Laser direct metal deposition has the potential to increase the material efficiency during the manufacture of superalloy aerospace components and also to reduce the need for welded joints to produce the necessary geometries. However, a possible problem is inconsistent microstructure, and therefore physical properties, in the deposited part. In this work, the factors that affect microstructure formation and evolution were examined in simple Waspaloy parts deposited using a high power diode laser and coaxial powder nozzle across a range of process parameters. Thermal imaging and embedded thermocouples were used to record the thermal cycle during deposition at different positions within the part and this is correlated with the wall characteristics and the final microstructures formed. Results allow the extent of the variations in sample properties with process parameters and position to be determined and indicate that intra melt pool factors such as local fluctuations in temperature gradients due to Marangoni flow and changes in nucleation density due to injected powder are significant.
REFERENCES
1.
Yan
, X.
& Gu
, P.
(1996
) A review of rapid prototyping technologies and systems Computer Aided Design
28
(4
), 307
–318
.2.
Gandini
, E.
, Agnesone
, F.
, Taricco
, F.
& Arrighi
, L.
(1997
) Advances in gas turbine blade repair by laser welding
, in Proceedings of the 1997 International Gas Turbine & Aeroengine Congress
, Jun 2-5 1997, Orlando, FL, USA
, 6
.3.
Hedges
, M.
(2003
) Economic rapid manufacture of performance materials by LENSTM
, in Proceedings of the International Users Conference for Rapid Prototyping
, Rapid Tooling and Rapid Manufacturing
, Frankfurt/Maine Germany
.4.
Griffith
, M.L.
, Ensz
, M.T.
, Puskar
, J.D.
, Robino
, C.V.
, Brooks
, J.A.
et al (2000
) Understanding the microstructure and properties of components fabricated by Laser Engineered Net Shaping (LENS)
, in Proceedings of the Solid Freeform and Additive Fabrication Conference
, San Francisco CA USA
, 9
–20
.5.
Rosenthal
, D.
(1946
) The theory of moving sources of heat and its application to metal treatments Transactions of the American Society of Mechanical Engineers (ASME)
68
(11
), 849
–866
.6.
Cline
, H.E.
& Anthony
, T.R.
(1977
) Heat treating and melting material with a scanning laser or electron beam
, Journal of Applied Physics
48
(9
), 3895
–3900
.7.
Pinkerton
, A.J.
& 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
), 1885
–1895
.8.
Hofmeister
, W.H.
, MacCallum
, D.O.
& Knorovsky
, G.A.
(1999
) Video monitoring and control of the LENS process
, in Proceedings of the 9th International Conference on Computer Technology in Welding
, Detroit MI USA
, 187
–196
.9.
Han
, L.
, Phatak
, K.M.
& Liou
, F.W.
(2005
) Modeling of laser deposition and repair process
, Journal of Laser Applications
17
(2
), 89
–99
.10.
Vasinonta
, A.
, Beuth
, J.
& Griffith
, M.
(2000
) Process maps for controlling residual stress and melt pool size in laser-based SFF processes
, in Proceedings of the 11th Solid Freeform Fabrication Symposium
, Austin TX USA
, 200
–208
.11.
Beuth
, J.
& Klingbeil
, N.
(2001
) The role of process variables in laser-based direct metal solid freeform fabrication
, JOM
53
(9
), 36
–39
.12.
Morvan
, D.
, Cipriani
, F.D.
, Dufresne
, D.
& Garino
, A.
(1991
) Thermocapillary effects in a melted pool during laser surface treatment
, Proceedings of SPIE 1397
(pt 2), 689
–692
.13.
Pericleous
, K.A.
& Bailey
, C.
(1995
) Study of Marangoni phenomena in laser-melted pools
, in Proceedings of the 7th Conference on Modeling of Casting
, Welding and Advanced Solidification Processes
, London UK
, 91
–100
.14.
Kurz
, W.
& Trivedi
, R.
(1994
) Rapid solidification processing and microstructure formation
, Materials Science and Engineering A: Structural Materials: Properties Microstructure and Processing
, 179-180
(1
), 46
–51
.15.
Klingbeil
, N.W.
, Brown
, C.J.
, Bontha
, S.
, Kobryn
, P.A.
& Fraser
, H.L.
(2002
) Prediction of microstructure in laser deposition of titanium alloys
, in Proceedings of the 13th Solid Freeform Fabrication Symposium
, Austin TX USA
, 142
–149
.16.
Rutter
, J.W.
& Chalmers
, B.
(1953
) A prismatic substructure formed during solidification of metals
, Canadian Journal of Physics
31
, 15
–39
.17.
Mullins
, W.W.
& Sekerka
, R.F.
(1964
) Stability of a planar interface during solidification of a dilute binary alloy
, Journal of Applied Physics
35
, 444
–451
.18.
