Extrusion Material

Abstract

An aluminium extrusion material for use in a hybrid metal extrusion and bonding process is provided. The composition of the extrusion material comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium extrusion material is in the 2xxx series, 0 to 0.05 wt % copper. The microstructure of the extrusion material is a deformed microstructure; and the nanostructure of the extrusion material comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix. An aluminium rod for manufacturing the extrusion material, a joint comprising a extrudate made from the extrusion material a method of manufacturing the extrusion material and the aluminium rod and a method of joining two aluminium components using the extrusion material are also provided.

Claims

1. An aluminium extrusion material for use in a hybrid metal extrusion and bonding process, wherein the composition of the extrusion material comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium extrusion material is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the extrusion material is a deformed microstructure; and wherein the nanostructure of the extrusion material comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

2. An aluminium extrusion material according to claim 1, wherein the nanostructure of the extrusion material comprises small iron particles.

3. An aluminium extrusion material according to claim 1 or 2, wherein the nanostructure is free of solute-rich metastable precipitates, large iron particles and coarse solute-rich equilibrium phases

4. An aluminium extrusion material according to claim 1, 2 or 3, wherein the microstructure is not a recrystallized microstructure.

5. An aluminium extrusion material according to any preceding claim, wherein the length to width ratio of the grains of the microstructure is at least 5:1.

6. An aluminium extrusion material according to any preceding claim, wherein the extrusion material comprises a grain refiner.

7. An aluminium extrusion material according to any preceding claim, wherein the extrusion material is a filler wire.

8. An aluminium extrusion material according to any preceding claim, wherein the hybrid metal extrusion and bonding process is a hybrid metal extrusion and bonding process joining two components.

9. An aluminium extrusion material according to claim 8, wherein at least one of the components is an aluminium component and wherein the composition of the extrusion material is of the same aluminium alloy series as the composition of at least one of the aluminium components.

10. An aluminium extrusion material according to any preceding claim, wherein the hybrid metal extrusion and bonding process is for depositing and bonding extruded extrusion material on a substrate.

11. An aluminium extrusion material according to any preceding claim, wherein the substrate is an aluminium component, and wherein the composition of the extrusion material is of the same aluminium alloy series as the composition of the aluminium component.

12. A system for joining two aluminium components by a hybrid metal extrusion and bonding process joining, the system comprising: two components which are to be joined; and an aluminium extrusion material according to any preceding claim.

13. A system for joining two aluminium components according to claim 12, wherein at least one of the components is an aluminium component.

14. A system for bonding an extrusion material on a component, the system comprising: a component on which the extrusion material will be deposited and bonded; and an extrusion material according to any of claims 1 to 11.

15. An aluminium rod for manufacturing an aluminium extrusion material for use in a hybrid metal extrusion and bonding process, wherein the composition of the aluminium rod comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the aluminium rod is a deformed microstructure; and wherein the nanostructure of the aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

16. An aluminium rod according to claim 15, wherein the nanostructure of the aluminium rod comprises small iron particles.

17. An aluminium rod according to claim 15 or 16, wherein the nanostructure is free of solute-rich metastable precipitates, large iron particles and coarse solute-rich equilibrium phases

18. An aluminium rod according to claim 15, 16 or 17, wherein the microstructure is not a recrystallized microstructure.

19. An aluminium rod according to any of claims 15 to 18, wherein the length to width ratio of the grains of the microstructure is at least 5:1.

20. An aluminium rod according to any of claims 15 to 19, wherein the aluminium rod comprises a grain refiner.

21. An aluminium rod according to any of claims 15 to 20, wherein the extrusion material is a filler wire.

22. An aluminium rod according to any of claims 15 to 21, wherein the hybrid metal extrusion and bonding process is a hybrid metal extrusion and bonding process joining two components.

23. An aluminium rod according to any of claims 15 to 22, wherein at least one of the components is an aluminium component and wherein the composition of the extrusion material is of the same aluminium alloy series as the composition of at least one of the aluminium components.

24. An aluminium rod according to any of claims 15 to 23, wherein the hybrid metal extrusion and bonding process is for depositing and bonding extruded extrusion material on a substrate.

