diffraction (XRD) patterns were refined with the lines of the austenitic γ -phase, Chromium Iron Carbide (Cr 2 Fe 14 C), Iron Carbide (Fe 2 C), and Iron Oxide (Fe 0.974 O (II)) for the Hadfield alloy, and the lines of the austenitic γphase, martensite (M), Mn 1.1 Al 0.9 phase and iron carbide (Fe 7 C 3 ) for the Fermanal alloy. Mössbauer spectra were fit with two sites for the Hadfield alloy, which displayed as a broad singlet because of the austenitic disordered phase, and had a magnetic hyperfine field distribution, which corresponds to the Cr 2 Fe 14 C ferromagnetic carbides found by XRD. There were two paramagnetic sites, a singlet, which corresponds to the austenite disordered phase, and a doublet, which can be attributed to the Fe 7 C 3 carbide. The obtained Rockwell C hardness for aged Hadfield and Fermanal alloys were 43.786 and 50.018 HRc, respectively.

The properties of the double iron and tungsten carbide prepared by mechanical alloying technique (MA) from elemental powders are reported. The samples were milled for 1, 3, 5, 10, 15, 20, 25 and 30 h. The alloy progress for each milling time was evaluated by X-ray diffraction (XRD) and 57 Fe Mössbauer spectrometry. Once the alloy was consolidated two sorts of paramagnetic sites and a magnetic distribution were detected according to the Mössbauer fitting. The majority doublet could correspond to Fe 6 W 6 C ternary carbide as X-ray diffraction suggests, and the other could be Fe 3 W 3 C. The hyper fine parameters are reported. Vickers microhardness measurements of 30 h milled sample was conducted at room temperature with a load of 0.245 N for 20 s.

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Time milling and composition effects on the magnetic and structural properties of the Fe x Mn 0.95-x Al 0.05 (0.40 < x < 0.80) system R. R. Rodríguez J.* The magnetic and structural properties of the Fe x Mn 0,95-x Al 0,05 system (0.40 < x < 0.80) were analyzed by X-ray diffraction and Mössbauer spectroscopy techniques. The samples were prepared by mechanical alloying during 12, 24, 36 and 48 hours. The X-ray patterns show a FCC type structural phase. The lattice parameter slightly decreases when iron concentration increases. The grain size shows a growing tendency between 12 and 24 h. Afterwards, a decreasing behavior for 36 h and it stabilizes for 48 h. The Mössbauer spectra present an antiferromagnetic peak; however, the magnetic phase shows a shifting through the paramagnetic state when the Fe-concentration grows. The Mean Hyperfine Field (MHF) decreases as Fe concentration increases. Despite the differences between our preparation method and that provided by the arc melting technique, the final results present good agreement among them.

Iron silicon carbide Fe 0.79 Si 0.09 C 0.12 was prepared by mechanical alloying from elemental powders, with a ball-to-powder weight ratio of 20:1. This synthesis was carried out in two stages: in the first stage cementite Fe 3 C was prepared from elemental iron and carbon powders, the mixed powders were milled for 30 hours. In the second stage Fe 0.79 Si 0.09 C 0.12 was prepared from cementite Fe 3 C and Silicon elemental powder as precursors, the samples were milled for 1, 3, 5, 10, 15, 20, 25, 30 and 35 hours. The alloy progress for each milling time was evaluated by X-ray diffraction (XRD) and 57 Fe Mössbauer spectrometry. Nanocrystalline Fe 3 C powders were obtained from Fe and C, with an average grain size of 15 nm. It was possible to prepare metastable iron silicon carbide such as Fe 0.79 Si 0.09 C 0.12 and Fe 0.81 Si 0.02 C 0.17 and their respective hyperfine parameters are reported.