It is of great scientific and technical interests to conduct fundamental studies on the laser interactions with nanoparticles-reinforced metals. This part of the study presents the effects of nanoparticles on surface tension and viscosity, thus the heat transfer and fluid flow, and eventually the laser melting process. In order to determine the surface tension and viscosity of nanoparticles-reinforced metals, an innovative measurement system was developed based on the characteristics of oscillating metal melt drops after laser melting. The surface tensions of Ni/Al2O3 (4.4 vol. %) and Ni/SiC (3.6 vol. %) at ∼1500 °C were 1.39 ± 0.03 N/m and 1.57 ± 0.06 N/m, respectively, slightly lower than that of pure Ni, 1.68 ± 0.04 N/m. The viscosities of these Ni/Al2O3 and Ni/SiC MMNCs at ∼1500 °C were 13.3 ± 0.8 mPa·s and 17.3 ± 3.1 mPa·s, respectively, significantly higher than that of pure Ni, 4.8 ± 0.3 mPa·s. To understand the influences of the nanoparticles-modified thermophysical properties on laser melting, an analytical model was used to theoretically predict the melt pool flows using the newly measured material properties from both Part I and Part II. The theoretical analysis indicated that the thermocapillary flows were tremendously suppressed due to the significantly increased viscosity after the addition of nanoparticles. To test the hypothesis that laser polishing could significantly benefit from this new phenomenon, systematic laser polishing experiments at various laser pulse energies were conducted on Ni/Al2O3 (4.4 vol. %) and pure Ni for comparison. The surface roughness of the Ni/Al2O3 was reduced from 323 nm to 72 nm with optimized laser polishing parameters while that of pure Ni only from 254 nm to 107 nm. The normalized surface roughness reduced by nearly a factor of two with the help of nanoparticles, validating the feasibility to tune thermophysical properties and thus control laser-processing outcomes by nanoparticles. It is expected that the nanoparticle approach can be applied to many laser manufacturing technologies to improve the process capability and broaden the application space.

References

References
1.
Rawal
,
S.
,
2001
, “
Metal-Matrix Composites for Space Applications
,”
JOM
,
53
(
4
), pp.
14
17
.
2.
Crainic
,
N.
, and
Marques
,
A. T.
,
2002
, “
Nanocomposites: A State-of-the-Art Review
,”
Key Eng. Mater.
,
230–232
, pp.
656
659
.
3.
Jiang
,
Q. C.
,
Li
,
X. L.
, and
Wang
,
H. Y.
,
2003
, “
Fabrication of TiC Particulate Reinforced Magnesium Matrix Composites
,”
Scr. Mater.
,
48
(
6
), pp.
713
717
.
4.
Yang
,
Y.
,
Lan
,
J.
, and
Li
,
X.
,
2004
, “
Study on Bulk Aluminum Matrix Nano-Composite Fabricated by Ultrasonic Dispersion of Nano-Sized SiC Particles in Molten Aluminum Alloy
,”
Mater. Sci. Eng. A
,
380
(
1–2
), pp.
378
383
.
5.
Cao
,
G.
,
Konishi
,
H.
, and
Li
,
X.
,
2008
, “
Mechanical Properties and Microstructure of Mg/SiC Nanocomposites Fabricated by Ultrasonic Cavitation Based Nanomanufacturing
,”
ASME J. Manuf. Sci. Eng.
,
130
(
3
), p.
031105
.
6.
Chen
,
L.
,
Konishi
,
H.
,
Fehrenbacher
,
A.
,
Ma
,
C.
,
Xu
,
J.
,
Choi
,
H.
,
Xu
,
H.
,
Pfefferkorn
,
F. E.
, and
Li
,
X.
,
2012
, “
Novel Nanoprocessing Route for Bulk Graphene Nanoplatelets Reinforced Metal Matrix Nanocomposites
,”
Scr. Mater.
,
67
(
1
), pp.
29
32
.
7.
Ma
,
C.
,
Chen
,
L.
,
Xu
,
J.
,
Fehrenbacher
,
A.
,
Li
,
Y.
,
Pfefferkorn
,
F. E.
,
Duffie
,
N. A.
,
Zheng
,
J.
, and
Li
,
X.
,
2013
, “
Effect of Fabrication and Processing Technology on the Biodegradability of Magnesium Nanocomposites
,”
J. Biomed. Mater. Res., Part B
,
101B
(
5
), pp.
870
877
.
8.
Low
,
C. T. J.
,
Wills
,
R. G. A.
, and
Walsh
,
F. C.
,
2006
, “
Electrodeposition of Composite Coatings Containing Nanoparticles in a Metal Deposit
,”
Surf. Coat. Technol.
,
201
(
1–2
), pp.
371
383
.
9.
Tuckerman
,
D. B.
, and
Weisberg
,
A. H.
,
1986
, “
Planarization of Gold and Aluminum Thin Films Using a Pulsed Laser
,”
IEEE Electron Device Lett.
,
7
(
1
), pp.
1
4
.
10.
Mai
,
T. A.
, and
Lim
,
G. C.
,
2004
, “
Micromelting and Its Effects on Surface Topography and Properties in Laser Polishing of Stainless Steel
,”
J. Laser Appl.
,
16
(
4
), pp.
221
228
.
11.
Wang
,
H.
,
Bourell
,
D. L.
, and
Beaman
,
J. J.
,
1998
, “
Laser Polishing of Silica Rods
,”
9th Solid Freeform Fabrication Symposium
, Austin, TX, pp.
37
46
.
12.
Bereznai
,
M.
,
Pelsöczi
,
I.
,
Tóth
,
Z.
,
Turzó
,
K.
,
Radnai
,
M.
