Abstract
Grain structure is an important and readily observable feature in cast aluminium alloys. Three different types of grain morphology are possible, namely, columnar, twinned columnar, and equiaxed. Inoculants in the form of master alloys are used to promote the formation of a fully equiaxed grain structure and this is termed grain refinement. Initially, fundamental aspects of solidification are outlined in order that the principles of grain refining using master alloys can be understood. Techniques for the commercial production and testing of common Al–Ti-based master alloys are then discussed briefly. The exact mechanisms by which grain refinement occurs are not yet fully understood and experimental and theoretical studies on the problem are critically reviewed with particular emphasis on (a) the role of solute titanium, (b) the thermodynamics of Al–Ti-based alloy systems, and (c) the nature of heterogeneous nuclei. Finally, current and future trends in the use of grain refining alloys are summarised.
Get full access to this article
View all access options for this article.
References
1.
FLEMINGS
M. C.
: ‘Solidification processing’, 6-17; 1974, New York, McGraw-Hill.
2.
EMLEY
E. F.
: Int . Met. Re
v ., 21, 75 –115 .
3.
EADY
J. A.
HOGAN
L. M.
: J. Cryst. Growth , 1974 , 23 , 129 –136 .
4.
FREDRIKSSON
H.
HILLERT
M.
: J. Mater. Sc
i ., 1971 , 6, 1350 -1354.
5.
MORRIS
L. R.
RYVOLA
M.
: in `Microstructural science', Vol. 9, (ed.
Petzow
G.
et al.), 241-248; 1981, Amsterdam, Elsevier North-Holland.
6.
GRANGER
D. A.
LIU
J.
: J. Met ., 1983 , 35 , (6 ), 54 –59 .
7.
LABARRE
L. C.
JAMES
R. S.
WITTERS
J. J.
O'MALLEY
R. J.
EMPTAGE
M. R.
: J. Phys. (Orsay) , 1987, 48, C3, Suppl. (9) , 93-102.
8.
GRANGER
D. A.
: in Proc. Int. Seminar on ‘Refining and alloying of liquid aluminium and ferro-alloys’ , Trondheim, Norway, 1985, 231-244.
9.
APELIAN
D.
SIGWORTH
G. K.
WHALER
K. R.
: Trans. AFS , 1984 , 92 , 297 –307 .
10.
HASHEMI-AHMADY
S. H.
: PhD thesis, University of Southampton, UK, 1988.
11.
CIBULA
A.
: J. Inst. Met ., 1949 -50, 76 , 321 –360 .
12.
FLEMINGS
M. C.
: ‘Solidification processing’, 290-300; 1974, New York, McGraw-Hill.
13.
KURZ
W.
FISHER
D. J.
: ‘Fundamentals of solidification’, 21-34; 1984, Switzerland, Trans. Tech. Publications.
14.
VERHOEVEN
J. D.
: ‘Fundamentals of physical metallurgy’, 382-386; 1975, New York, Wiley.
15.
CHRISTIAN
J. W.
: ‘The theory of transformations in metals and alloys’, 407-412; 1965, Oxford, Pergamon.
16.
KURZ
W.
FISHER
D. J.
: ‘Fundamentals of solidification’, 47-67; 1984, Switzerland, Trans. Tech. Publications.
17.
BURDEN
M.
HUNT
J. D.
: J. Cryst. Growth , 1974 ; 22 , 99 –108 .
18.
TASSA
M.
HUNT
J. D.
: J. Cnyst. Growth , 1976 , 38 , 34 –45 .
19.
BURDEN
M. H.
HUNT
J. D.
: J. Cryst. Growth , 1974 , 22 , 109 –118 .
20.
KURZ
W.
FISHER
D. J.
: Acta Metall ., 1981 , 29 , 11 –20 .
21.
TREVEDI
R.
SOMBOONSUK
K.
: Mater. Sci. Eng ., 1984 , 65 , 65 –74 .
22.
MAXWELL
I.
HELLAWELL
A.
: Acta Metall ., 1975 , 23 , 229 –237 .
23.
DUSTIN
I.
KURZ
W.
: Z. Metallkd ., 1986 , 77 , 265 –273 .
