Chip segmentation due to shear localization during machining of titanium alloys affects cutting forces and their machinability. Despite several studies on modeling and understanding influence of chip segmentation, little is known about the effect of preheating on it. This work therefore, involves orthogonal machining of Ti6Al4V alloy under preheating between 100 °C and 350 °C to investigate chip segmentation, shear band configuration, and microstructure of machined surfaces, through optical and scanning electron microscopy of chips and chip roots. Conceptual models of chip segment formation have been evolved. Shear band formation appears to be the dominant mechanism of chip segmentation up to 260 °C preheating, however at 350 °C, extent of fracture along the shear plane increases. The preheating increases spacing between shear bands in chips, reduces shear band thickness from 21 μm at 100 °C to 8 μm at 350 °C, and ultimately reduces cutting forces fluctuation, and compressive residual stresses in the machined surfaces.

References

References
1.
Recht
,
R.
,
1986
, “
Catastrophic Thermoplastic Shear
,”
ASME J. Appl. Mech.
,
86
, pp.
189
193
.10.1115/1.3629585
2.
Zhen-Bin
,
H.
, and
Komanduri
,
R.
,
1995
, “
On a Thermo mechanical Model of Shear Instability in Machining
,”
Ann. CIRP
,
44
, pp.
69
74
.10.1016/S0007-8506(07)62277-X
3.
Davies, A., Burns, T., and Evans, C., 1997, “On the Dynamics of Chip Formation in Machining Hard Metals,”
CIRP Ann. Manuf. Technol.
,
46
(1), pp. 25–30.10.1016/S0007-8506(07)60768-9
4.
Sun
,
S.
,
Brandt
,
M.
, and
Dargush
,
M.
,
2009
, “
Characteristics of Cutting Forces and Chip Formation in Machining
,”
Int. J. Mach. Tools Manuf.
,
49
, pp.
561
568
.10.1016/j.ijmachtools.2009.02.008
5.
Novak
,
J.
,
Shin
,
Y.
, and
Incropera
,
F.
,
1997
, “
Assessment of Plasma Enhanced Machining for Improved Machinability of Inconel 718
,”
ASME J. Manuf. Sci. Eng.
,
119
, pp.
125
129
.10.1115/1.2836550
6.
Jeon
,
Y.
, and
Pfefferkorn
,
F.
,
2008
, “
Effect of Laser Preheating the Workpiece on Micro End Milling of Metals
,”
ASME J. Manuf. Sci. Eng.
,
130
, p.
011004
.10.1115/1.2783219
7.
Tian
,
Y.
, and
Shin
,
Y.
,
2007
, “
Multi Scale Finite Element Modeling of Silicon Nitride Ceramics Undergoing Laser-Assisted Machining
,”
ASME J. Manuf. Sci. Eng.
,
129
, pp.
287
295
.10.1115/1.2673595
8.
Komanduri
,
R.
, and
Hou
,
Z.
,
2002
, “
On the Thermoplastic Shear Instability in the Machining of a Titanium Alloy (Ti–6Al–4V)
,”
Metall. Mater. Trans. A
,
33
, pp.
2995
3010
.10.1007/s11661-002-0284-1
9.
Xie
,
J.
,
Bayoumi
,
A.
, and
Zbib
,
H.
,
1996
, “
A Study on Shear Banding in Chip Formation of Orthogonal Cutting
,”
Int. J. Mach. Tools Manuf.
,
36
, pp.
836
847
.10.1016/0890-6955(95)00016-X
10.
Vyas
,
A.
, and
Shaw
,
M.
,
1999
, “
Mechanics of Saw-Tooth Chip Formation in Metal Cutting
,”
ASME J. Manuf. Sci. Eng.
,
211
, pp.
163
172
.10.1115/1.2831200
11.
Gentel
,
H.
,
Hoffmeister
,
H.
, and
Evans
,
C.
,
2001
, “
Chip Formation in Machining Ti6A14V at Extremely High Cutting Speeds
,”
CIRP Ann.
,
50
(
1
), pp.
49
52
.10.1016/S0007-8506(07)62068-X
12.
Atlati
,
S.
,
Haddag
,
B.
,
Nouari
,
M.
, and
Zenasni
,
M.
,
2011
, “
Analysis of a New Segmentation Intensity Ratio “SIR” to Characterize the Chip Segmentation Process in Machining Ductile Metals
,”
Int. J. Mach. Tools Manuf.
,
51
, pp.
687
700
.10.1016/j.ijmachtools.2011.05.007
13.
Kouadri
,
S.
,
Necib
,
K.
,
Haddag
,
B.
, and
Nouari
,
M.
,
2013
, “
Quantification of the Chip Segmentation in Metal Machining: Application to Machining the Aeronautical Aluminium Alloy AA2024-T351 With Cemented Carbide Tools WC-Co
,”
Int. J. Mach. Tools Manuf.
,
64
, pp.
102
113
.10.1016/j.ijmachtools.2012.08.006
14.
Rajagopal
,
S.
,
Plankenhorn
,
D.
