Cobalt-based Tribaloy alloys are strengthened mainly by a hard, intermetallic Laves phase consisting of Co3Mo2Si or/and CoMoSi; therefore, silicon content plays a large role in the microstructure and performance of these materials. In this research, the microstructures of two cobalt-based Tribaloy alloys that are largely different in Si content are studied using scanning electron microscopy (SEM) with an EDAX energy dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD), fatigue strength under rotating-bending test, mechanical behavior under nanoindentation, and hardness at room and elevated temperatures using a microindentation tester. It is revealed that with higher silicon content (2.6 wt. %), T-400 has a hypereutectic microstructure with Laves phase as primary phase, whereas with lower silicon content (1.2 wt. %), T-401 has a hypoeutectic microstructure with solid solution as primary phase. T-400, containing lager volume fraction of Laves phase, exhibits better fatigue strength, in particular, at high stresses, while T-401, with less volume fraction of Laves phase, has improved ductility, exhibiting better resistance to fatigue at low stresses. The hardness of both alloys decreases with temperature, and T-401 shows higher reduction rate. T-400 is harder than T-401.

References

References
1.
Davis
,
J. R.
,
2000
,
Nickel, Cobalt, and Their Alloys
,
ASM International
,
Materials Park, OH
, pp.
362
370
.
2.
Raghu
,
D.
, and
Wu
,
J. B.
,
1997
, “
Recent Developments in Wear- and Corrosion-Resistant Alloys for the Oil Industry
,”
Mater. Perform.
,
36
(
11
), pp.
27
36
.
3.
Mason
,
S. E.
, and
Rawlings
,
R. D.
,
1985
, “
The Fracture Behavior of Two Co–Mo–Cr–Si Wear Resistant Alloys
,”
J. Mater. Sci.
,
20
(
4
), pp.
1248
1256
.
4.
Cameron
,
C. B.
, and
Ferriss
,
D. P.
,
1975
, “
Tribaloy Intermetallic Materials: New Wear- and Corrosion-Resistant Alloys
,”
Anti-Corr. Meth. Mater.
,
22
(
4
), pp.
5
8
.
5.
Zhang
,
Y. D.
,
Yang
,
Z. G.
,
Zhang
,
C.
, and
Lan
,
H.
,
2008
, “
Oxidation Behavior of Tribaloy T-800 Alloy at 800 and 1000 °C
,”
Oxid. Met.
,
70
(
3
), pp.
229
239
.
6.
Cameron
,
C. B.
,
Hoffman
,
R. A.
, and
Poskitt
,
R. W.
,
1975
, “
Tribaloy Intermetallic Alloy Compositions: New Materials or Additives for Wear Resistant Applications
,”
Prog. Powder Metall.
,
31
, pp.
41
51
.
7.
Halstead
,
A.
, and
Rawlings
,
R. D.
,
1984
, “
Structure and Hardness of Co–Mo–Cr–Si Wear Resistant Alloys (Tribaloys)
,”
Met. Sci.
,
18
(
10
), pp.
491
500
.
8.
Halstead
,
A.
, and
Rawlings
,
R. D.
,
1985
, “
Effect of Iron Additions on the Microstructure and Properties of the ‘Tribaloy’ Co–Mo–Cr–Si Wear Resistant Alloys
,”
J. Mater. Sci.
,
20
(
5
), pp.
1693
1704
.
9.
Sahraoui
,
T.
,
Feraoun
,
H. I.
,
Fenineche
,
N.
,
Montavon
,
G.
,
Aourag
,
H.
, and
Coddet
,
C.
,
2004
, “
HVOF-Sprayed Tribaloy-400: Microstructure and First Principle Calculations
,”
Mater. Lett.
,
58
(
19
), pp.
2433
2436
.
10.
Tuominen
,
J.
,
Vuoristo
,
P.
, and
Tapio
,
M.
,
2004
, “
Microstructure and Dry Sliding Wear Properties of Laser Clad Tribaloy Coatings
,”
1st Pacific International Conference on Applications of Lasers and Optics
, Melbourne, Australia, Apr. 19–21, pp.
13
17
.
11.
Natishan
,
P. M.
,
Lawrence
,
S. H.
,
Foster
,
R. L.
,
Lewis
,
J.
, and
Sartwell
,
B. D.
,
2000
, “
Salt Fog Corrosion Behavior of High-Velocity Oxygen-Fuel Thermal Spray Coatings Compared to Electrodeposited Hard Chromium
,”
Surf. Coat. Technol.
,
130
(
2–3
), pp.
218
223
.
12.
Song
,
J. H.
, and
Kim
,
H. J.
,
1997
, “
Sliding Wear Performance of Cobalt-Based Alloys in Molten-Al-Added Zinc Bath
,”
Wear
,
210
(
1–2
), pp.
291
298
.
13.
Przybylowicz
,
J.
, and
Kusinski
,
J.
,
2000
, “
Laser Cladding and Erosive Wear of Co–Mo–Cr–Si Coatings
,”
Surf. Coat. Technol.
,
125
(
1–3
), pp.
13
18
.
14.
Yao
,
M. X.
,
Wu
,
J. B. C.
,
Yick
,
S.
,
Xie
,
Y. S.
, and
Liu
,
R.
,
2006
, “
High Temperature Wear and Corrosion Resistance of a Newly Developed Laves Phase Strengthened Co–Mo–Cr–Si Alloy
,”
Mater. Sci. Eng.: A
,
435–436
, pp.
78
83
.
15.
Xu
,
W.
,
Liu
,
R.
,
Patnaik
,
P. C.
,
Yao
,
M. X.
, and
Wu
,
X. J.
,
2007
, “
Mechanical and Tribological Properties of Newly Developed Tribaloy Alloys
,”
Mater. Sci. Eng.: A
,
452–453
, pp.
427
436
.
16.
Oliver
,
W. C.
, and
Pharr
,
G. M.
,
1992
, “
An Improved Technique for Determining Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments
,”
J. Mater. Res.
,
7
(06), pp.
1564
1583
.
17.
Musil
,
J.
,
Kunc
,
F.
,
Zeman
,
H.
, and
Polakova
,
H.
,
2002
, “
Relationships Between Hardness, Young's Modulus and Elastic Recovery in Hard Nanocomposite Coatings
,”
Surf. Coat. Technol.
,
154
(
2–3
), pp.
304
313
.
18.
Stephens
,
R. I.
,
Fatemi
,
A.
,
Stephens
,
R. R.
, and
Fuchs
,
H. O.
,
2001
,
Metal Fatigue in Engineering
,
2nd ed.
,
Wiley
,
New York
, pp.
59
92
.
19.
Yao
,
M. X.
,
Wu
,
J. B. C.
,
Xu
,
W.
, and
Liu
,
R.
,
2005
, “
Microstructural Characteristics and Corrosion Resistance in Molten Zn–Al Bath of Co–Mo–Cr–Si Alloys
,”
Mater. Sci. Eng.: A
,
407
(
1–2
), pp.
299
305
.
20.
Liu
,
R.
,
Xu
,
W.
,
Yao
,
M. X.
,
Patnaik
,
P. C.
, and
Wu
,
X. J.
,
2005
, “
A Newly Developed Tribaloy Alloy With Increased Ductility
,”
Scr. Mater.
,
53
(
12
), pp.
1351
1355
.
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