25. An aluminium rod according to claim 24, wherein the substrate is an aluminium component, and wherein the composition of the extrusion material is of the same aluminium alloy series as the composition of the aluminium components.

26. A joint, the joint comprising: two aluminium components; and an aluminium filler material therebetween, wherein the aluminium components have been joined together by the filler material using a hybrid metal extrusion and bonding process, wherein the composition of the filler material is of the same aluminium alloy series as the composition of at least one of the aluminium components; wherein the composition of the filler material comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium filler material is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the filler material is a deformed microstructure; and wherein the nanostructure of the filler material comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

27. A joint according to claim 26, wherein the filler material has been formed by extruding the extrusion material according to any of claims 1 to 11.

28. Method of manufacturing an aluminium rod for use in manufacturing an extrusion material for use in a hybrid metal extrusion and bonding process, the method comprising: providing an aluminium melt, wherein the composition of the aluminium melt comprises 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper; casting the aluminium melt to produce an aluminium billet, homogenizing the aluminium billet; hot deforming the billet to form the aluminium rod; and quenching the aluminium rod, wherein the microstructure of the quenched aluminium rod is a deformed microstructure; and wherein the nanostructure of the quenched aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

29. A method according to claim 28, wherein the aluminium melt is produced from virgin aluminium.

30. A method according to claim 28 or 29, wherein the casting is direct chill casting.

31. A method according to claim 28, 29 or 30, wherein the homogenizing temperature is between the solidus and solvus temperature of the aluminium alloy of the billet and is closer to the solvus temperature than the solidus temperature, as defined by the equilibrium phase diagram.

32. A method according to any of claims 28 to 31, wherein the billet is preheated by induction heating before hot deformation.

33. A method according to any of claims 28 to 32, wherein during hot deformation the temperature of the billet is controlled so that it is kept above the equilibrium solvus of the alloy, as defined by the equilibrium phase diagram.

34. A method according to any of claims 28 to 33, wherein the hot deformation is hot extrusion and wherein the minimum area reduction is at least 10:1.

35. A method according to any of claims 28 to 33, wherein the hot deformation is hot rolling and wherein the area reduction is at least 5:1.

36. A method according to any of claims 28 to 35, wherein the diameter of the hot deformed aluminium rod is about 1.5 to 2 times the diameter of the desired extrusion material.

37. A method according to any of claims 28 to 36, wherein the extrusion material is a filler wire.

38. A method according to any of claims 28 to 37, wherein the hybrid metal extrusion and bonding process is a hybrid metal extrusion and bonding process joining two components.

39. A method according to claim 38, wherein at least one of the components is an aluminium component and wherein the composition of the aluminium rod is of the same aluminium alloy series as the composition of at least one of the aluminium components.

40. A method according to any of claims 28 to 39, wherein the hybrid metal extrusion and bonding process is for depositing and bonding extruded extrusion material on a substrate.

41. A method according to claim 40, wherein the substrate is an aluminium component, and wherein the composition of the aluminium rod is of the same aluminium alloy series as the composition of the aluminium component.

42. Method of manufacturing an extrusion material for use in a hybrid metal extrusion and bonding process, the method comprising: providing an aluminium rod; wherein the composition of the aluminium rod comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the aluminium rod is a deformed microstructure; and wherein the nanostructure of the aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix; and deforming the aluminium rod to form the extrusion material, wherein the microstructure of the extrusion material is a deformed microstructure; and wherein the nanostructure of the extrusion material comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

43. A method according to claim 42, wherein deforming the aluminium rod comprises: cold shaving the aluminium rod; and drawing the aluminium rod.

44. A method of manufacturing a extrusion material according to claim 42 or 43, wherein the cold shaving and drawing of the aluminium rod are performed in one operation without the use of an intermediate heat treatment step.

45. A method of manufacturing a extrusion material according to claim 42, 43 or 44, wherein the drawing ratio is about 2:1 to 1.2:1.

46. A method of manufacturing a extrusion material according to any of claims 42 to 45, wherein wire cleaning is performed after drawing.

