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Comparison of Microstructure, Ageing Effect and Shape Memory Properties of Additively Manufactured NiTi Alloy using LENS and EBAM Methods

Dutkiewicz Jan, Rogal Łukasz, Węglowski Marek, Czujko Tomasz, Durejko Tomasz, Cesari Eduard

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

1103--1108

EN

Samples prepared using various additive manufacturing methods were compared in terms of structure, texture, transformation temperature and superelastic properties. Samples manufactured using laser engineered net shaping (LENS) method showed texture several degrees deviated from the <001> build direction, however with composition near to the initial powder composition, enabling superelastic effect. The electron beam additive manufacturing (EBAM) samples showed martensitic structure at room temperature due to a shift of transformation temperatures to the higher range. This shift occurs due to a lower Ni content resulting from different processing conditions. However, EBAM method produced sharper <001> texture in the build direction and made it possible to obtain a good superelastic effect above room temperature. Intermetallic particles of size 0.5-2 mm were identified as Ti2Ni phase using EDS and electron diffraction analyses. This phase was often formed at the grain boundaries. Contrary to the LENS method, the EBAM prepared samples showed Ni-rich primary particles resulted from different processing conditions that reduce the Ni content in the solid solution thus increase the martensitic transformation temperature. Ageing at 500°C allowed for shifting the martensitic transformation temperatures to the higher range in both, LENS and EBAM, samples. It resulted from the formation of Ni rich coherent precipitates. In samples prepared by both methods and aged at 500°C, the presence of martensite B19’ twins was observed mainly on {011} B19’ planes.

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SEM/TEM Investigation of Degradation of Bi-Layer (Cr,Al)N/Cr2N3 Duplex Coatings Exposed to AlSi Alloy High Pressure Die Casting Cycles

Wilczek A., Morgiel Jerzy, Sypień Anna, Pomorska Małgorzata, Rogal Łukasz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1341--1348

EN

High pressure die casting (HDPC) allows to produce aluminum parts for car industry of complicated shapes in long series. Dies used in this process must be robust enough to withstand long term injection cycling with liquid aluminum alloys, as otherwise their defects are imprinted on the product making them unacceptable. It is expected that nitriding followed by coating deposition (duplex treatment) should protect them in best way and increase intervals between the cleaning/repairing operations. The present experiment covered investigations of the microstructure of the as nitride and deposited with CrAlN coating as well as its shape after foundry tests. The observations were performed with the scanning and transmission electron microscopy (SEM/TEM) method. They showed that the bottom part of this bi-layer is formed by roughly equi-axed Cr2N crystallites, while the upper one with the fine columnar (CrAl)N crystallites. This bi-layers were matched with a set of 7x nano-layers of CrN/(CrAl)N, while at the coating bottom a CrN buffer layer was placed. The foundry run for up to 19 500 cycles denuded most of coated area exposed to fast liquid flow (40 m/s) but left most of bottom part of the coating in the areas exposed to slower flow (7 m/s). The acquired data indicated that the main weakness of this coating was in its porosity present both at the columnar grain boundaries (upper layer) as well as at the bottom of droplets imbedded in it (both layers). They nucleate cracks propagating perpendicularly and the latter at an angle or even parallel to the substrate. The most crack resistant part of the coating turned-out the bottom layer built of roughly equiaxed fine Cr2N crystallites. Even application of this relatively simple duplex protection in the form of CrAlN coating deposited on the nitride substrate helped to extend the die run in the foundry by more than three times.

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Effect of Pouring Temperature and Heating of Ceramic Shells Mould on Projection of Thin Wall Castings

Żółkiewicz Zdzisław, Rogal Łukasz, Maj Wojciech, Maziarz Wojciech, Tkaczewski Piotr, Madej Władysław, Garbień Piotr, Dydak Artur, Oleksy Wacław

Journal of Applied Materials Engineering

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2020

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Vol. 60, iss. 2-3

81--89

EN

One of the research directions of this study is to determine the possibility of making precise, thin-walled castings from selected iron alloys. The scope of research work is aimed at determining the applicability of the casting process of selected iron alloys with the technology of wax pattern, for making precise castings with a wall thickness of less than 3 mm. The article presents the results of tests carried out for experimental castings with the shape of steps, characterized by different wall thicknesses: 1 mm, 5 mm, 10 mm, 25 mm. The castings were made of LH14, Gs42crMo4, L35H7MP2, LH26N9, 316L cast steel, and a new alloy marked “0”. The metal was smelted in an induction furnace with a capacity of 150 kg. The technology of ceramic shell mould used in the plant was used to make the experimental castings. Ceramic shell moulds were heated in a chamber furnace at a fixed temperature. The time of annealing the ceramic mould was constant in a ceramic form. The following parameters were variable during the tests: iron alloy, pouring temperature, and annealing temperature of the ceramic shell mould.

