Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract and vita. Includes bibliographical references (leaves 130-134).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: lubricant pyrolysis; sintering; powder metallurgy; delubrication. Includes bibliographical references (p.69-70).

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Speyer, Robert; Committee Member: Judson, Elizabeth; Committee Member: Sanders, Thomas. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 148-158). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisors: Richard H. Crawford and Richard R. Neptune. Vita. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliographical references.

Thesis (M.S.) -- Worcester Polytechnic Institute. / Includes bibliographical references (leaves 60-61).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 90-93). Also available via the Internet.

Made available in DSpace on 2016-03-07T19:21:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-31. Added 1 bitstream(s) on 2016-03-07T19:25:29Z : No. of bitstreams: 1 000859657.pdf: 11263749 bytes, checksum: 51e907f4fbdf0d8ce56785c1c9af062c (MD5) / A liga Ti-6A-4V é um biomaterial que tem se mostrado muito adequado na fabricação de implantes para reparar lesões craniofaciais. Entre outros requisitos, é importante que o implante resista a solicitação mecânica para garantir uma resposta clínica satisfatória de modo a proporcionar conforto e segurança ao paciente. O propósito específico do presente trabalho de pesquisa é determinar a influência de diferentes ciclos térmicos na microestrutura da amostra da Ti-6Al-4V produzida pelo processo de sinterização direta de metal por laser (DMLS) e no micromecanismo de fratura resultante de tensionamento uniaxial em tração. Para isso foram fabricados corpos-de-prova de tração, utilizando a técnica DMLS, e os mesmos foram submetidos a diferentes ciclos térmicos de 650 °C/1h, 650 °C/3h, 800 °C/4h e 850 °C/2h. Posteriormente, os corpos-de-prova foram submetidos a ensaios de tração. A caracterização microestrutural foi realizada com auxílio de microscopia óptica (MO) e eletrônica de varredura (MEV). As superfícies de fratura resultantes para as diferentes condições de ciclos térmicos foram analisadas por microscopia eletrônica de varredura. A microestrutura final da amostra como produzida resultante do processo de manufatura aditiva por DMLS revelou uma microestrutura martensita hexagonal α'. Para a amostra A6501H, a microestrutura martensítica resultante do processo DMLS não se decompôs. Na amostra A6503H a microestrutura martensítica começa a se decompor, pois são observados precipitados da fase β. Já nas amostras A8004H e A8502H observa-se uma estrutura (α +β), com cristais de fase α e fase β precipitada nos contornos. De acordo com a análise fractográfica todas as condições estudadas apresentaram fratura dúctil caracterizada pela formação e coalescência de microcavidades com forma e tamanhos variados / The Ti-6A-4V alloy is a biomaterial that has proved very suitable for the manufacture of prostheses to repair craniofacial injuries. Among other requirements, it is important that the prosthesis resist mechanical stress to ensure a satisfactory clinical response in order to provide comfort and safety to patients. The specific purpose of this research is to determine the influence of thermal cycles - as prototyped, 650 °C (1h); 650 °C (3h), 800 °C (2h) and 850 °C (4h) - on the microstructure and fracture micromechanisms resulting from uniaxial tension in traction. Therefore it was manufactured by DMLS technique bodies - of - proof traction which were subsequently subjected to different thermal cycles. Then, the bodies -specimens were subjected to tensile test. Microstructural characterization was carried out using optical and scanning electron microscopy (SEM). The resulting fracture surfaces of the five conditions for thermal cycling were analyzed by SEM. The final sample microstructure produced as a result of the additive manufacturing process DMLS revealed a hexagonal martensitic microstructure α '. For A6501H sample, the resulting martensitic microstructure DMLS process is not decomposed. In A6503H martensitic microstructure sample begins to decompose, as are observed precipitates of β phase. Already in the samples A8004H and A8502H observe a structure (α + β) with α and β phase crystal phase precipitated in the contours. According to fractographic analysis of all studied showed ductile fracture conditions characterized by the formation and coalescence wells with varying shape and sizes

Made available in DSpace on 2014-10-09T12:24:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:23Z (GMT). No. of bitstreams: 1 01040.pdf: 2700481 bytes, checksum: 1f84b09901d3ff97219652b8e79365be (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP