Full Paper: Xiaoqing Wang, Xibing Gong, Kevin Chou, Review on powder-bed laser additive manufacturing of Inconel 718 parts, Proc. Inst. Mech. Eng. Part B J. Eng. Manuf. 231 (2017) 1890–1903. doi:10.1177/0954405415619883. Available at: http://www.academia.edu/29967012/Review_on_powder-bed_laser_additive_manufacturing_of_Inconel_718_parts

1. Review on Powder-bed Laser Additive
Manufacturing of Inconel 718 Parts
Xiaoqing Wang, Xibing Gong, Kevin Chou
Mechanical Engineering Department
The University of Alabama
June 9, 2015
1

2. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-
bed Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
2

3. Introduction of SLM
 A relatively new additive manufacturing process
1995, Fraunhofer IL T, Aachen, Germany
 Making high-density standard functional metallic parts
 Complex and strong components used in aerospace
 High accuracy of components: ± 50 um
3http://stage.slm-solutions.com/index.php?slm-280_enhttp://www.renishaw.com/en/laser-melting-metal-3d-printing-systems--15240

4. Introduction of SLM
 Advantages
 Saving both time and money
 Structurally stronger & more reliable
(Weld (X) )
 Application
 Build parts for America's flagship rocket
 Complex geometries & structures
 Have thin wall/hidden voids/channels/on
the hand
 Goal
 Manufacture parts on the first SLS test
flight in 2017 using SLM
4
Marshall Space Flight Center
http://www.nasa.gov/exploration/systems/sls/selective_melting.html#.VVpyTP7F860

5. 5
Introduction of SLM
Inert gas
Laser beams
Computer control
Fine powders
Diameter: 10 - 60 µm
Layer thickness
0.02 - 0.2 mm
Kruth, J. P. et al.,2005
Video animation: https://www.youtube.com/watch?v=Mjf6oaMVWr8

6. 6
Introduction of Inconel 718
First material researched and most widely used
Superior properties
 High-strength
 Excellent creep properties
 Superior oxidation/corrosion resistance
Application
 Liquid fuelled rockets
 Combustion chambers
 Turbine blades
 Nuclear reactors and pumps
Blisk Turbine

7. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
7

8. 8
Motivation
Defects, such as porosities, unmelt powder
Part characteristics sensitive to process parameters
No detail review in literature

9. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
9

10. 10
Inconel 718 Powder
Wang, Z., et al.,2012 [23]
SEM image
Powder characteristics
 Parts density
 Mechanical properties
 Surface roughness
Particles defects (Satellites, Pores)
 Flow ability
 Density after melting (Detrimental)
Powder particle size distribution
 Flow ability / Inhomogeneous
 Capacity for particle accommodation

11. 11
Inconel 718 Powder
 Gas-atomized (GA)
 Size: ~ 60 µm, 90% [40 100] µm [38]
 Fine: 44 - 74 µm, Coarse: 74 – 125 µm [9]
 Fine dendritic network / Rapid solidification
 Plasma rotating electrode processed (PREP)
 Size: 44 – 149 µm [9]
Parimi, L.L., et al.,2014 [38] Jia Q., et al.,2014 [40]
SEM image
Chemical compositions
Elements GA GA PREP
Ni BAL 53.05 54.82 51.75
Cr 18.4 18.23 18.08 19.68
Fe 17.7 17.58 17 16-18
Nb 5.1 5.1 5.17 4.91
Mo 4.2 3.06 3.1 3.18
Ti 0.9 0.94 0.89 0.97
Al 0.3 0.44 0.53 0.63
C 0.08 0.04 0.03 0.034
Co 0.27 0.17
Si 0.12 0.08
Ref. [40] [9] [9] ASM Standard
Qi H., et al., 2009 [9]

12. 12
Microstructure Study on Inconel 718
Coarse grain size
Heavy dendritic segregation
Properties
 Cast < Wrought
Casting Wrought
Miao, Z.-J., et al.,2012
(a) (b)
Yuan, H., et al.,2005 Qi, H., et al.,2009
Defects
 Shrinkage cavities,
Porosity
 Freckles and white
spots

