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1

Refinement of the Manufacturing Route and Evaluation of the Reinforcement Effect of MAX Phases in Al Alloy Matrix Composite Materials

Dmitruk Anna, Naplocha Krzysztof, Żak Andrzej, Strojny-Nędza Agata

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

141--148

EN

Microwave Assisted Self-propagating High-temperature Synthesis (MASHS) was used to prepare open-porous MAX phase preforms in Ti-Al-C and Ti-Si-C systems, which were further used as reinforcements for Al-Si matrix composite materials. The pretreatment of substrates was investigated to obtain open-porous cellular structures. Squeeze casting infiltration was chosen to be implemented as a method of composites manufacturing. Process parameters were adjusted in order to avoid oxidation during infiltration and to ensure the proper filling. Obtained materials were reproducible, well saturated and dense, without significant residual porosity or undesired interactions between the constituents. Based on this and the previous work of the authors, the reinforcement effect was characterized and compared for both systems. For the Al-Si+Ti-Al-C composite, an approx. 4-fold increase in hardness and instrumental Young's modulus was observed in relation to the matrix material. Compared to the matrix, Al-Si+Ti-Si-C composite improved more than 5-fold in hardness and almost 6-fold in Young's modulus. Wear resistance (established for different loads: 0.1, 0.2 and 0.5 MPa) for Al-Si+Ti-Al-C was two times higher than for the sole matrix, while for Al-Si+Ti-Si-C the improvement was up to 32%. Both composite materials exhibited approximately two times lower thermal expansion coefficients than the matrix, resulting in enhanced dimensional stability.

2

Development of Al-Ti-C porous structures for reinforcing aluminum matrix composites

Dmitruk Anna, Naplocha Krzysztof

Composites Theory and Practice

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2022

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R. 22, nr 3

172--177

EN

Open-porous preforms from Al-Ti-C compounds were successfully ignited and synthesized by combustion synthesis in a microwave field. The reaction course and the temperature were remarkably affected by the preparation method and molarratio of the substrates, as well as the position of the green sample in the microwave field generated by a single mode microwave reactor. The manufactured structures were characterized by SEM investigations. The addition of aluminum powder to the mixture moderates the reaction and temperaturę variations, allowing the course of synthesis in explosive mode to be avoided. Among the reported developed materials the following can be distinguished: Ti-Al intermetallics, titanium carbides and MAX phases belonging to the Ti-Al-C system. The prepared and selected Al-Ti C preforms were subsequently infiltrated with an AlSi12 aluminum alloy by the squeeze casting method. The composite materials exhibit a relatively homogeneous microstructure with low residual porosity and a good reinforcement/matrix interface.

PL

Otwarte porowate preformy ze związków Al-Ti-C z powodzeniem zapalono i zsyntetyzowano poprzez syntezę spaleniową w polu mikrofalowym. Znaczący wpływ na przebieg i temperaturę reakcji miał sposób przygotowania i stosunek molowy sub-stratów oraz położenie próbki w polu mikrofalowym generowanym przez jednomodowy reaktor mikrofalowy. Wytworzone struktury scharakteryzowano za pomocą badań SEM. Dodatek proszku aluminium do mieszaniny łagodzi przebieg reakcji i zmiany temperatury, pozwalając uniknąć przebiegu syntezy w trybie wybuchowym. Spośród wytworzonych materiałów można wyróżnić następujące: fazy międzymetaliczne Ti-Al, węgliki tytanu i fazy typu MAX należące do układu Ti-Al-C. Przygotowane i wyselekcjonowane preformy Al-Ti-C następnie infiltrowano stopem aluminium AlSi12 metodą prasowania ze stanu ciekłego. Materiały kompozytowe wykazują stosunkowo jednorodną mikrostrukturę o niskiej porowatości resztkowej i dobrej granicy faz umocnienie/osnowa.

