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Plastic anisotropy of additively manufactured maraging steel : influence of the build orientation and heat treatment

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dc.contributor.advisor Kourousis, Kyriakos I. Mooney, Barry 2019-02-18T15:52:40Z 2019-02-18T15:52:40Z 2018
dc.description peer-reviewed en_US
dc.description.abstract This study investigates the combined effect of three Additive Manufacturing (AM) build orientations (0° , 45° , and 90° ) and an extensive array of heat-treatment plans on the plastic anisotropy of EOS maraging steel 300 (coded by EOS as ’MS1’) fabricated on the EOSINT M280 Direct Metal Laser Sintering (DMLS) system. A comparison between the material microstructural characteristics, mechanical performance, plastic strain behaviour and anisotropy levels of identical parts fabricated on two of these independently operated DMLS systems was also conducted. Considerable plastic anisotropy has been confirmed in the as-built condition, which can be reduced by aging heat-treatment, as verified in this study. However, it has identified that a degree of transverse strain anisotropy is likely to remain due to the AM alloy’s fabrication history, a finding that has not been previously reported in the literature. Significant microstructural discrepancies, affecting mechanical performance, plasticity and anisotropy levels, have also been observed in the as-built samples obtained from the two DMLS systems. A difference in the angle of the laser scan strategy, in conjunction with unfavourable powder feedstock characteristics, are understood to have had a profound influence on the plasticity and anisotropy divergences observed. A comprehensive visual representation of the material’s overall mechanical properties against the various heat-treatment plans is offered through time-temperature contour maps. Moreover, the heat-treatment plan (6h at 490° C) recommended by the DMLS system manufacturer has been found not to be the optimal in terms of achieving high strength, hardness, ductility and low anisotropy for the MS1 material. With the use of the comprehensive experimental data collected and analysed in this study, and presented in the constructed contour maps, the alloy’s heat-treatment parameters (time, temperature) can be tailored to meet the desired strength/ductility/anisotropy design requirements, either for research or part production purposes. en_US
dc.language.iso eng en_US
dc.publisher University of Limerick en_US
dc.subject plastic anisotropy en_US
dc.subject additive manufacturing (AM) en_US
dc.title Plastic anisotropy of additively manufactured maraging steel : influence of the build orientation and heat treatment en_US
dc.type info:eu-repo/semantics/masterThesis en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.type.supercollection ul_theses_dissertations en_US
dc.contributor.sponsor IRC en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US

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