24.
RAPPAZ
M.
and Ph. THEVOZ : Acta Metall ., 1987 , 35 , 1487 –1497 .
25.
RAPPAZ
M.
and Ph. THEVOZ : Acta Metall ., 1987 , 35 , 2929 –2933 .
26.
LIPTON
J.
KURZ
W.
HEINEMANN
W.
: Concast Tech. J ., 1983 , 4 –7 .
27.
FREDRIKSSON
H.
OLSSON
A.
: Mater. Sci. Technol ., 1986 , 2 , 508 –516 .
28.
FLOOD
S. C.
HUNT
J. D.
: J. Cryst. Growth , 1987 , 82 , 552 –560 .
29.
HUNT
J. D.
: Mater. Sci. Eng ., 1984 , 65 , 75 –83 .
30.
MONDOLFO
L. F.
: ‘Aluminum alloys — Structure and properties’, 385-387; 1976, London, Butterworths.
31.
GIJZOWSKI
M. M.
SIGWORTH
G. K.
SENTNER
D. A.
: Trans ., 1987 , 18A , 603 –619 .
32.
McCARTNEY
D. G.
: Metall. Trans ., 1988 , 19A , 385 –387 .
33.
BAcicEauD
L.
: UK Pat . No . 1 333 957, 1971 .
34.
GUZOWSKI
M. M.
SENTNER
D. A.
SIGWORTH
G. K.
: UK Pat. Appl. No. GB 2162540A, 1986.
35.
REIF
W.
Pat
A. BANERJE UK
. Appl. No. GB 2171713A, 1986.
36.
KLANG
H.
: Chem. Comm. (Stockholm ), 1981 , (4 ).
37.
ARNBERG
L.
BACKERUD
L.
KLANG
H.
: Met. Technol ., 1982 , 9 , 1 –6 .
38.
BLAKE
N. W.
SMITH
R. W.
: in ‘Solidification technology in the foundry and cast house’ , 83-88; 1983, London, The Metals Society.
39.
JONES
G. P.
PEARSON
J.
: Metall. Trans ., 1976 , 7B , 223 –234 .
40.
SIGWORTH
G. K.
Guzowsio
M. M.
: Trans. AFS , 1985 , 93 , 907 –912 .
41.
KIRBY
J. L.
: in Proc. 1st int. conf. on ‘Aluminum alloys — Their physical and mechanical properties’, Charlottesville, VA, June 1986, Aluminum Association, 61-79.
42.
SAWKA
J.
: Giessereiforschung , 1986 , 38 , 112 –118 .
43.
CHARBONNIER
J.
: Trans. AFS , 1984 , 92 , 907 –922 .
44.
CROSSLEY
F. A.
MONDOLFO
L. F.
: Trans. AIME , 1951 , 191 , 1143 –1148 .
45.
CIBULA
A.
: J. Inst. Met ., 1951 -52, 80 , 1 –16 .
46.
GLASSON
L.
EMLEY
E. F.
: in ‘The solidification of metals’ , 1-9; 1968 , London , The Iron and Steel Institute .
47.
MAXWELL
I.
HELLAWELL
A.
: Acta Metall ., 1975 , 23 , 901 –909 .
48.
SIGWORTH
G. K.
: Metall. Trans ., 1984 , 15A , 223 –234 .
49.
ABDEL-HAMID
A. A.-R.
DURAND
F.
: Metall. Trans ., 1986 , 17A , 349 .
50.
ABDEL-HAMID
A. A.-R.
DURAND
F.
: J. Cryst. Growth , 1984 , 66 , 195 –204 .
51.
SIGWORTH
G. K.
: Metall. Trans ., 1986 , 17A , 349 –351 .
52.
MAXWELL
I.
HELLAWELL
A.
: Metall. Trans ., 1972 , 3 , 1487 –1491 .
53.
HELLAWELL
A.
: in ‘Solidification and casting of metals’ , 161-168; 1979, London, The Metals Society.
54.
KIUSALAAS
R.
: Chem. Comm. (Stockholm ), 1986 , (1 ).
55.
MARCANTONIO
J. A.
MONDOLFO
L. F.
: Metall. Trans ., 1971 , 2 , 465 –471 .
