The effect of evaporation and recoil pressure on energy loss and melt pool profile in selective electron beam melting

Mollamahmutoglu, Mehmet; Yilmaz, Oğuzhan; Ünal, Rahmi; Gümüş, Berkay; Tan, Evren

doi:10.1007/s00170-022-09017-2

Cited by 7 publications

(6 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Resultsmentioning

confidence: 99%

“…Since the Ni concentration of the matrix is reduced due to the formation of the Ni‐rich intermetallic compounds, for instance, Ni 4 Ti 3 and Ni 3 Ti, which also facilitates multistep phase transformations. [ 24,25 ] However, the formation of Ti‐rich precipitate such as Ti 4 Ni 2 O/Ti 2 Ni can cause a decrease in M s temperature due to the increasing of the Ni content. [ 28 ] Nevertheless, according to Frenzel et al [ 28 ] relating the M s temperature to Ni content in the matrix, the Ni ratio in the matrix could be estimated to be ≈50.4 at% for the vacuum cooling groups.…”

Section: Resultsmentioning

confidence: 99%

“…[24] The larger beam diameter increases the melt pool size, which in turn increases the recoil pressure and Marangoni flow, so that the melt pool turbulence and heat losses increase, creating defects such as keyholes. [25] In addition, the dimensional mismatch of manufactured parts with the used CAD model is another important variant, which should be studied with respect to the energy input, as well as the beam current. As shown in Figure 4a, no clear trend can be found for the dimensional mismatch of the parts when compared to the linear energy input.…”

Section: Process Parameter Optimizationmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium

et al. 2023

View full text Add to dashboard Cite

Electron beam powder bed fusion (PBF‐EB) is used to manufacture dense nickel titanium parts using various parameter sets, including the beam current, scan speed, and postcooling condition. The density of manufactured NiTi parts is investigated in relation to the linear energy input. The results imply that the part density increases with increasing linear energy density to over 98% of the bulk density. With a constant energy input, a combination of low power and low scan speed leads to denser parts. This is attributed to lower electrostatic repulsive forces from lower number density of the impacting electrons. After manufacturing, the densest parts with distinct parameter sets are categorized into three groups: 1) high power with high scan speed and vacuum slow cooling, 2) low power with low scan speed and vacuum slow cooling, and 3) low power with low scan speed and medium cooling rate in helium gas. Among these, a faster cooling rate suppresses phase transformation temperatures, while vacuum cooling combinations do not affect the phase transformation temperatures significantly. Herein, all the printed parts exhibit almost 8% pseudoelasticity regardless of the process parameters, while the parts cooled in helium have a higher energy dissipation efficiency (1 − η), which implies faster damping of oscillations.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Process Parameter Optimizationmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium

et al. 2023

View full text Add to dashboard Cite

show abstract

“…The powder layer has a porosity structure, and after solidification, the layer thickness decrease with the effect of the collapse depending on the relative powder density. There are approaches to this issue in the literature [19,20], and one of them is the calculation of effective solidified layer thicknesses for each layer [20]. Therefore, in this study, effective solidified layer thicknesses for each layer were calculated and defined by using the effective thickness expression [20].…”

Section: Figure 3 Thermal Conductivity and Specific Heat Capacity Pro...mentioning

confidence: 99%

“…There are approaches to this issue in the literature [19,20], and one of them is the calculation of effective solidified layer thicknesses for each layer [20]. Therefore, in this study, effective solidified layer thicknesses for each layer were calculated and defined by using the effective thickness expression [20].…”

Section: Figure 3 Thermal Conductivity and Specific Heat Capacity Pro...mentioning

confidence: 99%

Computational Evaluation of the Effect of Build Orientation on Thermal Behavior and in-situ Martensite Decomposition for Laser Powder-Bed Fusion (LPBF) Process

YILDIZ¹,

Mollamahmutoglu²,

Yilmaz³

2023

Gazi University Journal of Science

Self Cite

View full text Add to dashboard Cite

show abstract

Mechanism of Laser‐Induced Self‐Deposition of Nanoparticles Identified by In Situ Observation

Chen,

Matsuda,

Ito

et al. 2024

Laser & Photonics Reviews

View full text Add to dashboard Cite

Laser ablation has emerged as a promising technique for fabricating nanoparticles (NPs) on metal surfaces, as demonstrated by extensive experimental and simulation studies. However, the fundamental mechanisms underlying the self‐deposition of laser‐induced NPs remain unclear, owing to the complexity of the process influenced by various factors and their interactions. In contrast to prior research that solely focused on isolated factors, this research proposes an observation system designed to systematically elucidate the mechanisms of laser‐induced self‐deposition of NPs on a copper surface. This system integrates ultrashort exposure observation with the pump–probe method, enabling the capture of dynamically evolving phenomena within the time frame of laser ablation. The proposed probing techniques reveal that the plasma plume consistently aligns with the NP spatter boundary. Additionally, liquid NPs are observed to travel into the plume and evaporate at its boundary, while solid NPs are propelled in opposite directions owing to recoil pressure from jetting vapor, eventually settling around the laser‐irradiated area. This study offers comprehensive insights into the mechanisms of NP self‐deposition through laser ablation, which is critical for optimizing the laser parameters in micro/nanofabrication and advancing the fundamental research in laser manufacturing.

show abstract

The effect of evaporation and recoil pressure on energy loss and melt pool profile in selective electron beam melting

Cited by 7 publications

References 26 publications

Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium

Influence of Electron Beam Powder Bed Fusion Process Parameters on Transformation Temperatures and Pseudoelasticity of Shape Memory Nickel Titanium

Computational Evaluation of the Effect of Build Orientation on Thermal Behavior and in-situ Martensite Decomposition for Laser Powder-Bed Fusion (LPBF) Process

Mechanism of Laser‐Induced Self‐Deposition of Nanoparticles Identified by In Situ Observation

Contact Info

Product

Resources

About