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P. Sarmphim, S. Soontaranon, C. Sirisathitkul, P. Harding, S. Kijamnajsuk, B. Chayasombat, S. Pinitsoontorn and J. Chingunpitak

superparamagnetic nanoparticles water-dispersible”, Chem. Mater. 19, 1821‒1831 (2007). [12] T. Rieker, A. Hanprasopwattana, A. Datye, and P. Hubbard, “Particle size distribution inferred from small-angle X-ray scattering and transmission electron microscopy”, Langmuir 15, 638‒641 (1999). [13] M. Murawska, A. Skrzypczak, and M. Kozak, “Structure and morphology of gold nanoparticles in solution studied by TEM, SAXS and UV_Vis”, Acta Phys. Pol. A 121, 888‒892 (2012). [14] H. Borchert, E.V. Shevehenko, A. Robert, I. Mekis, A. Kornowski

Open access

T. Hara, T. Maekawa, T. Kawabata, K. Terayama, S. Ikeno and K. Matsuda

The microstructure of spheroidal graphites in ductile cast iron (FCD450) was investigated by TEM using cross sectional TEM samples prepared by FIB method. The spheroidal graphite consisted of many small areas, and all of these areas were indexed as the graphite structure and just carbon peak was detected from there.

Open access

M. Rozmus-Górnikowska and M. Blicharski

precipitates in Inconel 625 arc weld overlay coatings on boiler pipes, Arch. Metall. Mater. 60 , 2599-2605 (2015). [20] B. Mvola, P. Kah, J. Martikainen, Dissimilar ferrous metal welding using advanced gas metal arc welding proceses, Rev. Adv. Mater. Sci. 38 , 125-137 (2014). [21] W. Chung, J. Huang. L. Tsay, Ch. Chen, Microstructure and stress corrosion cracking behaviour of the weld metal in alloy 52-A508 dissimilar welds, Mater. Trans. 52 , 12-19 (2011). [22] Z R. Chen, Y.H. Lu, TEM observations of martensite layer at the weld interface of an A508III

Open access

H. Paul, J. Morgiel, T. Baudin, F. Brisset, M. Prażmowski and M. Miszczyk

Abstract

The layers near the interface of explosively welded plates were investigated by means of microscopic observations with the use of transmission electron microscopy (TEM) equipped with energy dispersive spectrometry and scanning electron microscopy equipped with electron backscattered diffraction facility (SEM/EBSD). The metal compositions based on carbon or stainless steels (base plate) and Ti, Zr and Ta (flyer plate) were analyzed. The study was focused on the possible interdiffusion across the interface and the changes in the dislocation structure of bonded plates in the layers near-the-interface.

It was found that the extremely rapid temperature increase followed by high cooling rates in the areas near the interface favour the formation of metastable phases. The crystalline or glassy nature of the phases formed inside melted zones strongly depends on the chemical composition of bonded metals. The amorphous phases dominates the melted zone of the (carbon or stainless steel)/Zr whereas the mixture of amorphous phases and nano- grains were identified in (carbon steel)/Ti and (stainless steel)/Ta clads. The elongated shape of the (sub)grains and the randomly distributed dislocations inside them as well as the shear bands and twins observed in the layers near-the-interface of all investigated clads, clearly indicated that during explosive welding, the deformation processes were prevailing over the softening ones.

Open access

J. Dworecka, E. Jezierska, J. Rębiś, K. Rożniatowski and W. Świątnicki

Abstract

The aim of this study was to analyse and to identify the phases which formed in 100CrMnSi6-4 bearing steel after the nanostructuring heat treatment. Especially designed thermal treatment parameters were applied in order to obtain a nanobainitic structure. Two different microscopic techniques were used for the precise examination of the microstructures obtained: transmission electron microscopy (TEM) and atomic force microscopy (AFM). Both analyses confirm that the examined steel has a nanocrystalline structure. However, it was discovered that the selected analysis methods affected the results of the plate thickness measurements.

