Microstructure and mechanical properties of additively manufactured stainless steel 316L
| dc.contributor.advisor | Mohammadi, Mohsen | |
| dc.contributor.author | Kalaie, Mohammad Reza | |
| dc.date.accessioned | 2023-03-01T16:38:03Z | |
| dc.date.available | 2023-03-01T16:38:03Z | |
| dc.date.issued | 2021 | |
| dc.date.updated | 2023-03-01T15:02:53Z | |
| dc.description.abstract | The effects of crystallographic texture and microstructure on the mechanical behavior of a selectively laser melted (SLM) 316L stainless steel subjected to uniaxial tensile loading was discussed. The microstructure of the as-built sample exhibits a hierarchical structure at macro-, micro-, and nano-scales, with good chemical homogeneity and no elemental segregation. The chemical homogeneity was attributed to a very high cooling rate (2.7 × 10[superscript 6]K/s) present in SLM, discrete melt pools, and the formation of nanosized silicon-rich oxides. Due to the formation of a dislocation network during additive manufacturing, 316L showed twinning-induced plasticity (TWIP) behavior with a high strain-hardening rate exhibited in five stages. Pre-existing dislocation networks, where their configuration was maintained during deformation, promoted the formation of nano-twins, resulting in enhanced twin-dislocation and dislocation-dislocation interactions. The formation of deformation-induced nano-twins maintained a constant high-level of strain hardening rate in two stages, enhanced by the development of pronounced <111> texture in the tensile direction and a fiber texture. In addition, the high yield strength of this alloy was attributed to the high density of dislocation cells. The dislocation cellular structure combined with distributed nano-oxide inclusions were responsible for the formation of nanometer ductile dimples (as a nano-scale structure). This microstructure hindered crack propagation and tailored several process-induced defects compared to traditionally manufactured ones. Plastic deformation was governed by dislocation glide and deformation-induced twinning; thus, the final microstructure contained several types of twins and highly misoriented dislocation boundaries. As a final stage, the high temperature behavior of 316L was also studies and some perspectives on its deformation was brought forward. | |
| dc.description.copyright | © Mohammad Reza Kalaie, 2021 | |
| dc.format | text/xml | |
| dc.format.extent | x, 73 pages | |
| dc.format.medium | electronic | |
| dc.identifier.uri | https://unbscholar.lib.unb.ca/handle/1882/14242 | |
| dc.language.iso | en_CA | |
| dc.publisher | University of New Brunswick | |
| dc.rights | http://purl.org/coar/access_right/c_abf2 | |
| dc.subject.discipline | Mechanical Engineering | |
| dc.title | Microstructure and mechanical properties of additively manufactured stainless steel 316L | |
| dc.type | master thesis | |
| thesis.degree.discipline | Mechanical Engineering | |
| thesis.degree.fullname | Master of Science in Engineering | |
| thesis.degree.grantor | University of New Brunswick | |
| thesis.degree.level | masters | |
| thesis.degree.name | M.Sc.E. |
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