Publications de Roland Logé | EPFL Graph Search

Avoiding cracks in multi-material printing by combining laser powder bed fusion with metallic foils: Application to Ti6Al4V-AlSi12 structures

Eric Boillat, Jamasp Jhabvala, Roland Logé

Laser powder bed fusion (LPBF) as an additive manufacturing (AM) technology has emerged as a powerful platform for producing multi-material metallic structures. The main drawbacks of using metallic powders for multi-material printing are related to technic ...

2025

Deconvoluting cracking mechanisms in fusion processing of steel-copper multi-materials via Operando X-ray characterisation

Roland Logé

This study investigates various cracking mechanisms and their prevalence in fusion processing of steel-copper multi-materials using operando X-ray diffraction and imaging during laser powder-bed fusion (LPBF) of 316L-CuCrZr multi-material. During this inve ...

Informa UK Limited2025

Solidification pathway induced microstructural differences in austenitic stainless steels produced by L-PBF

Christian Leinenbach, Roland Logé

Informa UK Limited2025

Microstructure and texture evolution in laser Shock Peened martensitic NiTi shape memory alloy

Cyril Cayron, Roland Logé, Junfeng Xiao, Yandong Jing

The Laser Shock Peening (LSP) is commonly used to strengthen the surface of materials. However, the microstructures after LSP impact are complex due to the intense forces involved. In this study, we explore how martensitic microstructures evolve in a half ...

2025

In-situ neutron diffraction revealing microstructure changes during laser powder bed fusion and in-situ laser heat treatments of 316L and 316L-Al1

Roland Logé

The versatility and flexibility in laser-based layer-wise additive manufacturing processes allow for the fabrication of metallic parts with tailorable mechanical properties. Interest in microstructure control during the process has led to varying applicati ...

2025

Formation mechanism and microstructural characteristics of a body-centered cubic phase in 3D printed 316L–CuCrZr multi-material structures, combining laser powder bed fusion with foils

Cyril Cayron, Jamasp Jhabvala, Roland Logé

Additive manufacturing of 316L/CuCrZr multi-material metallic structures has recently attracted significant attention, due to the ideal combination of structural and thermal/electrical properties. In this work, a unique multi-phase microstructure was produ ...

2025

A downsized laser powder bed fusion device for operando neutron studies: design and experiments

Roland Logé

This work reports on the development of a downsized laser powder bed fusion device for operando neutron characterization. The design considerations, device configurations, and detailed setup are described. The device is optimized for installations at neutr ...

2025

The role of interaction work in martensite deformation

Cyril Cayron, Roland Logé, Junfeng Xiao

This study elucidates the evolution of martensite deformation via Interaction Work (IW). The IW is the mechanical work done by external loading, assisting deformation by competing with the energy barrier. This interplay establishes the maximum IW (IWmax) c ...

2025

Toward Architected Microstructures Using Advanced Laser Beam Shaping in Laser Powder Bed Fusion of Ti-6al-4v

Mathijs Pieter van der Meer, Eric Boillat, Cyril Cayron, Jamasp Jhabvala, Roland Logé, Junfeng Xiao

Laser Powder Bed Fusion (LPBF) stations mostly use lasers with a Gaussian beam intensity distribution, as it has advantages like small divergence and high ability to be focused. This distribution creates significant thermal gradients leading to high coolin ...

WILEY-V C H VERLAG GMBH2025

Microstructures and outstanding mechanical properties of the 18 carat Au–Ti alloy after age-hardening

Cyril Cayron, Roland Logé

Watchmakers and jewellers are looking for novel 18 carat (ct) gold alloys (75 wt% Au) that combine superior hardness (≥ 300 HV) and scratch resistance with the excellent ductility and machinability characteristic of traditional 18 ct Au–Cu–Ag alloys. The A ...

