Aluminium-copper alloy for casting
An aluminium-copper alloy comprising substantially insoluble particles which occupy the interdendritic regions of the alloy, provided with free titanium in quantity sufficient to result in a refinement of the grain structure in the cast alloy.
1. An aluminium-copper alloy for casting, comprising substantially insoluble particles which occupy the interdendritic regions of the alloy, the substantially insoluble particles being present in an amount of at least 0.5 wt % up to 20 wt % and comprising titanium diboride particles, wherein the alloy comprises a hyperperitectic quantity of free titanium to result in a refinement of the grain structure in the cast alloy.
2. An alloy according to claim 1 comprising up to 1 wt % titanium.
3. An alloy according to claim 1 comprising up to 0.5 wt % titanium.
4. An aluminium-copper alloy according to claim 2 , comprising:
Cu
3.0-6.0 wt %
Mg
0.0-1.5 wt %
Ag
0.0-1.5 wt %
Mn
0.0-0.8 wt %
Fe
0.0-1.5 wt %
Si
0.0-1.5 wt %
Zn
0.0-4.0 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
at least 0.5 wt % up to 20 wt %
Al and inevitable impurities
Balance.
5. An alloy according to claim 2 comprising:
Cu
4.0-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.0-0.5 wt %
Mn
0.0-0.6 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
at least 0.5 wt % up to 10 wt %
Al and inevitable impurities
Balance.
6. An alloy according to claim 2 comprising:
Cu
4.0-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.4-1.0 wt %
Mn
0.0-0.6 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
at least 0.5 wt % up to 10 wt %
Al and inevitable impurities
Balance.
7. An alloy according to claim 2 comprising:
Cu
4.2-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.0-0.85 wt %
Mn
0.0-0.4 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
1.5-9.0 wt %
Al and inevitable impurities
Balance.
8. An alloy according to claim 2 comprising:
Cu
4.2-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.0-0.85 wt %
Mn
0.0-0.4 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
4.0-9.0 wt %
Al and inevitable impurities
Balance.
9. An alloy according to claim 2 comprising:
Cu
4.2-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.45-0.85 wt %
Mn
0.0-0.4 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
1.5-9.0 wt %
Al and inevitable impurities
Balance.
10. An alloy according to claim 2 comprising:
Cu
4.2-5.0 wt %
Mg
0.2-0.5 wt %
Ag
0.45-0.85 wt %
Mn
0.0-0.4 wt %
Fe
0.0-0.15 wt %
Si
0.0-0.15 wt %
Zn
0.0-1.8 wt %
Sb
0.0-0.5 wt %
Zr
0.0-0.5 wt %
Co
0.0-0.5 wt %
Ti
hyperperitectic
Insoluble particles
4.0-9.0 wt %
Al and inevitable impurities
Balance.
11. An alloy according to claim 1 wherein the insoluble particles are of a size which is at least in the region of an order of magnitude smaller than the dendrite arm spacing /grain size of the solid alloy, and occupy the interdendritic/intergranular regions of the alloy.
12. An alloy according to claim 11 wherein the insoluble particles have a particle size which lies in the range 0.5 to 25 μm.
13. An alloy according to claim 11 wherein the particle size lies in the range 0.5 to 15 μm.
14. An alloy according to claim 11 wherein the particle size lies in the range 0.5 to 5 μm.
15. An alloy according to claim 1 comprising 0.5 wt %-10 wt % titanium diboride particles.
16. An alloy according to claim 1 comprising 3 wt %-7 wt % titanium diboride particles.
17. An alloy according to claim 1 comprising 4 wt % titanium diboride particles.
18. An alloy according to claim 1 comprising 7 wt % titanium diboride particles.
19. A method of making a casting, comprising melting an aluminium copper alloy according to claim 1 and introducing the resulting alloy into a mold.
20. A method according to claim 19 comprising controlling the rate of cooling of the alloy in the mould.
21. A method according to claim 20 wherein the alloy comprises a hyperperitectic quantity of titanium, and the casting is made by one of sand casting or investment casting.