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Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization / JAMES JOHNSON

Swansea University Author: JAMES JOHNSON

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DOI (Published version): 10.23889/SUthesis.66147

Abstract

The gas turbine engine has had continual efforts for improvement, in terms of safety, efficiency and reducing their emissions. To achieve the goal of improved efficiency, jet engines are designed to be lighter and therefore more economical and greener to run. One such component that has received att...

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Published: Swansea University, Wales, UK 2024
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Lancaster, R. J.
URI: https://cronfa.swan.ac.uk/Record/cronfa66147
first_indexed 2024-04-24T11:14:42Z
last_indexed 2024-11-25T14:17:35Z
id cronfa66147
recordtype RisThesis
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A traditional design of a separate disc and blades has been developed into the BLISK, a bladed disc that incorporates the blades and disc into one single piece. This gives the advantages of a reduced weight and higher aerodynamic efficiency by eliminating leakage flow by reducing the clearance between the blade tip and casing, however it makes it difficult to repair or replace individual blades. Additive manufacturing has been adapted to partially or completely rebuild any damaged blades, with nickel based repairs already been shown to work, but has not been concluded for titanium based components as of yet.Directed energy deposition (DED) is a powder based additive manufacturing (AM) method, which canprovide near net shape components. This method lends itself to the repair of damaged blades, however before this method is used in practice, the mechanical properties and microstructure of the build needs to be understood and qualified. Since in AM, the geometry of the build will affect the microstructure and therefore the mechanical properties, it is difficult to create a representative microstructure, however it does have value in the early TRLs (technology readiness level). Instead, testing of samples extracted from components would give a much more representative result. The main drawback for this is that the component may not be the right size or shape for a standard sample to be extracted from it. In this case the use of small scale testing needs to be implemented. For this study, Ti 6242 was fabricated using laser DED for material characterisation and assessment of the mechanical properties using small scale testing.Small scale testing such as small punch testing is a small specimen test technique, where a disc with adiameter of 3-10 mm and a thickness of 0.2-0.5 mm is tested using a hemispherical punch. Small punch tensile and creep tests were performed with the aim to correlate the results to more traditional uniaxial testing. Small punch tensile testing showed good promise when comparing to uniaxial samples for the DED Ti 6242 as well as a forged Ti 6246 alloy. Small punch creep of both of these materials showed very inconsistent results and is a topic of future research. The difficulty in small punch testing is the nature of stress state. Translating biaxial stresses seen in small punch testing to uniaxial stresses is a challenging process, for which a universal equation does not exist. Previous developments have focused on steel alloys, which when transferred to titanium alloys, do not exhibit the same correlation. Therefore, new methods for small punch tensile and creep have been developed for uniaxial correlations for the forged Ti 6246 and additive Ti 6242 respectively. Additionally, shear punch testing was also undertaken and assessed, as the stress state exhibited by the flat punch tip is less complex compared to the hemispherical punch tip used for small punch testing. For this small scale test technique, it was shown that a universal approach using a range of different materials is also sufficient when adding both titanium alloys.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea University, Wales, UK</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Additive manufacturing, small punch testing</keywords><publishedDay>3</publishedDay><publishedMonth>3</publishedMonth><publishedYear>2024</publishedYear><publishedDate>2024-03-03</publishedDate><doi>10.23889/SUthesis.66147</doi><url/><notes>Due to export control restrictions, this thesis is not available via this service.Export control ratings of 1E001 and 1C002b3.</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Lancaster, R. J.</supervisor><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><degreesponsorsfunders>EPSRC Industrial case award, Rolls-Royce</degreesponsorsfunders><apcterm/><funders>EPSRC Industrial case award, Rolls-Royce</funders><projectreference/><lastEdited>2024-06-21T13:07:04.0513703</lastEdited><Created>2024-04-24T12:00:02.7621802</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Engineering and Applied Sciences - Materials Science and Engineering</level></path><authors><author><firstname>JAMES</firstname><surname>JOHNSON</surname><order>1</order></author></authors><documents/><OutputDurs/></rfc1807>
spelling 2024-06-21T13:07:04.0513703 v2 66147 2024-04-24 Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization 27b1f80ba128d6b8e17f9f9a21254089 JAMES JOHNSON JAMES JOHNSON true false 2024-04-24 The gas turbine engine has had continual efforts for improvement, in terms of safety, efficiency and reducing their emissions. To achieve the goal of improved efficiency, jet engines are designed to be lighter and therefore more economical and greener to run. One such component that has received attention is the engine compressor. A traditional design of a separate disc and blades has been developed into the BLISK, a bladed disc that incorporates the blades and disc into one single piece. This gives the advantages of a reduced weight and higher aerodynamic efficiency by eliminating leakage flow by reducing the clearance between the blade tip and casing, however it makes it difficult to repair or replace individual blades. Additive manufacturing has been adapted to partially or completely rebuild any damaged blades, with nickel based repairs already been shown to work, but has not been concluded for titanium based components as of yet.Directed energy deposition (DED) is a powder based additive manufacturing (AM) method, which canprovide near net shape components. This method lends itself to the repair of damaged blades, however before this method is used in practice, the mechanical properties and microstructure of the build needs to be understood and qualified. Since in AM, the geometry of the build will affect the microstructure and therefore the mechanical properties, it is difficult to create a representative microstructure, however it does have value in the early TRLs (technology readiness level). Instead, testing of samples extracted from components would give a much more representative result. The main drawback for this is that the component may not be the right size