2025

Fast and accurate laser powder bed fusion metamodels predicting melt pool dimensions, effective laser absorptivity and lack of fusion defects

Eric Boillat, Jamasp Jhabvala, Roland Logé, Milad Hamidi Nasab

The significant computational expenses associated with simulating the Laser Powder Bed Fusion (LPBF) process often restrict the insights gained from modeling endeavors to specific combinations of process parameters, hindering broader conclusions. In this s ...

2025

Tailoring mechanical properties and microstructures in laser powder bed fusion of 316 L stainless steel through aluminium alloying and combined ex-situ and in-situ heat treatments

Cyril Cayron, Roland Logé

Laser powder bed fusion (LPBF) is a bottom-up manufacturing technique using a high-energy laser to selectively melt metallic alloys, enabling the creation of complex microstructures. While rapid cooling rates and process stochasticity can lead to unpredict ...

2025

Partial crystallization in Pd-BMG systems: From understanding structure towards influencing functionality through temperature-time series

Roland Logé

Small quantities of crystalline domains created in an amorphous matrix are seen as an active driver for enhanced properties in bulk metallic glasses (BMGs). We investigated partial crystallization and phase transformations through a series of isotherms at ...

2024

Quantitative prediction of crystallization in laser powder bed fusion of a Zr-based bulk metallic glass with high oxygen content

Jamasp Jhabvala, Roland Logé, Hossein Ghasemi Tabasi, Navid Sohrabi, Toni Ivas

One of the main challenges in the fabrication of bulk metallic glasses (BMGs) via laser-based additive manufacturing (AM) is undesirable crystal phase formation, which usually deteriorates the mechanical properties of the BMG fabricated parts. Understandin ...

Elsevier Sci Ltd2024

Exploring crystallographic texture manipulation in stainless steels via laser powder bed fusion: insights from neutron diffraction and machine learning

Roland Logé

Laser powder bed fusion of metals (PBF-LB/M) is a pivotal additive manufacturing technique that enables the production of intricate components. In addition to enabling the production of complex shapes, it allows for a high degree of freedom in manipulating ...

2024

Tensile Properties of Ex-Situ Ti-TiC Metal Matrix Composites Manufactured by Laser Powder Bed Fusion

Roland Logé

Titanium-based Metal Matrix Composites (MMCs) manufactured by additive manufacturing offer tremendous lightweighting opportunities. However, processing the high reinforcement contents needed to substantially improve elastic modulus while conserving signifi ...

2024

Acoustic emission signature of martensitic transformation in laser powder bed fusion of Ti6Al4V-Fe, supported by operando X-ray diffraction

Mathijs Pieter van der Meer, Jamasp Jhabvala, Roland Logé, Milad Hamidi Nasab

This study focuses on investigating Acoustic Emission (AE) monitoring in the Laser Powder Bed Fusion (LPBF) process, using premixed Ti6Al4V-(x wt%) Fe, where x = 0, 3, and 6. By employing a structure-borne AE sensor, we analyze AE data statistically, uncov ...

2024

Monitoring of laser-induced fast recrystallization in SS-316L through synchrotron X-ray diffraction

Cyril Cayron, Roland Logé, Milad Hamidi Nasab

Laser based heat treatments have multiple applications for local tuning of microstructures. They are particularly relevant in the context of laser-based additive manufacturing (LAM), in order to relieve residual stresses or introduce equiaxed structures th ...

Elsevier Sci Ltd2024

Experimental quantification of inward Marangoni convection and its impact on keyhole threshold in laser powder bed fusion of stainless steel

Christian Leinenbach, Roland Logé, Milad Hamidi Nasab

Laser metal additive manufacturing has the potential to revolutionize the production of complex geometries with high precision across various industrial applications. To optimize the reliability of the process, a detailed understanding of the melt pool dyn ...

Elsevier2024

Operando phase mapping in multi-material laser powder bed fusion

Roland Logé

Layer-wise laser-based additive manufacturing techniques offer immense versatility and flexibility in fabricating metallic composites with complex shapes. Interest in producing new multi-materials with advanced characteristics outpaces the available method ...

2024