13. 13
Microstructure Study on Inconel 718
(c)
Qi, H., et al.,2005
Typical directional
columnar grain
 White particles
 Shape: Globular/Irregular
 Phase: Laves, MC and TiN
 Reason: Segregated/Fast Solidification
 Fine Sec. dendrites
Avg. dendrite arm
~ 5 μm

14. 14
Microstructure Study on Inconel 718
SLM formation features
Line by line / Layer by layer
Melted tracks/Arcs/Gauss energy distribution
Cross section Vertical section
Wang, Z., et al.,2012

15. 15
Microstructure Study on Inconel 718
 Dendrites / Growing direction / Z
Schematic view
Amato, K.N., et al.,2012
Vertical section

16. 16
Microstructure Study on Inconel 718
Parimi, L.L. et al.,2014
SEM micrographs showing the intermetallic precipitates
 Laves phases
Size: of ~1–2 μm
Shape: White irregularly
Reason: Nb segregation with the
other alloying elements
Where: Inter-dendritic regions
 γ′ and γ″ phases
Size: less than 20 nm/ cannot
be observed in SEM pictures
 Carbides
Size: ~ 200 – 300 nm
Shape: Square & Spherical

17. 17
Microstructure Study on Inconel 718
SEM micrograph
Parimi, L.L. et al.,2014
Phase Type Shape Crystal Structure Composition
γ Matrix Base Ni
γ″ Major
Strengthening
Disk bct Ni3Nb
γ′ Spheroidal Cubic, Ordered fcc Ni3(Al, Ti, Nb)
δ
Brittle,
Intermetallic
Needle/plate-like Orthorhombic Ni3Nb
Laves
Irregularly
(Round/Island-like)
(Ni, Fe, Cr)2(Mo, Nb, Ti)
Carbides MC/Complex Ni3(Ti, Nb)
Chemical compositions

18. 18
Microstructure Study on Inconel 718
As-deposited + Heat treatment: Cross section (Left) & Vertical section (Right)
Heat treatment
The regular dendritic structure disappears
γ′ and γ″ phases dissolve in the matrix
Laves phase dissolving in the matrix
Needle-like δ phase precipitates at grain boundaries
Wang, Z., et al.,2012

19. 19
Microstructure Study on Inconel 718
 Residual thermal stress
Thermal cracks
 Dendrite
 Interdendritic zones
Reason
 High scan speed
 Repeated rapid
melting/solidification
Jia, Q., et al.,2014
SEM
 Solutions
Heating of the substrate plate
Increase the temperature inside the processing chamber
Post heat treatment

20. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
20

21. 21
Main Process Deficiencies
Tabernero, I., et al., 2011
 Porosities and unmelt powder are typical defects
Affected the density and porosity
Act as strong stress raiser / leading to failure
Song, B., et al., 2013

22. 22
Main Process Deficiencies
 Initial powder contaminations / evaporation / local voids
GA Powder
Jia Q., et al., 2014 Qi. H, et al., 2009Parimi, L.L. et al.,2014

23. 23
Main Process Deficiencies
 Spherical shape pores
 Entrapped gas bubbles / molten
metal bead
 High scan speed
 Protective gas, argon /
encapsulated inside
180J/m, 110W, 400 mm/s 275J/m, 110W, 600 mm/s
Jia Q., et al., 2014 Qi. H, et al., 2009Parimi, L.L. et al.,2014
Open pores
 High viscosity /
impeded / spreading
out smoothly

24. 24
Main Process Deficiencies
 Solutions / Using PREP powder or fine GA powder
Fine GA Powder PREP Powder
Jia Q., et al., 2014Qi. H, et al., 2009

25. 25
Main Process Deficiencies
Using high laser deposition linear energy level
(Energy density: 330 J/m, 98.4%)
HIPing of the final solid components
300J/m, 120W, 400 mm/s 330J/m, 130W, 400 mm/s
Jia Q., et al., 2014Qi. H, et al., 2009

26. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
26

27. Comparable
27
Yield strength
903
830
552 590
650
758
1034
0
200
400
600
800
1000
1200
Wang(SLM)
Amato(SLM)
Qi(LNSM)
Zhao(LRF)
Blackwell(LDM)
AMS(Cast)
AMS(Wrought)
YS,GPa
Studies

28. Variation -> Different structures
(composition, pore size, and porosity distribution, etc)
28
Ultimate tensile strength
1142.5 1120
904 845
1000
862
1276
0
200
400
600
800
1000
1200
1400
Wang(SLM)
Amato(SLM)
Qi(LNSM)
Zhao(LRF)
Blackwell
(LDM)
AMS(Cast)
AMS(Wrought)
UTS,GPa
Studies
(b)

29. General: Comparable
Cast < SLM < Wrought
SLM > Other laser technologies
29
Elastic modulus
204 208
0
30
60
90
120
150
180
210
240
Wang (SLM) ASM (Wrought)
E,GPa
Studies
(c)

30. 30
Yield Strength (Heat Treatment)
1133
1170
1098
1132
930
1204
1257
1084
1007
949
758
1034
0
200
400
600
800
1000
1200
1400
Zhao(DLD(GA)+Aged)
Zhao(DLD(PREP)+Aged)
Zhang(DLD+Heated)
Wang(SLM+Heated)
Amato(SLM+Annealed)
Blackwell(DLD+Aged)
Blackwell(Fullheated)
Qi(LNSM+Aged)
Qi(LNSM+STA)
Qi(LNSM+H..+STA)
AMS(Cast)
AMS(Wrought)
YS,GPa
Studies
(a)

31. 31
Ultimate tensile strength (Heat Treatment)
1240
1360
1321
1319
1200
1393
1436
1333
1221
1194
862
1276
0
300
600
900
1200
1500
Zhao(DLD(GA)+Aged)
Zhao(DLD(PREP)+Aged)
Zhang(DLD+Heated)
Wang(SLM+Heated)
Amato(SLM+Annealed)
Blackwell(DLD+Aged)
Blackwell(Fullheated)
Qi(LNSM+Aged)
Qi(LNSM+STA)
Qi(LNSM+H..+STA)
AMS(Cast)
AMS(Wrought)
UTS,GPa
Studies
(b)

32. Ductility (↓) ← Fine Laves particles @ Interdendritic
regions
Homogenization treatment → Elongation (↑) (19.9%) &
Lower tensile strength, 1194 MPa
32
Mechanical Properties Study
23
16.2
16.2 16.2
11
5
12
16
8.4
16
19.9
9
0
5
10
15
20
25
30
Wang(SLM)
Qi(LNSM)
Qi(LNSM)
Qi(LNSM)
Zhao(LRF)
AMS(Cast)
AMS
(Wrought)
PlasticElongation,%
Studies
As Deposited
With Heat treatment

33. 33
Other Testing
 The hardness of the layer produced with laser metal deposition
(LMD) did not show obvious difference along the height of the layer
either for the as-deposited layer or for the heat treated layer.
 The microhardness of the LMD zone after heat treatment was
obviously higher than that after the as-deposited treatment.
Methods Test Values Ref.
SLM Vickers 3.9 Gpa
Amato et al.
2012
HIP Vickers 5.7 Gpa
Annealed Vickers 4.6 Gpa
SLM Vickers 3.58 Gpa Wang et al.
2012SLM+HTed Vickers 4.61 Gpa
LRF Rockwell 2.3 Gpa (HRC 17) Zhao et al.
2008LRF + Heated Rockwell 3.9 GPa (HRC 41)

34. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
34

35. 35
SLM, a complicated process
Necessary to understand the process physics
Improving the process performance and part
quality consistency
Few literatures in process modeling/simulations
of SLM
Process Studies

