Solution heat-treatment of Nb-modified MAR-M247 superalloy

Silva, Paulo Ricardo Soares Azevedo e; Baldan, Renato; Nunes, Carlos Ângelo; Coelho, Gilberto Carvalho; Costa, Ana Maria Duarte Dias

doi:10.1016/j.matchar.2012.11.006

Cited by 28 publications

(6 citation statements)

References 11 publications

(11 reference statements)

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“…The initial as-cast microstructures of the investigated alloys were similar, presenting dendritic segregations with c¢ particles and MC-type carbides dispersed in the c matrix, in agreement with other studies found in the literature for alloys with similar composition. [10][11][12][13][14][15][16][17][18] At 1000°C, parabolic oxidation behavior was observed only in the first 100 hours of oxidation for both alloys, before oxide scale spallation began to be the predominant degradation mechanism. On the other hand, the oxidation curves at 800°C and 900°C presented parabolic behavior for the entire tests' duration.…”

Section: Discussionmentioning

confidence: 99%

High Temperature Oxidation Behavior of Conventional and Nb-Modified MAR-M246 Ni-Based Superalloy

Alkmin

Chaia

Utada

et al. 2021

Metall Mater Trans A

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The present investigations focused on the thermal oxidation of two variants of MAR-M246 alloy having the same contents of Ta and Nb in at. pct, considering the effects of total replacement of Ta by Nb. The alloys were produced by investment casting using high purity elements in induction furnace under vacuum atmosphere. The alloys were oxidized pseudo-isothermally at 800°C, 900°C and 1000°C up to 1000 hours under lab air. Protective oxidation products growing on the surface of the oxidized samples were mainly Al 2 O 3 , Cr 2 O 3 . Other less protective oxide such as spinels (NiCr 2 O 4 and CoCr 2 O 4 ) and TiO 2 were also detected as oxidation products. The conventional alloy exhibited slight internal oxidation at 800°C and an enhanced resistance at 900°C and 1000°C. The Nb-modified alloy presented an exacerbated internal oxidation and nitridation at 900°C and 1000°C and an enhanced resistance at 800°C. At 1000°C, Nb-modified alloy was particularly affected by excessive spalling as the main damage mechanisms. From a kinetic point of view, both alloys exhibit the same behavior at 800°C and 900°C, with k p values typical of alumina forming alloys (2 9 10 À14 to 3.6 9 10 À13 g 2 cm À4 s À1 ). However, Ta modified alloys exhibited superior oxidation resistance at 1000°C when compared to the Nb modified alloy due to better adherence of the protective oxide scale.

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Section: Discussionmentioning

confidence: 99%

High Temperature Oxidation Behavior of Conventional and Nb-Modified MAR-M246 Ni-Based Superalloy

Alkmin

Chaia

Utada

et al. 2021

Metall Mater Trans A

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“…The recommended temperature for this treatment is approximately 1260˚C for 8 hours, which enables the alloy to achieve a homogeneous gamma matrix with fine gamma prime phases. However, incipient melting was observed at 1280˚C in this alloy [9]. Thermodynamic calculations have shown that the lower temperature for solutioning in Mar-M247 superalloy is around 1220˚C.…”

Section: Introductionmentioning

confidence: 74%

Carbides Formation in MarM247 Directional Solidified during Stress-Rupture Test at High Temperature

Moreno,

Mizrahi,

Lipkin

et al. 2023

JMMCE

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In our study, stress-rupture tests were conducted at elevated temperatures to examine the impact of high temperature on MarM247 LC (low carbon). Our main objective was to investigate the alterations in the microstructure, particularly the carbon precipitation, during long-term stress-rupture tests. It was observed that cracks developed near the sample neck, following the path of the carbides and the gamma matrix, rather than occurring in the gamma-gamma prime eutectic. This occurred despite the formation of carbides because of prolonged exposure to high temperature and load, and the crack propagation did not follow that path. Based on these findings, we suggest that a reduction in the carbon content of Mar-M247 LC can enhance the sample's lifespan when subjected to temperatures below 760˚C and a stress of 690 MPa.

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“…3a, 3b). In the microstructure, M 23 C 6 -, M 6 C-, and MC-type carbides can be present [2]. Evidence of an MC-type carbide (Hf, Ta)C was confirmed during energy dispersive spectroscopy (Fig.…”

Section: Fig 2 Cast Mar-m247: A) Microstructure; B) Eds Spectrummentioning

confidence: 86%

“…: AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Krakow, Poland; lrakoczy@agh.edu.pl at high temperatures, and high mechanical properties (including creep strength) made it a widely used alloy in gas turbine structures. Its combination of unique properties contributed to MAR-M247's use for rotating components in aircraft engines, including turbine blades and segments [1,2]. Strengthening of the alloy mainly corresponds with semicoherent precipitation γ' .…”

Section: Introductionmentioning

confidence: 99%

Hot Cracking of Nickel-Based Superalloy Turbine Blade

Rakoczy

Tuz

Pańcikiewicz

2015

mafe

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The aim of this study was to present the hot cracking behavior of a blade originating from a turbine blade segment. The crack was induced by a gas tungsten arc welding process, and the research material was a MAR-M247 nickel based superalloy. This alloy is considered to be difficult to weld because of its high tendency to crack. Light microscopy and scanning electron microscopy show the occurrence of cracking in the melted zone, heat-affected zone, and base alloy. A scanning electron microscopy investigation revealed that cracks are propagated by stresses and liquation of the low temperature constituent. Keywords: superalloys, nickel alloys, liquation, hot cracking, turbine blades StreszczenieCelem pracy była analiza mikrostrukturalna pęknięcia gorącego na powierzchni łopatki z segmentu van cluster. Pęknięcie powstało w wyniku oddziaływania skoncentrowanego źródła ciepła, jakim był łuk elektryczny jarzący się w osłonie argonu. Łopatka została wykonana z nadstopu na osnowie niklu o nazwie handlowej MAR-M247. W przypadku konwencjonalnych metod spawania jest on uważany za trudno spawalny. Przeprowadzono badania makrostruktury i mikrostruktury za pomocą mikroskopii świetlnej i skaningowej. Na podstawie wykonanych badań stwierdzono występowanie pęknięć ciągłych zarówno w obszarze przetopionym, strefie wpływu ciepła, jak i materiale rodzimym. Obserwacje za pomocą skaningowej mikroskopii elektronowej pozwoliły na stwierdzenie, że pęknięcie propagowało w wyniku naprężeń, jak również likwacji niskotopliwych składników mikrostruktury.

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Solution heat-treatment of Nb-modified MAR-M247 superalloy

Cited by 28 publications

References 11 publications

High Temperature Oxidation Behavior of Conventional and Nb-Modified MAR-M246 Ni-Based Superalloy

High Temperature Oxidation Behavior of Conventional and Nb-Modified MAR-M246 Ni-Based Superalloy

Carbides Formation in MarM247 Directional Solidified during Stress-Rupture Test at High Temperature

Hot Cracking of Nickel-Based Superalloy Turbine Blade

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