Ultra-short pulsed laser powder bed fusion of Al-Si alloys: Impact of pulse duration and energy in comparison to continuous wave excitation

Ullsperger, Tobias; Li, Dongmei; Yürekli, Burak; Matthäus, Gabor; Schade, Lisa; Seyfarth, Brian; Kohl, Hagen; Ramm, Roland; Rettenmayr, Markus; Nolte, Stefan

doi:10.1016/j.addma.2021.102085

Cited by 19 publications

(8 citation statements)

References 52 publications

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“…These 3D structures fabricated were 8 mm in diameter, consisting of 120 layers with 30 microns for each layer thickness and a final wall thickness of 100 microns [38]. Moreover, Ullsperger et al [183] carried out comparative studies on laser-assisted powder bed fusion of Al-40Si (40 percent Si by weight). They utilised an fs laser source operating at a 1030 nm wavelength with a repetition rate between 6 and 20 MHz as well as a CW laser operating at a 1070 nm wavelength.…”

Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

“…Higher ablation has been reported with a fluence greater than 0.4 J/cm 2 . With ultrafast laser pulses of 500 fs and 20 ps operating at 20 MHz, the lowest melting pool width of 70 µm was formed, and enhanced fabricated parts with higher hardness were reported [183]. fs and 20 ps operating at 20 MHz, the lowest melting pool width of 70 µm was formed, and enhanced fabricated parts with higher hardness were reported [183].…”

Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

“…With ultrafast laser pulses of 500 fs and 20 ps operating at 20 MHz, the lowest melting pool width of 70 µm was formed, and enhanced fabricated parts with higher hardness were reported [183]. fs and 20 ps operating at 20 MHz, the lowest melting pool width of 70 µm was formed, and enhanced fabricated parts with higher hardness were reported [183]. fs and 20 ps operating at 20 MHz, the lowest melting pool width of 70 µm was formed, and enhanced fabricated parts with higher hardness were reported [183].…”

Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

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Femtosecond Laser-Based Additive Manufacturing: Current Status and Perspectives

Kaligar

Kumar

Ali

et al. 2022

QuBS

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The ever-growing interest in additive manufacturing (AM) is evidenced by its extensive utilisation to manufacture a broad spectrum of products across a range of industries such as defence, medical, aerospace, automotive, and electronics. Today, most laser-based AM is carried out by employing continuous-wave (CW) and long-pulsed lasers. The CW and long-pulsed lasers have the downside in that the thermal energy imparted by the laser diffuses around the irradiated spot and often leads to the creation of heat-affected zones (HAZs). Heat-affected zones may degrade the material strength by producing micro-cracks, porous structures and residual stresses. To address these issues, currently, attempts are being made to employ ultrafast laser sources, such as femtosecond (fs) lasers, in AM processes. Femtosecond lasers with pulse durations in the order of 10−15 s limit the destructive laser–material interaction and, thus, minimise the probability of the HAZs. This review summarises the current advancements in the field of femtosecond laser-based AM of metals and alloys. It also reports on the comparison of CW laser, nanosecond (ns)/picosecond (ps) lasers with fs laser-based AM in the context of heat-affected zones, substrate damage, microstructural changes and thermomechanical properties. To shed light on the principal mechanisms ruling the manufacturing processes, numerical predictions are discussed and compared with the experimental results. To the best of the authors’ knowledge, this review is the first of its kind to encompass the current status, challenges and opportunities of employing fs lasers in additive manufacturing.

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Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

Section: Femtosecond Laser Sintering Of Aluminium Alloymentioning

confidence: 99%

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Femtosecond Laser-Based Additive Manufacturing: Current Status and Perspectives

Kaligar

Kumar

Ali

et al. 2022

QuBS

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“…Lasers can be categorized based on their operational mode as continuous-wave (CW) or pulsed lasers. CW lasers deliver continuous energy onto the surface of the material, whereas pulsed lasers emit energy in pulses [ 10 , 11 , 12 ]. Herein, we used picosecond laser pulses for the nanostructure’s generation.…”

Section: Introductionmentioning

confidence: 99%

Advanced Fabrication of 3D Micro/Nanostructures of Gallium Oxide with a Tuned Band Gap and Optical Properties

Jamwal,

Kiani

2024

Micromachines

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Gallium oxide (Ga2O3) is a promising material for high-power semiconductor applications due to its wide band gap and high breakdown voltage. However, the current methods for fabricating Ga2O3 nanostructures have several disadvantages, including their complex manufacturing processes and high costs. In this study, we report a novel approach for synthesizing β-Ga2O3 nanostructures on gallium phosphide (GaP) using ultra-short laser pulses for in situ nanostructure generation (ULPING). We varied the process parameters to optimize the nanostructure formation, finding that the ULPING method produces high-quality β-Ga2O3 nanostructures with a simpler and more cost-effective process when compared with existing methods. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the samples, which indicated the presence of phosphorous. X-ray photoelectron spectroscopy (XPS) confirmed the formation of gallium oxide, along with a minor amount of phosphorus-containing compounds. Structural analysis using X-ray diffraction (XRD) revealed the formation of a monoclinic β-polymorph of Ga2O3. We also measured the band gap of the materials using reflection electron energy loss spectroscopy (REELS), and found that the band gap increased with higher nanostructure formation, reaching 6.2 eV for the optimized sample. Furthermore, we observed a change in the heterojunction alignment, which we attribute to the change in the oxidation of the samples. Our results demonstrate the potential of ULPING as a novel, simple, and cost-effective method for fabricating Ga2O3 nanostructures with tunable optical properties. The ULPING method offers a green alternative to existing fabrication methods, making it a promising technology for future research in the field of Ga2O3 nanostructure fabrication.

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“…These two parameters control the number of pulses that reach the powder bed per surface unit area in the scanning direction and perpendicularly to it. A vast majority of industrial AM processes (using CW or long-pulsed lasers) create high-speed and relatively stable distribution of laser pulses in order to obtain a constant energy density value [35][36][37][38]; in doing so, the pulse overlap in every direction is kept constant.…”

Section: Introductionmentioning

confidence: 99%