The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating

Thermally sprayed MCrAlY bond coats are important elements of thermal barrier coating (TBC) systems which are applied to the surface of gas turbine components to protect them in high temperature environments. Knowledge of their mechanical properties is essential in preventing TBC failure which can h...

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Main Authors: Jackson, G.A., Sun, Wei, McCartney, D.G.
Format: Article
Published: Trans Tech Publications 2017
Subjects:
Online Access:https://eprints.nottingham.ac.uk/41777/
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author Jackson, G.A.
Sun, Wei
McCartney, D.G.
author_facet Jackson, G.A.
Sun, Wei
McCartney, D.G.
author_sort Jackson, G.A.
building Nottingham Research Data Repository
collection Online Access
description Thermally sprayed MCrAlY bond coats are important elements of thermal barrier coating (TBC) systems which are applied to the surface of gas turbine components to protect them in high temperature environments. Knowledge of their mechanical properties is essential in preventing TBC failure which can have catastrophic consequences. However, limited data on modulus, strength and ductility are available for such coatings. In this work, the ductile to brittle transition behaviour of a CoNiCrAlY coating has been investigated via the small punch tensile test (SPTT). Displacement controlled tests were carried out on free standing coatings at room temperature (RT) and between 400-750 °C at a rate of 1 μms-1. At low temperatures there was evidence of elastic-brittle behaviour and at high temperatures there was clear evidence of yielding and plastic deformation. The ductile to brittle transition temperature was found to be between 500-750 °C. The yield stress ranged from 1000-1500 MPa below 600 °C to less than 500 MPa above 650 °C. The elastic modulus was found to be approximately 200-230 GPa at 500 °C and 55 GPa above 700 °C. At room temperature the fracture surface showed flat, smooth features indicating brittle failure whereas at 700 °C there was evidence of ductile tearing.
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spelling nottingham-417772020-05-04T18:42:21Z https://eprints.nottingham.ac.uk/41777/ The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating Jackson, G.A. Sun, Wei McCartney, D.G. Thermally sprayed MCrAlY bond coats are important elements of thermal barrier coating (TBC) systems which are applied to the surface of gas turbine components to protect them in high temperature environments. Knowledge of their mechanical properties is essential in preventing TBC failure which can have catastrophic consequences. However, limited data on modulus, strength and ductility are available for such coatings. In this work, the ductile to brittle transition behaviour of a CoNiCrAlY coating has been investigated via the small punch tensile test (SPTT). Displacement controlled tests were carried out on free standing coatings at room temperature (RT) and between 400-750 °C at a rate of 1 μms-1. At low temperatures there was evidence of elastic-brittle behaviour and at high temperatures there was clear evidence of yielding and plastic deformation. The ductile to brittle transition temperature was found to be between 500-750 °C. The yield stress ranged from 1000-1500 MPa below 600 °C to less than 500 MPa above 650 °C. The elastic modulus was found to be approximately 200-230 GPa at 500 °C and 55 GPa above 700 °C. At room temperature the fracture surface showed flat, smooth features indicating brittle failure whereas at 700 °C there was evidence of ductile tearing. Trans Tech Publications 2017-04-20 Article PeerReviewed Jackson, G.A., Sun, Wei and McCartney, D.G. (2017) The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating. Key Engineering Materials, 734 . pp. 144-155. ISSN 1662-9795 Small punch tensile testing CoNiCrAIY MCrAIY HVOF DBTT Mechanical properties
spellingShingle Small punch tensile testing
CoNiCrAIY
MCrAIY
HVOF
DBTT
Mechanical properties
Jackson, G.A.
Sun, Wei
McCartney, D.G.
The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title_full The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title_fullStr The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title_full_unstemmed The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title_short The application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed CoNiCrAlY coating
title_sort application of the small punch tensile test to evaluate the ductile to brittle transition of a thermally sprayed conicraly coating
topic Small punch tensile testing
CoNiCrAIY
MCrAIY
HVOF
DBTT
Mechanical properties
url https://eprints.nottingham.ac.uk/41777/