36. 36
Process Simulations
Microscale model
J. Schilp, C. Seidel, et al., 2014
[100 W]
Macroscale simulation
Prediction
 Possible systematic errors
Deterioration
 Part quality and deformations

37. 37
Process Simulations
Microscale simulation (Turbine blade)
J. Schilp, C. Seidel, et al., 2014
[100 W]
 Detailed understanding
 Realistic temperature
cycles during hatching
 Detecting
 Geometry-dependent systematic
 Random irregularities

38. 38
Finite element model developed
 Asingle track process
 Conical moving heat flux
Model verified (Simulate results vs. Literature Wang et al.)
Process Simulations
Model validation check

39. 39
Process Simulations
Simulated temperature profiles and gradients comparison.
 Temp. (↓)  Temp. Preheating / a very short distance
below top surface
 Laser speed (↑)  Tmax of melt pool (↓)
 Laser speed (↑)  | Temp. Gradient | (↑)

40. Outline
Introduction of SLM & Inconel 718
Motivation of this review
Review on Inconel 718 produced by Power-bed
Laser AM technology
Microstructure study
Defects
Mechanical properties
Process simulations and measurements
Summary
40

41. r
41
 SLM is able to manufacture high-density functional metallic
parts
 The accuracy of the components could achieve to ± 50 um
 Inconel 718 alloy have various applications popularly in the
aerospace
 Using PREP powder or fine GA powder could decrease the
porosities
Summary

42. r
42
 SLM fabricated Inconel 718 parts present a fine columnar dendrites
structure
 SLMed Inconel 718 parts with heat treatment typically have
comparable (to wrought counterparts) or superior mechanical
properties: high YS and UTS
 After heat treatment, the regular dendritic structure disappears
and a needle-like δ phase precipitates at grain boundaries when γ′
and γ″ phases dissolve in the matrix.
Summary

43. r
43
Sponsor
NASA, No. NNX11AM11A
Collaborator
Marshall Space Flight Center (Huntsville, AL),
Advanced Manufacturing Team
Acknowledgement

44. r
44

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Reference
[1] Pinkerton, A. J., and Li, L., 2004, "Modelling the geometry of a moving laser melt pool and deposition track via energy
and mass balances," Journal of Physics D: Applied Physics, 37(14), pp. 1885-1895.
[2] Safdar, S., Li, L., and Sheikh, M., 2007, "Numerical analysis of the effects of non-conventional laser beam geometries
during laser melting of metallic materials," Journal of Physics D: Applied Physics, 40(2), pp. 593-603.
[3] Gu, D., Meiners, W., Hagedorn, Y.-C., Wissenbach, K., and Poprawe, R., 2010, "Bulk-form TiCx/Ti nanocomposites with
controlled nanostructure prepared by a new method: selective laser melting," Journal of Physics D: Applied Physics,
43(29), p. 295402.
[4] Kruth, J. P., Leu, M. C., and Nakagawa, T., 1998, "Progress in Additive Manufacturing and Rapid Prototyping," CIRP
Annals - Manufacturing Technology, 47(2), pp. 525-540.
[5] Kruth, J. P., Levy, G., Klocke, F., and Childs, T. H. C., 2007, "Consolidation phenomena in laser and powder-bed based
layered manufacturing," CIRP Annals - Manufacturing Technology, 56(2), pp. 730-759.
[6] Thijs, L., Verhaeghe, F., Craeghs, T., Humbeeck, J. V., and Kruth, J.-P., 2010, "A study of the microstructural evolution
during selective laser melting of Ti–6Al–4V," Acta Materialia, 58(9), pp. 3303-3312.
[7] Osakada, K., and Shiomi, M., 2006, "Flexible manufacturing of metallic products by selective laser melting of powder,"
International Journal of Machine Tools and Manufacture, 46(11), pp. 1188-1193.
[8] Leo Prakash, D. G., Walsh, M. J., Maclachlan, D., and Korsunsky, A. M., 2009, "Crack growth micro-mechanisms in the
IN718 alloy under the combined influence of fatigue, creep and oxidation," International Journal of Fatigue, 31(11–12),
pp. 1966-1977.
[9] Qi, H., Azer, M., and Ritter, A., 2009, "Studies of Standard Heat Treatment Effects on Microstructure and Mechanical
Properties of Laser Net Shape Manufactured INCONEL 718," Metall and Mat Trans A, 40(10), pp. 2410-2422.
[10] Radhakrishna, C. H., and Prasad Rao, K., 1997, "The formation and control of Laves phase in superalloy 718 welds,"
Journal of Materials Science, 32(8), pp. 1977-1984.
[11] Paulonis, D. F., and Schirra, J. J., 2001, "Alloy 718 at Pratt & Whitney–Historical perspective and future challenges,"
Superalloys, 718(625,706), pp. 13-23.
[12] Murr, L. E., Gaytan, S. M., Ceylan, A., Martinez, E., Martinez, J. L., Hernandez, D. H., Machado, B. I., Ramirez, D. A.,
Medina, F., Collins, S., and Wicker, R. B., 2010, "Characterization of titanium aluminide alloy components fabricated by
additive manufacturing using electron beam melting," Acta Materialia, 58(5), pp. 1887-1894.
[13] Blackwell, P. L., 2005, "The mechanical and microstructural characteristics of laser-deposited IN718," Journal of
Materials Processing Technology, 170(1–2), pp. 240-246.
[14] Ma, J., Kong, F., Liu, W., Carlson, B., and Kovacevic, R., 2014, "Study on the strength and failure modes of laser welded
galvanized DP980 steel lap joints," Journal of Materials Processing Technology, 214(8), pp. 1696-1709.

