Full Paper: Xiaoqing Wang, Xibing Gong, Kevin Chou, Scanning Speed Effect on Mechanical Properties of Ti- 6Al-4V Alloy Processed by Electron Beam Additive Manufacturing, Procedia Manufacturing 1 (2015) 287–295. doi:10.1016/j.promfg.2015.09.026. Available at: https://www.academia.edu/29967143/Scanning_Speed_Effect_on_Mechanical_Properties_of_Ti-_6Al-4V_Alloy_Processed_by_Electron_Beam_Additive_Manufacturing

1. Scanning Speed Effect on Mechanical Properties
of Ti-6Al-4V Alloy Processed by Electron Beam
Additive Manufacturing
Xiaoqing Wang, Xibing Gong , Kevin Chou
Mechanical Engineering Department
The University of Alabama
June 11, 2015
1

2. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
2

3. Introduction of EBAM
 1997, Arcam in Sweden
 Freedom of design
 High productivity
 Excellent material properties
 Too-less manufacturing
3
Arcam A2X
http://www.arcam.com/technology/products/arcam-a2x-3/
 Making full-density functional metallic parts or cellular parts
 Complex and strong components used in aerospace industries and
medical implant (Orthopedic)

4. 4
Introduction of EBAM
Electrons
Kinetic energy: ~ 60 KeV
Temperature: > 2500 °C
In vacuum environment
Layer thickness: 0.05 ~ 0.2 mm
Manufacturing process:
Powder spreading
Pre-hearting
Contour melting
Hatch melting
Oak Ridge NL National Laboratory https://www.youtube.com/watch?v=M_qSnjKN7f8&list=PLUMSQMrg3EMs7uEcy-AF0ua087ErJH2r8

5. 5
Introduction of EBAM
Electron beam technology
Fast beam translation
High scan speed
Efficient manufacturing
High energy beam
High melting capacity
Ultimately high productivity
Vacuum environment
Eliminates impurities
Warm process
Decreases the residual stresses & distortion
Arcam Q10

6. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
6

7. 7
Motivation of this study
The effects of beam scanning speed
Microstructure
Mechanical properties (E, H)
Nanoindentation test

8. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
8

9. 9
Experiments / Manufacturing of Ti-6Al-4V parts
Table 1. Compositions of Ti6Al4V powder
Composition Al V C Fe O N H Ti
Arcam Ti6Al4V
(wt. %)
6 4 0.03 0.1 0.15 0.01 0.003 Balance
*1 Torr=0.0013157895 atm
Powders diameter: 45 ~ 100 µm

10. 10
Experiments / Manufacturing of Ti-6Al-4V parts
EBAM parts
(60 (L) × 5.5 (W) × 25 (H) mm )
Process parameters
Beam size: 0.5 mm
Upper chamber
 7.5 × 10−7
Toll*
 Keep beam quality
Fabrication chamber
 7.5 × 10−5 Torr
 Avoid oxidation
Layer thickness: ~ 70 um
*1 Torr=0.0013157895 atm

11. Y
Z
X
2
1
BuildingDirection
60 mm
25mm
5.5 mm
11
Samples preparation
Dimension (mm)
 11 (L) × 5.5 (W) ×7 (H)
Method
 Electrical discharge machining

12. 12
Samples preparation
Mounted
Epoxy resin
Ground
Silicon carbide grinding paper
Size: 120 down to 1000 grits
Coolant: Water
Polish solution
Diamond suspension
Size: 6 ~ 0.5 μm

13. 13
Samples preparation
For microstructural analysis
Etched solution
1 ml hydrofluoric acid (50 wt. %)
3 ml (60 wt. %) nitric acid
7 ml distilled water.
Observed & analyzed
optical microscope (OM)

14. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
14

15. 15
Nanoindentation test
 Triboindenter
 Resolution: 0.04 nm
 Tip
Type: Berkovich
Radius: 100 nm
Included angle: 142.3°

16. 16
Nanoindentation test
Applied Load Function
Load Function
Control: Open loop
Shape: Trapezoid
Maximum load: 5000 uN
Loading Rate: Constant
Dwell Time: 10 s
Unloading Rate: Constant

17. 17
 Test
Pattern: 5 × 5
Spacing: 5 um
Thermal equilibrium time: 0.5 h
Test time: 3
Nanoindentation test

