Friction stir processing (FSP) is a relatively new technology for microstructure refinement of metallic alloys. At high processing speeds, excessive heating due to severe plastic deformation and friction may result in local melting at the interface between the FSP tool and the workpiece. In this work, a computational fluid dynamics (CFD) approach is applied to model material flow and heat evolution during friction stir processing of AZ31B magnesium alloy, taking into consideration the possibility of local melting in the stirring region. This is achieved by introducing the latent heat of fusion into an expression for heat capacity and accounting for possible effects of liquid formation on viscosity and friction. Results show that the temperature in the stirring region increases with the increase in rotational speed and drops slightly with the increase in translational speed. As liquid phase begins to form, the slope of temperature rise with rotational speed decreases and the maximum temperature in the stirring region stabilizes below the liquidus temperature at high rotational speeds. It is also shown that the formation of a semi-molten layer around the tool may result in a reduction in the shearing required for microstructure refinement.

References

References
1.
Thomas
,
M. W.
,
Nicholas
,
E. D.
,
Needham
,
J. C.
,
Murch
,
M. G.
,
Temple-Smith
,
P.
, and
Dawes
,
C. J.
,
1991
, “
Friction Stir Butt Welding,
” GB Patent No. 9125978.8.
2.
Mishra
,
R. S.
,
Mahoney
,
M. W.
,
McFadden
,
S. X.
,
Mara
,
N. A.
, and
Mukherjee
,
A. K.
,
1999
, “
High Strain Rate Superplasticity in a Friction Stir Processed 7075 Al Alloy
,”
Scr. Mater
,
42
, pp.
163
168
.10.1016/S1359-6462(99)00329-2
3.
Charit
,
I.
, and
Mishra
,
R. S.
,
2003
, “
High Strain Rate Superplasticity in a Commercial 2024 Al Alloy Via Friction Stir Processing
,”
Mater. Sci. Eng. A
,
359
, pp.
290
296
.10.1016/S0921-5093(03)00367-8
4.
Mishra
,
R. S.
, and
Mahoney
,
M. W.
,
2001
, “
Friction Stir Processing: A New Grain Refinement Technique to Achieve High Strain Rate Superplasticity in Commercial Alloys
,”
Mater Sci. Forum
,
357
, pp.
507
514
.10.4028/www.scientific.net/MSF.357-359.507
5.
Morisada
,
Y.
,
Fujii
,
H.
,
Nagaoka
,
T.
, and
Fukusumi
,
M.
,
2006
, “
MWCNTs/AZ31 Surface Composites Fabricated by Friction Stir Processing
,”
Mater. Sci. Eng. A
,
419
, pp.
344
348
.10.1016/j.msea.2006.01.016
6.
Chuang
,
C.
,
Huang
,
J.
, and
Hsieh
,
P.
,
2005
, “
Using Friction Stir Processing to Fabricate MgAlZn Intermetallic Alloys
,”
Scr. Mater.
,
53
, pp.
1455
1460
.10.1016/j.scriptamat.2005.08.019
7.
Mishra
,
R. S.
, and
Ma
,
Z. Y.
,
2005
, “
Friction Stir Welding and Processing
,”
Mater. Sci. Eng.
,
R 50
, pp.
1
78
.
8.
Buffa
,
G.
,
Hua
,
J.
,
Shivpuri
,
R.
, and
Fratini
,
L.
,
2006
, “
Design of the Friction Stir Welding Tool Using the Continuum Based FEM Model
,”
Mater. Sci. Eng. A
,
419
, pp.
389
396
.10.1016/j.msea.2005.09.040
9.
Chen
,
C. M.
, and
Kovacevic
,
R.
,
2003
, “
Finite Element Modeling of Friction Stir Welding-Thermal and Thermomechanical Analysis
,”
Int. J. Mach. Tools Manuf.
,
43
, pp.
1319
1326
.10.1016/S0890-6955(03)00158-5
10.