46. r
46
[15] Liu, S., Liu, W., Harooni, M., Ma, J., and Kovacevic, R., 2014, "Real-time monitoring of laser hot-wire cladding of Inconel 625," Optics
& Laser Technology, 62(0), pp. 124-134.
[16] Shankar, V., Bhanu Sankara Rao, K., and Mannan, S. L., 2001, "Microstructure and mechanical properties of Inconel 625 superalloy,"
Journal of Nuclear Materials, 288(2–3), pp. 222-232.
[17] Baldridge, T., Poling, G., Foroozmehr, E., Kovacevic, R., Metz, T., Kadekar, V., and Gupta, M. C., 2013, "Laser cladding of Inconel 690
on Inconel 600 superalloy for corrosion protection in nuclear applications," Optics and Lasers in Engineering, 51(2), pp. 180-184.
[18] Ahmad, M., Akhter, J. I., Shahzad, M., and Akhtar, M., 2008, "Cracking during solidification of diffusion bonded Inconel 625 in the
presence of Zircaloy-4 interlayer," Journal of Alloys and Compounds, 457(1–2), pp. 131-134.
[19] González-Fernández, L., del Campo, L., Pérez-Sáez, R. B., and Tello, M. J., 2012, "Normal spectral emittance of Inconel 718
aeronautical alloy coated with yttria stabilized zirconia films," Journal of Alloys and Compounds, 513(0), pp. 101-106.
[20] Zheng, L., Schmitz, G., Meng, Y., Chellali, R., and Schlesiger, R., 2012, "Mechanism of intermediate temperature embrittlement of ni
and ni-based superalloys," Critical Reviews in Solid State and Materials Sciences, 37(3), pp. 181-214.
[21] Kuo, C. M., Yang, Y. T., Bor, H. Y., Wei, C. N., and Tai, C. C., 2009, "Aging effects on the microstructure and creep behavior of Inconel
718 superalloy," Materials Science and Engineering: A, 510–511(0), pp. 289-294.
[22] Zhang, Q.-l., Yao, J.-h., and Mazumder, J., 2011, "Laser Direct Metal Deposition Technology and Microstructure and Composition
Segregation of Inconel 718 Superalloy," Journal of Iron and Steel Research, International, 18(4), pp. 73-78.
[23] Wang, Z., Guan, K., Gao, M., Li, X., Chen, X., and Zeng, X., 2012, "The microstructure and mechanical properties of deposited-IN718
by selective laser melting," Journal of Alloys and Compounds, 513(0), pp. 518-523.
[24] Dadbakhsh, S., and Hao, L., 2012, "Effect of Al alloys on selective laser melting behaviour and microstructure of in situ formed
particle reinforced composites," Journal of Alloys and Compounds, 541(0), pp. 328-334.
[25] Song, B., Dong, S., Coddet, P., Zhou, G., Ouyang, S., Liao, H., and Coddet, C., 2013, "Microstructure and tensile behavior of hybrid
nano-micro SiC reinforced iron matrix composites produced by selective laser melting," Journal of Alloys and Compounds, 579(0), pp.
415-421.
[26] Vrancken, B., Thijs, L., Kruth, J.-P., and Van Humbeeck, J., 2012, "Heat treatment of Ti6Al4V produced by Selective Laser Melting:
Microstructure and mechanical properties," Journal of Alloys and Compounds, 541(0), pp. 177-185.
[27] Zhang, B., Fenineche, N.-E., Liao, H., and Coddet, C., 2013, "Microstructure and Magnetic Properties of Fe–Ni Alloy Fabricated by
Selective Laser Melting Fe/Ni Mixed Powders," Journal of Materials Science & Technology, 29(8), pp. 757-760.
[28] Zhang, B., Liao, H., and Coddet, C., 2013, "Microstructure evolution and density behavior of CP Ti parts elaborated by Self-
developed vacuum selective laser melting system," Applied Surface Science, 279(0), pp. 310-316.
[29] Dong, L. X., and Wang, H. M., 2008, "Microstructure and corrosion properties of laser-melted deposited Ti2Ni3Si/NiTi intermetallic
alloy," Journal of Alloys and Compounds, 465(1–2), pp. 83-89.
[30] Zhang, B., Liao, H., and Coddet, C., 2013, "Selective laser melting commercially pure Ti under vacuum," Vacuum, 95(0), pp. 25-29.
[31] Yadroitsev, I., and Smurov, I., 2010, "Selective laser melting technology: From the single laser melted track stability to 3D parts of
complex shape," Physics Procedia, 5, Part B(0), pp. 551-560.
Reference