Fisher
, D.J.
& Kurz
, W.
(1980
) Theory of branching limited growth of irregular eutectics
, Acta Metallurgica
28
(6
), 777
–794
.19.
Kurz
, W.
& Fisher
, D.J.
(1981
) Dendrite growth at the limit of stability: tip radius and spacing
, Acta Metallurgica
29
(1
), 11
–20
.20.
Kurz
, W.
& Trivedi
, R.
(1996
) Banded solidification microstructures, Metallurgical and Materials Transactions A
: Physical Metallurgy and Materials Science
27
(3
), 625
–634
.21.
Hunt
, J.D.
(1984
) Steady state columnar and equiaxed growth of dendrites and eutectic
, Materials Science and Engineering
65
(1
), 75
–83
.22.
Shao
, G.
& Tsakiropoulos
, P.
(1994
) Prediction of phase selection in rapid solidification using time dependent nucleation theory
, Acta Metallurgica et Materialia
42
(9
), 2937
–2942
.23.
Gaumann
, M.
, Trivedi
, R.
& Kurz
, W.
(1997
) Nucleation ahead of the advancing interface in directional solidification
, Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
A226-22
, 763
–769
.24.
Gaumann
, M.
, Bezencon
, C.
, Canalis
, P.
& Kurz
, W.
(2001
) Single-crystal laser deposition of superalloys: Processing-microstructure maps
, Acta Materialia
49
(6
), 1051
–1062
.25.
Rappaz
, M.
& Gandin
, C.-A.
(1993
) Probabilistic modelling of microstructure formation in solidification processes
, Acta Metallurgica et Materialia
41
(2
), 345
–360
.26.
Grujicic
, M.
, Cao
, G.
& Figliola
, R.S.
(2001
) Computer simulations of the evolution of solidification microstructure in the LENS rapid fabrication process
, Applied Surface Science
183
(1-2
), 43
–57
.27.
Vitek
, J.M.
(2005
) The effect of welding conditions on stray grain formation in single crystal welds - theoretical analysis
, Acta Materialia
53
(1
), 53
–67
.28.
Liu
, W.
& DuPont
, J.N.
(2004
) Effects of melt-pool geometry on crystal growth and microstructure development in laser surface-melted superalloy single crystals. Mathematical modeling of single-crystal growth in a melt pool (part I)
, Acta Materialia
52
(16
), 4833
–4847
.29.
Hofmeister
, W.
, Griffith
, M.
, Ensz
, M.
& Smugeresky
, J.
(2001
) Solidification in direct metal deposition by LENS processing
, JOM
53
(9
), 30
–34
.30.
Donachie
, M.J.
& Donachie
, S.J.
(2002
) Superalloys: a technical guide
, ASM International
.31.
Preuss
, M.
, Pang
, J.W.L.
, Withers
, P.J.
& Baxter
, G.J.
(2002
) Inertia welding nickel-based superalloy: Part I. Metallurgical characterization
, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
33
(10
), 3215
–3225
.32.
Colaco
, R.
, Costa
, L.
, Guerra
, R.
& Vilar
, R.
(1994
) A simple correlation between the geometry of laser cladding tracks and process parameters
, in Proceedings of the 1994 NATO Advanced Study Institute Conference on Laser Processing: Surface Treatment and Film Deposition
, Sesimbra Portugal
, 421
–429
.33.
Gaumann
, M.
, Henry
, S.
, Cleton
, F.
, Wagniere
, J.-D.
& Kurz
, W.
(1999
) Epitaxial laser metal forming: analysis of microstructure formation
, Materials Science and Engineering A
271
(1-2
), 232
–241
.34.
Keicher
, D.M.
& Smugeresky
, J.E.
(1997
) The laser forming of metallic components using particulate materials
, JOM
49
(5
), 51
–54
.35.
Vasinonta
, A.
, Beuth
, J.
& Ong
, R.
(2001
) Melt pool size control in thin-walled and bulky parts via process maps
, in Proceedings of the 12th Solid Freeform Fabrication Symposium
, Austin TX USA
, 432
–440
.36.
Pirch
, N.
, Kreutz
, E.W.
, Ollier
, B.
& He
, X.
(1996
) The modelling of heat, mass and solute transport in surface processing with laser radiation
, in Proceedings of the 1994 NATO Advanced Study Institute Conference on Laser Processing: Surface Treatment and Film Deposition
, Sesimbra Portugal
, 177
–193
.37.
Takeda
, T.
, Steen
, W.M.
& West
, D.R.F.
(1984
) Laser cladding with mixed powder feed
, in Proceedings of the 3rd International Congress on Applications of Lasers and Electro-optics (ICALEO
), Boston MA USA
, 151
–158
.
This content is only available via PDF.
© 2005 Laser Institute of America.
2005
Laser Institute of America
You do not currently have access to this content.