3

A Comparative Study of the Feasibility of Cellular MAX Phase Preforms Formation by Microwave-Assisted SHS and SPS Techniques

Dmitruk A., Lagos M., Naplocha K., Egizabal P.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

575--582

EN

Two methods were evaluated in terms of manufacturing of MAX phase preforms characterized with open porosity: microwave-assisted self-propagating high-temperature synthesis (SHS) and spark plasma sintering (SPS). The main purpose of fabrication of such open-porous preforms is that they can be successfully applied as a reinforcement in metal matrix composite (MMC) materials. In order to simulate the most similar conditions to microwave-assisted SHS, the sintering time of SPS was significantly reduced and the pressure was maintained at a minimum value. The chosen approach allows these two methods to be compared in terms of structure homogeneity, complete reactive charge conversion and energy effectivity. Study was performed in Ti-Al-C system, in which the samples were compacted from elemental powders of Ti, Al, C in molar ratio of 2:1:1. Manufactured materials after syntheses were subjected to SEM, XRD and STEM analyses in order to investigate their microstructures and chemical compositions. As was concluded, only microwave-assisted SHS synthesis allows the creation of MAX phases in the studied system. SPS technique led only to the formation of intermetallic secondary phases. The fabrication of MAX phases’ foams by microwave-assisted SHS presents some interesting advantages compared to conventional manufacturing methods. This work presents the characterization of foams obtained by microwave-assisted SHS comparing the results with materials produced by SPS. The analysis of SPS products for different sintering temperatures provided the better insight into the synthesis of MAX phases, supporting the established mechanism. Dissimilarities in the heating mechanisms that lead to the differing synthesis products were also discussed.

4

Thermal properties of Al alloy matrix composites reinforced with MAX type phases

Dmitruk A., Naplocha K., Strojny-Nędza A.

Composites Theory and Practice

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2018

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R. 18, nr 1

32--36

EN

A method was developed for manufacturing Al-Si alloy matrix composites reinforced with MAX phases by squeeze casting pressure infiltration of porous preforms. MAX phases in the Ti-Al-C system were synthesized using self-propagating hightemperature synthesis (SHS) in the microwave assisted mode in order to obtain spatial structures with open porosity consisting of a mixture of Ti2AlC and Ti3AlC2. The manufactured composite together with a reference sample of sole matrix material were subjected to the testing of thermal properties such as: thermal conductivity, thermal diffusivity and thermal expansion in the temperature range of 50÷500°C, which corresponds to the expected working temperatures of the material. The specific heat and mass change during heating were also established by means of thermogravimetric analysis. The obtained thermal conductivity coefficients for the Al-Si+Ti-Al-C composite were higher than for the sole MAX phases and equaled 27÷29 W/m·K. The thermal expansion values for the composite material were reduced two-fold in comparison with the matrix.

PL

Opracowano metodę wytwarzania kompozytów na osnowie stopu Al-Si wzmocnionego fazami typu MAX metodą infiltracji ciśnieniowej porowatych preform. Fazy typu MAX syntezowano metodą samorozprzestrzeniającej się syntezy wysokotemperaturowej (SHS), wspomaganej mikrofalami w układzie Ti-Al-C, w celu uzyskania przestrzennych struktur o porowatości otwartej z mieszaniny faz Ti2AlC i Ti3AlC2. Wytworzone materiały kompozytowe wraz z próbką referencyjną w postaci materiału osnowy poddano badaniom właściwości cieplnych, tj. przewodności cieplnej, dyfuzyjności cieplnej oraz rozszerzalności cieplnej w zakresie temperatur 50÷500°C, który przyjęto jako spodziewany zakres temperatur pracy wytworzonych materiałów. Wyznaczono również wartości ciepła właściwego oraz, za pomocą analizy termograwimetrycznej, zmiany masy w stosunku do zmiany temperatury. Uzyskane współczynniki przewodności cieplnej dla materiału kompozytowego Al-Si+Ti-Al-C były wyższe niż dla samych faz typu MAX i wynosiły 27÷29 W/m·K. Zmierzone wartości współczynnika rozszerzalności cieplnej dla materiału kompozytowego były dwukrotnie niższe w odniesieniu do materiału osnowy.

5

Microwave assisted self-propagating high-temperature synthesis of Ti3SiC2 MAX phase

Dmitruk A., Naplocha K., Lagos M., Egizabal P., Grzęda J.

