Skip to Main content Skip to Navigation
Theses

Modélisation et développement expérimental du procédé de fabrication additive par fusion laser sélective d'un lit de poudre métallique : influence de la pression de l'atmosphère

Abstract : The selective laser melting process (SLM) of a metallic powder bed is an innovative process that allows the manufacturing of complex shape parts directly from a CAD file via a complete melting of powder layers deposited successively. During the SLM process, the high laser energy density creates many thermal cycles: melting - vaporization - solidification.The purpose of this work was: 1) to better characterize and understand experimentally the phenomena that occur during the laser beam - powder / molten metal pool interaction and 2) to develop a numerical model taking into account the phenomena of melting and vaporizing of the material and the presence of the surrounding gas in the build chamber.In a first time, considering simple geometries (tracks and surfaces) and 316L stainless steel as material, we studied the interaction between the laser beam, the powder bed and the liquid metal pool using several experimental techniques (spectrometry, calorimetry, ...) in order to understand the nature and the role of the metal vapor generated during the process. The results showed that the vapor has no effect on the transmission of the laser beam energy to the material during the SLM process. Meanwhile it leads to the deposition of condensed vapor and also drag some molten metal droplets.In a second time a numerical model was developed to determine the influence of the pressure of the surrounding environment on the melting process of a powder bed by a laser beam. Parameters characterizing the evolution of the physical properties of the material and of the gaseous medium according to the temperature and pressure were incorporated into the model database. Some material parameters were determined from the literature and others were obtained empirically using specific experimental measurements.Finally, this numerical model, complementing experimental results, was used to treat the main subject of the thesis which is the effect of the surrounding pressure on the SLM process. The model helped to clarify the physical phenomena provided by the change in the pressure level and its validity was checked through experimental measurements.
Complete list of metadatas

Cited literature [35 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01871204
Contributor : Abes Star :  Contact
Submitted on : Monday, September 10, 2018 - 2:59:10 PM
Last modification on : Tuesday, October 1, 2019 - 4:24:23 PM
Long-term archiving on: : Tuesday, December 11, 2018 - 3:03:52 PM

File

These_MASMOUDI_UTBM.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01871204, version 1

Collections

Citation

Amal Masmoudi. Modélisation et développement expérimental du procédé de fabrication additive par fusion laser sélective d'un lit de poudre métallique : influence de la pression de l'atmosphère. Matériaux. Université de Technologie de Belfort-Montbeliard, 2016. Français. ⟨NNT : 2016BELF0287⟩. ⟨tel-01871204⟩

Share

Metrics

Record views

613

Files downloads

2284