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1

Microstructure Evolution, Phase Composition, Tensile and Hardness Properties Investigation of CrCuFeNi2Tix-Based High-Entropy Alloys

Chen Long

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

881--886

EN

CrCuFeNi2Tix high-entropy alloys (HEAs) (x = 0.1 ~ 0.7) are prepared and studied in this paper to investigate the effect of titanium on the microstructure, phase composition, and mechanical properties of the CrCuFeNi2Tix-based system. Microstructural studies using scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed that the addition of titanium could induce the formation of a body-centered cubic lattice (BCC) and intermetallic compounds (Ni3Ti) of the CrCuFeNi2Tix-based system. The practical formation of the phases meet the theory of the atomic size difference δ, mixing enthalpy ΔHmix, mixing entropy ΔSmix, valence electron concentration (VEC), and electronegativity difference Δχ. Additionally, the tensile and hardness properties of the CrCuFeNi2Tix-based system are investigated in this study. Generally, CrCuFeNi2Tix HEAs show low stiffness and good flexibility in mechanical properties. When the x value is relatively small, the HEAs show good ductility in the tensile test, which is the result of a face-centered cubic lattice (FCC) in the phase composition at this stage; when the x value becomes larger, due to the formation of the intermetallic compounds Ni3Ti, the HEAs show high hardness.

2

Identification of the tensile damage of degraded carbon steel and ferritic alloy-steel by acoustic emission with in situ microscopic investigations

Lyasota Igor, Kozub Barbara, Gawlik Józef

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

274--285

EN

The paper presents results obtained from the destructive laboratory investigation conducted on materials from pressure vessels after long-term operation in the refinery industry. Tested materials contained structural defects, which arose from improper heat treatment during steel plate manufacturing. Detailed metallographic and chemical composition tests and static tensile tests were conducted. Next, complex tensile tests were conducted with simultaneous acoustic emission (AE) monitoring while observing microstructural changes by light microscopy. From the laboratory tests, the correlations between the AE signal parameters and material microstructural damage during the tensile tests were developed. The results will be used as a basis of new algorithms for the structural condition assessment of in-service pressure equipment.

3

Experimental study of spot weld parameters in resistance spot welding process

Habib L., Ahmed R. S., Habib B., Guagliano M.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 1

179--186

EN

Resistance spot welding is a comparatively clean and efficient welding process that is widely used in sheet metal joining. This process involves electrical, thermal and mechanical interactions. Resistance spot welding primarily takes place by localized melting at the inter-face of the sheets followed by its quick solidification under sequential control of water cooled electrode pressure and ?ow of required electric current for certain duration. In this experimental work the tensile tests and the spot weld diameter were studied. The objectives of this analysis is to understand the physics of the process and to show the influence of the electrical current, weld time and the type material in resistance spot welding process.

4

Teoretyczna i doświadczalna analiza procesu formowania profili kompozytowych typu GLARE

Śliwa R. E., Wilk M. S.

Rudy i Metale Nieżelazne Recykling

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2016

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R. 61, nr 1

3--13

PL

W artykule przedstawiono teoretyczną i doświadczalną analizę procesu formowania profili kompozytowych typu GLARE wykonanych z udziałem fazy metalicznej ze stopów aluminium 2024, 6061 oraz 7075 oraz prepregu kompozytowego. Profile kompozytowe wykonano poprzez formowanie plastyczne cienkich arkuszy blach metalu o grubości 0,4 mm, następnie ukształtowane profile ułożono naprzemiennie z warstwami nieutwardzonego prepregu epoksydowego wzmocnionego włóknem szklanym i łączono w procesie autoklawowym. Dokonano oceny jakości makro- i mikrostruktury otrzymanych profili o strukturze kompozytów typu GLARE, poddano je również statycznym badaniom wytrzymałościowym. Wykazano, że profile kompozytowe typu GLARE wykonane z zastosowaniem procesu formowania plastycznego fazy metalicznej charakteryzuje dobra adhezja poszczególnych faz oraz wysokie parametry wytrzymałościowe.

EN

The paper presents a theoretical and experimental analysis of the forming process of GLARE type composite profiles made of aluminum alloy 2024, 6061 and 7075 and epoxy prepreg. Composite profiles were made by the plastic forming of thin metal sheets with a thickness of 0.4 mm. The shaped profiles were arranged with layers of uncured epoxy prepreg reinforced with glass fiber and cured with an autoclave process. An evaluation of the quality of macro- and microstructure obtained profiles of the type of GLARE composite, subjected to the static tensile tests. It has been shown that the composite profiles made by using the plastic forming process of the metallic phase it is characterized by good adhesion of the individual phases and as it has high strength parameters.

