Journal ArticleDOI
The role of recoil pressure in energy balance during laser materials processing
V. V. Semak,Akira Matsunawa +1 more
TLDR
A theoretical analysis of the energy balance in the laser - metal interaction zone is carried out in this article, where heat transfer due to the recoil-pressure-induced melt flow is taken into consideration.Abstract:
A theoretical analysis of the energy balance in the laser - metal interaction zone is carried out. The heat transfer due to the recoil-pressure-induced melt flow is taken into consideration. It is shown that, for the absorbed laser intensities typical in welding and cutting, the recoil pressure induces high-velocity melt-flow ejection from the interaction zone. This melt flow carries away from the interaction zone a significant portion of the absorbed laser intensity (about 70 - 90% at low laser intensities); thus, convection-related terms can be ignored neither in calculations of the energy balance in the interaction zone nor in calculations of the thermal field in the vicinity of the weld pool or cutting front.read more
Citations
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Journal ArticleDOI
Laser powder-bed fusion additive manufacturing: Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones
TL;DR: In this paper, the effect of the recoil pressure and Marangoni convection in laser powder bed fusion (L-PBF) of 316L stainless steel was demonstrated. And the results were validated against the experiments and the sensitivity to laser absorptivity was discussed.
Journal ArticleDOI
Real-time monitoring of laser powder bed fusion process using high-speed X-ray imaging and diffraction
Cang Zhao,Kamel Fezzaa,Ross B. Cunningham,Haidan Wen,Francesco De Carlo,Lianyi Chen,Anthony D. Rollett,Tao Sun +7 more
TL;DR: The high-speed synchrotron hard X-ray imaging and diffraction techniques used to monitor the laser powder bed fusion (LPBF) process of Ti-6Al-4V in situ and in real time demonstrate that many scientifically and technologically significant phenomena in LPBF, including melt pool dynamics, powder ejection, rapid solidification, and phase transformation, can be probed with unprecedented spatial and temporal resolutions.
Journal ArticleDOI
On the limitations of Volumetric Energy Density as a design parameter for Selective Laser Melting
Umberto Scipioni Bertoli,Alexander J. Wolfer,Manyalibo J. Matthews,Jean-Pierre R. Delplanque,Julie M. Schoenung +4 more
TL;DR: In this paper, a review of the current literature on additive manufacturing of 316L stainless steel (SS) related to input parameter scaling relations is presented, where the authors identify a range of Volumetric Energy Density (VED) values that should lead to fully dense parts.
Journal ArticleDOI
Microstructure, defects and mechanical behavior of beta-type titanium porous structures manufactured by electron beam melting and selective laser melting
Yujing Liu,Yujing Liu,Shujun Li,Hailong Wang,W. T. Hou,Yang Hao,Ren-Fu Yang,Timothy B. Sercombe,Lai-Chang Zhang +8 more
TL;DR: In this article, the differences in the microstructure, defects and mechanical behavior of porous structures from a β-type Ti 24Nb 4Zr 8Sn manufactured by electron beam melting (EBM) and selective laser melting (SLM) were investigated and correlated to the compressive mechanical and fatigue properties.
Journal ArticleDOI
Melt pool temperature and cooling rates in laser powder bed fusion
TL;DR: In this paper, a two-wavelength imaging setup is used to account for changes in emissivity and temperature fields are captured at 100 kHz with a resolution of 20μm during the processing of a simple Ti6Al4V component.
References
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Journal ArticleDOI
A model of deep penetration laser welding based on calculation of the keyhole profile
TL;DR: In this article, a model describing the process of deep-penetration laser welding has been developed by calculating the keyhole profile using a point-by-point determination of the energy balance at the key hole wall.
Model of deep penetration laser welding based on calculation of the keyhole profile
TL;DR: In this article, a model describing the process of deep-penetration laser welding has been developed by calculating the keyhole profile using a point-by-point determination of the energy balance at the key hole wall.
Journal ArticleDOI
The simulation of front keyhole wall dynamics during laser welding
Akira Matsunawa,Vlad V Semak +1 more
TL;DR: In this article, a physical model of keyhole support and propagation during high-translation-speed laser welding is described and a numerical code for the simulation of the front keyhole wall behaviour is developed on the basis of a ''hydrodynamic'' physical model assuming that only the front part of the key hole wall is exposed to the high-intensity laser beam.
Journal ArticleDOI
Heat balance and flow conditions for electron beam and laser welding
TL;DR: In this paper, the conditions of energy and material flow during beam welding are investigated theoretically to determine the factors which govern the shape of the vapor cavity and of the molten zone, and the penetration is limited by the beam power or by the absorption of the beam.