Aluminum Alloy with Improved Strength and Ductility

The present application is claiming priority from U.S. Provisional Application No. 63/364,891 filed May 18, 2022, content of which is hereby incorporated by reference in its entirety.

This disclosure relates to the field of aluminum alloys such as Al—Mg—Si alloys, particularly aluminum alloys useful in the automotive industry.

Aluminum alloys are used in the automotive industry because they have desirable mechanical properties suitable for that industry. In automotive extrusion applications, increased strength is desirable to increase the energy absorption and to permit a reduction in wall thickness of a part allowing the weight of the automotive vehicle to be reduced. Good ductility is also a requirement to accommodate plastic deformation during part forming operations and to withstand the severe plastic deformation in crash situations without cracking, which can limit energy absorption. With existing Al—Mg—Si based extrusion alloys, strength can be increased by increasing the concentration of the major elements Mg and Si but in general, any strength increase is associated with a loss of ductility as measured by bend testing or fracture strain.

It would be desirable to produce an aluminum alloy with increased strength without compromising the ductility, particularly for the use in the automotive industry.

In one aspect, there is provided an aluminum alloy comprising, in weight percent: 0.45-0.60 Si; ≤0.3 Fe; 0.30-0.65 Cu; 0.71-0.90 Mg; ≤0.20 Mn; ≤0.12 Cr; and the balance being aluminum and inevitable impurities. In some embodiments, the inevitable impurities comprise less than 0.1 wt. % of the aluminum alloy and each inevitable impurity is present at a maximum of 0.05 wt. %. In some embodiments, the inevitable impurities comprise ≤0.05 wt. % Ni. In some embodiments, the inevitable impurities comprise ≤0.05 wt. % Zn. In some embodiments, the inevitable impurities comprise ≤0.05 wt. % Ti. In some embodiments, the inevitable impurities comprise ≤0.05 wt. % B. In some embodiments, the inevitable impurities comprise ≤0.05 wt. % V. In some embodiments, the aluminum alloy comprises 0.50-0.59 Si. In some embodiments, the aluminum alloy comprises ≤0.25 Fe. In some embodiments, the aluminum alloy comprises 0.36-0.61 Cu. In some embodiments, the aluminum alloy comprises 0.74-0.85 Mg. In some embodiments, the aluminum alloy comprises at least 0.10 Fe. In some embodiments, the aluminum alloy comprises ≤0.05 Mn. In some embodiments, the aluminum alloy comprises ≤0.05 Cr. In some embodiments, at least one of Cr or Mn is at least 0.05. In some embodiments, at least one of Cr or Mn is more than 0.05. In some embodiments, the combined Cr and Mn concentration is at least 0.15 wt. %. In some embodiments, the aluminum alloy further comprising a grain refiner.

In one aspect there is provided an aluminum product comprising the aluminum alloy of the present disclosure. In some embodiments, the aluminum product has a recrystallized grain structure.

Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.

The present disclosure concerns an aluminum alloy with improved strength and ductility. The aluminum alloy composition of the present disclosure achieves a superior strength/ductility combination compared to existing Al—Mg—Si alloys. The aluminum alloy of the present disclosure provides a superior strength/ductility combination as compared to existing medium strength Al—Mg—Si alloys such as AA6061, 6005A and AA6008. Moreover, the present aluminum alloy can also exhibit a superior or equivalent strength/ductility combination when compared to a non-recrystallised AA6082 alloy. The aluminum alloy is particularly suitable for applications requiring a yield strength of more than 290 MPa, in some cases more than 300 MPa, for example automotive applications and parts.

As provided herewith, the aluminum alloy encompassed comprises, in weight percent 0.45-0.60 Si; ≤0.3 Fe; 0.30-0.65 Cu; 0.71-0.90 Mg; ≤0.20 Mn; ≤0.12 Cr; and the balance being aluminum and inevitable impurities.

The Al—Mg—Si alloy of the present disclosure surprisingly achieves the improved strength and ductility combination through the addition of one or more of Mn or Cr in the range of up to 0.20 wt. % and up to 0.12 wt. % respectively, in combination with an increased Cu concentration in the range of from 0.30 to 0.65 wt. %. Accordingly, the aluminum alloy of the present disclosure comprises in weight percent with respect to the total weight of the alloy composition, from 0.45 to 0.60 Si, up to 0.30 Fe, from 0.30 to 0.65 Cu, from 0.71 to 0.90 Mg, up to 0.20 Mn, and up to 0.12 Cr with the balance being aluminum and inevitable impurities.

In an embodiment, Al—Mg—Si alloy of the present disclosure comprises ≤0.05 Mn, ≤0.05 Cr; at least one of Cr or Mn is at least 0.05; at least one of Cr or Mn is more than 0.05; or the combined Cr and Mn concentration is at least 0.15 wt. %.