47. A method according to any of claims 42 to 46, wherein the extrusion material is a filler wire.

48. A method according to any of claims 42 to 47, wherein the hybrid metal extrusion and bonding process is a hybrid metal extrusion and bonding process joining two components.

49. A method according to claim 48, wherein at least one of the components is an aluminium component and wherein the composition of the extrusion material is of the same aluminium alloy series as the composition of at least one of the aluminium components.

50. A method according to any of claims 42 to 49, wherein the hybrid metal extrusion and bonding process is for depositing and bonding extruded extrusion material on a substrate.

51. A method according to claim 50, wherein the substrate is an aluminium component, and wherein the composition of the extrusion is of the same aluminium alloy series as the composition of the aluminium component.

52. A method of manufacturing an extrusion material according to any of claims 42 to 51, wherein the aluminium rod is manufactured according to the method of any of claims 28 to 41.

53. A method of manufacturing an extrusion material according to claim 52, wherein when the material is hot extruded the extrusion ratio is at least 5 times larger than the drawing ratio and when the material is hot rolled the rolling ratio is at least 2 times larger than the drawing ratio.

54. A method of joining two aluminium components, the method comprising: providing the two aluminium components, wherein the aluminium components each have a joining surface which is to be joined to the other aluminium component; providing a extrusion material according to claims 1 to 11, removing oxide from the joining surfaces of the two aluminium components, and extruding the extrusion material between the joining surfaces of the two aluminium components.

55. A method according to claim 54, wherein the method comprises manufacturing the extrusion material according to any of claims 42 to 53.

56. A method of bonding an extrudate to a component, the method comprising: providing the component, wherein the component has a surface on which the extrudate will be deposited and bonded; providing a extrusion material according to claims 1 to 11, removing oxide from the surfaces of the component, and extruding the extrusion material onto the surface of the component.

57. An aluminium filler wire for use in a hybrid metal extrusion and bonding process joining two aluminium components, wherein the composition of the filler wire is of the same aluminium alloy series as the composition of at least one of the aluminium components; wherein the composition of the filler wire comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium filler wire is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the filler wire is a deformed microstructure; and wherein the nanostructure of the filler wire comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

58. A system for joining two aluminium components by a hybrid metal extrusion and bonding process joining, the system comprising: two aluminium components which are to be joined; and an aluminium filler wire according to claim 56.

59. An aluminium rod for manufacturing an aluminium filler wire for use in a hybrid metal extrusion and bonding process joining two aluminium components, wherein the composition of the aluminium rod is of the same aluminium alloy series as the composition of at least one of the aluminium components; wherein the composition of the aluminium rod comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the aluminium rod is a deformed microstructure; and wherein the nanostructure of the aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

60. Method of manufacturing an aluminium rod for use in manufacturing a filler wire for use in a hybrid metal extrusion and bonding process joining two aluminium components, the method comprising: providing an aluminium melt, wherein the composition of the aluminium melt is of the same aluminium alloy series as the composition of at least one of the aluminium components; wherein the composition of the aluminium melt comprises 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper; casting the aluminium melt to produce an aluminium billet, homogenizing the aluminium billet; hot deforming the billet to form the aluminium rod; and quenching the aluminium rod, wherein the microstructure of the quenched aluminium rod is a deformed microstructure; and wherein the nanostructure of the quenched aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

61. Method of manufacturing a filler wire for use in a hybrid metal extrusion and bonding process joining two aluminium components, the method comprising: providing an aluminium rod; wherein the composition of the aluminium rod is of the same aluminium alloy series as the composition of at least one of the aluminium components; wherein the composition of the aluminium rod comprises: 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium rod is in the 2xxx series, 0 to 0.05 wt % copper, wherein the microstructure of the aluminium rod is a deformed microstructure; and wherein the nanostructure of the aluminium rod comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix, cold shaving the aluminium rod; and drawing the aluminium rod to form the filler wire, wherein the microstructure of the filler wire is a deformed microstructure; and wherein the nanostructure of the filler wire comprises an aluminium matrix with dislocations and dispersoids, and wherein the majority of the alloying elements are in solid solution in the aluminium matrix.

