Chemical Composition Microanalysis Research Articles

Structure formation during sheet steel production in a unit of continuous casting and deformation

The paper considers the main problem of improving quality of steel sheets for welded pipes obtained at plate rolling mills and the main reasons that reduce it. There is a possibility of improving quality of steel sheets using technological capabilities of the unit of combined continuous casting and deformation. Problem of determining stress state of metal in cyclic deformation zone is posed and solved. The results of obtaining 09G2S sheet steel in pilot unit of continuous casting and deformation are presented. Magnitude of stresses in the center of cyclic deformation during production of steel sheets was determined for welded pipes at the unit. The authors present results of experimental study of the process of steel sheets production at pilot unit of continuous casting and deformation. The article considers the results of microstructure analysis, microhardness determination and microanalysis of chemical composition of the studied steel in various zones of the strip cross section. Structural inhomogeneity development in ferritic-pearlitic steel is interpreted along the thickness of sheet under conditions of combined thermomechanical processing of metal solidified in the mold. Predominantly ferritic microstructure is generated in the central light interlayer of the strip compared to base metal, characterized by a sharp decrease in carbon concentration in it. There is a possibility of such structure genesis at the first stages of crystallization during forging of low-carbon steel, when the excess phase of high-temperature ferrite that solidifies first is located mainly in the strip center. The size of pearlite grains in the light interlayer covariates with the grain structure of pearlite in the strip base metal and does not form precipitates of lath morphology, which increase tendency of steel to brittle fracture.

Polymer Composites Based on Glycol-Modified Poly(Ethylene Terephthalate) Applied to Additive Manufacturing Using Melted and Extruded Manufacturing Technology.

As part of the work, innovative polymer composites dedicated to 3D printing applications were developed. For this purpose, the influence of modified fillers, such as silica modified with alumina, bentonite modified with quaternary ammonium salt, and hybrid filler lignin/silicon dioxide, on the functional properties of composites based on glycol-modified poly(ethylene terephthalate) (PET-G) was investigated. In the first part of the work, using the proprietary technological line, filaments from unfilled polymer and its composites were obtained, which contained modified fillers in an amount from 1.5% to 3.0% by weight. The fittings for the testing of functional properties were obtained using the 3D printing technique in the Melted and Extruded Manufacturing (MEM) technology and the injection molding technique. In a later part of the work, rheological properties such as mass melt flow rate (MFR) and viscosity, and mechanical properties such as Rockwell hardness, Charpy impact strength, and static tensile strength with Young’s modulus were presented. The structure of the obtained composites was also described and determined using scanning electron microscopy with an attachment for the microanalysis of chemical composition (SEM/EDS) and the atomic force microscope (AFM). The correct dispersion of the fillers in the polymer matrix was confirmed by wide-angle X-ray scattering analysis (WAXS). In turn, the physicochemical properties were presented on the basis of the research results: thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR). On the basis of the obtained results, it was found that both the amount and the type of fillers used significantly affected the functional properties of the tested composites.

Luminescence from ZrO2 Nanopowders Doped with Sm3+ Ions Processed by Polyol Method at Low Processing Temperature

ZrO2 and ZrO2:Sm3+ nanopowders are synthesized by means of polyol method, from [Zr(NO3)2.xH2O] and (SmCl3·6H2O) precursors dissolved in a diethylene glycol medium. X‐ray diffraction (XRD) results show polymorphic powders because monoclinic structure and tetragonal are exhibited. The crystal size is estimated by Scherrer formula; an averaged crystallite size of 9 nm is obtained. Surface morphology study, by means of SEM, evidences multiform particles, some with straight edges associated with monoclinic or tetragonal structure. The chemical composition microanalysis results indicate agreement with ideal stoichiometry for ZrO2 and ZrO2:Sm3+ powders. The photoluminescence emission spectra show that maximum intensity is reached at λ = 614 nm due to transition 4G5/2→6H7/2, exciting with λex = 240 nm, which corresponds to sample ZrO2:Sm3+ (0.75 at%); this sample is labeled as M3. Very similar results are obtained by cathodoluminescence studies. On the contrary, exciting with λex = 380 nm (monitoring emission band peaked at 614 nm), emission bands of host lattice and ZrO2:Sm3+ are favored simultaneously. The luminescent quenching phenomenon occurs when doping concentration (Sm3+ ions) is >=0.75 at%. The photoluminescent emission exhibits a reddish orange color, characteristic of Sm3+ ions, and yellowish‐orange for cathodoluminescence emission.