,
Bor
,
Z.
, and
Fazekas
,
A.
,
2003
, “
Surface Modifications Induced by ns and Sub-ps Excimer Laser Pulses on Titanium Implant Material
,”
Biomaterials
,
24
(
23
), pp.
4197
4203
.
13.
Kim
,
Y. G.
,
Ryu
,
J. K.
,
Kim
,
D. J.
,
Kim
,
H. J.
,
Lee
,
S.
,
Cha
,
B. H.
,
Cha
,
H.
, and
Kim
,
C. J.
,
2004
, “
Microroughness Reduction of Tungsten Films by Laser Polishing Technology With a Line Beam
,”
Jpn. J. Appl. Phys.
,
43
, pp.
1315
1322
.
14.
Nüsser
,
C.
,
Wehrmann
,
I.
, and
Willenborg
,
E.
,
2011
, “
Influence of Intensity Distribution and Pulse Duration on Laser Micro Polishing
,”
Phys. Procedia
,
12
, pp.
462
471
.
15.
Hafiz
,
A. M. K.
,
Bordatchev
,
E. V.
, and
Tutunea-Fatan
,
R. O.
,
2012
, “
Influence of Overlap Between the Laser Beam Tracks on Surface Quality in Laser Polishing of AISI H13 Tool Steel
,”
J. Manuf. Processes
,
14
(
4
), pp.
425
434
.
16.
Bordatchev
,
E. V.
,
Hafiz
,
A. M. K.
, and
Tutunea-Fatan
,
O. R.
,
2014
, “
Performance of Laser Polishing in Finishing of Metallic Surfaces
,”
J. Adv. Manuf. Technol.
,
73
(
1
), pp.
35
52
.
17.
Perry
,
T. L.
,
Werschmoeller
,
D.
,
Duffie
,
N. A.
,
Li
,
X.
, and
Pfefferkorn
,
F. E.
,
2009
, “
Examination of Selective Pulsed Laser Micropolishing on Microfabricated Nickel Samples Using Spatial Frequency Analysis
,”
ASME J. Manuf. Sci. Eng.
,
131
(
2
), p.
021002
.
18.
Vadali
,
M.
,
Ma
,
C.
,
Duffie
,
N. A.
,
Li
,
X.
, and
Pfefferkorn
,
F. E.
,
2012
, “
Pulsed Laser Micro Polishing: Surface Prediction Model
,”
J. Manuf. Processes
,
14
(
3
), pp.
307
315
.
19.
Vadali
,
M.
,
Ma
,
C.
,
Duffie
,
N. A.
,
Li
,
X.
, and
Pfefferkorn
,
F. E.
,
2013
, “
Effects of Pulse Duration on Laser Micro Polishing Using Spatial Gaussian Intensity Distribution
,”
ASME J. Micro Nano Manuf.
,
1
(
1
), p.
011006
.
20.
Pfefferkorn
,
F. E.
,
Duffie
,
N. A.
,
Li
,
X.
,
Vadali
,
M.
, and
Ma
,
C.
,
2013
, “
Improving Surface Finish in Pulsed Laser Micro Polishing Using Thermocapillary Flow
,”
CIRP Ann.
,
62
(
1
), pp.
203
206
.
21.
Ma
,
C.
,
Vadali
,
M.
,
Duffie
,
N. A.
,
Pfefferkorn
,
F. E.
, and
Li
,
X.
,
2013
, “
Melt Pool Flow and Surface Evolution During Pulsed Laser Micro Polishing of Ti6Al4V
,”
ASME J. Manuf. Sci. Eng.
,
135
(
6
), p.
061023
.
22.
Ma
,
C.
,
Vadali
,
M.
,
Li
,
X.
,
Duffie
,
N. A.
, and
Pfefferkorn
,
F. E.
,
2014
, “
Analytical and Experimental Investigation of Thermocapillary Flow in Pulsed Laser Micropolishing
,”
ASME J. Micro Nano Manuf.
,
2
(
2
), p.
021010
.
23.
Ma
,
C.
,
Chen
,
L.
,
Xu
,
J.
,
Zhao
,
J.
, and
Li
,
X.
,
2015
, “
Control of Fluid Dynamics by Nanoparticles in Laser Melting
,”
J. Appl. Phys.
,
117
(
11
), p.
114901
.
24.
Wang
,
Q.
,
Morrow
,
J. D.
,
Ma
,
C.
,
Duffie
,
N. A.
, and
Pfefferkorn
,
F. E.
,
2015
, “
Surface Prediction Model for Thermocapillary Regime Pulsed Laser Micro Polishing of Metals
,”
J. Manuf. Processes
,
20
, pp.
340
348
.
25.
Rhim
,
W.
,
Ohsaka
,
K.
,
Paradis
,
P.
, and
Spjut
,
R. E.
,
1999
, “
Noncontact Technique for Measuring Surface Tension and Viscosity of Molten Materials Using High Temperature Electrostatic Levitation
,”
Review of Scientific Instruments
, Vol. 70, pp.
2796
2801
.
26.
American Society of Mechanical Engineers (ASME)
,
2009
, Surface Texture: Surface Roughness, Waviness, and Lay, ASME B46.1-2009 (Revision of ASME B46.1-2002).
27.
Mills
,
K. C.
,
2002
, Recommended Thermophysical Properties for Selected Commercial Alloys, Woodhead Publishing Limited, Cambridge, UK.
28.
Corcione
,
M.
,
2011
, “
Empirical Correlating Equations for Predicting the Effective Thermal Conductivity and Dynamic Viscosity of Nanofluids
,”
Energy Conversion and Management
,
52
(
1
), pp.
789
793
.
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