47. r
47
[32] Kruth, J.-P., Mercelis, P., Van Vaerenbergh, J., Froyen, L., and Rombouts, M., 2005, "Binding mechanisms in selective laser
sintering and selective laser melting," Rapid prototyping journal, 11(1), pp. 26-36.
[33] Meola, C., Squillace, A., Minutolo, F. M. C., and Morace, R. E., 2004, "Analysis of stainless steel welded joints: a
comparison between destructive and non-destructive techniques," Journal of Materials Processing Technology, 155–156(0),
pp. 1893-1899.
[34] Çam, G., and Koçak, M., 1998, "Progress in joining of advanced materials," International Materials Reviews, 43(1), pp. 1-
44.
[35] Liu, F., Lin, X., Huang, C., Song, M., Yang, G., Chen, J., and Huang, W., 2011, "The effect of laser scanning path on
microstructures and mechanical properties of laser solid formed nickel-base superalloy Inconel 718," Journal of Alloys and
Compounds, 509(13), pp. 4505-4509.
[36] Chang, S.-H., 2009, "In situ TEM observation of γ′, γ″ and δ precipitations on Inconel 718 superalloy through HIP
treatment," Journal of Alloys and Compounds, 486(1–2), pp. 716-721.
[37] Izquierdo, B., Plaza, S., Sánchez, J. A., Pombo, I., and Ortega, N., 2012, "Numerical prediction of heat affected layer in the
EDM of aeronautical alloys," Applied Surface Science, 259(0), pp. 780-790.
[38] Parimi, L. L., Clark, D., and Attallah, M. M., 2014, "Microstructural and texture development in direct laser fabricated
IN718," Materials Characterization, 89, pp. 102-111.
[39] Amato, K., Gaytan, S., Murr, L., Martinez, E., Shindo, P., Hernandez, J., Collins, S., and Medina, F., 2012, "Microstructures
and mechanical behavior of Inconel 718 fabricated by selective laser melting," Acta Materialia, 60(5), pp. 2229-2239.
[40] Jia, Q., and Gu, D., 2014, "Selective laser melting additive manufacturing of Inconel 718 superalloy parts: Densification,
microstructure and properties," Journal of Alloys and Compounds, 585, pp. 713-721.
[41] Huang, X., Chaturvedi, M., and Richards, N., 1996, "Effect of homogenization heat treatment on the microstructure and
heat-affected zone microfissuring in welded cast alloy 718," Metallurgical and Materials Transactions A, 27(3), pp. 785-790.
[42] Miao, Z.-j., Shan, A.-d., Wu, Y.-b., Lu, J., Hu, Y., Liu, J.-l., and Song, H.-w., 2012, "Effects of P and B addition on as-cast
microstructure and homogenization parameter of Inconel 718 alloy," Transactions of Nonferrous Metals Society of China,
22(2), pp. 318-323.
[43] Yuan, H., and Liu, W. C., 2005, "Effect of the δ phase on the hot deformation behavior of Inconel 718," Materials Science
and Engineering: A, 408(1–2), pp. 281-289.
[44] Özgün, Ö., Gülsoy, H. Ö., Yılmaz, R., and Fındık, F., 2013, "Microstructural and mechanical characterization of injection
molded 718 superalloy powders," Journal of Alloys and Compounds, 576(0), pp. 140-153.
[45] Azadian, S., Wei, L.-Y., and Warren, R., 2004, "Delta phase precipitation in Inconel 718," Materials Characterization, 53(1),
pp. 7-16.
Reference

