Mould Components Impact on Structure and Quality of Elektron 21 Alloy

Magnesium alloys due to their low density and high strength-to-weight ratio are promising material for the automotive and aerospace industries. Many elements made from magnesium alloys are produced by means of sand casting. It is essential to investigate impact of the applied mould components on the microstructure and the quality of the castings. For the research, six identical, 100x50x20mm plates has been sand cast from the Elektron 21 magnesium casting alloy. Each casting was fed and cooled in a different way: one, surrounded by mould sand, two with cast iron chills 20mm and 40mm thick applied, another two with the same chills as well as feeders applied and one with only the feeder applied. Solid solution grain size and eutectics volume fraction were evaluated quantitatively in Met-Ilo program, casting defects were observed on the scanning electron microscope Hitachi S3400N. The finest solid solution grain was observed in the castings with only the chills applied. Non metallic inclusions were observed in each plate. The smallest shrinkage porosity was observed in the castings with the feeders applied

Structural and quantitative analysis of die cast AE44 magnesium alloy

Purpose: The main objective of this study was development of determination of phase fraction methodology in cast magnesium alloy containing aluminum and rare earth elements. Design/methodology/approach: The study was conducted on magnesium alloy containing 4 %wt. aluminum and 4 %wt. mixture of rare earth elements (mischmetal) in the as-cast condition. The mischmetal includes cerium, lanthanum, neodymium and praseodymium. In this study, several methods were used such as: optical light microscopy, quantitative metallography, scanning electron microscopy and X-ray diffraction. The Rietveld method with Hill and Howard procedure was applied for determination of lattice parameters and phase abundance. Findings: The microstructure of investigated alloy consists of α-Mg solid solution, globular, lamellar and acicular precipitations of Al11RE3 and Al2RE phases. The results show that the accurate determination of phase contents in AE44 alloy can not perform using quantitative metallography. In this purpose X-ray investigations should be applied. Research limitations/implications: Developed methodology will be used to quantitative phase analysis of investigated alloy after creep tests and die cast with different parameters. Practical implications: AE44 magnesium alloy is used in automotive industry. Moreover, this alloy has a new potential application and results of investigations may be useful for preparing optimal technology of die casting. Originality/value: Procedure described in this paper may be useful as the best experimental techniques for quantitative phase analysis of the intermetallic phases occurring in the AE series magnesium alloys

Novel piezoelectric paper based on SbSI nanowires

A novel piezoelectric paper based on antimony sulfoiodide (SbSI) nanowires is reported. The composite of tough sonochemically produced SbSI nanowires (with lateral dimensions 10–100 nm and length up to several micrometers) with very flexible cellulose leads to applicable, elastic material suitable to use in fabrication of, for example, piezoelectric nanogenerators. For mechanical energy harvesting, cellulose/SbSI nanocomposite may be used. Due to its high values of electromechanical coefficient (k33 = 0.9) and piezoelectric coefficient (d33 = 1 9 10-9 C/N), SbSI is a very attractive material for such devices. The preliminary investigations of a simple cellulose/SbSI nanogenerator for shock pressure (p = 3 MPa) and sound excitation (f = 175 Hz, Lp = 90 dB) allowed to determine its open circuit voltage 2.5 V and 24 mV, respectively. For a load resistance equal to source impedance (ZS = 2.90(11) MX), maximum output power density (PL = 41.5 nW/cm3 for 0.05-mm-thick sheet of this composite) of the cellulose/SbSI nanogenerator was observed. Cellulose/SbSI piezoelectric paper may also be useful to construct gas nanosensors and actuators

Modifications of the chemical composition and microstructure of flash smelting copper slags in the process of their reduction

Blister copper smelting in a flash smelting furnace results in generation of slag that contains high amounts of copper, iron and lead. Most commonly, this material is subjected to reduction with coke in an electrical furnace. In the present paper, results of investigations on reduction of slag with another reducer, i.e. anthracite dust, are discussed. Each experimental slag was analysed for its microstructure, chemical composition and phase composition. Based on the results, a decopperisation level of the study material was estimated. It was shown that anthracite dust might be considered as an alternative for currently used reducers

