BazTech - Yadda

1

Influence of Alloying Elements on the Microstructure and Selected High-Temperature Properties of New Cobalt-Based L12-Reinforced Superalloys

Kierat Milena, Moskal Grzegorz, Zieliński Adam, Jung Tymoteusz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

495--500

EN

The study investigated the primary structure of the new generation of superalloys based on Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb cobalt. Research on a group of cobalt-based materials was initiated in 2006 by J. Sato [1]. These materials may replace nickel-based superalloys in the future due to their excellent properties at elevated temperatures relative to nickel-based superalloys. The primary microstructure characterisation of the Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb alloy are the basic subject of this article. The Co-10Al-5Mo-2Nb and Co-20Ni-10Al-5Mo-2Nb alloy are tungsten free alloys of a new type with the final microstructure based on the Co-based solid solution L12 phase of the Co3(Al,Mo,Nb) type as a strengthened structural element. The analysed alloys were investigated in an as-cast state after a vacuum casting process applied on graphite moulds. The primary microstructure of the alloys and the chemical constituent of dendritic and interdendritic areas were analysed using light, scanning electron and transmission microscopy. Currently, nickel-strengthened γ’ phase steels are still unrivalled in aerospace applications, however, cobalt based superalloys are a response to their existing limitations, which do not allow maintaining the current rate of development of aircraft engines.

2

Influence of 2% titanium addition on microsctructure and selected high-temperature properties of a novel Co-based superalloy strenghtened with L12 phase

Kierat Milena, Liśkiewicz Maciej

Journal of Metallic Materials

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2021

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Vol. 73, no. 4

11--14

EN

This paper contains selected results of primary microsctructure analysis of a novel superalloy, Co-20Ni-10Al-5Mo-2Nb-2Ti. Research on this class of superalloys was started by J. Sato in 2006, and further expanded by S.K. Makineni in 2015. It is implied that Co-based, W-free superalloys will resolve the issues that the aircraft industry currently faces with Ni-based γ/γ’ superalloys. It is believed that the addition of the Ti alloying element will help with γ’ stabilisation due to high Co3(Mo, Al, Nb) fragmentation. Ti content has to be carefully selected to avoid precipitation of harmful phases, such as Co(Ti, Al).

PL

Artykuł zawiera wyniki badań mikrostrukturalnych nowego nadstopu Co-20Ni-10Al-5Mo-2Nb-2Ti. Badania nad tą klasą superstopów zostały zapoczątkowane w 2006 r. przez J. Sato, a następnie rozwinięte w 2015 r. przez S.K. Makineni. Powszechna jest wiara, że nadstopy oparte na Co i wolne od W rozwiążą problemy z jakimi boryka się obecnie branża lotnicza, w której powszechne jest stosowanie nadstopów Ni γ/γ’. Uważa się, że dodatek Ti do nadstopu spowoduje stabilizację fazy γ’ poprzez silną fragmentację fazy Co3(Mo, Al., Nb). Ilość Ti w badanym stopie została dobrana ze szczególną starannością w celu uniknięcia wydzielania szkodliwych faz takich jak Co(Ti, Al).

3

Influence of alloying elements on the microstructure of new cobalt matrix superalloys reinforced with phase - L12

Jung Tymoteusz, Kierat Milena

Journal of Metallic Materials

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2020

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Vol. 72, no. 4

27--30

EN

The article presents selected results of research on the primary structure of a new generation of cobalt-based Co-20Ni-10Al-5Mo-2Nb superalloys. Research on this group of materials was started in 2006 by J. Sato. These materials are anticipated to be able to replace nickel-based superalloys in the future due to their superior elevated temperature properties compared to the nickel-based superalloys. Today, γ’ nickel-based superalloys are still unrivalled in aerospace applications, however, cobalt-based superalloys are a response to their existing limitations, which do not allow the current pace of aircraft engine development to be maintained.