62. A method of joining two aluminium components, the method comprising: providing the two aluminium components, wherein the aluminium components each have a joining surface which is to be joined to the other aluminium component; providing a filler wire according to claim 56, removing oxide from the joining surfaces of the two aluminium components, and extruding the filler wire between the joining surfaces of the two aluminium components.

Description

[0192] Certain preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0193] FIG. 1 is a schematic of a joint formed by the HYB process;

[0194] FIGS. 2a and b are micrographs of the microstructure of two experimental AA6xxx extrusion wires used in laboratory testing;

[0195] FIG. 3 is a schematic of a nanostructure;

[0196] FIG. 4 is a schematic of another nanostructure;

[0197] FIG. 5a is a schematic of yet another nanostructure;

[0198] FIG. 5b is a graph of FW alloy strength vs RT storage time, log t;

[0199] FIG. 6 is a schematic showing a manufacturing route;

[0200] FIGS. 7a, b and c illustrate possible hot deformation methods;

[0201] FIGS. 8a to e show schematics of example joints and their strength levels; and

[0202] FIG. 9 is a graphical representation of the overlap in Si and Mg contents between different aluminium grades belonging to the same 6xxx series.

[0203] A joint 1 formed by a hybrid metal extrusion and bonding (HYB) process is shown in FIG. 1. The joint 1 is formed by extruding a filler wire between two aluminium components 2 to form a filler material 4 as described in WO 2003/04775.

[0204] The filler wire may be produced by shaving and drawing an aluminium rod as discussed in greater detail below.

[0205] The filler wire may also be used to bond a resulting extrudate onto the surface of a substrate, i.e. component. Thus, the filler wire does not necessary have to fill a gap between two components but could be deposited on the surface of a component. The filler wire may thus also be referred to more generally as an extrusion material. By referring to the extrusion material as a filler wire does not imply that it has to be extruded between two components and an extrusion material deposited on the surface of a component can equally be referred to as a filler material.

[0206] In the case that the filler wire is used to join two aluminium components, the filler wire used in the HYB process should be an aluminium alloy which is in the same series as at least one aluminium alloy of the aluminium components 2.

[0207] If the filler wire is used to join an aluminium component to a non-aluminium component, or used to deposit a layer on an aluminium component, the filler wire used in the HYB process may be an aluminium alloy which is in the same series as the aluminium alloy of the aluminium component.

[0208] The composition of the filler wire should contain 0 to 0.25 wt % iron; at least 0.05 wt % dispersoid-forming elements, wherein the dispersoid-forming elements comprise 0 to 1.2 wt % manganese, 0 to 0.25 wt % chromium, 0 to 0.25 wt % zirconium and 0 to 0.25 wt % scandium; and, except when the aluminium alloy of the aluminium filler wire is in the 2xxx series, 0 to 0.05 wt % copper.

[0209] The other components of the composition may be chosen to provide a final filler material 4 with appropriate properties in view of the joint 1 being joined (or component being coated with the extrudate) and the intended application of the final product.

[0210] The filler wire should have a deformed (fibrous) microstructure as shown in FIG. 2a. The microstructure should not be a recrystallized microstructure as shown in FIG. 2b. FIGS. 2a and 2b are micrographs of the microstructures of two experimental AA6xxx filler wires. The scale in the bottom right hand corner of the micrographs shows the length of 500 m.

[0211] The composition and production of the filler wire should be controlled so that the deformed microstructure of FIG. 2a is achieved rather than the recrystallized microstructure of FIG. 2b. This is the same for an aluminium rod used to make the aluminium filler wire and the final filler material 4 of the joint 1.

[0212] On the nanoscale the aluminium alloy of the filler wire/aluminium rod/filler material should comprise an aluminium matrix 6 with dispersoids 8, small iron particles 10 (e.g. less than 4 m) and dislocations 12 therein as shown schematically in FIG. 3. The majority of the alloying elements should be in solid solution in the aluminium matrix 6.

[0213] The nanostructure should be free of metastable phases 14, large iron particles 16 (e.g. greater than 4 m) and equilibrium phases 18. This is because these features will reduce the amount of alloying elements in solid solution and detrimentally degrade the physical properties of the aluminium alloy. FIG. 4 shows schematically an undesirable nanostructure.