18. 18
Nanoindentation test
 Calculation of the elastic modulus
1
𝐸𝐸𝑟𝑟
=
1−𝜈𝜈𝑖𝑖
2
𝐸𝐸𝑖𝑖
+
1−𝜈𝜈𝑠𝑠
2
𝐸𝐸𝑠𝑠
Indenter
 Poisson's ratio: νi=0.07
 Young’s modulus: Ei=1140 GPa
 Reduced elastic modulus: Er
 Ti-6Al-4V
 Poisson's ratio: νs=0.342

19. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
19

20. 20
Results and discussion / Elastic modulus
COMPARABLE
128
118 117
108
120
114 116
112
80
90
100
110
120
130
140
[13] [11] [26] [7] [14] [15] Z X
E,GPa
Studies

21. 21
Results and discussion / Hardness
 Literature: Microhardness
 Different hardness testing methods  Variance of the hardness
 Nanoindentation hardness vs. Microhardness (>10-30%)
COMPARABLE/HIGHER
4.0
3.5
3.1
4.2 4.0
5.9 6.0
2.0
3.0
4.0
5.0
6.0
[13] [11] [26] [20] [21] Z X
H,GPa
Studies
Qian et al. 2005

22. 22
Results and discussion / H – Z-Plane
Beam Scanning Speed (↑)  Hardness (↑)
SF 65
5.59 5.87 6.11
5.33
3.0
4.0
5.0
6.0
7.0
20 36 50 65
H,GPa
Speed Function

23. 23
Results and discussion / H – X-Plane
5.24
6.00
6.52
5.62
3.0
4.0
5.0
6.0
7.0
20 36 50 65
H,GPa
Speed Function

24. 24
Results and discussion / E – Z-Plane
115.4 116.3 119.0
114.3
80
90
100
110
120
130
20 36 50 65
E,GPa
Speed Function

25. 25
Results and discussion / E – X-Plane
Z-plane vs. X-plane
113.2 111.7
125.3
108.2
80
95
110
125
140
20 36 50 65
E,GPa
Speed Function
>

26. 26
Results and discussion
The principle of the EBAM
 Layer by layer → Weaker bonding force on the
X-plane → Building defects (↑)

27. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
27

28. 28
Microstructure / X-Plane
Prior β grains
Grew along the build direction
Across multiple layers
Typical in high-energy materials processing
 Align the steepest temperature gradients

29. 29
Microstructures / X-Plane
Martensitic phase, α′, appears as plates
Transformed from the β phase / high cooling rate / >
410 ℃/s
Commonly observed in Ti-6Al-4V alloy / rapid
solidifications / selective laser melting & electron
beam welding

30. 30
Microstructures / Z-plane
Equiaxed grains

31. 31
Typical Microstructures / Z-plane
More homogeneous microstructure
β fraction (↓) / Nanoindentation more
opportunity @ α platelet / Hard

32. 32
Width of the columnar prior β
109.7
41.6 37.1
48.6
85.2
50.1 48.7 50.8
20
60
100
140
180
220
260
300
10 20 30 40 50 60 70
0
20
40
60
80
100
120
140
Equiaxedβsize,µm
Speed Function
Columnarβwidth,µm
Columnar β
Equiaxed β
 Scanning speed (↑) → Columnar structure width (↓) / Certain point
 SF20 (214 mm/s) / 109.7 µm vs. SF65 (529 mm/s) / 37.1 µm
 Speed Function 65

33. 33
Relation of Microstructure & Mechanical properties
Hall-Petch’s relation
 Finer Microstructure → Stronger
SF 65 samples
Coarser microstructure
Defects
 Insufficient melt
 Percentage of pores
 Melting pool & Melting temperature (↓)
 Beam scanning speed (↑) → Serious

34. Outline
Introduction of EBAM
Motive of this study
Experiments
Manufacturing & samples preparation
Nanoindenation test
Results and discussion
Mechanical properties
Microstructure analysis
Summary
34

35. 35
Elastic Modulus: 111.7~119.0 Gpa
Hardness: 5.24~6.52 Gpa
EBAM vs. Wrought: Superior / Comparable
Z-plane vs. X-plane: > Strengths (E, H)
Summary

36. 36
Effect of Speed function
Beam scanning speed (↑) → E & H (↑)
 Attributed to the finer microstructure
Optimized mechanical properties
 SF36 ~ SF50
Summary

37. 37
Sponsor: NASA
No. NNX11AM11A
Collaborator: Advanced Manufacturing Team,
Marshall Space Flight Center,
Huntsville, AL
Acknowledgement

38. 38
Thanks for your attention!