Schmidt
,
H.
, and
Hattel
,
J.
,
2005
, “
A Local Model for the Thermomechanical Conditions in Friction Stir Welding
,”
Modell. Simul. Mater. Sci. Eng.
,
13
, pp.
77
93
.10.1088/0965-0393/13/1/006
11.
Aljoaba
,
S.
,
Dillon
,
O. W.
,
Khraisheh
,
M.
, and
Jawahir
,
I. S.
,
2011
, “
Modeling the Effects of Coolant Application in Friction Stir Processing on Material Microstructure Using 3D CFD Analysis
,”
J. Mater. Eng. Perfom.
,
20
, pp.
1
10
.
12.
Aljoaba
,
S.
,
Jawahir
,
I. S.
,
Dillon
,
O. W.
,
Ali
,
M. H.
, and
Khraisheh
,
M. K.
,
2009
, “
Modeling of Friction Stir Processing Using 3D CFD Analysis
,”
Int. J. Mater. Form.
,
2
, pp.
315
318
.10.1007/s12289-009-0662-y
13.
Cho
,
J. H.
,
Boyce
,
D. E.
, and
Dawson
,
P. R.
,
2005
, “
Modeling Strain Hardening and Texture Evolution in Friction Stir Welding of Stainless Steel
,”
Mater. Sci. Eng. A
,
398
, pp.
146
163
.10.1016/j.msea.2005.03.002
14.
Colegrove
,
P. A.
, and
Shercliff
,
H.
,
2005
, “
3-Dimensional CFD Modeling of Flow Round a Threaded Friction Stir Welding Tool Profile
,”
J. Mater. Process. Technol.
,
169
, pp.
320
327
.10.1016/j.jmatprotec.2005.03.015
15.
Nandan
,
R.
,
Roy
,
G. J.
,
Lienert
,
T. J.
, and
Debroy
,
T.
,
2007
, “
Three-Dimensional Heat and Material Flow During Friction Stir Welding of Mild Steel
,”
Acta Mater.
,
55
, pp.
883
895
.10.1016/j.actamat.2006.09.009
16.
Ulysse
,
P.
,
2002
, “
Three-Dimensional Modeling of the Friction Stir-Welding Process
,”
Int. J. Mach. Tools Manuf.
,
42
, pp.
1549
1557
.10.1016/S0890-6955(02)00114-1
17.
Heurtier
,
P.
,
Jones
,
M. J.
,
Desrayaud
,
C.
,
Driver
,
J. H.
,
Montheillet
,
F.
, and
Allehaux
,
D.
,
2006
, “
Mechanical and Thermal Modeling of Friction Stir Welding
,”
J. Mater. Process. Technol.
,
171
, pp.
348
357
.10.1016/j.jmatprotec.2005.07.014
18.
Zhang
,
H. W.
,
Zhang
,
Z.
, and
Chen
,
J. T.
,
2007
, “
3D Modeling of Material Flow in Friction Stir Welding Under Different Process Parameters
,”
J. Mater. Process. Technol.
,
183
, pp.
62
70
.10.1016/j.jmatprotec.2006.09.027
19.
Song
,
M.
, and
Kovacevic
,
R.
,
2003
, “
Thermal Modeling of Friction Stir Welding in a Moving Coordinate System and Its Validation
,”
Int. J. Mach. Tools Manuf.
,
43
, pp.
605
615
.10.1016/S0890-6955(03)00022-1
20.
Frigaard
,
O.
,
Grong
,
O.
,
Hjelen
,
J.
,
Gulbrandsen-Dahl
,
S.
, and
Midling
,
O.
,
1999
, “
Characterization of the Subgrain Structure in Friction Stir Welded Aluminium Alloys Using the SEM-EBSD Technique
,”
Proceedings of the 1st International Symposium on Friction Stir Welding
, June
14–16, Thousand Oaks
,
CA
.
21.
