Modeling of thermal behavior and mass transport in multi-layer laser additive manufacturing of Ni-based alloy on cast iron

Gan, Zhengtao; Líu, Hao; Li, Shaoxia; He, Xiuli; Yu, Gang

doi:10.1016/j.ijheatmasstransfer.2017.04.055

Cited by 169 publications

(42 citation statements)

References 31 publications

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“…The contour of the cooling rate is shown in Figure 17 (c), where the cooling rate is highest at the top and bottom of the initial melt pool's borders and has its lowest values in the middle of the centerline. The cooling rate is a good indicator for the size of the grains or dendrites forming during solidification where lower cooling rates lead to bigger grain or dendrite sizes [15], [16]. Thijs et al [63] reported that the microstructure at the bottom of the melt pool is much finer than the one found in the internal region, which is in accordance with the cooling rate contour shown in Figure 17 (c).…”

Section: Case Idsupporting

confidence: 64%

A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

Bayat

Mohanty

Hattel

2019

International Journal of Heat and Mass Transfer

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Section: Case Idsupporting

confidence: 64%

A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

Bayat

Mohanty

Hattel

2019

International Journal of Heat and Mass Transfer

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“…Monitoring of advanced manufacturing processes to evaluate changes in thermal history, structure and properties is crucial for an understanding of the physical phenomena that occur during the process and for closed-loop control of built properties in AM 16–18 . In particular, thermal models of powder-blown additive manufacturing processes use simplified laser absorptivity parameters for the substrate and powders even though absorptivity changes with laser power, scan speed, powder flow rate, the laser induced vapor-plasma plume and the inert gas environment 18–22 . The predicted thermal histories and structures from such models are highly sensitive to laser energy absorptivity during the process 23–26 , underscoring the need for experiments that reveal how the substrate and powder deposition absorb the laser beam.…”

Section: Introductionmentioning

confidence: 99%

In-situ high-speed X-ray imaging of piezo-driven directed energy deposition additive manufacturing

Wolff

Parab

et al. 2019

Sci Rep

114

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Powder-blown laser additive manufacturing adds flexibility, in terms of locally varying powder materials, to the ability of building components with complex geometry. Although the process is promising, porosity is common in a built component, hence decreasing fatigue life and mechanical strength. The understanding of the physical phenomena during the interaction of a laser beam and powder-blown deposition is limited and requires in-situ monitoring to capture the influences of process parameters on powder flow, absorptivity of laser energy into the substrate, melt pool dynamics and porosity formation. This study introduces a piezo-driven powder deposition system that allows for imaging of individual powder particles that flow into a scanning melt pool. Here, in-situ high-speed X-ray imaging of the powder-blown additive manufacturing process of Ti-6Al-4V powder particles is the first of its kind and reveals how laser-matter interaction influences powder flow and porosity formation.

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“…Temperature gradient G and growth rate R have influence on the morphology and size of solidification microstructure, as shown in Figure 3b. As the simulation result of multi-layer deposited [30,31], G/R and G × R is 177 s/mm 2 and 6010 K/s at first layer where its second dendrite arm spacing is 1.9 μm. The G/R and G × R is 154 s/mm 2 and 3980 K/s at the sixth layer where its second dendrite arm spacing decreased to 3.1 μm.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Specific Energy Density on Microstructure and Corrosion Resistance of CoCrMo Alloy Fabricated by Laser Metal Deposition

Ren

Liu

et al. 2019

Materials

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With the development of modern medical implants, there are significantly increasing demands for personalized prosthesis. Corrosion-resistance and dense cobalt alloy specimens have been successfully fabricated by laser metal deposition. The relationship between specific energy density, microstructure and corrosion resistance of the specimens is investigated. The results show that higher specific energy density promotes the formation of columnar grain and leads to coarse grain size. The evolution and distribution of deposited microstructure from bottom to top are summarized in a metallographic sketch. The corrosion current of deposited specimens increases from 2.071 × 10−6 A/cm2 to 6.86 × 10−5 A/cm2 and rapidly drops to 9.88 × 10−7 A/cm2 with increase of specific energy density from 318.8 J/g to 2752.3 J/g. The columnar and equiaxed structure of deposited specimens have lower corrosion current than mixed structure due to finer grain and less Mo segregation. The deposited have low level metal released because of passive film. The passive film have different formation routes in Hank’s solution and acidic saliva. The specific energy density has an important effect on the microstructure of deposited, which improves corrosion resistance and life span in implant.

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Modeling of thermal behavior and mass transport in multi-layer laser additive manufacturing of Ni-based alloy on cast iron

Cited by 169 publications

References 31 publications

A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

In-situ high-speed X-ray imaging of piezo-driven directed energy deposition additive manufacturing

The Effect of Specific Energy Density on Microstructure and Corrosion Resistance of CoCrMo Alloy Fabricated by Laser Metal Deposition

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