48. r
48
[46] Clark, D., Bache, M., and Whittaker, M., 2010, "Microstructural Characterization of a Polycrystalline Nickel-Based
Superalloy Processed via Tungsten-Intert-Gas-Shaped Metal Deposition," Metall and Materi Trans B, 41(6), pp. 1346-1353.
[47] Sjfberg, G., and Ingesten, N., "Grain boundary Y-phase morphology, carbides and notch rupture sensitivities of cast alloy
718," Superalloy.
[48] Liu, F., Lin, X., Yang, G., Song, M., Chen, J., and Huang, W., 2011, "Recrystallization and its influence on microstructures
and mechanical properties of laser solid formed nickel base superalloy Inconel 718," Rare Metals, 30(1), pp. 433-438.
[49] Zhao, X., Chen, J., Lin, X., and Huang, W., 2008, "Study on microstructure and mechanical properties of laser rapid
forming Inconel 718," Materials Science and Engineering: A, 478(1–2), pp. 119-124.
[50] Mercelis, P., and Kruth, J.-P., 2006, "Residual stresses in selective laser sintering and selective laser melting," Rapid
Prototyping Journal, 12(5), pp. 254-265.
[51] Shiomi, M., Osakada, K., Nakamura, K., Yamashita, T., and Abe, F., 2004, "Residual stress within metallic model made by
selective laser melting process," CIRP Annals-Manufacturing Technology, 53(1), pp. 195-198.
[52] Vilaro, T., Colin, C., Bartout, J.-D., Nazé, L., and Sennour, M., 2012, "Microstructural and mechanical approaches of the
selective laser melting process applied to a nickel-base superalloy," Materials Science and Engineering: A, 534, pp. 446-451.
[53] Tabernero, I., Lamikiz, A., Martínez, S., Ukar, E., and Figueras, J., 2011, "Evaluation of the mechanical properties of Inconel
718 components built by laser cladding," International Journal of Machine Tools and Manufacture, 51(6), pp. 465-470.
[54] Zhang, Y., Cao, X., Wanjara, P., and Medraj, M., 2013, "Fiber Laser Deposition of Inconel 718 Using Powders.”
Reference