Mikrostruktura wygrzewanych pokryć cynkowych typu galfan na podłożu stalowym

The commercially available Galfan coating containing 5-7wt.% of Al deposited on the low carbon steel substrate by hot dipping has been examined with respect to the microstructure of the coating/substrate interface area. The application of several experimental techniques (SEM/EDS, XRD, TEM/AEM/EDS/ED) allowed demonstrating the two-phase structure of the alloy coating in non-treated, commercially available Galfan samples: Zn-rich pre-eutectoid phase grains are surrounded by lamellar eutectics of -Al and -Zn. The transition layer between the alloy coating and steel substrate with the considerably higher Al content (SEM/EDS, TEM/EDS) has been found in both non-treated and annealed samples (600oC/5 minutes). Only the monoclinic FeAl3Znx phase however was revealed in the annealed sample (TEM/electron diffraction) remaining uncertain the presence of the orthorhombic Fe2Al5Znx phase, reported by several authors

Properties of Sonochemically Prepared CuInxGa1-xS2 and CuInxGa1-xSe2

Nanoparticles of chalcopyrites copper indium gallium sul de (CuInxGa1xS2 or CIGS) and copper indium gallium selenide (CuInxGa1xSe2 or CIGSe) were fabricated sonochemically. They were characterized by Xray di raction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy, selected area electron di raction, and di use re ectance spectroscopy. The electrical and photoelectrical properties of the fabricated nanomaterials were investigated

Research on Extruded Products of Mgalzn Alloys – Microstructure and Mechanical Properties / Badania Wyrobów Wyciskanych Ze Stopów Mgalzn – Mikrostruktura I Właściwości Mechaniczne

The aim of the study was to test and assess products extruded from the magnesium alloys type MgAlZn: AZ31, AZ61 and AZ80A alloys in the form of Ø35mm round bars and 80x15mm flat bars. The test material was extruded in a direct system with the ram feed speed of 1 mm/s and the extrusion ratio λ = 7 ÷ 9. The extruded bars were examined in as-extruded state and after heat treatment to the T5 temper and T6 temper. The strength properties were tested and microstructure was examined with calculation of the average grain size.Praca miała na celu zbadanie wyrobów uzyskanych w procesie wyciskania stopów magnezu typu MgAlZn: AZ 31, AZ 61 oraz AZ 80A w postaci prętów Ø35mm oraz płaskowników 80x15mm. Materiał do badań został wyciśnięty w systemie współbieżnym z prędkością posuwu tłoka 1 mm/s, przy współczynniku wydłużenia λ=7÷9. Wyciśnięte pręty analizowano w stanie wyciskanym oraz po obróbce cieplnej do stanu T5 i T6. Zbadano ich właściwości wytrzymałościowe jak również poddano analizie mikrostruktury z określeniem średniej wielkości ziarna

Zastosowanie modelu dynamicznego magic do rekonstrukcji i prognozowania długoterminowych zmian chemicznych wód jezior w Karkonoszach =Use of the dynamic model magic to reconstruction and predicting of long-term changes in lakes water chemistry in the Karkonosze Mts

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The Influence of Strontium on the Microstructure of Cast Magnesium Alloys Containing Aluminum and Calcium

The structure of Mg-9Al-2Ca-xSr alloys is composed of a-Mg grains and the Al2Ca and Al4 Sr phases in the interdendritic areas. These phases are formed as a result of eutectic reactions. Globular particles of the Al8Mn5 phase are observed within the interior of the grains. The addition of strontium to Mg-9Al-2Ca-0.4Mn alloys causes the formation of the Al4Sr phase and increase of its volume fraction with increasing strontium levels. Moreover, increase of the strontium amount causes a decrease of aluminum content in the a-Mg solid solution.W artykule przedstawiono wyniki badań wpływu strontu na mikrostrukturę odlewniczych stopów magnezu zawierających aluminium i wapń. Jakościową analizę fazową przeprowadzono za pomocą rentgenowskiej analizy fazowej i metody EBSD. Do ilościowej analizy fazowej zastosowano metody analizy obrazu. Po odlewaniu mikrostruktura stopów zawierających 9% mas. aluminium, 2% mas. wapnia, 0,3% mas. strontu i 0,4% mas. manganu składa się z roztworu stałego α-Mg oraz wydzieleń faz międzymetalicznych Al2Ca, Al4Sr i Al8Mn5. Zwiększenie zawartości strontu do 2% mas. powoduje zwiększenie udziału objętościowego fazy Al4Sr i zmniejszenie stężenia aluminium w roztworze stałym α-Mg