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SUMMARY:IMX Talks - Towards defect-free and 3D architected microstructures
  in additive manufacturing of metals and alloys
DTSTART:20240603T130000
DTEND:20240603T140000
DTSTAMP:20260416T003505Z
UID:7034a3466724d4595a7fb4985852e202cbdb93f4af662b2ff4b20fc0
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Roland Logé\, Laboratory of Thermomechanical Metallurgy
  - PX Group Chair\nAdditive Manufacturing (AM) is often mentioned as a sou
 rce of renewal in the metallurgy community. There is indeed a long-standin
 g “dream” of fabricating metallic parts with full spatial control of d
 efect content\, microstructure\, and chemical composition. Processes from 
 past centuries have shown multiple ways of designing properties of final p
 roducts based on partial control of thermo-mechanical processes. However\,
  the spatial resolution at which microstructures could be designed\, and t
 he available degrees of freedom to achieve such design\, were limited. In 
 the AM context\, the developments of monitoring approaches and numerical m
 odelling at the relevant space and time scales provide the opportunity of 
 a bottom-up manufacture\, which may even include multiple materials. While
  the literature has focused most of the attention on the minimization of d
 efects\, the last few years have shown increasing trends in controlling mi
 crostructures\, typically from tuned heat source (laser\, electron beam) p
 arameters\, or beam profile (i.e. beam shaping). Considering the partly st
 ochastic nature of AM\, the vision consists in optimizing the processing c
 onditions\, while keeping the option of corrective actions whenever undesi
 red events are detected.\n\nIn this presentation\, I will discuss our rece
 nt advances in the 3D control of defects and microstructures with the Lase
 r Powder Bed Fusion (LPBF) process. A first part will describe the inventi
 on of a new hybrid process\, combining traditional LPBF with periodic Lase
 r Shock Peening (LSP) treatments. This approach proved effective in contro
 lling residual stresses in 3D (thereby increasing processability and/or fa
 tigue life)\, healing cracks\, tuning dislocation density\, and improving 
 geometrical accuracy. A second part will focus on operando experiments\, t
 o follow defect formation and microstructure changes during LPBF or upon l
 ocal laser heat treatment. The experiments are monitored with high energy 
 X-Rays (at the PSI Synchrotron) as well as with acoustic emission\, and pr
 omote the development of advanced monitoring methods that could be impleme
 nted in commercial LPBF machines. Combined with multiscale LPBF thermal mo
 dels\, they help defining optimal time-dependent laser parameters. Example
 s will include the detection and healing of porosity through acoustic emis
 sion monitoring\, laser induced martensite decomposition in Ti-6Al-4V\, an
 d selective recrystallization in 316L steel. They represent important mile
 stones in the objective of building defect-free 3D architected materials.\
 n\nBio: Roland Logé is an associate professor at EPFL (Switzerland)\, hol
 der of the PX Group Chair\, with a primary affiliation to the Materials In
 stitute\, and a secondary affiliation to the Electrical and Microengineeri
 ng Institute. He is the head of the Laboratory of Thermomechanical Metallu
 rgy\, and active in the field of processing of metals and alloys\, focusin
 g on the ability to tailor microstructures\, and the associated material p
 roperties. Topics of interest include recrystallization\, precipitation\, 
 grain growth\, textures and grain boundary engineering\, phase transformat
 ions\, internal stresses and cracking phenomena\, with applications to bul
 k metal forming and additive manufacturing. They are the subject of more t
 han 150 academic papers.\nRoland Logé received in 2008\, with Yvan Chaste
 l\, the ALCAN award from the French Academy of Sciences\; in 2019\, the Ma
 terials Science best teacher award from EPFL\; in 2021\, the THERMEC Disti
 nguished Award\; and in 2022\, the SF2M Albert Portevin Medal. He has been
  a member of the Editorial Board of Metals\, of the Scientific Advisory Bo
 ard of the SEAM laboratory of Excellence (France)\, of the Swiss Spallatio
 n Neutron Source Scientific Committee (PSI\, Switzerland)\, of the THERMEC
  International Advisory Committee\, of the CNRS National committee\, of SF
 2M and TMS.
LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201 https://epfl.zoom.us/j/
 62987278651
STATUS:CONFIRMED
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