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The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements
Thesis (PhD)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867614081407516672 |
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| access_status_str | Open Access |
| author | Makhetha, William Motsoko Ishmael |
| author2 | Becker, Thorsten Hermann |
| author_browse | Becker, Thorsten Hermann Makhetha, William Motsoko Ishmael |
| author_facet | Becker, Thorsten Hermann Makhetha, William Motsoko Ishmael |
| author_sort | Makhetha, William Motsoko Ishmael |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126915 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:46:21.556Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126915 The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements Makhetha, William Motsoko Ishmael Becker, Thorsten Hermann Sacks, Natasha Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering. Additive manufacturing Electron beam melting Materials -- Electric properties Computer-aided design Manufacturing industries -- Technological innovations Thesis (PhD)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Broadly, additive manufacturing (AM) is defined as a canopy term of manufacturing technologies used to join material layer by layer to make three-dimensional (3D) products from computer aided design (CAD) models. Additive manufacturing is well known for polymer processing, but there is a growing interest to optimize capabilities for metal additive manufacturing (MAM) technologies. While various materials are being explored for MAM, more research has been conducted on titanium alloys such as Ti-6Al-4V. The combined properties of this alloy make it an excellent choice for structural parts in applications such as airframes, aero-engines and bio-medical devices. Although the potential of MAM technologies such as laser powder bed fusion (LPBF) are well recognized in industry and research communities, with parts already finding applications in aircraft components and medical implants, the drawbacks associated with as-built parts continue to impede its wider application and update. Despite the ongoing efforts to improve the integrity by process parameter optimization, the as-built parts are inherently characterized by high surface roughness, high residual stresses, martensitic microstructure, high porosity and anisotropic properties. Therefore, post-processing solutions are essential to link the as-built parts with industry specific functional requirements. There is a significant range of post-processing solutions available, however there is no open literature on clear post-processing frameworks. Consequently, there is lack of clear guidelines to help in the selection of the most feasible post-processing solutions. This research project was conducted to address this gap by providing a methodological guideline on the available post-processing solutions for making LPBF Ti-6Al-4V parts which qualify for application. All research activities were organized into five phases. The approach used was to extract existing knowledge from the literature to find key areas of consensus with the aim of gaining a better understanding of the links between the process and integrity of the parts produced. This understanding was then used to develop a conceptual LPBF post-processing framework for industry application, which was then validated through experiments. The validation was planned in collaboration with Aerosud, which provided directives from the industry perspective. The directive was to define what it means for a part to be qualified, which in turn informed what aspects of the proposed framework needed to be carried out through the experiments. The directives were in accordance with the safety classification and quality level assigned to aircraft parts. The research findings add to the body of knowledge on how industries should apply the AM technology with two important novelties. Firstly, the presentation of four key attributes (microstructure, porosity, residual stresses, and surface roughness) into one framework. Secondly, a holistic approach, which in turn offers the end-users of the AM technology an opportunity to clearly and quickly identify possible options when seeking to qualify Ti-6Al-4V parts produced by LPBF. The author concludes that the study is unique in that, as opposed to previous studies, it emphasizes the need for such attributes to be considered collectively towards qualifying the LPBF Ti-6Al-4V parts because of their shared influence on mechanical properties. AFRIKAANS OPSOMMING: Toevoegingsvervaardiging (TV) word oor die algemeen gedefinieer as ’n oorkoepelende term vir vervaardigingstegnologieë wat gebruik word om materiaal laag vir laag saam te voeg om driedimensionele (3D) produkte te maak