Towards Automatic Detection of Precipitates in Inconel 625 Superalloy Additively Manufactured by the L-PBF Method.

In our study, the comparison of the automatically detected precipitates in L-PBF Inconel 625, with experimentally detected phases and with the results of the thermodynamic modeling was used to test their compliance. The combination of the complementary electron microscopy techniques with the microanalysis of chemical composition allowed us to examine the structure and chemical composition of related features. The possibility of automatic detection and identification of precipitated phases based on the STEM-EDS data was presented and discussed. The automatic segmentation of images and identifying of distinguishing regions are based on the processing of STEM-EDS data as multispectral images. Image processing methods and statistical tools are applied to maximize an information gain from data with low signal-to-noise ratio, keeping human interactions on a minimal level. The proposed algorithm allowed for automatic detection of precipitates and identification of interesting regions in the Inconel 625, while significantly reducing the processing time with acceptable quality of results.

Photoluminescent ZrO2:Tb3+ thin films synthesized by USP technique using a metal-organic precursor

Photoluminescent ZrO2 and ZrO2:Tb3+ thin films were synthesized from metal-organic precursor, zirconium acetylacetonate [Zr(C5H7O2)4], using Ultrasonic Spray Pyrolysis method. These thin films were deposited on Corning glass substrates at several deposition temperatures. ZrO2 and ZrO2:Tb3+ (X a/o) films were characterized by x-ray diffraction to identify the crystalline structure; results showed tetragonal phase of zirconia; with a crystalline size of approximately 4 nm according to Scherrer’s formula. Also, SEM micrographs revealed that surface morphology of these films is very flat. Chemical composition microanalysis showed presence of oxygen and zirconium as major species. Analysis by Infrared spectroscopy demonstrates that 900 and 760 nm bands correspond to presence of ZrO2. In addition, these films showed optical transmittances from 75 to 98 % in the visible range. Photoluminescent features varied as a function of excitation wavelength; when excited at λ ex = 286 nm strong green emission is observed, which is associated to electronic transitions 5D4 → 7Fn (n = 6, 5, 4, 3) corresponding to Tb3+ ions. Excitation with λ ex = 336 nm exhibits spectra with simultaneous emissions from host lattice and Tb3+ ions; here, observed color was blue-green.

A Study on Material Properties of Intermetallic Phases in a Multicomponent Hypereutectic Al-Si Alloy with the Use of Nanoindentation Testing.

The paper concerns modeling the microstructure of a hypereutectic aluminum-silicon alloy developed by the authors with the purpose of application for automobile cylinder liners showing high resistance to abrasive wear at least equal to that of cast-iron liners. With the use of the nanoindentation method, material properties of intermetallic phases and matrix in a hypereutectic Al-Si alloy containing Mn, Cu, Cr, Ni, V, Fe, and Mg as additives were examined. The scanning electron microscope equipped with an adapter for chemical composition microanalysis was used to determine the chemical composition of intermetallics and of the alloy matrix. Intermetallic phases, such as Al(Fe,Mn,M)Si, Al(Cr,V,M)Si, AlFeSi, AlFeNiM, AlCuNi, Al2Cu, and Mg2Si, including those supersaturated with various alloying elements (M), were identified based on results of X-ray diffraction (XRD) tests and microanalysis of chemical composition carried out with the use of X-ray energy dispersive spectroscopy (EDS). Shapes of the phases included regular, irregular, or elongated polygons. On the disclosed intermetallic phases, silicon precipitations, the matrix, values of the indentation hardness (HIT), and the indentation modulus (EIT) were determined by performing nanoindentation tests with the use of a Nanoindentation Tester NHT (CSM Instruments) equipped with a Berkovich B-L 32 diamond indenter. The adopted maximum load value was 20 mN.

Precipitates in Additively Manufactured Inconel 625 Superalloy.