, and
Hill
,
V.
,
1982
, “
Machining Aerospace Alloys With the Aid of a 15 kW Laser
,”
J. Appl. Metal Work.
,
2
(
3
), pp.
170
184
.10.1007/BF02834035
15.
Lesourd
,
B.
,
Maıtre
,
F.
, and
Thomas
,
T.
,
1995
, “
The Chip Formation in Conventional and Laser Assisted Machining-Application to the Milling Process
,”
Manuf. Syst.
,
24
, pp.
279
286
.
16.
Lacalle
,
L.
,
Sanchez
,
J.
,
Lamikiz
,
A.
, and
Celaya
,
A.
,
2004
, “
Plasma Assisted Milling Heat-Resistant Superalloys
,”
ASME J. Manuf. Sci. Eng.
,
126
, pp.
274
285
.10.1115/1.1644548
17.
Sun
,
S.
,
Harris
,
J.
, and
Brandt
,
M.
,
2008
, “
Parametric Investigation of Laser-Assisted Machining of Commercially Pure Titanium
,”
Adv. Eng. Mater.
,
10
, pp.
565
572
.10.1002/adem.200700349
18.
Dandekar
,
C.
,
Shin
,
Y.
, and
Barnes
,
J.
,
2010
, “
Machinability Improvement of Titanium Alloy (Ti-6Al-4V) Via LAM and Hybrid Machining
,”
Int. J. Mach. Tools Manuf.
,
50
, pp.
174
182
.10.1016/j.ijmachtools.2009.10.013
19.
Sun
,
S.
,
Harris
,
J.
,
Durandet
,
Y.
, and
Brandt
,
M.
,
2008
, “
Effect of Laser Beam on Machining of Titanium Alloys
,”
Proceedings of the Third Pacific International Conference on Application of Lasers and Optics
,
Beijing, China
, April 16–18, p.
108
.
20.
Cahn
,
R.
, and
Haasen
,
P.
,
1996
,
Physical Metallurgy Vol. III
,
4th ed.
,
Elsevier Science B.V.,
Amsterdam
, The Netherlands, pp.
2410
2430
.
21.
Lee
,
W.
, and
Lin
,
C.
,
1998
, “
Plastic Deformation and Fracture Behaviour of Ti- 6Al-4V Alloy
,”
Mater. Sci. Eng.
, A.,
241
, pp.
48
59
.10.1016/S0921-5093(97)00471-1
22.
Ye
,
G.
,
Xue
,
S.
,
Jiang
,
M.
,
Tong
,
X.
, and
Dai
,
L.
,
2013
, “
Modeling Periodic Adiabatic Shear Band Evolution During High Speed Machining Ti-6Al-4V Alloy
,”
Int. J. Plast.
,
40
, pp.
39
55
10.1016/j.ijplas.2012.07.001
23.
Peirsa
,
J.
,
Tirryb
,
W.
,
Amin-Ahmadib
,
B.
,
Coghec
,
F.
,
Verleysena
,
P.
,
Rabetc
,
L.
,
Schryversb
,
D.
, and
Degriecka
,
J.
,
2013
, “
Microstructure of Adiabatic Shear Bands in Ti6Al4V
,”
Mater. Charact.
,”
75
, pp.
79
92
10.1016/j.matchar.2012.10.009
24.
Astakov
,
V.
,
2006
,
Tribology of Metal Cutting
,
1st ed.
,
Elsevier Ltd.
,
London
, pp.
78
85
.
25.
Kroneberg
,
M.
,
1966
,
Machining Science and Application
,
Pergamon Press
,
Oxford
, UK, pp.
140
150
.
26.
Boothroyds
,
G.
, and
Knight
,
W.
,
2006
,
Fundamental of Machining and Machine Tool
,
3rd ed.
,
CRC Press
,
Boca Raton
, FL, pp.
87
88
.
27.
Barnes
,
S.
,
Pashby
,
I.
, and
Mok
,
D.
,
1966
, “
The Effect of Workpiece Temperature on the Machinability of an Aluminum/SiC MMC
,”
ASME J. Manuf. Sci. Eng.
,
118
, pp.
422
427
.10.1115/1.2831047
28.
Huang
,
J.
,
Olson
,
W.
,
Sutherland
,
J.
, and
Aifentis
,
E.
,
1996
, “
On the Shear Instability in Chip Formation in Orthogonal Machining
,”
J. Mech. Behav. Mater.
,
7
(
4
), pp.
279
292
.10.1515/JMBM.1996.7.4.279
29.
Hull
,
D.
, and
Bacon
,
D.
,
2001
,
Introduction to Dislocation
,
4th ed.
,
Butterworth-Heinemann
,
Woburn
, MA, pp.
158
160
.
30.
Xue
,
Q.
,
Mayers
,
M.
, and
Nesterenko
,
V.
,
2002
, “
Self-Organization of Shear Band in Titanium and Ti6Al4V Alloy
,”
Acta Mater.
,
50
, pp.
575
596
.10.1016/S1359-6454(01)00356-1
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