39. 39
Reference
[1] Murr LE, Gaytan SM, Ramirez DA, Martinez E, Hernandez J, Amato KN, Shindo PW, Medina FR, and
Wicker RB. Metal fabrication by additive manufacturing using laser and electron beam melting
technologies. Journal of Materials Science & Technology 2012; 28(1): 1-14.
[2] Harrysson O, Deaton B, Bardin J, West H, Cansizoglu O, Cormier D and Marcellin-Little D. Evaluation of
titanium implant components directly fabricated through electron beam melting technology. In: Proc.
Conf. Mater. Process. Med. Dev., 2005, pp.15-20.
[3] Parthasarathy J, Starly B, Raman S, and Christensen A. (2010). Mechanical evaluation of porous
titanium (Ti6Al4V) structures with electron beam melting (EBM). Journal of the Mechanical Behavior of
Biomedical Materials 2010; 3(3): 249-259.
[4] Gong X, Lydon J, Cooper K and Chou K. Microstructure Analysis and Nanoindentation Characterization
of Ti-6Al-4V Parts from Electron Beam Additive Manufacturing. In: Proc. ASME 2014 Int. Mech. Eng.
Congr. Expo., 2014, pp.1-8.
[5] Gong X, Anderson T and Chou K. Review on powder-based electron beam additive manufacturing
technology. Manufacturing Review 2014; 1: 1-12.
[6] Ladani L and Roy L. Mechanical Behavior of Ti-6Al-4V Manufactured by Electron Beam Additive
Fabrication. In: Proc. ASME 2013 Inter. Manuf. Sci. Eng. Conf., 2013, pp. V001T001A001.
[7] Larosa MA, Jardini AL, Zavaglia CAdC, Kharmandayan P, Calderoni DR and Maciel Filho R.
Microstructural and Mechanical Characterization of a Custom-Built Implant Manufactured in Titanium
Alloy by Direct Metal Laser Sintering. Advances in Mechanical Engineering 2014; 2014:1-8.
[8] Mohammadhosseini A, Fraser D, Masood S and Jahedi M. Microstructure and mechanical properties of
Ti-6Al-4V manufactured by electron beam melting process. Materials Research Innovations 2013; 17:
s106-s112.

40. 40
[9] Puebla K, Murr LE, Gaytan SM, Martinez E, Medina F and Wicker RB. Effect of melt scan rate on
microstructure and macrostructure for electron beam melting of Ti-6Al-4V. Materials Sciences and
Applications 2012; 3: 259.
[10] Cheng X, Li S, Murr L, Zhang Z, Hao Y, Yang R, Medina F and Wicker R. Compression deformation
behavior of Ti-6Al-4V alloy with cellular structures fabricated by electron beam melting. Journal of the
Mechanical Behavior of Biomedical Materials 2012; 16: 153-162.
[11] Facchini L, Magalini E, Robotti P and Molinari A. Microstructure and mechanical properties of Ti-6Al-
4V produced by electron beam melting of pre-alloyed powders. Rapid Prototyping Journal 2009;
15(3): 171-178.
[12] Murr L, Gaytan S, Medina F, Martinez E, Hernandez D, Martinez L, Lopez M, Wicker R and Collins S.
Effect of build parameters and build geometries on residual microstructures and mechanical properties
of Ti-6Al-4V components built by electron beam melting (EBM). In: Proc. 20th Solid Freeform Fabr.
Symp., 2009, pp.3-5.
[13] Murr LE, Esquivel EV, Quinones SA, Gaytan SM, Lopez MI, Martinez EY, Medina F, Hernandez DH,
Martinez E, Martinez JL, Stafford SW, Brown DK, Hoppe T, Meyers W, Lindhe U and Wicker RB.
Microstructures and mechanical properties of electron beam-rapid manufactured Ti-6Al-4V biomedical
prototypes compared to wrought Ti-6Al-4V. Materials Characterization 2009; 60(2): 96-105.
[14] Schroeder J. Advanced Manufacturing Technology Changes the Way Implants are Designed and
Produced. BoneZone 2006; 5(3): 17-20.
[15] Thundal S. Rapid Manufacturing of Orthopedic Implants. Advanced Material Process 2008; 166(10):
60-62.
Reference