5

Analysis of plastic deformation of double reduced sheets

Spišák E., Majerníková J., Duľová-Spišáková M., Kaščák L.

Acta Mechanica et Automatica

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2016

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Vol. 10, no. 4

271--274

EN

This paper discusses the causes and the effects of plastic deformation of double reduced sheets under uniaxial and biaxial loading. It focuses on the specific inhomogeneity and localization of plastic deformation, which is analysed in detail. The uniaxial and the hydraulic biaxial tensile tests were used for material testing and the results were compared and evaluated. The final part of the paper deals with the microstructure of material deformations.

6

Internal Round Robin Tests for Operators of Mechanical Tests

Madejski B.

Fatigue of Aircraft Structures

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2015

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Iss. 7

52--60

EN

For the characterisation of materials, the aeronautical industry accesses the expertise and the support of independent test laboratories. For the execution of characterisation tests of materials it is important that the test laboratory can fulfil the requirements of the testing expertly and continuously improves knowledge related to the tests. Quality systems are very helpful in this respect. One element of quality management systems is the internal round robin tests. This paper presents a procedure of teaching new operators to carry out tests. In addition, this article underlines how the importance of interlaboratory tests for finding and eliminating mistakes made by new operators. The analysis was performed for tensile tests. This test enables the assessment of operators and significantly improves the quality of tests.

7

Quasi-static and dynamic tensile properties of Ti-6Al-4V alloy

Wojtaszek M., Śleboda T., Czulak A., Weber G., Hufenbach W. A.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 4

1261--1265

EN

Ti-6Al-4V alloy is widely used, mainly in aircraft industry, due to its low density, excellent corrosion/oxidation resistance and attractive mechanical properties. This alloy has relatively low formability, so forming parts of complex geometries out of this alloy requires precisely controlled thermomechanical processing parameters. In industrial conditions Ti-6Al-4V alloy is usually processed by forging or extrusion. Ti-6Al-4V alloy is applied for structural parts of aircrafts, which are often exposed to variable loads and high or cyclically changing strain rates. Moreover, Ti-6Al-4V alloy is often used for structural parts providing good ballistic performance. That is why the knowledge of the mechanical behaviour of this alloy under dynamic conditions is important. This work is aimed at the analysis of Ti-6Al-4V alloy behaviour under quasi-static and dynamic deformation conditions. Both dynamic and quasi-static tensile tests were performed in this research. Moreover, ARAMIS system, a non-contact and material independent measuring system providing accurate 2D displacements, surface strain values and strain rates, was applied. The influence of tensile test strain rate on chosen mechanical properties of the investigated alloy was also discussed. The investigations showed a significant influence of processing strain rate on the mechanical behaviour of Ti-6Al-4V alloy.

PL

Stop Ti-6A1-4V jest szeroko stosowany głównie w przemyśle lotniczym ze względu na niski ciężar właściwy, dużą odporność na korozję oraz wysokie własności mechaniczne. Ze względu na stosunkowo małą podatność do odkształceń plastycznych stopu Ti-6A1-4V. kształtowanie części o skomplikowanej geometrii z tego stopu wymaga bardzo dokładnego doboru warunków przeróbki cieplno-mechanicznej. W warunkach przemysłowych stop ten jest najczęściej kształtowany w procesach kucia lub wyciskania, które charakteryzują się różnymi zakresami prędkości odkształcania wsadu. Zastosowanie stopu Ti-6A1-4V obejmuje w dużej mierze wytwarzanie odpowiedzialnych elementów konstrukcji lotniczych, które są eksponowane na zmienne obciążenia w warunkach wysokich lub cyklicznie zmiennych prędkości, oraz które często muszą charakteryzować się doskonałymi parametrami balistycznymi. Dlatego istotna w przypadku przedmiotowego materiału jest znajomość charakterystyk jego zachowania w warunkach obciążeń dynamicznych. Zauważyć można, że w odróżnieniu od danych otrzymanych w statycznych warunkach, ilość publikowanych informacji na ten temat jest niewielka. W pracy przeprowadzono próby jednoosiowego roz- ciągania próbek ze stopu Ti-6A1-4V, które prowadzono przy dużych prędkościach odkształcenia oraz, celem porównania, w warunkach quasi-statycznych. Do analizy wykorzystano system do bezkontaktowych trójwymiarowych pomiarów odkształceń ARAMIS. Badano wpływ prędkości odkształcenia na wybrane własności mechaniczne stopu, obserwacji i analizie poddano także powstałe podczas realizacji próby rozciągania powierzchnie zniszczenia.

8

Wpływ dodatków stopowych (Ni, Fe, Zr) na wybrane własności mechaniczne stopów AlCuMg przeznaczonych do pracy w podwyższonych temperaturach

Krakowiak M., Bojar T.

