Denudation of metal powder layers in laser powder bed fusion processes

被引:601
作者
Matthews, Manyalibo J. [1 ]
Guss, Gabe [1 ]
Khairallah, Saad A. [1 ]
Rubenchik, Alexander M. [1 ]
Depond, Philip J. [1 ]
King, Wayne E. [1 ]
机构
[1] Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA
关键词
Selective laser melting; Powder bed fusion; Surface structure; Defects; Fluid dynamics; Finite element modeling; High speed imaging; 316L STAINLESS-STEEL; HEAT-TRANSFER; MICROSTRUCTURE; COMPONENTS; SPATTER; BEAM;
D O I
10.1016/j.actamat.2016.05.017
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Understanding laser interaction with metal powder beds is critical in predicting optimum processing regimes in laser powder bed fusion additive manufacturing of metals. In this work, we study the denudation of metal powders that is observed near the laser scan path as a function of laser parameters and ambient gas pressure. We show that the observed depletion of metal powder particles in the zone immediately surrounding the solidified track is due to a competition between outward metal vapor flux directed away from the laser spot and entrainment of powder particles in a shear flow of gas driven by a metal vapor jet at the melt track. Between atmospheric pressure and similar to 10 Torr of Ar gas, the denuded zone width increases with decreasing ambient gas pressure and is dominated by entrainment from inward gas flow. The denuded zone then decreases from 10 to 2.2 Torr reaching a minimum before increasing again from 2.2 to 0.5 Torr where metal vapor flux and expansion from the melt pool dominates. The dynamics of the denudation process were captured using high-speed imaging, revealing that the particle movement is a complex interplay among melt pool geometry, metal vapor flow, and ambient gas pressure. The experimental results are rationalized through finite element simulations of the melt track formation and resulting vapor flow patterns. The results presented here represent new insights to denudation and melt track formation that can be important for the prediction and minimization of void defects and surface roughness in additively manufactured metal components. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd.
引用
收藏
页码:33 / 42
页数:10
相关论文
共 24 条
[1]   On the formation of A1Si10Mg single tracks and layers in selective laser melting: Microstructure and nano-mechanical properties [J].
Aboulkhair, Nesma T. ;
Maskery, Ian ;
Tuck, Chris ;
Ashcroft, Ian ;
Everitt, Nicola M. .
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, 2016, 230 :88-98
[2]  
[Anonymous], ALE3D ARBITRARY LAGR
[3]   SURFACE RIPPLING INDUCED BY SURFACE-TENSION GRADIENTS DURING LASER SURFACE MELTING AND ALLOYING [J].
ANTHONY, TR ;
CLINE, HE .
JOURNAL OF APPLIED PHYSICS, 1977, 48 (09) :3888-3894
[4]   Modeling of laser interactions with composite materials [J].
Boley, Charles D. ;
Rubenchik, Alexander M. .
APPLIED OPTICS, 2013, 52 (14) :3329-3337
[5]  
B┬u├▒uerle D., 2013, LASER PROCESSING CHE
[6]  
Chivel Y., 2014, 8 INT C PHOT TECHN L, P1
[7]   Dynamic Mechanical Behavior of Additively Manufactured Ti6Al4V With Controlled Voids [J].
Fadida, Refael ;
Rittel, Daniel ;
Shirizly, Amnon .
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME, 2015, 82 (04)
[8]  
Gladush G.G., 2011, Physics Of Laser Materials Processing Theory and Experiment
[9]   Laser additive manufacturing of metallic components: materials, processes and mechanisms [J].
Gu, D. D. ;
Meiners, W. ;
Wissenbach, K. ;
Poprawe, R. .
INTERNATIONAL MATERIALS REVIEWS, 2012, 57 (03) :133-164
[10]   Heat transfer modelling and stability analysis of selective laser melting [J].
Gusarov, A. V. ;
Yadroitsev, I. ;
Bertrand, Ph. ;
Smurov, I. .
APPLIED SURFACE SCIENCE, 2007, 254 (04) :975-979