41. 41
[16] Murr L, Gaytan S, Medina F, Lopez M, Martinez E and Wicker R. Additive Layered Manufacturing of
Reticulated Ti-6Al-4V Biomedical Mesh Structures by Electron Beam Melting. In: Proc. 25th Southern
Biomed. Eng. Conf., 2009, pp.23-28.
[17] Koike M, Greer P, Owen K, Lilly, G., Murr LE, Gaytan SM, Martinez E and Okabe T. Evaluation of
Titanium Alloys Fabricated Using Rapid Prototyping Technologies-Electron Beam Melting and Laser
Beam Melting. Materials 2011; 4(10): 1776-1792.
[18] Gong X, Lydon J, Cooper K and Chou K. Beam Speed Effects on Ti-6Al-4V Microstructures in
Electron Beam Additive Manufacturing. Journal of Materials Research 2014; 29(17): 1951-1959.
[19] Zäh MF and Lutzmann S. Modelling and simulation of electron beam melting. Production
Engineering 2010; 4(1): 15-23.
[20] Xue W, Wang C, Chen R and Deng Z. Structure and properties characterization of ceramic coatings
produced on Ti-6Al-4V alloy by microarc oxidation in aluminate solution. Materials Letters 2002;
52(6): 435-441.
[21] Barbieri F, Otani C, Lepienski C, Urruchi W, Maciel H and Petraconi G. Nanoindentation study of
Ti6Al4V alloy nitrided by low intensity plasma jet process. Vacuum 2002; 67(3): 457-461.
[22] Karlsson J, Snis A, Engqvist H. and Lausmaa J. Characterization and comparison of materials
produced by Electron Beam Melting (EBM) of two different Ti-6Al-4V powder fractions. Journal of
Materials Processing Technology 2013; 213(12): 2109-2118.
[23] Gong X, Lydon J, Cooper K and Chou K. Characterization of Ti-6Al-4V powder in electron beam
melting additive manufacturing. International Journal of Powder Metallurgy 2015; 51(1): 1-10.
[24] Arcam (2008). Ti6Al4V Titanium Alloy, http://www.arcam.com/wp-content/uploads/Arcam-Ti6Al4V-
Titanium-Alloy.pdf.
Reference

42. 42
[25] Gong X and Chou K. Characterization of Sintered Ti-6Al-4V Powders in Electron Beam Additive
Manufacturing. In: Proc. ASME 2013 Inter. Manuf. Sci. Eng. Conf., 2013, pp.V001T001A002.
[26] Baufeld B and Van der Biest O. Mechanical properties of Ti-6Al-4V specimens produced by shaped
metal deposition. Science and Technology of Advanced Materials 2009; 10(1): 015008.
[27] Qian L, Li M, Zhou Z, Yang H. and Shi X. Comparison of nano-indentation hardness to
microhardness. Surface and Coatings Technology 2005; 195(2-3): 264-271.
[28] Li R, Riester L, Watkins TR, Blau PJ and Shih AJ. Metallurgical analysis and nanoindentation
characterization of Ti-6Al-4V workpiece and chips in high-throughput drilling. Materials Science and
Engineering: A 2008; 472(1-2): 115-124.
[29] Ahmed T and Rack H. Phase transformations during cooling in α+β titanium alloys. Materials
Science and Engineering: A 1998; 243(1): 206-211.
[30] Liu S, Liu W, Harooni M, Ma J and Kovacevic R. Real-time monitoring of laser hot-wire cladding of
Inconel 625. Optics & Laser Technology 2014; 62(0): 124-134.
[31] Ma J, Kong F, Liu W, Carlson B and Kovacevic R. Study on the strength and failure modes of laser
welded galvanized DP980 steel lap joints. Journal of Materials Processing Technology 2014; 214(8):
1696-1709.
Reference