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Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour

Thesis (MEng)--Stellenbosch University, 2017.

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Main Author: Ter Haar, Gerrit Matthys
Other Authors: Becker, Thorsten Hermann
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2017
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access_status_str Open Access
author Ter Haar, Gerrit Matthys
author2 Becker, Thorsten Hermann
author_browse Becker, Thorsten Hermann
Ter Haar, Gerrit Matthys
author_facet Becker, Thorsten Hermann
Ter Haar, Gerrit Matthys
author_sort Ter Haar, Gerrit Matthys
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MEng)--Stellenbosch University, 2017.
format Thesis
id oai:scholar.sun.ac.za:10019.1/102946
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:43:21.794Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2017
publishDateRange 2017
publishDateSort 2017
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
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source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/102946 Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour Ter Haar, Gerrit Matthys Becker, Thorsten Hermann Blaine, S. C. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Ti6Al4V Crystallography Metals -- Heat treatment Titanium alloys -- Heat treatment Microstructure Tension structure UCTD Thesis (MEng)--Stellenbosch University, 2017. ENGLISH ABSTRACT: The ability to manufacture complex shapes and structures with little material waste, among other advantages, makes the metal additive manufacturing technique of Selective Laser Melting a superior manufacturing technique. The titanium alloy, Ti6Al4V, serves as a great material of choice for this manufacturing technique due to its excellent mechanical properties and its biocompatibility. These factors make Ti6Al4V parts produced through SLM highly applicable and valuable in the biomedical and aerospace industries. Due to limited research and development in the field however, part quality in terms of achievable mechanical properties, residual stress and density has been below standard (such as that achieved by wrought Ti6Al4V parts). The study aimed to gain a fundamental understanding of the influence of annealing strategies on the microstructure of SLM-produced Ti6Al4V to improve and optimise the tensile properties of the material. SLM-produced Ti6Al4V tensile samples were subject to various tailored heat treatment strategies. Analysis of microstructure through optical and electron backscatter diffraction allowed for correlations to be made between the annealing strategies and the microstructure as well as between the printing process and the microstructure. Tensile test results of annealed samples show a decrease in tensile strength with an increase in annealing temperature as well as an increase in ductility and stiffness with an increase in annealing temperature. It was found that the fine martensitic (α’) microstructure of the as-built samples decomposes into a dual-phase (α+β) microstructure at ~800 °C, thereby improving ductility and stiffness. An optimal duplex annealing strategy allows for a bi-lamellar microstructure to be formed which allows for a substantial increase in ductility while maintaining a high material strength. AFRIKAANSE OPSOMMING: Die vermoë om komplekse vorms en strukture te vervaardig met min afvalmateriaal, om slegs een voordeel te noem, maak die metaaltoevoegingsvervaardiging tegniek van Selektiewe Laser Smelting (SLM) ʼn tegniek van voorkeur. Die titanium legering, Ti6Al4V, dien as die materiaal van keuse vir hierdie tegniek as gevolg van sy uitstekende meganiese eienskappe en sy vermoë om suksesvol met biologiese weefsel te integreer. Hierdie faktore maak Ti6Al4V dele geproduseer deur SLM hoogs toepaslik en waardevol in die biomediese en ruimte industrieë. Weens beperkte navorsing en ontwikkeling tot dusver in die gebied, is part kwaliteit, in terme van haalbare meganiese eienskappe, residuele spanning en digtheid, onder standaard (soos wat bereik word deur smee Ti6Al4V dele). Die studie was daarop gemik om 'n fundamentele begrip van die invloed van uitgloeiing strategieë op die mikrostruktuur van SLM-geproduseerde Ti6Al4V te kry, om sodoende die meganiese eienskappe van die materiaal te verbeter en te optimaliseer. SLM-geproduseerde Ti6Al4V trek monsters was onderhewig aan verskeie hitte behandeling strategieë. Ontleding van die mikrostruktuur deur optiese en elektroniese terugstrooiings diffraksie het toegelaat om die uitgloeiing strategieë met die mikrostruktuur te korreleer, asook die SLM-proses met die mikrostruktuur. Trektoetsresultate van uitgegloeide monsters het 'n afname in treksterkte met 'n toename in uitgloeiing temperatuur asook 'n toename in smeebaarheid en styfheid met 'n toename in uitgloeiing temperatuur getoon. Daar is bevind dat die fyn martensitiese (α') mikrostruktuur van die as-vervaardigde monsters ontbind in 'n dubbele-fase (α+β) mikrostruktuur by ~800 ° C, en sodoende verbeter smeebaarheid en styfheid van die materiaal. 'n Optimale dupleks uitgloeiing strategie het toegelaat vir 'n dubbel-lamellêre mikrostruktuur om gevorm te word. Dié mikrostruktuur het 'n aansienlike toename in smeebaarheid getoon, asook ʼn behoud van hoë materiaal sterkte. 2017-11-19T19:00:47Z 2017-12-11T11:15:35Z 2017-11-19T19:00:47Z 2017-12-11T11:15:35Z 2017-12 Thesis http://hdl.handle.net/10019.1/102946 en_ZA Stellenbosch University 158 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Ti6Al4V
Crystallography
Metals -- Heat treatment
Titanium alloys -- Heat treatment
Microstructure
Tension structure
UCTD
Ter Haar, Gerrit Matthys
Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title_full Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title_fullStr Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title_full_unstemmed Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title_short Selective laser melting-produced Ti6Al4V: Influence of annealing strategies on crystallographic microstructure and tensile behaviour
title_sort selective laser melting produced ti6al4v influence of annealing strategies on crystallographic microstructure and tensile behaviour
topic Ti6Al4V
Crystallography
Metals -- Heat treatment
Titanium alloys -- Heat treatment
Microstructure
Tension structure
UCTD
url http://hdl.handle.net/10019.1/102946
work_keys_str_mv AT terhaargerritmatthys selectivelasermeltingproducedti6al4vinfluenceofannealingstrategiesoncrystallographicmicrostructureandtensilebehaviour