Composites Theory and Practice

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2018

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R. 18, nr 4

241--244

EN

A method was developed to manufacture Ti3SiC2 MAX phase preforms characterized by open porosity. Samples compacted from elemental powders of Ti, SiC and C with the molar ratio of 3:1.2:1 were heated and synthesized in a microwave field under atmospheric pressure. As this particular composition of elements exhibits rather low reactivity, it was necessary to apply the “coupled” mode of the SHS method. The initiated synthesis first proceeded with the formation of Si-Ti intermetallic and TiC precipitates, whose highly exothermic reactions resulted in a significant increase in temperature to ca. 1800°C. Next, these phases were almost completely transformed into a plate-like Ti3SiC2 MAX phase forming the porous structure of the samples. Although the majority of the synthesized material consisted of Ti3SiC2, some inclusions such as TiSi2, TiC and SiC were also found and identified in the material by the means of scanning electron microscopy and XRD analysis. The manufactured preforms can be used for components working in extreme conditions (heat exchangers, catalyst substrates, filters) or as a reinforcement for composite materials.

PL

Opracowano metodę wytwarzania preform fazy Ti3SiC2 typu MAX o porowatości otwartej. Sprasowane z proszków elementarnych Ti, SiC i C w stosunku molowym 3:1.2:1 próbki ogrzewano i syntetyzowano w polu mikrofalowym pod ciśnieniem atmosferycznym. Ponieważ ta szczególna kompozycja pierwiastków wykazuje relatywnie niską reaktywność, konieczne było zastosowanie "sprzężonego" trybu metody SHS. Po inicjacji syntezy jako pierwsze wytworzone zostają fazy: Si-Ti i TiC, pomiędzy którymi zachodzą wysoce egzotermiczne reakcje powodujące gwałtowny wzrost temperatury do ok. 1800°C. Następnie fazy te są niemal całkowicie przekształcane w płytkowe wydzielenia fazy Ti3SiC2 typu MAX, formując jednocześnie porowatą strukturę kształtek. Pomimo faktu, iż w przeważającej część otrzymany materiał stanowiło Ti3SiC2, znaleziono w nim również niewielkie ilości wtrąceń, które za pomocą skaningowej mikroskopii elektronowej (SEM) oraz analizy składu chemicznego metodą dyfrakcji rentgenowskiej (XRD) zidentyfikowano jako TiSi2, TiC i SiC. Wytworzone preformy mogą znaleźć zastosowanie w budowie elementów pracujących w ekstremalnych warunkach (wymienniki ciepła, katalizatory, filtry) lub jako wzmocnienia materiałów kompozytowych.

6

Manufacturing of Al Alloy Matrix Composite Materials Reinforced with MAX Phases

Dmitruk A., Naplocha K.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

198--202

EN

A method for manufacturing of Al-Si alloy (EN AC-44200) matrix composite materials reinforced with MAX type phases in Ti-Al-C systems was developed. The MAX phases were synthesized using the Self-propagating High-Temperature Synthesis (SHS) method in its microwave assisted mode to allow Ti2AlC and Ti3AlC2 to be created in the form of spatial structures with open porosity. Obtained structures were subjected to the squeeze casting infiltration in order to create a composite material. Microstructures of the produced materials were observed by the means of optical and SEM microscopies. The applied infiltration process allows forming of homogeneous materials with a negligible residual porosity. The obtained composite materials possess no visible defects or discontinuities in the structure, which could fundamentally deteriorate their performance and mechanical properties. The produced composites, together with the reference sample of a sole matrix material, were subjected to mechanical properties tests: nanohardness or hardness (HV) and instrumental modulus of longitudinal elasticity (EIT).

7

Microwave assisted self-propagating high-temperature synthesis of Ti2AlC MAX phase

Koniuszewska A., Naplocha K.