direk vanaf rekenaargesteunde ontwerpsmodelle (RSO-modelle). Toevoegingsvervaardiging is bekend vir polimeerprosessering, maar daar is groeiende belangstelling in die optimalisering van die potensiaal daarvan vir metaal-toevoegingsvervaardigingstegnologieë (MTV-tegnologieë). Verskeie materiale word ondersoek vir MTV, maar meer navorsing is al gedoen oor titaanallooie soos Ti-6Al-4V. Die gekombineerde kenmerke van hierdie allooi maak dit ’n uitstekende keuse vir strukturele onderdele in toepassings soos vliegrame, vliegtuigenjins en biomediese toestelle. Alhoewel die potensiaal van MTV-tegnologieë soos laser poeierbedfusie (LPBF) erken word in industrie- en navorsingsgemeenskappe, met onderdele wat alreeds gebruik word in vliegtuigkomponente en mediese inplantings, belemmer die nadele wat geassosieer word met soos-geboude onderdele steeds die breër gebruik en modernisering daarvan. Ten spyte van die voortgaande pogings om die integriteit te verbeter deur proses-parameter-optimalisering, word die soos-geboude onderdele inherent gekarakteriseer deur hoë oppervlakgrofheid, hoë resspannings, martensitiese mikrostruktuur, hoë porositeit en anisotropiese eienskappe. Post-prosesseringsoplossings is daarom belangrik om die soos-geboude onderdele te verbind met industrie-spesifieke funksionele vereistes. Daar is ’n beduidende hoeveelheid post-prosesseringsoplossings beskikbaar, maar daar is geen geredelik beskikbare literatuur oor duidelike post-prosesseringsraamwerke nie. Gevolglik is daar ’n tekort aan klinkklare riglyne om te help met die keuse van die mees praktiese post-prosesseringsoplossings. Hierdie navorsingsprojek is uitgevoer om dié gaping aan te spreek deur ’n metodologiese riglyn te bied ten opsigte van die beskikbare post-prosesseringsoplossings vir die vervaardiging van LPBF Ti-6Al-4V-onderdele wat geskik is vir gebruik. Alle navorsingsaktiwiteite is opgedeel in vyf fases. Die benadering wat gebruik is, was om bestaande kennis uit die literatuur te ontgin ten einde sleutelareas van konsensus te vind om ’n beter begrip te vorm van die verband tussen die proses en die integriteit van die geproduseerde onderdele. Hierdie begrip is toe gebruik om ’n konseptuele LPBF post-prosesseringsraamwerk te ontwikkel vir industriegebruik. Die raamwerk is gevalideer deur eksperimente. Die validaring is beplan in samewerking met Aerosud wat ’n riglyn gebied het vanuit die industrie-perspektief, naamlik om te definieer wat dit beteken vir ’n onderdeel om gekwalifiseer te word. Dit het op sy beurt toegelig watter aspekte van die voorgestelde raamwerk uitgevoer moes word deur die eksperimente. Die riglyne was in ooreenstemming met die veiligheidsklassifikasie en kwaliteitsvlak wat toegeken word aan vliegtuigonderdele. Die navorsingsbevindings dra by tot bestaande kennis oor hoe industrieë die TV-tegnologie behoort te gebruik, met twee belangrike nuwe insigte. Eerstens, die aanbieding van vier sleutelkenmerke (mikrostruktuur, porositeit, resspanning en oppervlakgrofheid) in een raamwerk. Tweedens, ’n holistiese benadering wat op sy beurt vir eindgebruikers van TV-tegnologie ’n geleentheid bied om duidelik en vinnig die moontlike opsies te identifiseer wanneer hulle Ti-6Al-4V-onderdele geproduseer deur LPBF wil beoordeel. Die outeur kom tot die gevolgtrekking dat hierdie studie uniek is in soverre dit, anders as vorige studies, die noodsaaklikheid beklemtoon vir sulke kenmerke om kollektief oorweeg te word in die geskiktheidsbepaling van LPBF Ti-6Al-4V-onderdele, weens hulle gedeelde invloed op meganiese eienskappe. Doctorate 2023-01-30T14:52:17Z 2023-05-18T06:55:37Z 2023-01-30T14:52:17Z 2023-05-18T06:55:37Z 2023-03 Thesis http://hdl.handle.net/10019.1/126915 en_ZA en_ZA Stellenbosch University xxi, 184 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Additive manufacturing Electron beam melting Materials -- Electric properties Computer-aided design Manufacturing industries -- Technological innovations Makhetha, William Motsoko Ishmael The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title | The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title_full | The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title_fullStr | The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title_full_unstemmed | The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title_short | The effect of LPBF post-processing solutions on material properties to meet functional Ti-6Al-4V requirements |
| title_sort | effect of lpbf post processing solutions on material properties to meet functional ti 6al 4v requirements |
| topic | Additive manufacturing Electron beam melting Materials -- Electric properties Computer-aided design Manufacturing industries -- Technological innovations |
| url | http://hdl.handle.net/10019.1/126915 |
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