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Materials for Additive Manufacturing by Direct Energy Deposition

Mattias Miedzinski
Göteborg : Chalmers tekniska högskola, 2017. 63 s. Diploma work - Department of Materials and Manufacturing Technology, Chalmers University of Technology, 2017.
[Examensarbete på avancerad nivå]

The interest in additive manufacturing techniques such as direct energy deposition has increased recently. However, the number of alloys that are available for the various processes is very limited. A better understanding of process parameters and material behavior facilitates the design of new materials that can meet future requirements. This work investigates materials for direct energy deposition, where the focus is on material parameters such as thermal expansion coefficient, thermal conductivity, viscosity and wetting of the materials during printing and examining how these parameters affect the building process. Criteria were identified and used to select materials suitable for direct energy deposition. The selected materials investigated where 316L, which is austenitic stainless steel and 316L HSi which is a variant of 316L with higher silicon in order to improve fluidity of melt pool. These two materials have the same levels of thermal expansion and thermal conductivity but they differs in viscosity of the melt. To have a different material with different properties in thermal expansion and thermal conductivity, one NiFeCrSi (1530-CE) alloy was selected. The materials were evaluated by manufacturing a single-track wall, consisting of 20 deposited layers for each build. Each material requires its own set of optimum process parameters. Therefore, optimum process parameter for each material were identified so that builds with minimum amount of defects could be manufactured. These samples were then evaluated with using metallography, light optical microscopy and scanning electron microscopy with electron backscattering diffraction imaging. Single-track walls could be build with 316L, 316L HSi and 1530-CE, without any significant defects.

Nyckelord: Additive manufacturing, Direct energy deposition, Stainless steel, Nickel alloys

Publikationen registrerades 2017-12-15. Den ändrades senast 2017-12-15

CPL ID: 253822

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