56.
FINK
W. L.
: Trans AIME , 1931 , 93 , 421 .
57.
ARNBERG
L.
BÄCKERUD
L.
KLANG
H.
: Met. Technol ., 1982 , 9 , 7 –13 .
58.
HADLET
D.
McCARTNEY
D. G.
THISTLETHWAITE
S. R.
: in ‘Solidification processing 1987’ , 141-144; 1988, London, The Institute of Metals.
59.
HOGAN
L. M.
St
D. H.
. JOHN : J. Cryst. Growth , 1979 , 46 , 387 –389 .
60.
HADLET
D.
McCARTNEY
D. G.
THISTLETHWAITE
S. R.
: in ‘Aluminium technology '86’ , (ed.
Sheppard
T.
), 125-132; 1986, London, The Institute of Metals.
61.
SCHURHOFF
J. H.
: Z. Metallkd ., 1983 , 74 , 133 –138 .
62.
HORI
S.
TAI
H.
NARITA
Y.
: Jpn Inst. Light Met ., 1982 , 32 , 596 –603 .
63.
ARNBERG
L.
BÄCKERUD
L.
KLANG
H.
: Met. Technol ., 1982 , 9 , 14 –17 .
64.
DAVIES
I. G.
DENNIS
J. M.
HELLAWELL
A.
: Metall. Trans ., 1970 , 1 , 275 –280 .
65.
KIUSALAAS
R.
BÄCKERUD
L.
: in ‘Solidification processing 1987’ , 137-140; 1988, London, The Institute of Metals.
66.
CORNISH
A. J.
: Met. Sci ., 1975 , 9 , 477 –484 .
67.
MORICEAU
J.
: Mein. Sci. Rev. Metall ., 1970 , 77 , 787 –794 .
68.
KARDUCK
P.
SCHCIRHOFF
H. J.
BURCHARD
W. G.
: Mikrochim. Acta, 1983, Suppl. 10, 231-239.
69.
JONES
G. P.
: in Proc. Int. Seminar on ‘Refining and alloying of liquid aluminium and ferro-alloys’, Trondheim, Norway, 1985.
70.
JONES
G. P.
: in ‘Solidification processing 1987’ , 496-499; 1988, London, The Institute of Metals.
71.
JONES
G. P.
: ‘New ideas on the mechanism of heterogeneous nucleation in liquid aluminium’, NPL Report, DMA (A) 19, National Physical Laboratory, Teddington, London, Nov. 1983.
72.
PEARSON
J.
BIRCH
M. E. J.
HADLET
D.
: in ‘Solidification technology in the foundry and cast house’ , 74-78; 1983, London, The Metals Society.
73.
PEARSON
J.
BIRCH
M. E. J.
: J. Met ., 1979 , 31 , (11 ), 27 –31 .
74.
PEARSON
J.
BIRCH
M. E. J.
: in
‘Light metals’ , (ed.
Geer
J. P.
), 1217 -1229; 1984 , Warrendale, PA, Metallurgical Society of AIME .
75.
THISTLETHWAITE
S. R.
HADLET
D.
HOFF
J. C.
: in
‘Light metals’ , (ed.
Bohner
H.
), 1169 -1178; 1985 , Warrendale, PA, Metallurgical Society of AIME .
76.
BIRCH
M. E. J.
FISHER
P.
: in ‘Aluminium technology '86’ , (ed.
Sheppard
T.
), 117-124; 1986, London, The Institute of Metals.
77.
BIRCH
M. E. J.
COWELL
A. J. J.
: J. Phys. (Orsay), 1987, 48, C3, Suppl. (9).
78.
BIRCH
M. E. J.
COWELL
A. J. J.
: in ‘Solidification processing 1987’ , 149-152; 1988, London, The Institute of Metals.
79.
LU
H. T.
WANG
L. C.
KUNG
S. K.
: J. Chin. Foundrymen's Assoc ., 1981 , 29 , 10 –18 .
80.
VADER
M.
NOORDEGRAAF
J.
: in ‘Light metals’ , 463-466; 1988, Warrendale, PA, Metallurgical Society of AIME.