The aluminum alloy of the present disclosure has a Si content in weight percent with respect to the total weight of the aluminum alloy of from 0.45 to 0.60, 0.46 to 0.60, 0.47 to 0.60, 0.48 to 0.60, 0.49 to 0.60, 0.50 to 0.60, 0.51 to 0.60, 0.52 to 0.60, 0.45 to 0.59, 0.46 to 0.59, 0.47 to 0.59, 0.48 to 0.59, 0.49 to 0.59, 0.50 to 0.59, 0.51 to 0.59, 0.52 to 0.59, 0.45 to 0.58, 0.46 to 0.58, 0.47 to 0.58, 0.48 to 0.58, 0.49 to 0.58, 0.50 to 0.58, 0.51 to 0.58, 0.52 to 0.58, 0.49 to 0.57, 0.50 to 0.56, 0.51 to 0.55 or 0.52 to 0.54. Silicon improves the strength of Al alloys by combining with Mg and Cu to give precipitation hardening and also promotes the formation of Al—Mn—Fe—Si dispersoids which can prevent slip localisation.

The aluminum used to produce the alloy of the present invention can be a primary aluminum alloy or a recycled material. Fe is a natural impurity in primary aluminum and can also be found at increased levels in recycled material and the claimed ranges reflect the use of material from these two sources. The aluminum alloy of the present disclosure has a Fe content in weight percent with respect to the total weight of the aluminum alloy of up to 0.3, up to 0.25, up to 0.20, up to 0.19, up to 0.18, up to 0.17, from 0.10 to 0.30, from 0.10 to 0.25, from 0.10 to 0.22, from 0.10 to 0.20, from 0.12 to 0.19, from 0.13 to 0.18 or from 0.14 to 0.17. The amount of Fe is limited to up to 0.3, preferably up to 0.25, more preferably up to 0.20 to avoid any negative impact on the mechanical properties of the aluminum alloy. Fe has a low solubility in aluminum and usually forms Al—Fe—Si type intermetallics or constituent particles during casting and homogenisation which can be detrimental to the surface finish of the profile and when present at high concentrations can be detrimental to ductility. For this reason an upper limit on Fe content is desirable as described herein, for example up to 0.3, up to 0.25 or up to 0.2.

The aluminum alloy of the present disclosure has a Cu content in weight percent with respect to the total weight of the aluminum alloy of from 0.30 to 0.65, from 0.31 to 0.65, from 0.32 to 0.65, from 0.33 to 0.65, from 0.34 to 0.65, from 0.35 to 0.65, from 0.36 to 0.65, from 0.37 to 0.65, from 0.38 to 0.65, from 0.30 to 0.64, from 0.30 to 0.63, from 0.30 to 0.62, from 0.30 to 0.61, from 0.30 to 0.60, from 0.30 to 0.59, from 0.31 to 0.64, from 0.32 to 0.64, from 0.33 to 0.63, from 0.34 to 0.63, from 0.35 to 0.62, from 0.36 to 0.61, from 0.37 to 0.60, from 0.38 to 0.59 or from 0.45 to 0.65. In some embodiments, the Cu content may be in weight percent from 0.33 to 0.44, from 0.34 to 0.43, from 0.35 to 0.42, from 0.36 to 0.41, from 0.37 to 0.40 or from 0.38 to 0.39. In some embodiments, the Cu content may be in weight percent from 0.54 to 0.64, from 0.55 to 0.63, from 0.56 to 0.62, from 0.57 to 0.61, from 0.58 to 0.60 or is 0.59. Cu promotes the formation of Al—Mg—Si—Cu ageing precipitates such as Q″ or Q′ in addition to the normal MgSi precipitates which can improve the dispersion of slip during plastic deformation.

The aluminum alloy of the present disclosure has a Mg content in weight percent with respect to the total weight of the aluminum alloy of from 0.71 to 0.90, from 0.72 to 0.90, from 0.73 to 0.90, from 0.74 to 0.90, from 0.75 to 0.90, from 0.76 to 0.90, from 0.77 to 0.90, from 0.78 to 0.90, from 0.71 to 0.89, from 0.71 to 0.88, from 0.71 to 0.87, from 0.71 to 0.86, from 0.71 to 0.85, from 0.71 to 0.84, from 0.71 to 0.83, from 0.71 to 0.82, from 0.71 to 0.81, from 0.72 to 0.89, from 0.73 to 0.88, from 0.74 to 0.87, from 0.74 to 0.86, from 0.75 to 0.85, from 0.75 to 0.84, from 0.76 to 0.83, from 0.73 to 0.86, from 0.74 to 0.85, from 0.77 to 0.85, from 0.77 to 0.83 or from 0.78 to 0.82. The main role of magnesium is to combine with Si and Cu to provide precipitation hardening.