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Opracowanie i wdrożenie innowacyjnej technologii odlewania dedykowanej dla przemysłu zbrojeniowego i motoryzacyjnego w PIO Specodlew Sp. z o.o.

Żółkiewicz Zdzisław, Maziarz Wojciech, Maj Wojciech, Rogal Łukasz, Tkaczewski Piotr, Madej Władysław, Garbień Piotr, Oleksy Wacław

Przegląd Odlewnictwa

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2019

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Vol. 69, nr 7-8

224--228

PL

Przedsiębiorstwo Innowacyjne Odlewnictwa Specodlew Sp. z o.o. jest znanym w Polsce producentem odlewów, w tym precyzyjnych. Realizacja badań ujętych w harmonogramie projektu ma stworzyć możliwość znacznego poszerzenia zakresu możliwości wykonawczych zakładu o cienkościenne odlewy staliwne, o założonych własnościach mechanicznych dotychczas w Polsce nie produkowanych. Połączenie opracowanych w ramach projektu: innowacyjnego tworzywa modelu woskowego, składu i sposobu wykonania formy ceramicznej, składu chemicznego tworzywa odlewu z innowacyjną technologią odlewania precyzyjnego oraz obróbką cieplną wykonanych cienkościennych odlewów pozwoli na wykonanie z przebadanych stopów żelaza wyrobów o dużej dokładności wymiarowej, założonej wytrzymałości mechanicznej oraz wdrożenie tej technologii do własnej produkcji przemysłowej.

EN

PIO Specodlew Sp. z o.o. is a known manufacturer of castings in Poland, including precision ones. The implementation of the research included in the project's schedule aims to create the possibility of significantly broadening the scope of the plant's implementation capabilities, with thin-walled steel castings, procesing mechanical properties that are not yet produced in Poland. The combination of innovative wax-based material, composition and method of the ceramic mold making, chemical composition of a cast material with innovative precision casting technology and heat treatment of thin-walled castings developed within the framework of the project will allow us to manufacture products of high dimensional accuracy, mechanical strength assumed from tested iron alloys and implementing this technology for own industrial production.

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Analysis of fatigue strength of multi-layer coatings type Cr/CrN/(CrN-Me1Me2N)multinano/(Me1Me2N-VN)multinano

Smolik Jerzy, Mazurkiewicz Adam, Bujak Jan, Paćko Daniel, Rogal Łukasz

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

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2019

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no. 3

31--38

EN

The article presents the results of tests of resistance to mechanical fatigue of multilayer coatings type Cr/CrN/(CrN-Me1Me2N)multinano/(Me1Me2N-VN)multinano, where metals Me1 and Me2 were chosen from Al, Cr, Ti, Zr, and Si. Multilayer coatings designed for the research were generated by the Arc Evaporation method. On the basis of the results of hardness and adhesion tests, calculations of the fatigue strength of the multilayer coatings were carried out. The obtained results showed that the chemical composition of individual component layers in the multilayer coating can be decisive in the process of creating a microstructure resistant to the fatigue cracking process.

PL

W artykule przedstawiono wyniki badań odporności na zmęczenie mechaniczne powłok wielowarstwowych typu Cr/CrN/(CrN-Me1Me2N)multinano/(Me1Me2N-VN)multinano, gdzie metale Me1 ,Me2 dobierano spośród Al, Cr, Ti, Zr, Si. Powłoki wielowarstwowe przeznaczone do badań wytworzono metodą Arc Evaporation. Na podstawie wyników badań twardości i adhezji przeprowadzono obliczenia wytrzymałości zmęczeniowej badanych powłok wielowarstwowych. Badania wykazały, że skład chemiczny poszczególnych warstw składowych w powłoce wielowarstwowej może mieć decydujące znaczenie w procesie tworzenia się mikrostruktury odpornej na proces pękania zmęczeniowego.