Progress on Experimental Study of Melt Pool Flow Dynamics in Laser Material Processing

Xiao, Xin; Lu, Cong; Fu, Yanshu; Yao, Xiaojun; Song, Lijun

doi:10.5772/intechopen.97205

Cited by 12 publications

(4 citation statements)

References 34 publications

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“…EDS analysis indicated that the segregation areas exhibited a high nickel content. This segregation phenomenon can be attributed to the complex flow dynamics within the melt pool, driven by forces such as Marangoni, buoyancy, gravity, and recoil pressure [58]. Elemental segregation in additively manufactured samples can significantly influence corrosion resistance [59].…”

Section: Discussionmentioning

confidence: 99%

A Comparative Investigation of Duplex and Super Duplex Stainless Steels Processed through Laser Powder Bed Fusion

Gargalis,

Karavias,

Graff

et al. 2023

Metals

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The aim of this paper was to compare duplex (DSS) and super duplex stainless steel processed by laser powder bed fusion (LPBF) based on the process parameters and microstructure–nanomechanical property relationships. Each alloy was investigated with respect to its feedstock powder characteristics. Optimum process parameters including scanning speed, laser power, beam diameter, laser energy density, and layer thickness were defined for each alloy, and near-fully dense parts (>99.9%) were produced. Microstructural analysis was performed via optical (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The samples were subjected to stress relief and high-temperature annealing. EBSD revealed the crystallographic orientation and quantified the phases in the as-built and annealed sample conditions. The as-built samples revealed a fully ferritic microstructure with a small amount of grain boundary austenite in the SDSS microstructure. High-temperature solution annealing resulted in the desired duplex microstructure for both alloys. There were no secondary phases present in the microstructure after both heat treatments. Nanoindentation generated nanomechanical (modulus) mapping grids and quantified the nanomechanical (both hardness and modulus) response; plasticity and stress relief were also assessed in all three conditions (as-built, stress-relieved, and annealed) in both DSS and SDSS. Austenite formation in the annealed condition contributed to lower hardness levels (~4.3–4.8 Gpa) and higher plastic deformation compared to the as-built (~5.7–6.3 Gpa) and stress-relieved conditions (~4.8–5.8 Gpa) for both alloys. SDSS featured a ~60% austenite volume fraction in its annealed and quenched microstructure, attributed to its higher nickel and nitrogen contents compared to DSS, which exhibited a ~30% austenite volume fraction.

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Section: Discussionmentioning

confidence: 99%

A Comparative Investigation of Duplex and Super Duplex Stainless Steels Processed through Laser Powder Bed Fusion

Gargalis,

Karavias,

Graff

et al. 2023

Metals

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“…The primary result of the interaction between the laser and materials is the formation of a melt pool. Understanding the characteristics of the melt pool is crucial for achieving high-quality products [52]. Cunningham et al [53] utilized synchrotron X-ray imaging to reveal the sequence of keyhole formation in PBF-LB for metal additive manufacturing, based on laser power density.…”

Section: Melt Pool Dynamicsmentioning

confidence: 99%

Combined Use of Acoustic Measurement Techniques with X-ray Imaging for Real-Time Observation of Laser-Based Manufacturing

Samimi,

Saadabadi,

Hosseinlaghab

2024

Metrology

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Ensuring high-quality control in laser additive manufacturing and laser welding relies on the implementation of reliable and cost-effective real-time observation techniques. Real-time monitoring techniques play an important role in understanding critical physical phenomena, namely, melt pool dynamics and defect formation, during the manufacturing of components. This review aims to explore the integration of acoustic measurement techniques with X-ray imaging for studying these physical phenomena in laser manufacturing. A key aspect emphasized in this work is the importance of time synchronization for real-time observation using multiple sensors. X-ray imaging has proven to be a powerful tool for observing the dynamics of the melt pools and the formation of defects in real time. However, X-ray imaging has limitations in terms of accessibility which can be overcome through combination with other more-accessible measurement methods, such as acoustic emission spectroscopy. Furthermore, this combination simplifies the interpretation of acoustic data, which can be complex in its own right. This combined approach, which has evolved in recent years, presents a promising strategy for understanding acoustic emission signals during laser processing. This work provides a comprehensive review of existing research efforts in this area.

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“…During the solidification of the melt pool, the centre of the melt pool experienced the maximum temperature, followed by a radial drop, causing a difference in the melt pool surface tension, which led to rounded peaks due to the outward flow of the melt pool. 25…”

Section: Effect Of Lp/ss On Kurtosis and Skewnessmentioning

confidence: 99%

Surface morphology and dimensional accuracy of additively manufactured Ti-6Al-4V alloy: Effect of variable scanning speed with constant laser power in widespread energy density

Kumar

Jebaraj

2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The present study aims at analysing the combined role of laser power (LP) and scanning speed (SS) on the surface topography and dimensional accuracy of Titanium (Ti–6Al–4V) alloy fabricated through a laser-based powder bed fusion process. The widespread volumetric energy densities (VEDs) ranging from 25 J/mm3 (S1) to 120 J/mm3 (S10) were chosen with five different combinations of LP with varying SS, such as 150 W (276 and 850 mm/s), 250 W (630 and 990 mm/s), 300 W (395 and 465 mm/s), 350 W (405 and 1100 mm/s), and 370 W (850 and 1270 mm/s). Sample S1 (25 J/mm3) revealed the presence of partially melted track and VED beyond 60 J/mm3 producing a detrimental surface quality due to over-burning. At low LPs of 150 and 250 W, a reduction in SS led to a decrease in surface roughness, owing to sufficient melting of the powder layers. Meanwhile, at high LPs of 300 and 350 W, a reduction in SS caused the burning of the layer which led to an increase in the roughness. In contrast, at a high LP of 370 W, a reduction in SS caused a decrease in the roughness parameters. Both LP and SS were found to have strong interdependence in the achievement of the as-built surface quality. Further, the samples fabricated with excessive VED S7 (75 J/mm3), S8 (90 J/mm3), S9 (105 J/mm3) and S10 (120 J/mm3) caused delamination of layers and resulted in severe angular distortion.

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Progress on Experimental Study of Melt Pool Flow Dynamics in Laser Material Processing

Cited by 12 publications

References 34 publications

A Comparative Investigation of Duplex and Super Duplex Stainless Steels Processed through Laser Powder Bed Fusion

A Comparative Investigation of Duplex and Super Duplex Stainless Steels Processed through Laser Powder Bed Fusion

Combined Use of Acoustic Measurement Techniques with X-ray Imaging for Real-Time Observation of Laser-Based Manufacturing

Surface morphology and dimensional accuracy of additively manufactured Ti-6Al-4V alloy: Effect of variable scanning speed with constant laser power in widespread energy density

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