[0214] The micro- and nanostructure of the aluminium filler wire is important because the filler wire is not melted during the HYB process and thus the micro- and nanostructure of the filler wire will affect the micro- and nanostructure of the filler material. This in turn will greatly affect the properties of the final joint 1 prepared by the HYB process.

[0215] If the aluminium alloy is left at room temperature (which may be the case between the production of the aluminium rod and the filler wire) it will naturally age and form clusters and GP zones 20 as shown schematically in FIG. 5a.

[0216] As shown in FIG. 5b, which is a graph with filler wire alloy strength on the x axis and room temperature storage time in log t on the y axis, as these clusters and GP zones form, the alloy strength will increase. Whilst this should not cause a problem for the HYB process as the high temperatures during the subsequent extrusion of the filler wire will result in the clusters and GP zones 20 dissolving back into the aluminium matrix 6, it should be taken into account in the further processing of the aluminium alloy to form the aluminium filler wire.

[0217] FIG. 6 shows schematically a manufacturing method for manufacturing the filler wire using hot extrusion. However, other hot deformation processes, such as hot rolling, could be performed instead of hot extrusion.

[0218] The method may comprise a melt treatment 22. Virgin aluminium may be provided directly from a smelter. This will help ensure that the content of impurities such as iron and copper are at acceptable levels. Alloying elements such as the dispersoid-forming elements are added to the melt to form the desired composition. Grain refiners such as AlB.sub.2 and TiB.sub.2 may also be added to the melt. These may be added immediately before casting.

[0219] The aluminium melt can then be cast 24 to form an aluminium billet or ingot. This may be performed by direct chill casting.

[0220] The billet may then be homogenized 26. The homogenizing temperature will depend on the composition of the billet but it may be between the solvus and the solidus temperature of the alloy. The homogenizing temperature may be closer to the solvus temperature rather than the solidus temperature as this may create a finer dispersion of dispersoids.

[0221] The billet may then be preheated 28 and this may be by means of induction heating. The temperature to which the billet is preheated will depend on the composition of the aluminium alloy.

[0222] The billet may then be hot deformed 30 to form an aluminium rod which can be used for forming the filler wire. This hot deformation step 30 may be achieved by hot extrusion (as illustrated in FIG. 7a or 7b) or hot rolling (as shown in FIG. 7c).

[0223] FIG. 7a shows a billet 100 in a container 102. The billet 100 is forced through a die 104 by action of ram 106 so as to form an aluminium rod 108.

[0224] FIG. 7b, shows a billet/feedstock 110 being forced by means of a wheel 112 through a die between an abutment 114 and a shoe 116 so as to form an aluminium rod 118.

[0225] FIG. 7c shows an aluminium rod 122 being rolled between two rollers 120.

[0226] The extrusion ratio (original area/final area) may be at least 10:1 and the rolling ratio (original area/final area) may be at least 5:1. Once deformed to form the aluminium rod the aluminium alloy may be quenched 32. The quenched rod may then be spooled 34 for storage and transportation before further processing to form the filler wire. These steps 22 to 34 (shown with a solid arrow) may be performed by an aluminium metal producer.

[0227] To form the filler wire the aluminium rod may be shaved 36 and drawn 38. The shaving 36 and drawing 38 may be done cold, in one operation, without the use of intermediate heat treatment such as soft annealing. This may be to ensure that the final filler wire has an appropriate microstructure without the use of detrimental soft annealing and/or expensive and time-consuming heat treatments to repair the structural damage that the previous soft annealing has caused. The drawing ratio (original area/final area) may be about 2:1 to 1.2:1, or higher.

[0228] The extrusion ratio may be about 5 to 10 times larger than the drawing ratio and the rolling ratio may be about 2 to 5 times larger than the drawing ratio.

[0229] The surface of the filler wire should be smooth and free of cracks. This is to minimise the risk of contaminants being trapped on the surface of the filler wire which may then negatively affect the quality of the final joint 1, particularly the interfacial bond strength.

