Shape memory alloys (SMAs) are used in a wide variety of applications including medical stents, couplings, actuators, jointless monolithic structures for actuation and manipulation, etc. Due to the SMA’s poor machinability it is advantageous to use rapid prototyping (RP) techniques for the manufacturing of SMA structures. However, the influence of the RP process on the properties of the SMA is not fully explored yet. A laser based direct metal deposition (DMD) RP process was used in this work to manufacture NiTi SMA samples and to investigate their physical properties using optical microscopy, differential scanning calorimetry (DSC), chemical analysis with secondary ion mass spectrometry (SIMS), and energy dispersive x-ray spectrometry (EDS) with a scanning electron microscope (SEM). DSC analysis has shown that the thermally treated parts possess smooth and pronounced reversible martensite-austenite transformation peaks that are the prerequisite for the shape memory effect (SME) in SMAs. DSC has also shown that quenching affects the peaks. The density of the produced parts was close to the theoretical density of the material as determined by porosity measurements. Finally, SIMS depth profile analysis has shown very low amounts of contamination in the material manufactured by DMD. The major conclusion is that the DMD RP process can be used to manufacture high-quality SMA structures from SMA powders.

1.
Van Humbeeck
,
J.
, 2001, “
Shape Memory Alloys: A Material and a Technology
,”
Adv. Eng. Mater.
1438-1656,
3
(
11
), pp.
837
850
.
2.
Wuttig
,
M.
,
Quandt
,
E.
,
Ludwig
,
A.
, and
Winzek
,
B.
, 1999, “
Shape Memory and Magnetostrictive Materials for MEMS
,”
Materials Science of Microelectromechanical Systems (MEMS) Devices Symposium
,
A. H.
Heuer
and
S. J.
Jacobs
eds., Mater. Res. Soc.,
Warrendale
,
PA
, pp.
145
151
.
3.
Bellouard
,
Y.
,
Clavel
,
R.
,
Sidler
,
T.
, and
Gotthardt
,
R.
, 2000, “
Monolithic Shape Memory Alloys: a Smart Material for the Micro-Factory
,”
2nd International Workshop on Microfactories
, Ed. FSRM 2000, Fribourg, Switzerland, pp.
51
54
.
5.
Peirs
,
J.
,
Reynaerts
,
D.
, and
Brussel
,
H.
, 2001, “
The ‘True’ Power of SMA Micro-Actuation
,”
Proc. MME 2001 (Micromechanics Europe Workshop)
,
Cork, Ireland
, pp.
217
220
.
6.
Maekawa
,
H.
, and
Komoriya
,
K.
, 2001, “
Development of a Micro Transfer Arm for a Microfactory
,”
Proceedings of the IEEE International Conference on Robotics & Automation
,
Seoul, Korea
, pp.
1444
1451
.
7.
Otsuka
,
K.
, and
Wayman
,
C. M.
, 1998,
Shape Memory Materials
,
Cambridge University Press
,
New York
, pp.
284
.
8.
Otsuka
,
K.
, and
Ren
,
X.
, 2002, “
Factors Affecting the Ms Temperature And Its Control in Shape Memory Alloys
,”
Mater. Sci. Forum
0255-5476,
394–395
, pp.
177
184
.
9.
Ren
,
X.
, and
Otsuka
,
K.
, 2000, “
Why Does the Martensitic Transformation Temperature Strongly Depend on Composition
?”
Mater. Sci. Forum
0255-5476,
327–328
, pp.
429
432
.
10.
Otsuka
,
K.
, and
Ren
,
X.
, 1999, “
Recent Development in the Research of Shape Memory Alloys
,”
Intermetallics
0966-9795,
7
, pp.
511
528
.
11.
Bram
,
M.
,
Ahmad-Khanlou
,
A.
,
Heckmann
,
A.
,
Fuchs
,
B.
,
Buchkremer
,
H. P.
, and
Stover
,
D.
, 2002, “
Powder Metallurgical Fabrication Processes for NiTi Shape Memory Alloy Parts
,”
Mater. Sci. Eng., A
0921-5093,
337
, pp.
254
263
.
12.
Yi
,
H. C.
, and
Moore
,
J. J.
, 1988, “
A Novel Technique for Producing NiTi Shape Memory Alloy Using the Thermal Explosion Mode of Combustion Synthesis
,”
Scr. Metall.
0036-9748,
22
, pp.
1889
1892
.
13.
Griffith
,
M. L.
,
Keicher
,
D M
,
Atwood
,
C. L.
,
Romero
,
J. A.
,
Smugeresky
,
J. E.
,
Harwell
,
L. D.
, and
Greene
,
D. L.
, 1996, “
Free Form Fabrication of Metallic Components Using Laser Engineered Net Shaping (LENS®)
,”
Proceedings of the Solid Freeform Fabrication Symposium
, p.
125
.
14.
Lewis
,
G K.
, and
Schlienger
,
E.
, 2000, “
Practical Considerations and Capabilities for Laser Assisted Direct Metal Deposition
,”
Mater. Des.
0264-1275,
21
(
4
), pp.
417
423
.
15.
Mazumder
,
J.
,
Schiffer
,
A.
, and
Choi
,
J.
, 1999, “
Direct Materials Deposition: Designed Macro and Microstructure
,”
Mater. Res. Innovations
1432-8917,
3
(
3
), pp.
118
131
.
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