Anisotropic mechanical behaviors and microstructural evolution of thin-walled additively manufactured metals

التفاصيل البيبلوغرافية
العنوان:	Anisotropic mechanical behaviors and microstructural evolution of thin-walled additively manufactured metals
بيانات النشر:	Linköpings universitet, Konstruktionsmaterial Linköpings universitet, Tekniska fakulteten Linköping 2020
تفاصيل مُضافة:	Yu, Cheng-Han
نوع الوثيقة:	Electronic Resource
مستخلص:	Additive manufacturing (AM), also known as 3D printing, is a concept and method of a manufacturing process that builds a three-dimensional object layer-by-layer. Opposite to the conventional subtractive manufacturing, it conquers various limitations on component design freedom and raises interest in various fields, including aerospace, automotive and medical applications. This thesis studies the mechanical behavior of thin-walled component manufactured by a common AM technique, laser powder bed fusion (LPBF). The studied material is Hastelloy X, which is a Ni-based superalloy, and it is in connection to a component repair application in gas turbines. The influence of microstructure on the deformation mechanisms at elevated temperatures is systematically investigated. This study aims for a fundamental and universal study that can apply to different material grades with FCC crystallographic structure. It is common to find elongated grain and subgrain structure caused by the directional laser energy input in the LPBF process, which is related to the different printing parameters and brands of equipment. This thesis will start with the study of scan rotation effect on stainless steel 316L in an EOS M290 equipment. The statistic texture analysis by using neutron diffraction reveals a clear transition when different level of scan rotation is applied. Scan rotation of 67° is a standard printing parameter with intention to lower anisotropy, yet, the elongated grain and cell structure is still found in the as-built microstructure. Therefore, the anisotropic mechanical behavior study is carried out on the sample printed with scan rotation of 67° in this thesis. Thin-walled effects in LPBF are investigated by studying a group of plate-like HX specimens, with different nominal thicknesses from 4mm down to 1mm, and a reference group of rod-like sample with a diameter of 18mm. A texture similar to Goss texture is found in rod-like sample, and it becomes <011>//BD fiber text Additiv tillverkning, eller 3D-utskrifter, är tillverkningsmetoder där man skapar ett tredimensionellt objekt genom att tillföra material lager for lager. Till skillnad från konventionella avverkande tillverkningsmetoder elimineras många geometriska begränsningar vilket ger större designfrihet och metoderna har därför väckt stort intresse inom en rad olika områden, inklusive flyg-, fordons- och medicinska tillämpningar. I denna avhandling studeras mekaniska egenskaper hos tunnväggiga komponenter tillverkade med en vanligt förekommande laserbaserad pulverbädds-teknik, laser powder bed fusion (LPBF). Det studerade materialet är Hastelloy X, en Ni-baserad superlegering som är vanligt förekommande for både nytillverkning och reparation av komponenter för gasturbiner. Inverkan av mikrostruktur på deformationsmekanismerna vid förhöjda temperaturer undersöks systematiskt. Detta arbete syftar till att ge grundläggande och generisk kunskap som kan tillämpas på olika materialtyper med en kubiskt tätpackad (FCC) kristallstruktur. Det är vanligt att man hittar en utdragen kornstruktur orsakad av den riktade tillförseln av laserenergi i LPBF-processen, vilket kan relateras till olika processparametrar och kan variera mellan utrustningar frän olika leverantörer. Denna avhandling inleds med studien av effekten av scanningsstrategi vid tillverkning av rostfritt stål 316L i en EOS M290-utrustning. En statistisk texturanalys med hjälp av neutrondiffraktion påvisar en tydlig övergång mellan olika mikrostrukturer när olika scanningsstrategier tillämpas. En scanningsrotation på 67 mellan varje lager är en typisk standardinställning med avsikt att sanka anisotropin i materialet, dock finns den utdragna kornstrukturen oftast kvar. I denna avhandling studeras därför de anisotropa egenskaperna hos material tillverkade med 67 scanningsrotation. Effekten av tunnväggiga strukturer i LPBF undersöks genom att studera en uppsättning platta HX-prover, med olika nominella tjocklekar från 4 mm ner t
مصطلحات الفهرس:	hot tensile testing, slow strain rate tensile testing, creep, anisotropy, crystallographic texture evolution, deformation twinning, Varmdragprov, Dragprov med låg töjningshastighet, kryp, anisotropi, kristallografisk textur, deformationstvillingar, Other Materials Engineering, Annan materialteknik, Licentiate thesis, comprehensive summary, info:eu-repo/semantics/masterThesis, text
DOI:	10.3384.lic.diva-169054
URL:	http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-169054 Linköping Studies in Science and Technology. Licentiate Thesis, 0280-7971 ; 1884
الإتاحة:	Open access content. Open access content info:eu-repo/semantics/openAccess
ملاحظة:	application/pdf English
أرقام أخرى:	UPE oai:DiVA.org:liu-169054 urn:isbn:9789179298111 doi:10.3384/lic.diva-169054 1234424795
المصدر المساهم:	UPPSALA UNIV LIBR From OAIster®, provided by the OCLC Cooperative.
رقم الأكسشن:	edsoai.on1234424795
قاعدة البيانات:	OAIster

الوصف
DOI:	10.3384.lic.diva-169054