Densification behavior of gas and water atomized 316L stainless steel powder during selective laser melting

Li, Ruidi; Shi, Yusheng; Wang, Zhigang; Wang, Li; Liu, Jinhui; Jiang, Wei

doi:10.1016/j.apsusc.2010.02.030

Cited by 405 publications

(166 citation statements)

References 17 publications

Supporting

Mentioning

160

Contrasting

Unclassified

Order By: Relevance

“…This is due to the relatively high E caused by lower scanning speed that promotes a stable melt pool by increasing molten materials temperature. This may also lower the surface tension and enhance the wetting characteristics of molten materials resulting in smooth scan tracks and dense structure 22,25) . However, when the E was applied over 200 J/mm 3 , the density of the as-built samples decreased again.…”

Section: Methodsmentioning

confidence: 99%

Densification Behavior of 316L Stainless Steel Parts Fabricated by Selective Laser Melting by Variation in Laser Energy Density

et al. 2016

View full text Add to dashboard Cite

Selective laser melting (SLM) is an attractive manufacturing technique for the production of metal parts with complex geometries and high performance. This manufacturing process is characterized by highly localized laser energy inputs during short interaction times which signicantly affect the densi cation process. In this present work, experimental investigation of fabricating 316L stainless steel parts by SLM process was conducted to determine the effect of different laser energy densities on the densi cation behavior and resultant microstructural development. It was found that using a low laser energy density below 50 J/mm 3 produced an instable melt pool that resulted in the formation of unmelted particles, pores, cracks, and balling in the as-built parts with low densi cation. In contrast, the as-built parts at a high energy density above 200 J/mm 3 showed irregular scan tracks with a number of pores and metal balls that decreased part density. The optimal laser energy density range was accordingly determined to be 58-200 J/mm 3 by eliminating obvious SLM defects, which led to near full densi cation. The SLM samples fabricated using optimal parameters allowed observation of a microhardness of 280 Hv, ultimate strength of 570 MPa, and yield strength of 530 MPa that were higher than those of the as-cast and wrought 316L stainless steel.

show abstract

Section: Methodsmentioning

confidence: 99%

Densification Behavior of 316L Stainless Steel Parts Fabricated by Selective Laser Melting by Variation in Laser Energy Density

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Thijs et al [116] suggested that the large pores with the dimensions of 100∼200 µm result mostly from (a) the accumulations of the powder denudation within the melt pools within a layer, and (b) the surface roughness across the layers. The balling phenomenon (i.e., the melt pool is solidified into discontinuous balls due to poor wettability) can also introduce a large number of irregular pores enclosing non-molten powder and worse surface roughness [117][118][119].…”

Section: Porositymentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

View full text Add to dashboard Cite

Linköping 2018Cover image: A fracture surface of EBM IN718 after tensile test at room temperature.During the course of research underlying this thesis, Dunyong Deng was enrolled in Agora Materiae, a multidiciplinary doctoral program at Linköping University, Sweden. Printed by LiU-Tryck 2018 © Dunyong Deng AbstractAdditive manufacturing (AM), also known as 3D printing, has gained significant interest in aerospace, energy, automotive and medical industries due to its capabilities of manufacturing components that are either prohibitively costly or impossible to manufacture by conventional processes. Among the various additive manufacturing processes for metallic components, electron beam melting (EBM) and selective laser melting (SLM) are two of the most widely used powder bed based processes, and have shown great potential for manufacturing high-end critical components, such as turbine blades and customized medical implants. The futures of the EBM and SLM are doubtlessly promising, but to fully realize their potentials there are still many challenges to overcome.Inconel 718 (IN718) is a nickel-base superalloy and has impressive combination of good mechanical properties and low cost. Though IN718 is being mostly used as a turbine disk material now, the initial introduction of IN718 was to overcome the poor weldability of superalloys in 1960s, since sluggish precipitation of strengthening phases γ ′ /γ ′′ enables good resistance to strain-age cracking during welding or post weld heat treatment. Given the similarity between AM and welding processes, IN718 has been widely applied to the metallic AM field to facilitate the understandings of process-microstructure-property relationships.The work presented in this licentiate thesis aims to better understand microstructures and mechanical properties EBM and SLM IN718, which have not been systematically investigated. Microstructures of EBM and SLM IN718 have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and correlated with the process conditions. Monotonic mechanical properties (e.g., Vickers microhardness and tensile properties) have also been measured and rationalized with regards to the microstructure evolutions before and after heat treatments.For EBM IN718, the results show the microstructure is not homogeneous but dependant on the location in the components, and the anisotropic mechanical properties are probably attributed to alignment of porosities rather than texture.iii Post heat treatment can slightly increase the mechanical strength compared to the as-manufactured condition but does not alter the anisotropy. SLM IN718 shows significantly different microstructure and mechanical properties to EBM IN718. The as-manufactured SLM IN718 has very fine dendritic microstructure and Laves phases in the interdendrites, and is "work-hardened" by the residual strains and dislocations present in the material. Mechanical properties are different between horizontally and vertically built samples, and heat treatment can m...

