scholarly journals Creep behaviour and life assessment of a cast nickel – base superalloy MAR – M247

2019 ◽  
Vol 38 (2019) ◽  
pp. 590-600
Author(s):  
Marie Kvapilova ◽  
Jiri Dvorak ◽  
Petr Kral ◽  
Karel Hrbacek ◽  
Vaclav Sklenicka
Keyword(s):  
Creep Behaviour ◽  
Life Assessment ◽  
Dislocation Creep ◽  
Nickel Base Superalloy ◽  
Creep Characteristics ◽  
Different Temperatures ◽  
High Temperature Components ◽  
Lower Temperature ◽  
Nickel Base ◽  
Different Grain Size

AbstractThe cast nickel-base MAR-M247 superalloy has been widely used for high-temperature components. In this work, the creep behaviour of two alternates of MAR-M247 superalloy with different grain size processed at different temperatures of casting are compared. Under the creep testing conditions used in this study, only negligible differences of creep behaviour of the alternate alloys were found and the evaluated creep characteristics correspond to the power-law or dislocation creep. The microstructure of the alloys consists of a𝛾matrix with a eutectic,𝛾'strengthening cubic precipitates, and M6C and M23C6carbides. Increasing the temperature induces the dissolution of some M23C6carbides. Fractures of both variants of alloys exhibit a more ductile character at higher temperatures, while at lower temperature a mixture of brittle and ductile fracture modes was observed, which changes the creep fracture ductility.

Effect of Intermittent Heating on Creep Behaviour of Advanced 9-12%Cr Power Plant Steels

2007 ◽  
Vol 561-565 ◽  
pp. 81-84 ◽  
Author(s):  
Vàclav Sklenička ◽  
Květa Kuchařová ◽  
Milan Svoboda ◽  
Ivan Saxl
Keyword(s):  
Creep Strength ◽  
Creep Behaviour ◽  
Laboratory Simulation ◽  
Dislocation Creep ◽  
Martensitic Steels ◽  
Significant Deterioration ◽  
Start Up ◽  
Creep Characteristics ◽  
Intermittent Heating ◽  
High Temperature Components

Critical high temperature components of machines and structures are often subjected to complicated load and temperature histories. The closest laboratory simulation of service loading conditions involves creep under nonsteady temperatures and stresses. For example, the start up and shut down cycles can be well simulated by temperature variation by use of intermittent heating tests. Such approach is illustrated by recent experimental results on advanced high creep strength 9- 12%Cr ferritic-martensitic steels (P91, P92 and E911). A comparison between the creep characteristics of nonsteady and monotonously creep specimens has revealed no significant deterioration of the creep strength and fracture resistance of these steels in power-law (dislocation) creep.

Creep Processes in MAR-M247 Nickel-Base Superalloy

2016 ◽  
Vol 258 ◽  
pp. 603-606
Author(s):  
Marie Kvapilová ◽  
Květa Kuchařová ◽  
Karel Hrbáček ◽  
Vàclav Sklenička
Keyword(s):  
Creep Deformation ◽  
Elevated Temperatures ◽  
Dislocation Creep ◽  
Nickel Base Superalloy ◽  
Deformation And Fracture ◽  
Creep Life Prediction ◽  
Controlling Mechanism ◽  
Nickel Base ◽  
Creep Regime ◽  
Base Superalloy

Creep processes in MAR-M247 Nickel - Base Superalloy were studied at elevated temperatures. The stress exponents of creep rate n and time to fracture m indicate power-low (dislocation) creep regime and suggest the same controlling mechanism for the creep deformation and fracture. The variation of values of parameter n within the interval of applied stress may indicate changes in the rate-controlling creep deformation mechanism. The possibility of using of Monkman-Grant relationship for creep life prediction was demonstrated.

GTD111 Alloy Material Study

1998 ◽  
Vol 120 (2) ◽  
pp. 375-382 ◽  
Author(s):  
J. A. Daleo ◽  
J. R. Wilson
Keyword(s):  
Nickel Base Superalloy ◽  
Polycrystalline Nickel ◽  
Heat Treated ◽  
Property Data ◽  
Alloy Material ◽  
Different Temperatures ◽  
Specific Material ◽  
Blade Alloy ◽  
Nickel Base ◽  
Term Creep

Very few property data on this common turbine blade alloy have been published. As longer hours of service are accumulated, maintenance considerations such as developing optimum component life strategies and repair processes become important. The lack of specific material data hampers the effort of users and repair facilities to achieve optimum service from this alloy. This study measured some of the basic mechanical and metallurgical characteristics of this polycrystalline nickel base superalloy. Tensile and short-term creep rupture properties as well as microstructural and fracture characteristics are presented. Both the as-heat-treated and thermally exposed characteristics at two different temperatures are examined.

Modelling and analysis of the oxidation influence on creep behaviour of thin-walled structures of the single-crystal nickel-base superalloy René N5 at 980 °C

2010 ◽  
Vol 58 (5) ◽  
pp. 1607-1617 ◽  
Author(s):  
Matthias Bensch ◽  
Johannes Preußner ◽  
Rainer Hüttner ◽  
Georgia Obigodi ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Creep Behaviour ◽  
Nickel Base Superalloy ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Nickel Base ◽  
Base Superalloy

The Cyclic Creep Behaviour of Nickel Base Superalloy IN738LC

1995 ◽  
Vol 86 (5) ◽  
pp. 365-370
Author(s):  
Yanging Wang ◽  
Debashis Mukherji ◽  
Weiye Chen ◽  
Thomas Kuttner ◽  
Rajeshwar Prasad Wahi ◽  
...  
Keyword(s):  
Creep Behaviour ◽  
Cyclic Creep ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Superalloy In738lc ◽  
Base Superalloy ◽  
Cyclic Creep Behaviour

Creep Response and Microstructural Changes during Intermittent Heating of Advanced Tempered Martensitic 9-12%Cr Steels

2008 ◽  
Vol 604-605 ◽  
pp. 367-377
Author(s):  
Vaclav Sklenička ◽  
Květa Kuchařová ◽  
Milan Svoboda ◽  
Ivan Saxl
Keyword(s):  
Creep Behaviour ◽  
Thermodynamic Calculations ◽  
Dislocation Creep ◽  
Significant Deterioration ◽  
Creep Characteristics ◽  
Intermittent Heating ◽  
Cr Steels ◽  
Good Agreement ◽  
Made In

Significant developments have been made in recent years in the description of microstructure evolution and its effects on the creep behaviour in advanced 9-12%Cr steels. However, data available for assessing the predictability of the creep behaviour are somewhat scarce since creep testing has generally been for constant temperature and load conditions. The present investigation was conducted on three advanced 9-12%Cr martensitic/ferritic steels (P91, P92 and E911) in an effort to obtain more complete description and understanding of the role of degradation processes in high temperature creep during intermittent heating. A comparison between the creep characteristics of non-steady and monotonously loaded creep specimens has revealed no significant deterioration of the creep strength and fracture resistance of the steels P91, P92 and E911 under non-steady loading in power-law (dislocation) creep. The final part of this paper deals with detailed experimental microstructural and fractographic investigations of crept specimens to explain the observed creep behaviour. Special attention is paid to the thermodynamic calculations using the software package Thermo-Calc, that have been used to predict precipitation reactions during intermittent heating of 9-12% chromium steels. The results of the thermodynamic calculations are in a good agreement with experimental data.

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