The aluminum alloy of the present disclosure has a Mn content in weight percent with respect to the total weight of the aluminum alloy of up to 0.20, up to 0.19, up to 0.18, up to 0.17, up to 0.16, up to 0.15, up to 0.14, up to 0.13, up to 0.12, up to 0.11, up to 0.10, up to 0.09, up to 0.08, up to 0.07, up to 0.06, up to 0.05, up to 0.04, up to 0.03, from 0.03 to 0.20, from 0.03 to 0.19, from 0.03 to 0.18, from 0.03 to 0.17, from 0.03 to 0.16, from 0.03 to 0.15, from 0.03 to 0.14, from 0.03 to 0.13, from 0.03 to 0.12, from 0.03 to 0.11, from 0.03 to 0.10, from 0.03 to 0.09, from 0.05 to 0.20, from 0.05 to 0.19, from 0.05 to 0.18, from 0.05 to 0.17, from 0.05 to 0.16, from 0.05 to 0.15, from 0.05 to 0.14, from 0.05 to 0.13, from 0.05 to 0.12, from 0.05 to 0.11, from 0.05 to 0.10, from 0.05 to 0.09, from 0.06 to 0.12, from 0.07 to 0.12, from 0.08 to 0.12, from 0.07 to 0.11 or from 0.08 to 0.10. In some embodiments, the minimal content of Mn is at least 0.03 wt. %, at least 0.04 wt. %, at least 0.05 wt. %, or more than 0.05 wt. %. Mn can contribute to the strength of the Al alloys by dispersoid strengthening and solid-solution hardening. Mn promotes the formation of Al—Mn—Fe—Si submicron dispersoid particles during homogenisation. These dispersoids act to disperse slip during plastic deformation which can delay the formation of internal stress concentrations and fracture events. Mn also promotes extrudability by facilitating the transformation of the beta Al—(Fe, Mn) Si constituent phase to alpha. However, an excessive quantity of dispersoids can increase the flow stress of the alloy at extrusion temperature and adversely affect extrusion speed along with inhibiting recrystallisation to form either coarse recrystallised or non-recrystallised grain structures.

The aluminum alloy of the present disclosure has a Cr content in weight percent with respect to the total weight of the aluminum alloy of up to 0.12, up to 0.11, up to 0.10, up to 0.09, up to 0.08, up to 0.07, up to 0.06, from 0.03 to 0.12, from 0.03 to 0.11, from 0.03 to 0.10, from 0.03 to 0.09, from 0.05 to 0.12, from 0.05 to 0.11, from 0.05 to 0.10, from 0.05 to 0.09, from 0.06 to 0.12, from 0.06 to 0.11, from 0.06 to 0.10, from 0.06 to 0.09 or from 0.07 to 0.08. In some embodiments, the minimal content of Cr is at least 0.03 wt. %, at least 0.04 wt. %, at least 0.05 wt. %, or more than 0.05 wt. %. The dispersoid particles formed by additions of Cr and Mn have similar crystal cubic structures with similar lattice parameters and are mutually soluble in one another such that to some extent the two elements are interchangeable.

In some embodiments, at least one of Mn or Cr is a deliberate addition, for example in a minimal content of at least 0.03 wt. %, at least 0.04 wt. %, at least 0.05 wt. %, or more than 0.05 wt. %. In some embodiments, only one of Mn or Cr is a deliberate addition, for example in a minimal content of at least 0.03 wt. %, at least 0.04 wt. %, at least 0.05 wt. %, or more than 0.05 wt. %. In some embodiments, both Mn and Cr are deliberate additions, for example in a minimal content of at least 0.03 wt. %, at least 0.04 wt. %, at least 0.05 wt. %, or more than 0.05 wt. % each. In some embodiments, a Mn+Cr content is defined being at least 0.05, at least 0.06, at least 0.07, at least 0.08, at least 0.09, at least 0.10, at least 0.11, at least 0.12, at least 0.13, at least 0.14, at least 0.15, at least 0.16, at least 0.17, at least 0.18, at least 0.19, from 0.05 to 0.20, from 0.06 to 0.20, from 0.07 to 0.20, from 0.08 to 0.20, from 0.09 to 0.20, from 0.10 to 0.20, from 0.05 to 0.19, from 0.06 to 0.19, from 0.07 to 0.19, from 0.08 to 0.18, from 0.09 to 0.18, or from 0.10 to 0.17. In some embodiments, Cr may be used instead of Mn and vice versa. The equivalent content of Cr to Mn is roughly 1:2, for example 0.07 Cr can be equivalent to 0.15 Mn. Accordingly, in some embodiments, the alloy comprises no deliberate additions of Mn when the Cr content is at least 0.05 wt. %. In other embodiments, the alloy comprises no Cr when the Mn is at least 0.1 wt. %.