Wert
,
J. A.
,
2003
, “
Microstructures of Friction Stir Weld Joints Between an Aluminium-Base Metal Matrix Composite and a Monolithic Aluminium Alloy
,”
Scr. Mater.
,
49
, pp.
607
612
.10.1016/S1359-6462(03)00215-X
22.
Karthikeyan
,
L.
,
Senthilkumar
,
V. S.
, and
Padmanabhan
,
K. A.
,
2010
, “
On the Role of Process Variables in the Friction Stir Processing of Cast Aluminum A319 Alloy
,”
Mater. Des.
,
31
, pp.
761
771
.10.1016/j.matdes.2009.08.001
23.
Robson
,
J. D.
,
Cui
,
S.
, and
Chen
,
Z. W.
,
2010
, “
Incipient Melting During Friction Stir Processing of AZ91 Magnesium Castings
,”
Mater. Sci. Eng. A
,
527
, pp.
7299
7304
.10.1016/j.msea.2010.07.093
24.
Darras
,
B. M.
,
Khraisheh
,
M. K.
,
Abu-Farha
,
F. K.
, and
Omar
,
M. A.
,
2007
,
Friction Stir Processing of Commercial AZ31 Magnesium Alloy
,”
J. Mater. Process. Technol.
,
191
, pp.
77
81
.10.1016/j.jmatprotec.2007.03.045
25.
Cardarelli
,
F.
,
2008
,
Materials Handbook
,
2nd ed.
,
Springer-Verlag
,
London
.
26.
Mirkovic
,
D. M.
, and
Schmid-Fetzer
,
R.
,
2007
, “
Solidification Curves for Commercial Mg Alloys Determined From Differential Scanning Calirometry With Improved Heat-Transfer Modeling
,”
Metall. Mater. Trans. A
,
38
, pp.
2575
2592
.10.1007/s11661-007-9237-z
27.
Harvey
,
P. D.
,
1982
,
Engineering Properties of Steels
,”
American Society for Metals
,
Metals Park, OH
.
28.
Bayer
,
A. M.
,
Vasco
,
T.
, and
Walton
,
L. R.
,
1990
, “
Properties and Selection: Irons, Steels, and High-Performance Alloys
,”
Metals Handbook
,
10th ed.
,
ASM International
,
Materials Park, OH
, Vol.
1
.
29.
Sellars
,
C. M.
, and
Tegart
,
W. J.
,
1972
, “
Hot Workability
,”
Int. Metall. Rev.
,
17
, pp.
1
23
.10.1179/095066072790137765
30.
Tello
,
K. E.
,
Gerlich
,
A. P.
, and
Mendez
,
P. F.
,
2010
, “
Constants for Hot Deformation Constitutive Models for Recent Experimental Data
,”
Sci. Technol. Welding Joining
,
15
, pp.
260
266
.10.1179/136217110X12665778348380
31.
Poirier
,
D. R.
, and
Geiger
,
G. H.
,
1994
,
Transport Phenomena in Materials Processing
,
Minerals, Metals and Materials Society
,
Warendale, PA
, pp.
68
71
.
32.
Hatamleh
,
O.
,
Smith
,
J.
,
Cohen
,
D.
, and
Bradley
,
R.
,
2009
, “
Surface Roughness and Friction Coefficient in Peened Friction Stir Welded 2195 Aluminum Alloy
,”
Appl. Surf. Sci.
,
255
, pp.
7414
7426
.10.1016/j.apsusc.2009.04.011
33.
Khraisheh
,
M. K.
,
Darras
,
B. M.
,
Kalu
,
P.
,
Adams-Hughes
,
M.
, and
Chandra
,
N.
,
2005
, “
Correlation Between the Microstructure and Forces Generated During Friction Stir Processing of AA5052
,”
Mater. Sci. Forum
,
475–479
, pp.
3043
3046
.10.4028/www.scientific.net/MSF.475-479.3043
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