or shape for a standard sample to be extracted from it. In this case the use of small scale testing needs to be implemented. For this study, Ti 6242 was fabricated using laser DED for material characterisation and assessment of the mechanical properties using small scale testing.Small scale testing such as small punch testing is a small specimen test technique, where a disc with adiameter of 3-10 mm and a thickness of 0.2-0.5 mm is tested using a hemispherical punch. Small punch tensile and creep tests were performed with the aim to correlate the results to more traditional uniaxial testing. Small punch tensile testing showed good promise when comparing to uniaxial samples for the DED Ti 6242 as well as a forged Ti 6246 alloy. Small punch creep of both of these materials showed very inconsistent results and is a topic of future research. The difficulty in small punch testing is the nature of stress state. Translating biaxial stresses seen in small punch testing to uniaxial stresses is a challenging process, for which a universal equation does not exist. Previous developments have focused on steel alloys, which when transferred to titanium alloys, do not exhibit the same correlation. Therefore, new methods for small punch tensile and creep have been developed for uniaxial correlations for the forged Ti 6246 and additive Ti 6242 respectively. Additionally, shear punch testing was also undertaken and assessed, as the stress state exhibited by the flat punch tip is less complex compared to the hemispherical punch tip used for small punch testing. For this small scale test technique, it was shown that a universal approach using a range of different materials is also sufficient when adding both titanium alloys. E-Thesis Swansea University, Wales, UK Additive manufacturing, small punch testing 3 3 2024 2024-03-03 10.23889/SUthesis.66147 Due to export control restrictions, this thesis is not available via this service.Export control ratings of 1E001 and 1C002b3. COLLEGE NANME COLLEGE CODE Swansea University Lancaster, R. J. Doctoral Ph.D EPSRC Industrial case award, Rolls-Royce EPSRC Industrial case award, Rolls-Royce 2024-06-21T13:07:04.0513703 2024-04-24T12:00:02.7621802 Faculty of Science and Engineering School of Engineering and Applied Sciences - Materials Science and Engineering JAMES JOHNSON 1
title Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
spellingShingle Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
JAMES JOHNSON
title_short Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
title_full Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
title_fullStr Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
title_full_unstemmed Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
title_sort Additive Manufacturing for the Restoration and Enhancement of Titanium Compressor Blades in Jet Engines: Small-Scale Testing and Characterization
author_id_str_mv 27b1f80ba128d6b8e17f9f9a21254089
author_id_fullname_str_mv 27b1f80ba128d6b8e17f9f9a21254089_***_JAMES JOHNSON
author JAMES JOHNSON
author2 JAMES JOHNSON
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publishDate 2024
institution Swansea University
doi_str_mv 10.23889/SUthesis.66147
college_str Faculty of Science and Engineering
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hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Materials Science and Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Materials Science and Engineering
document_store_str 0
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description The gas turbine engine has had continual efforts for improvement, in terms of safety, efficiency and reducing their emissions. To achieve the goal of improved efficiency, jet engines are designed to be lighter and therefore more economical and greener to run. One such component that has received attention is the engine compressor. A traditional design of a separate disc and blades has been developed into the BLISK, a bladed disc that incorporates the blades and disc into one single piece. This gives the advantages of a reduced weight and higher aerodynamic efficiency by eliminating leakage flow by reducing the clearance between the blade tip and casing, however it makes it difficult to repair or replace individual blades. Additive manufacturing has been adapted to partially or completely rebuild any damaged blades, with nickel based repairs already been shown to work, but has not been concluded for titanium based components as of yet.Directed energy deposition (DED) is a powder based additive manufacturing (AM) method, which canprovide near net shape components. This method lends itself to the repair of damaged blades, however before this method is used in practice, the mechanical properties and microstructure of the build needs to be understood and qualified. Since in AM, the geometry of the build will affect the microstructure and therefore the mechanical properties, it is difficult to create a representative microstructure, however it does have value in the early TRLs (technology readiness level). Instead, testing of samples extracted from components would give a much more representative result. The main drawback for this is that the component may not be the right size or shape for a standard sample to be extracted from it. In this case the use of small scale testing needs to be implemented. For this study, Ti 6242 was fabricated using laser DED for material characterisation and assessment of the mechanical properties using small scale testing.Small scale testing such as small punch testing is a small specimen test technique, where a disc with adiameter of 3-10 mm and a thickness of 0.2-0.5 mm is tested using a hemispherical punch. Small punch tensile and creep tests were performed with the aim to correlate the results to more traditional uniaxial testing. Small punch tensile testing showed good promise when comparing to uniaxial samples for the DED Ti 6242 as well as a forged Ti 6246 alloy. Small punch creep of both of these materials showed very inconsistent results and is a topic of future research. The difficulty in small punch testing is the nature of stress state. Translating biaxial stresses seen in small punch testing to uniaxial stresses is a challenging process, for which a universal equation does not exist. Previous developments have focused on steel alloys, which when transferred to titanium alloys, do not exhibit the same correlation. Therefore, new methods for small punch tensile and creep have been developed for uniaxial correlations for the forged Ti 6246 and additive Ti 6242 respectively. Additionally, shear punch testing was also undertaken and assessed, as the stress state exhibited by the flat punch tip is less complex compared to the hemispherical punch tip used for small punch testing. For this small scale test technique, it was shown that a universal approach using a range of different materials is also sufficient when adding both titanium alloys.
published_date 2024-03-03T03:00:22Z
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score 11.064692

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