Laser-based additive manufacturing processes are increasingly used for fabricating components made of nickel-based superalloys. The microstructure development, and in particular the precipitation of secondary phases, is of great importance for the properties of additively manufactured nickel-based superalloys. This paper summarizes the literature data on the microstructure of Inconel 625 superalloy manufactured using laser-based powder-bed fusion and directed energy deposition processes, with particular emphasis on the phase identification of precipitates. The microstructure of Inconel 625 manufactured by laser-based directed energy deposition in as-built condition is investigated by means of light microscopy and transmission electron microscopy. Phase analysis of precipitates is performed by the combination of selected area electron diffraction and microanalysis of chemical composition. Precipitates present in the interdendritic areas of as-built Inconel 625 are identified as MC and M23C6 carbides as well as the Laves phase.

Pitting Corrosion of the Resistance Welding Joints of Stainless Steel Ventilation Grille Operated in Swimming Pool Environment

This work focuses on the pitting corrosion of ventilation grilles operated in swimming pool environments. The ventilation grille was made by resistance welding of stainless steel rods. Based on the macroscopic and microscopic examinations, the mechanism of the pitting corrosion was confirmed. Chemical composition microanalysis of sediments as well as base metal using scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS) method was carried out. The weldments did not meet the operating conditions of the swimming pool environment. The wear due to the pitting corrosion was identified in heat affected zones of stainless steel weldment and was more severe than the corrosion of base metal. The low quality finish of the joints and influence of the welding process on the weld metal microstructure lead to accelerated deposition of corrosion effecting elements such as chlorine.

Analysis of Damage of Solder Joint of Heat Exchanger

The paper focus on the metallographic analysis of damaged heat exchanger made of high‑alloy austenitic steel by soldering. The object in question is a soldered joint of main mounting plate of the heat exchanger and first heat exchanging plate of it. In this part of the heat exchanger after the vibration and pressure test crack appeared. The subject of the analysis is the evaluation of the microstructure of the solder joint (high-alloy austenitic steel and copper), and evaluation of the appeared crack. The problematic is solved with aid of metallographic analysis of the microstructure of the material, using light microscopy and scanning electron microscopy and the EDS microanalysis of chemical composition.

The influence of high temperature annealing and creep on the microstructure and chemical element distribution in the γ, γ′ and TCP phases in single crystal Ni-base superalloy

The development of the microstructure in the CMSX-4 superalloy caused by high temperature annealing and creep and its relation with the chemical composition evolution of the γ, γ′ and topologically close-packed (TCP) phases was investigated at the micro- and nanoscales. The samples were creep deformed at a temperature of 900 °C and 1000 °C without previous treatment, and after pre-annealing at a temperature of 1100 °C. The changes in microstructure and elemental composition of phases were investigated using analytical electron microscopy, electron tomography and X-ray diffractometry methods. The combination of the different imaging techniques with the high precision of chemical composition microanalysis in nanoareas allowed to examine the compositional changes which accompany coalescence of the γ′ particles as well as precipitation and growth of the TCP phases in single-crystal nickel base superalloys. It was determined that in the temperature range of 900–1100 °C the P and μ phases with TCP structure are present in the CMSX-4 superalloy. The μ phase exhibits almost perfect crystal structure, while the P phase contains numerous planar defects. Precipitation of the TCP phases at the expense of the γ phase dissolution in their vicinity leads only to the localized depletion in refractory elements in the surrounding γ′ phase. The concentration of these elements in the γ phase remains on the similar level close to the TCP phases and away from them.

The influence of sodium chlorides fog on corrosion resistance of heat exchangers used in automotive

Abstract In the work, the most important factors which influence on the exploitative durability of heat exchangers are classified. Particular attention was paid to the compounds of sodium chloride used in the winter season for road maintenance. In order to determine their impact on automotive heat exchanger corrosion resistance, a test of heaters in a salt chamber which imitates the conditions of their work was realized. It also allows to verify the durability of these products. To evaluate the corrosion changes, observation with the use of light microscopy and scanning microscopy SEM were made supplemented with microanalysis of chemical composition by EDS spectroscopy method. Critical areas in the heat exchangers which are mostly exposed to damage including the formation of local corrosion pits were located and analyzed.