PL

W pracy przedstawiono wybrane wyniki badań nad pierwotną strukturą nowej generacji nadstopów na osnowie kobaltu typu Co-20Ni-10Al-5Mo-2Nb. Badania nad tą grupą materiałów rozpoczął w 2006 roku J. Sato. Przewiduje się, że materiały te w przyszłości mogą zastąpić nadstopy na osnowie niklu ze względu na ich doskonałe właściwości w podwyższonej temperaturze w porównaniu z nadstopami na osnowie niklu. Obecnie nadstopy na osnowie niklu wzmacniane fazą γ’ są nadal bezkonkurencyjne w zastosowaniach lotniczych, jednak nadstopy na bazie kobaltu są odpowiedzią na ich istniejące ograniczenia, które nie pozwalają na utrzymanie obecnego tempa rozwoju silników lotniczych.

4

Primary Microstructure Characterization of As-Casted Co-20Ni-7Al-7W Superalloy

Tomaszewska A., Moskal G., Mikuszewski T., Junak G., Płachta A.

Archives of Foundry Engineering

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2019

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iss. 3

78--83

EN

The primary microstructure of new Co-based superalloy of Co-20Ni-7Al-7W (at.%) type was showed in this article. The alloy was manufactured by induction melting in vacuum furnaces. This alloy is a part of new group of high-temperature materials based on Co solid solution and strengthened by coherent L12 phase similar to Ni-based superalloys with γʹ phase. The final form of Coss/L12 microstructure is obtained after fully heat treatment included homogenization, solutionizing and aging processes. But first step of heat treatment thermal parameters determination is characterization of primary microstructure of alloys after casting process with special attentions on segregations of alloying elements in solid solution and presences of structural elements such as eutectic areas, and other phases precipitations. In analysed case the relatively high homogeneity of chemical composition was expected especially in the case of W distribution, what was confirmed be SEM/EDS analysis in dendritic and interdendritic areas.

5

Characterization of primary microstructure of γ–γʹ Co–Al–W cobalt-based superalloy

Mikuszewski T., Tomaszewska A., Moskal G., Migas D., Niemiec D.

Inżynieria Materiałowa

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2017

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Vol. 38, nr 5

217--223

EN

Present paper concerns primary structure of cobalt-based superalloys Co–9Al–9W with γ/γʹ structure, casted via induction melting process. Common problems described in literature, concerning difficulties in obtaining uniform distribution of tungsten, particularly in interdendritic areas were reason of utilization of modified casting process. Alter method is based on tungsten dosing into liquid metal bath of cobalt and aluminium during melting. This method allows to obtain microstructure characterized by considerably decreased microsegregation, especially in case of tungsten. This type of primary structure results in simplified and more economical homogenization performance of casts before further technological processes. Used method of casting give the possibility to obtain samples with small effect of segregations of alloying elements. Observed effect of interdendritic segregations were related to higher level of aluminium concentration and lower cobalt, but in both cases the measured difference was 2 to 4 % at.

PL

Celem artykułu jest charakterystyka mikrostruktury pierwotnej stopu Co–9Al–9W w stanie bezpośrednio po odlaniu, z uwzględnieniem rozmieszczenia składników stopowych w rdzeniach dendrytów i obszarach międzydendrytycznych w różnych strefach odlewu oraz profilu mikrotwardości. Ważną kwestią była jednorodność rozmieszczenia wolframu w obszarach rdzeni dendrytów i w przestrzeniach międzydendrytycznych, co jest typowym problemem w stopach z dodatkiem wolframu.

6

Application of quantitative metallography methods in the study of primary microstructure of low alloyed welds.

Adamiec J., Cwajna J.

Inżynieria Materiałowa

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2001

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R. XXII, nr 4

177-180

EN

The application of quantitative metallography methods in the study of primary microstructure of welds obtained by Transferred Ionized Molten Energy method (T.I.M.E.), which belongs to highly efficient active gas welding process (MAG-M) was shown. The effect of arc linear energy on size, shape and distribution of primary austenite crystal in welds was determined.

PL

W pracy przedstawiono ilościowy opis struktury pierwotnej spoiny wykonanej wysokoenergetyczną odmianą spawania w osłonie mieszanek gazowych T.I.M.E. (Transferred Ionized Molten Energy). Określono wpływ energii liniowej łuku na wielkość, kształt oraz rozkład pierwotnych kryształów austenitu w strukturze spoiny.