show abstract

“…[5][6][7][8] This process is also believed to lower the production time of complex parts, to maximize material utilization, and is considered to be environmentally friendly. 9 Most of the SLM research is focused on the following alloys: (i) pure iron, stainless steel, and different tool steel grades in the directions of parameter optimization, structure optimization, and evaluation of mechanical properties [10][11][12][13] ; (ii) Al-based alloys, like Al-12Si and AlSi10Mg, mainly focused on parameter optimization and evaluation of various properties [14][15][16] (iii) Ti6Al4V (for high strength aerospace applications), pure titanium and beta titanium alloys (bulk and porous scaffolds for bio-medical applications) focusing on the parameter optimization and evaluation of related bio-medical, corrosion and mechanical properties [17][18][19][20] ; (iv) Ni-based alloys like nitinol, inconels, and waspaloys (for high temperature properties and shape memory effects) mainly focused on parameter optimization and high temperature properties [21][22][23][24] and (v) Co-based alloys (CoCrMo as dental implants) focused on the microstructure and biomedical properties. 25,26 Altogether, the majority of the research shows that parts produced by SLM have improved properties compared to parts produced by conventional casting/powder metallurgy techniques.…”

Section: Introductionmentioning

confidence: 99%

Processing of Al–12Si–TNM composites by selective laser melting and evaluation of compressive and wear properties

et al. 2015

View full text Add to dashboard Cite

Al-12Si (80 vol%)-Ti 52.4 Al 42.2 Nb 4.4 Mo 0.9 B 0.06 (at.%) (TNM) composites were successfully produced by the selective laser melting (SLM). Detailed structural and microstructural analysis shows the formation of the Al 6 MoTi intermetallic phase due to the reaction of the TNM reinforcement with the Al-12Si matrix during SLM. Compression tests reveal that the composites exhibit significantly improved properties (;140 and ;160 MPa higher yield and ultimate compressive strengths, respectively) compared with the Al-12Si matrix. However, the samples break at ;6% total strain under compression, thus showing a reduced plasticity of the composites. Sliding wear tests were carried out for both the Al-12Si matrix and the Al-12Si-TNM composites. The composites perform better under sliding wear conditions and the wear rate increases with increasing loads. At high loads, the wear takes place at three different rates and the wear rate decreases with increasing experiment duration.

show abstract

Densification behavior of gas and water atomized 316L stainless steel powder during selective laser melting

Cited by 405 publications

References 17 publications

Densification Behavior of 316L Stainless Steel Parts Fabricated by Selective Laser Melting by Variation in Laser Energy Density

Densification Behavior of 316L Stainless Steel Parts Fabricated by Selective Laser Melting by Variation in Laser Energy Density

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Processing of Al–12Si–TNM composites by selective laser melting and evaluation of compressive and wear properties

Contact Info

Product

Resources

About