Influence of contaminants on part quality during Laser-Based Powder Bed Fusion of nickel base alloys

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM processes principles. Selective Laser Melting (SLM) is a widespread Powder Bed Fusion (PBF) AM process that due to its superior advantages, such as capability to print complex and highly customized components, which leads to an increasing attention paid by industries and academia. Temperature distribution and melt pool dynamics have paramount importance to be well simulated and correlated by part quality in terms of surface finish, induced residual stress and microstructure evolution during SLM. Summarizing numerical simulations of SLM in this survey is pointed out as one important research perspective as well as exploring the contribution of adopted approaches and practices. This review survey has been organized to give an overview of AM processes such as extrusion, photopolymerization, material jetting, laminated object manufacturing, and powder bed fusion. And in particular is targeted to discuss the conducted numerical simulation of SLM to illustrate a uniform picture of existing nonproprietary approaches to predict the heat transfer, melt pool behavior, microstructure and residual stresses analysis.

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Study on Laser Powder Bed Fusion of Nickel-base Alloy: Scanning Strategy, Properties and Compression Properties

10.21203/rs.3.rs-128086/v1 ◽

2020 ◽

Author(s):

Bo Qian ◽

Hongri Fan ◽

Tengfei Li ◽

Jianrui Zhang ◽

Jiangtao Xi ◽

...

Keyword(s):

Surface Structure ◽

Base Alloy ◽

Powder Bed Fusion ◽

Nickel Base Alloy ◽

Laser Powder Bed Fusion ◽

Scanning Strategy ◽

Powder Bed ◽

Compression Performance ◽

Nickel Base ◽

Scanning Strategies

Abstract Aiming at laser powder bed fusion of GH3536 nickel base alloy, the effects of different scanning strategies on microstructure, porosity and mechanical properties were explored. In the aspect of microstructure and micro hardness of the sample, three scanning strategies had little difference; in the aspect of macro mechanical properties of the sample, the slope subarea scanning was better than the helix and island scanning. On this basis, the slope subarea scanning was selected as the optimal scanning strategy to form the G-surface structure, and the compression performance of G-surface was studied. The results showed that: (1) the compression performance of G-surface structure was smaller than that of solid structure; while G-surface structure had a smooth compression curve, which indicated the good energy absorption characteristics; (2) with the increase of wall thickness, the mechanical performance of G-surface structure was also enhanced, while the energy absorption capacity was constantly reduced; (3) with the same wall thickness, the compression performance of sample in building direction (BD) is higher than that in horizontal direction (HD).

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Microstructure of In738Lc Fabricated Using Laser Powder Bed Fusion Additive Manufacturing

Journal of Turbomachinery ◽

10.1115/1.4052404 ◽

2021 ◽

pp. 1-19

Author(s):

Nandana Menon ◽

Tanjheel Hasan Mahdi ◽

Amrita Basak

Keyword(s):

Additive Manufacturing ◽

Electron Backscatter Diffraction ◽

Small Scale ◽

Second Phase ◽

Face Centered Cubic ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Nickel Base Superalloys ◽

Nickel Base

Abstract Nickel-base superalloys are extensively used in the production of gas turbine hot-section components as they offer exceptional creep strength and superior fatigue resistance at high temperatures. Such improved properties are due to the presence of precipitate-strengthening phases such as Ni3Ti or Ni3Al (gγ phases) in the normally face-centered cubic (FCC) structure of the solidified nickel. Although this second phase is the main reason for the improvements in properties, the presence of such phases also results in increased processing difficulties as these alloys are prone to crack formation. In this work, specimens of IN738LC are fabricated on a Coherent Creator laser powder bed fusion (L-PBF) additive manufacturing (AM) equipment. Optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-Ray diffraction (XRD) are carried out to characterize the deposit region. Metallurgical continuity is achieved in the entire deposit region and the specimens do not show any warpage. However, the specimens show voids (e.g., pores and cracks) in the deposit region. The results show that the percentage void area decreases along the build height direction. The deposited IN738LC shows polycrystalline grains in the entire deposit region as confirmed by XRD and EBSD. The grain size also shows variations along the build direction. In summary, the results open opportunities for academic researchers and small scale businesses in fabricating high-gγ nickel-base superalloys on a desktop laser powder bed fusion AM equipment

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Increasing the productivity of laser powder bed fusion: Influence of the hull-bulk strategy on part quality, microstructure and mechanical performance of Ti-6Al-4V

Additive Manufacturing ◽

10.1016/j.addma.2020.101129 ◽

2020 ◽

Vol 33 ◽

pp. 101129 ◽

Cited By ~ 2

Author(s):

Charlotte de Formanoir ◽

Umberto Paggi ◽

Thomas Colebrants ◽

Lore Thijs ◽

Guichuan Li ◽

...

Keyword(s):

Mechanical Performance ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Part Quality

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Influence of metal powder cross-contaminations on part quality in Laser Powder Bed Fusion: copper alloy particles in maraging steel feedstock

Procedia CIRP ◽

10.1016/j.procir.2020.09.032 ◽

2020 ◽

Vol 94 ◽

pp. 167-172

Author(s):

Max Horn ◽

Lukas Langer ◽

Mario Schafnitzel ◽

Simone Dietrich ◽

Georg Schlick ◽

...

Keyword(s):

Metal Powder ◽

Maraging Steel ◽

Copper Alloy ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Part Quality ◽

Alloy Particles

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Microstructure of IN738LC Fabricated Using Laser Powder Bed Fusion Additive Manufacturing

10.1115/gt2021-58786 ◽

2021 ◽

Author(s):

Nandana Menon ◽

Tanjheel Hassan Mahdi ◽

Amrita Basak

Keyword(s):

Additive Manufacturing ◽

Electron Backscatter Diffraction ◽

Small Scale ◽

Second Phase ◽

Face Centered Cubic ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

Nickel Base Superalloys ◽

Nickel Base

Abstract Nickel-base superalloys are extensively used in the production of gas turbine hot-section components as they offer exceptional creep strength and superior fatigue resistance at high temperatures. Such improved properties are due to the presence of precipitate-strengthening phases such as Ni3Ti or Ni3Al (γ′ phases) in the normally face-centered cubic (FCC) structure of the solidified nickel. Although this second phase is the main reason for the improvements in properties, the presence of such phases also results in increased processing difficulties as these alloys are prone to crack formation. In this work, specimens of IN738LC are fabricated on a Coherent Creator laser powder bed fusion (L-PBF) additive manufacturing (AM) equipment. Optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-Ray diffraction (XRD) are carried out to characterize the deposit region. Metallurgical continuity is achieved in the entire deposit region and the specimens do not show any warpage. However, the specimens show voids (e.g., pores and cracks) in the deposit region. The results show that the percentage void area decreases along the build height direction. The deposited IN738LC shows polycrystalline grains in the entire deposit region as confirmed by XRD and EBSD. The grain size also shows variations along the build direction. In summary, the results open opportunities for academic researchers and small-scale businesses in fabricating high-γ′ nickel-base superalloys on a desktop laser powder bed fusion AM equipment.

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