Open access

Y. Matsuoka, K. Watanabe, J. Nakamura, W. Lefebvre, S. Saikawa, S. Ikeno and K. Matsuda

Abstract

In this study, the early stage of aging in Mg-Gd-Y alloys has been observed by transmission electron microscopy (TEM), high angle annular dark field – scanning transmission electron microscopy (HAADF-STEM) and calculations of images and electron density and bond overlap population (BOP) by first principal to understand the origin of precipitation in this alloy. The small hexagon of 0.37 nm is the first precipitate in this alloy, and this is the evidence of short range ordering of D019 structure. This is referred as the pre β”-phase. In the peak aged condition, β’ phase with bco structure was mainly observed.

Open access

Krzysztof Łęczycki

Abstract

Firing from gun armament generates a wide range of physico-chemical phenomena contributing to the degradation of barrel material, e.g. pressure, high temperature, chemically aggressive character of post-detonation gases and friction of a driving band. In this work the technique of thin foils was used in Transmission Electron Microscopy (TEM) to study the influence of physicochemical phenomena on the material microstructure of aircraft gun barrel. A mechanism and reason of premature wear-out of the barrel under consideration was also outlined by utilising light microscopy and hardness measurements.

Open access

K. Konopka, L. Litynska-Dobrzynska and J. Dutkiewicz

Methods of enhancing of mechanical properties of ceramic-metal composites, particularly fracture toughness by introducing dispersed metal particles such as W, Mo, Ni, Al, etc to a ceramic matrix are well known. However, the dependence of the microstructures, especially interfaces, on the properties of composites is not well understood yet. Moreover, the ceramic-metal interfaces play a crucial role in tailoring the composite properties.

In this paper we examine the alumina matrix composite with NiAl2O4 spinel phase and present the SEM and TEM studies of spinel distribution, size and crystallographic orientation. The composites were prepared by sintering Al2O3 and Ni powders below the melting point of Ni in argon. During the process of sintering the spinel phase appeared. It was not homogeneously distributed in the alumina matrix. The spinel phase areas were linked together and constituted an almost continuous form. We observed that the distribution and size of spinel influenced the fracture toughness of the composite.

Open access

J. Morgiel, N. Sobczak, M. Pomorska, R. Nowak and J. Wojewoda-Budka

The interaction of liquid aluminium (5N) with single crystal MgO substrates of [100], [110] and [111] orientations (surface roughness <1 nm) were studied using sessile drop wettability test performed at 1000ºC for 1 hour in vacuum (5 x 10-6 mbar). The observations performed using scanning electron microscopy (SEM) showed that the interaction of liquid metal with MgO crystals in all cases resulted in the formation of reaction products region (RPR) of thickness varying from ∽40 up to ∽80 microns in depth. In each case the RPR consisted mainly of coarse dendrite-like crystallites of few microns thick surrounded by net of much thinner channels. Occasionally away from the RPR centre the areas built of much finner but also dendrite- or filament-like crystallites were noted. The thin foils for transmission electron microscopy (TEM) investigations were cut using focused ion beam system (FIB) both from drop/RPR as well as RPR/MgO interfacial regions. The electron diffractions proved that the dominating coarse dendrite-like crystallites are of the same α-Al2O3 type throughout the whole RPR for all substrates orientations. Similarly, the colonies of finer crystallites always showed diffraction patterns characteristic for MgAl2O4 spinel. Therefore, the performed investigation indicated, that both the reaction layer depth and the reaction path represented by the sequence and type of phases present in Al/MgO RPR remain roughly similar for all examined orientations, i.e. that the substrate orientation control neither reaction kinetics, nor affects final phase composition of RPR.

Open access

H. Paul, A. Morawiec, T. Baudin and T. Czeppe

grain boundary in hot deformed AA3104 aluminium alloy, Mater. Character 62 , 81-89 (2011). [27] H. Paul, T. Baudin, F. Brisset, Effect of strain path and sec-ond phase particles on microstructure and texture evolution of AA3104 aluminum alloy processed by ECAP, Arch. Metall. Mater. 56 , 245-261 (2011). [28] H. Paul, A. Morawiec, T. Baudin, Early stages of recrystallization in ECAP-deformed AA3104 alloy investigated using SEM and TEM orientation mappings, Metall. Mater. Trans. A 43A , 4777-4793 (2012). [29] S. Bhaumik, X. Molodova, G. Gottstein, Effect of