Speaker
Description
The AISI 316L stainless steel is use for additive manufacturing due to its welding capacity, its relatively high mechanical properties and its high-temperature performance. The DED (Directed Energy Deposition) is a process of additive manufacturing that uses a laser to produce a melt pool, where the metal powder is injected through the nozzle and directly deposited. The additive manufacturing in DED have a direct impact on the microstructure of the material and consequently on the mechanical properties.
The fatigue properties of materials obtained from additive manufacturing are usually identified at a macroscopic scale. However, these parameters highly depend on the plasticity mechanisms at the microscopic scale of the material [1].
The purpose of this study is to explore the relation between microstructure and mechanical properties by characterizing the local microstructural response via in situ test.
For this, the mechanical properties were characterizing with in-situ monotonic and cyclic tests, under a scanning electron microscope (SEM) combined with high resolution digital image correlation (HR-DIC) and Electron Backscatter Diffraction (EBSD) maps.
The samples were extracted from bidirectionally-printed single-track thickness 316L stainless steel walls built by directed energy deposition. The wall microstructure has morphologic and crystallographic textures, with large columnar grains located within the printed layer and small equiaxed grains located at the layer’s interfaces.
In view of the particular morphology, the in-situ tests were performed according to three loading directions, either 0°, 45° and 90° regarding the printing direction. The different orientation exhibit different deformation mechanisms. These observations permit to justify the differences in yield and ultimate strength noticed during macroscopic tensile tests for these three configurations.
[1] Y. Balit, L.R.Joly, F.Szmytka, S.Durbecq, E.Charkaluk, A.Constantinescu. Materials Science and Engineering: A 786, (2020).
| Speaker Country | France |
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