Analysis of Coupling Segment of Belt Conveyor

The paper focuses on the metallographic analysis of damaged belt-conveyor coupling segments made of high-alloy austenitic steel. The object in question is a weldment – a bar with a ring welded on it at either end. The subject of the analysis is the evaluation of the microstructure of the base material of the two components (weldment and weld metal), the quality of the execution of the weld joints, subsequent heat treatment of the weldment, and the overall state of the component part after operational loading. The suitability of the design solution of the whole weldment is also discussed. The problematic is solved with the aid of a metallographic analysis of the microstructure of the material, using light microscopy, scanning electron microscopy inclusive of the EDS microanalysis of chemical composition, and microhardness measurement.

The Influence of Turbine Blade Geometry and Process Parameters on the Structure of Zr Modified Aluminide Coatings Deposited by CVD Method on the ZS6K Nickel Superalloy

The Zr modified aluminide coatings is an alternative concept for replacing Pt-modified aluminide bondcoat for thermal barrier coatings. In the paper the influence of process parameters on the chemical composition and the thickness of aluminide coatings will be presented. The zirconia-doped aluminide coating was deposited on turbine blades made from ZS6K nickel superalloy during the low-activity CVD process. In recent work the influence of turbine blade geometry on thickness of coating was observed. The thickest coating was observed on the trailing and leading edge on the blade cross-section. In the conducted research, the light and scanning electron microscopy were used as well as the EDS chemical composition microanalysis.

INVESTIGATIONS OF PALEONTOLOGICAL OBJECTS USING ELECTRON MICROSCOPY AND X-RAY MICROANALYSIS METHODS

Potentialities of a modern scanning microscope equipped with devices for X-ray microanalysis of chemical composition and crystal structure study by diffraction pictures of reflected electrons are illustrated by the example of researching into paleontological objects.

Morphology and chemical composition microanalysis of 2D and 3D ordered structures on porous InP

AbstractPorous InP proves to be promising for use in nanotechnologies due to the possibility to fabricate ordered structures like two‐dimensional (2D) single crystals of nanopores. The main goal of this paper is to demonstrate that, along with 2D structures, one can fabricate 3D ordered porous structures on InP using alternative anodic current superimposed to a constant current or by pulsing the current. The dependence of the efficiency of pore diameter modulation upon the current frequency was explored. The stoichiometric composition of 2D and 3D porous InP structures was evidenced by chemical composition microanalysis. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Nanocrystallisation of Soft Magnetic Fe-Co-Zr-Cu-B Alloys

In the present study, Fe 4 1 Co 4 1 B 1 0 Zr 7 Cu 1 alloy has been investigated in order to evaluate its thermal stability and structure after heat treatment, as well as the impact of heat treatment on magnetic properties. X-ray diffractometry, differential scanning calorimetry, chemical composition microanalysis, transmission electron microscopy, and magnetic hysteresis loop measurement techniques were employed. The crystallisation temperature of the as-quenched alloy is 490°C (continuous heating at 5°C/min). The melt-spun ribbon having 27 μm in thickness was annealed for 1 hour at temperatures from 400 to 700°C. The alloy after treatment at about 550°C underwent primary crystallisation, with the average size of crystals under 20 nm. This specimen shows the coercive field of 38 A/m, as compared to about 160 A/m reported for a similar alloy (Fe 4 4 Co 4 4 B 4 Zr 7 Cu 1 ) with a similar structure, annealed at 600°C.

Microanalysis of debris formed during rotary EDM of titanium alloy (Ti 6A1 4V) and die steel (T 215 Cr12)

This paper presents the scanning electron microscopy investigation on formation of debris during rotary electrodischarge machining of titanium alloy and high carbon high chromium die steel. Microanalysis of chemical composition of debris, in the form of globules after resolidification of ejected material from the workpiece surface, has been carried out using qualitative energy-dispersive spectroscopy and electron probe microanalysis. Scanning electron micrographs indicate the various types of debris particles which are collected from the dielectric as well as the particles which remain attached on the workpiece surface. Many distinct types of spheroidal particles (globules) are witnessed and the mechanism of their formation has been discussed. The chemical composition of these particles differs considerably, from its parent material due to migration of material from the rotating tool electrode (copper-tungsten) and the dielectric fluid.