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Spinodal decomposition of the ferritic phase, a thermally induced phase transformation process is studied in an LDX 2101 type leanduplex stainless steel by different examination methods. This phase transformation in duplex stainless steels has special importance because it is responsible for the so called "475 °C embrittlement". This deterioration process causes a decrease in toughness and corrosion resistance. Fe-Cr alloys, thus several stainless steels, are susceptible to the spinodal decomposition at intermediate and low temperatures (<600 °C). Therefore, it is important to study this phenomenon in novel lean-duplex stainless steels as well. Our results revealed that spinodal decomposition occurs to a lesser extent in the studied type of lean-duplex stainless steel but its effect is not negligible in applications. [ABSTRACT FROM AUTHOR]

The microstructure and the dislocation density in as-quenched ferrous lath martensite were studied by different methods. The blocks, packets and variants formed due to martensitic transformation were identified and their sizes were determined by electron backscatter diffraction (EBSD). Concomitant transmission electron microscopy (TEM) investigation revealed that the laths contain subgrains with the size between 50 and 100 nm. A novel evaluation procedure of EBSD images was elaborated for the determination of the density and the space distribution of geometrically necessary dislocations from the misorientation distribution. The total dislocation density obtained by X-ray diffraction line profile analysis was in good agreement with the value determined by EBSD, indicating that the majority of dislocations formed due to martensitic transformation during quenching are geometrically necessary dislocations. [ABSTRACT FROM AUTHOR]

Abstract: Surface rolling is a cold-working technique used for hardening the surface of steel and ductile cast iron components. This process increases the surface hardness and improves the fatigue properties of components, so it is commonly used to treat railroad car wheel axles. The present paper examines the influence of this surface strengthening technique on the microstructure of the railroad car wheel axle material by hardness tests, optical microscopy (OM), and other novel examination methods, such as scanning electron microscopy (SEM), X-ray line profile analysis (XLPA), non-destructive magnetic evaluation (NDE) and automated electron backscatter diffraction (EBSD). The results show that surface rolling causes an increase in hardness down to a depth of ~10mm. It is also shown, that the increase in hardness is not due to grain refinement or change in grain morphology; thus it is likely to be caused by an increase in dislocation density. [Copyright &y& Elsevier]

In highly alloyed and duplex stainless steels the range of alloying elements leads to many different phases precipitating at higher temperatures. Duplex stainless steels consist of almost equal ratios of austenite and ferrite, and between 923 and 1273 K the ferrite begins decomposing into secondary austenite (γ2) and the σ phase. Several orientation relations between the austenitic, ferritic and σ phases have been determined by other researchers. The calculation and testing of mathematical expressions for these orientations are important for a close understanding of changes in duplex steel hardness, ductility, and other qualitative measures imposed by annealing or heat ageing. The method described in this article also offers an approach for determining parent phase orientations from inherited orientations in other metallic microstructures. When the orientation relations of adjacent grains calculated from mathematical equations and those measured by electron backscatter diffraction were compared, naturally it was found that the average orientation differs less between grains that inherit matrix structure from common parents. However, it was also found that the degree of difference depended on the variants involved in the orientations. This phenomenon can be explained by features of the microstructure and decomposition of the ferritic phase: initially the microstructure contains only primary austenite (γ1) and ferrite, then after a while it contains [beside primary (γ1) austenite] increasing amounts of secondary (γ2) austenite and the σ phase, and decreasing amounts of ferrite. The presence of two variants of austenite makes it difficult to verify parent relations for secondary (γ2) austenites. [ABSTRACT FROM AUTHOR]

We report here for the first time the composition and mineralogical studies on a new meteorite, which was found in August 2012 near the village of Csátalja, Hungary (46°0׳21׳׳N; 18°59׳27׳E). The Csátalja meteorite is classified as a H4–5 ordinary chondrite with shock stage S2 and a degree of weathering W1 and the total mass is 15 kg. The Csátalja meteorite is characterized by well-defined chondrules composed either of olivine or pyroxene. X-ray diffractogram shows the primary phases olivine, pyroxene, kamacite, and albite. Metal particles were extracted from the bulk powdered samples exhibit only kamacite and small amounts of the intergrowth taenite/kamacite. Raman spectra of forsterite indicate that Csátalja meteorite suffered from relatively low shock pressure regime. The texture of chondrules varies from nonporphyritic (e.g., barred olivine, radial pyroxene) to porphyritic ones (e.g., granular olivine as well as olivine pyroxene). The meteorite name has not yet approved by the Nomenclature Committee of the Meteoritical Society. [ABSTRACT FROM AUTHOR]

The paper presents the microstructure and corrosion behavior of an AlTiNiCuAgSn new equiatomic multicomponent alloy. The alloy was obtained using the vacuum arc remelting (VAR) technique in MRF-ABJ900 equipment. The microstructural analysis was performed by optical and scanning electron microscopy (SEM microscope, SEM-EDS) and the phase transformations were highlighted by dilatometric analysis and differential thermal analysis (DTA). The results show that the as-cast alloy microstructure is three-phase, with an average microhardness of 487 HV0.1/15. The obtained alloy could be included in the group of compositionally complex alloys (CCA). The corrosion resistance was studied using the potentiodynamic method in saline solution with 3.5% NaCl. Considering the high corrosion resistance, the obtained alloy can be used for surface coating applications. [ABSTRACT FROM AUTHOR]