[0230] After drawing 38 the wire may be cleaned 40 and then spooled and packaged 42. The wire may be packed in a sealed, vacuum packed environment. This is to try to keep the filler wire in an appropriate condition (e.g. free of contaminants on the surface) for use in the HYB process. Steps 36 to 42 (shown with a dotted arrow) may be performed by an aluminium filler wire manufacturer.

[0231] A filler wire designer may know the composition and micro/nanostructure they require for the HYB process. With this information the processing steps may be adjusted accordingly to allow the desired filler wire to be produced.

EXAMPLES

[0232] Example joints 1 are shown in FIGS. 8 a to e. The examples illustrate how a tailor-made filler wire of a specific composition according to the present invention will respond to butt joining of different AlMgSi plates belonging to the same alloy series.

[0233] The graph above each schematic joint illustrates the relative strength of the join compared to the components being joined.

[0234] In each of the examples in FIGS. 8a, 8b and 8c the filler wire composition is assumed to lie within the upper right corner of the composition window for AA6082 which is illustrated in FIG. 9, i.e. the composition is relatively high in magnesium and silicon content. Moreover, the filler wire nanostructure is that illustrated in FIG. 5a. The appropriate filler wire alloy designation would then be AA6xxxgrade A, where grade A means that the filler wire is high in Si and Mg.

[0235] The example in FIG. 8a shows butt joining of two AA6082-T6 base plates using AA6xxxgrade A as a filler wire

[0236] The T6 temper designation means that the material of the aluminium components being joined is artificially aged to peak strength before joining. Thus, when a matching filler wire is used during the joining operation, an even-strength-level across the joint should be obtained, as illustrated in FIG. 8a.

[0237] The example in FIG. 8b shows butt joining of AA6082-T7 base plates using AA6xxxgrade A as the filler wire.

[0238] The T7 temper designation means that the same material of the aluminium components being joined is used in the over-aged condition. Hence, its strength is lower than that of the T6 heat treated base plates in the example of FIG. 8a. Accordingly, after joining the filler material strength will be higher than that of the base metal, as illustrated in FIG. 8b, a state which is referred to as filler material over-match.

[0239] The example in FIG. 8c shows butt joining of AA6060-T6 base plates using AA6xxxgrade A as filler wire

[0240] The alloy designation AA6060 means that this base material of the aluminium component has a lower content of the major alloying elements Si and Mg compared to AA6082 (see FIG. 9). Hence, its peak strength will be lower than that of the T6 heat treated base plates in the example of FIG. 8a. Therefore, the desired degree of filler material over-match is also achieved in this case, as illustrated in FIG. 8c, although the filler wire alloy composition is the same as the in the other two examples of FIGS. 8a and 8b.

[0241] FIGS. 8d and e show examples of possible use of a specific filler wire for joining of dissimilar aluminium alloys

[0242] In both these examples the filler wire composition is assumed to lie within the middle of the composition window for AA6060 in FIG. 9. Moreover, the filler wire structure is assumed to be similar to that shown in FIG. 5a. The appropriate filler wire alloy designation would then be AA6xxxgrade B, where grade B means that the filler wire is low in Si and Mg.

[0243] FIG. 8d shows an example of butt joining of dissimilar AA6082 base plates (AA6082-T6 on the left-hand side and AA6082-T7 on the right hand side) using AA6xxxgrade B as filler wire.

[0244] The T6 temper designation means that the base material on the left-hand side of the dissimilar joint in FIG. 8d is artificially aged to its peak strength before joining, whereas the T7 temper designation means that the other base plate instead is used in the over-aged condition. Thus, when a filler wire of strength that matches the softest base metal is used during the joining operation, the joint strength will drop from the initial T6 value to the lower T7 base material strength, as illustrated in FIG. 8d.

[0245] Turning to FIG. 8e, which shows joining AA 6082-T6 on the left hand side to AA6060-16 on the right hand side, the alloy designation AA6082 means that this base material has a higher content of the major alloying elements Si and Mg compared to AA6060 (see FIG. 9). Hence, its peak strength will be higher than that of the T6 heat treated AA6060 base material. Accordingly, after joining, using the same filler wire as in the previous example, the filler material strength will fall in between the strength of the two base plates, as illustrated in FIG. 8e.