Hutnik, Wiadomości Hutnicze

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2012

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Vol. 79, nr 5

324--327

PL

Wyroby wykonane ze stopów metali lekkich znajdują coraz częściej zastosowanie tam, gdzie wymagana jest wysoka wytrzymałość na obciążenia w podwyższonym zakresie temperatur eksploatacji. W przypadku elementów aluminiowych utwardzanych wydzieleniowo, praca w temperaturze powyżej 180 °C przez określony czas powoduje zmiany w ich strukturze, co niesie za sobą spadek własności mechanicznych. Zatem występuje zapotrzebowanie na technologie wytwarzania nowych zaawansowanych technicznie stopów aluminiowych (do pracy w podwyższonych temperaturach). Przedmiotem badań jest określenie wpływu dodatków stopowych (Ni, Fe, Zr) na wybrane własności mechaniczne stopu AlCuMg.

EN

The components made of aluminium based alloys usually works at low temperature range that is a major limitation of these materials. Working at temperatures above 180 °C for a specified period of time causes changes in structure of Al alloys precipitation hardened and leads to decrease of mechanical properties. There is a need for technologies to develop new technically advanced aluminium alloys dedicated to work at elevated temperatures. The object of the study is to determine the influence of alloying additions (Ni, Fe, Zr) on some mechanical properties of AlCuMg alloy.

9

Elasto-Viscoplastic Properties of AA2017 Aluminium Alloy

Ambroziak A., Kłosowski P., Pyrzowski L.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2011

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Vol. 15, No 1

5-20

EN

This paper describes a procedure for the identification of material parameters for the elasto-viscoplastic Bodner-Partom model. A set of viscoplastic parameters is identified for AA2017 aluminium alloy. The evaluation of material parameters for the Bodner-Partom constitutive equations is carried out using tensile tests. Numerical simulations of material behaviour during constant strain-rate tests are compared with direct uniaxial tensile experiments. A review of the models applied to concisely describe aluminium alloy is also given.

10

Wyznaczanie modułu Younga w płaszczyźnie papieru na podstawie prób ściskania

Szewczyk W.

Przegląd Papierniczy

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2007

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R. 63, nr 7

419-422

PL

W ramach badań przeprowadzonych w Instytucie Papiernictwa i Poligrafii Politechniki Łódzkiej przetestowano różne metody wyznaczania modułu Younga w płaszczyźnie papieru, w oparciu o próby jednokierunkowego ściskania. Ponadto, dokonano porównania wartości modułu Younga wyznaczonych w oparciu o próby rozciągania i ściskania. Na podstawie uzyskanych wyników stwierdzono, że różnice pomiędzy wartościami modułu uzyskiwanymi w różnych próbach są związane ze zróżnicowaniem metodyki badań, a w szczególności wymiarów i sposobu mocowania próbek. Przy zachowaniu identycznych warunków badań w próbach ściskania i rozciągania uzyskano takie same wartości modułu Younga.

EN

Within the research work carried out at the Institute of Papermaking and Printing of the Technical University of Łodz various methods of Young's mudulus determination in the paper plane were tested on the basis of unidirectional compression tests. In addition, the author compared the values of Young's modulus determined with tensile and compression tests. The results showed that the differences between the modulus obtained in different tests were connected with the diversification of testing methods, mainly the size and fixing type of test sample. The identical values of Young's modulus values were achieved in the same testing conditions of tensile and compression tests.

11

Fracture analysis of selected magnesium alloys after different testing methods

Čižek L., Greger M., Dobrzański L. A., Kocich R., Tański T., Praźmowski M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 2

131-134

EN

Purpose: of this paper is to extend a complex evaluation of magnesium alloys which requires very often knowledge mechanical properties. These properties are connected with microstructure that is influenced by metallurgical and technological factors and conditions of exploitation. Very important information for design and exploitation of these alloys is knowledge of fracture characteristics. Design/methodology/approach: Testing methods used magnesium alloys were based on tensile test and torsion test. The methods of the light microscopy and SEM for metallographic and fracture analyses of alloys after testing were used. Findings: Objective of this work consisted in determination of changes of mechanical properties and fracture characteristics of magnesium alloy in dependence on testing methods. Mg-Al alloy with graduate aluminium content as cast state and after heat treatment was used. It was confirmed that during heating at chosen temperatures there occurs partial dissolution of minority phases. Research limitations/implications: According to the alloys characteristic, the applied cooling rate and alloy additions seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and aging process. Practical implications: The results may be utilized for a relation between plastic and strength properties of the investigated material in process of research and manufacturing. Originality/value: These results contribute to complex evaluation of properties magnesium alloys namely for explanation of fracture mechanism in changing condition of testing and exploitation. The results of this paper are determined for research workers deal by development new exploitations of magnesium alloys.