Composites Theory and Practice

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2016

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R. 16, nr 2

109--112

EN

A novel manufacturing method of Ti2AlC MAX phases with TiC carbides was elaborated. Compacted from elemental powders, the samples were heated and synthesized in a microwave field under atmospheric pressure. Microwave radiation selectively heats the reactant particles, though additional SiC support was required. Graphite can be classified as a good absorber whereas in Al, Ti metallic particle electric eddy currents are induced only on the surface. Microwaves heat material from the inside to the outside and usually concentrate on the interface between materials with a different dielectric loss factor. Therefore, it is possible to induce and conduct the reaction, on the microscale, at metal-ceramic or even metal-metal contact points. Energy was transferred from the magnetron through the waveguide and after a few seconds synthesis began and spread to the entire volume of the cylindrical sample. The initiated SHS synthesis first proceeded with the formation of Al-Ti intermetallic and TiC precipitates whose highly exothermic reactions resulted in a significant increase in temperature to ca. 1600°C. Next, these phases are almost completely transformed into plate-like Ti-Al-C MAX phases forming a porous structure of the samples. Such materials can be ideal for components working in extreme conditions (heat exchangers, catalyst substrates, filters) or for composite reinforcing.

PL

Opracowano metodę wytwarzania MAX faz typu Ti2AlC zawierającej wtrącenia węglików TiC. W celu zainicjowania syntezy wypraskę z proszków nagrzewano w polu mikrofalowym pod ciśnieniem atmosferycznym. Promieniowanie mikrofalowe selektywnie nagrzewa proszki substratów, jednakże zastosowano dodatkowo podkładkę wykonaną z SiC, która pełniła rolę absorbera. Grafit jest uważany za materiał dobrze pochłaniający energię mikrofalową, natomiast na powierzchni drobnych cząstek metalicznych Al, Ti są indukowane prądy elektryczne, co przy określonej oporności skutkuje wzrostem temperatury. Mikrofale nagrzewają materiał od wewnątrz i często koncentrują się na styku pomiędzy materiałami o różnym współczynniku strat dielektrycznych. W związku z tym możliwe jest indukowanie i kontrolowanie reakcji na styku cząstek metal-ceramika czy nawet metal-metal. Energia mikrofalowa była przenoszona z magnetronu, za pomocą falowodu, do komory procesowej, aby po kilku sekundach uruchomić syntezę SHS, która rozprzestrzeniała się w całej objętości cylindrycznej próbki. Po zainicjowaniu reakcji powstawały związki międzymetaliczne typu Ti-Al oraz węgliki TiC, co wydzielało znaczne ilości ciepła, powodując wzrost temperatury do ok. 1600°C. Następnie, związki te prawie całkowicie przekształcają się w płytkowe Ti-Al-C MAX fazy, które w makroskali tworzą porowatą strukturę próbki. Materiały takie mogą być wykorzystane na elementy pracujące w ekstremalnych warunkach (wymienniki ciepła, katalizatory, filtry) lub jako umocnienie materiałów kompozytowych.

8

Sintering of diamond composites with SHS-prepared bonding phases

Putyra P., Jaworska L., Stobierski L., Morgiel J, Bućko M., Rozmus M., Wyżga P.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

268--273

EN

Purpose: The aim of this study was to investigate materials with reduced cobalt content as well as diamond compacts with non-cobalt bounding phase. Design/methodology/approach: Phases Ti3SiC2 and Cr3AlC obtained using the self-propagating High-Temperature Synthesis (SHS) technique were used as a PCD (polycrystalline diamond) bonding phases. Diamond composites with 10-20 mass% of SHS bonding phase were prepared by using a Bridgmann-type High Pressure - High Temperature (HP-HT) apparatus. Sintering of the composites were carried out at 1950±50°C and 8±0.2 GPa. Phase compositions of MAX powders and compacts were tested using X-ray diffraction. Microstructure investigations were performed using scanning (JEOL) and transmission (Tecnai FEG 200kV) microscopes and high spation resolution EDS mapping. Findings: During the sintering processes, bonding phase decomposition processes occur in the material. Mainly carbides and silicides are formed. Diamond phase materials are characterized by multi-phase composition. Research limitations/implications: Future research in the field of reduced cobalt content composites and cobalt replaced by bonding phase with Cr2AlC should focus on reduction of the graphite which affects on lower composite hardness. Such materials require an improvement in stress deposition. Originality/value: Due to the low thermal stability of the cobalt as a bonding phase in PCD there is a need to reduce its volume in the composite. Application of the newest non-cobalt bonding phases (Ti3SiC2 and Cr3AlC) obtained by SHS sythesis.