The weight percentage concentration for the aluminum alloy are provided with the balance being aluminum and inevitable impurities. In some embodiments, each of the inevitable impurity is present at a maximum of 0.05 (and in some embodiments 0.03) and the total inevitable impurities comprise less than 0.10. In some embodiments, it is to be understood herein that the term “inevitable impurity” means that there was no deliberate addition.

In some embodiments, the inevitable impurities include Ni in a concentration of less than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01. Ni has very low solubility in aluminum and forms undesirable constituent particles. Ni can be present as an impurity from the anodes in the reduction process.

In some embodiments, the inevitable impurities include Zn in a concentration of less than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01. The presence of Zn may have a negative impact on the corrosion performance of the alloy. In an embodiment, the inevitable impurities comprise less than 0.1 wt. % of the aluminum alloy and each inevitable impurity is present at a maximum of 0.05 wt. %.

In some embodiments, the inevitable impurities include Ti in a concentration of less than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01.

In some embodiments, the inevitable impurities include B in a concentration of less than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01.

In some embodiments, the inevitable impurities include V in a concentration of less than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01. V is detrimental to the extrudability of the aluminum alloy and is generally only an impurity from the aluminum reduction process.

In some embodiments, the inevitable impurities include Zr in a concentration of than or equal to 0.05, less than or equal to 0.04, less than or equal to 0.03, less than or equal to 0.02, less than or equal to 0.01.

In some embodiments, the aluminum alloy of the present disclosure comprises, consists essentially of or consists of any combination of the concentration ranges recited above for Si, Fe, Cu, Mg, Mn, Cr, Mn+Cr and the inevitable impurities.

In some embodiments, the aluminum alloy optionally further comprises a grain refiner, such as titanium, titanium boride, or titanium carbide to solidify aluminum alloys. In an embodiment, the grain refiner is in the form of Ti, TiB or TiC. When TiB is used as a grain refiner, this may result in a B content of up to 0.05 wt. % in the alloy. When TiC is used as a grain refiner, this may result in a C content of up to 0.01 wt. % in the alloy. The dissolved Ti in molten aluminum can enhance the formation of interfacial TiAllayer between TiB/melt interface, which subsequently provokes nucleation of Al grains.

The present disclosure also provides a process for making a high strength aluminum product using the aluminum alloy of the present disclosure. In a first step, the process comprises casting the aluminum alloy of the present disclosure to obtain a cast aluminum product. The casting step can include, for example, direct chill casting, continuous casting and/or semi-continuous casting. A Properzi continuous casting may be used, which may be a wheel and belt casting process or a track & belt casting. The track & belt process replaces the casting wheel by a plurality of copper blocks. Other options include a twin roll caster may be used. The twin roll caster has two rolls that rotate and advance the mold continuously. The rolls may be chilled to aid in solidification of the molten aluminum alloy. Further options include a block caster that has blocks adapted to function as belts. The blocks may be chilled to aid in solidification of the molten aluminum alloy.

In a second step, the cast aluminum product is extruded into an extruded aluminum product. During extrusion the aluminum alloy is heated to a temperature where the alloy is malleable. A press container may be used in front of a die orifice. A hydraulic ram can be used to apply pressure to force the aluminum alloy to fill the container and through the die to make the desired shape. After the hot deformation (i.e., extrusion or Properzi hot rolling), the aluminum alloy may be actively cooled by the use of cooling fans and/or water spray or a full water quench. In preferred embodiments, a quench rate between 500 and 300° C. of 20° C./s is utilized. Most automotive extrusions are hollow to improve stiffness and crush performance. Accordingly, in some embodiments, the extrusion is a hollow extrusion such as a hollow automotive extrusion. Water quenching, usually spray quenching, at the press exit is generally beneficial to ductility as compared to air quenching for example and is thus preferred. The improvement of water quenching over air quenching can be associated with microstructural changes at grain boundaries.

Fully recrystallized grain structures offer advantages over non recrystallized grain structures (typically with a coarse recrystallized grain surface layer) for automotive applications. These include reduced sensitivity of strength to press quench rate, freedom from surface orange peel which can be an initiation site for fatigue and corrosion and local extrusion weld line ductility. In addition, the higher levels of dispersoid forming elements such as Mn and Cr required to produce a non-recrystallized grain structure typically can result in inferior extrudability and strength quench sensitivity. In some embodiments, the present aluminum alloy achieves a fully recrystallized grain structure to benefit from these advantages and the fully recrystallized structure is a feature of the product.

In one embodiment, the process further comprises after casting and before extruding, heat treating or homogenising the cast aluminum product. The heat treatment conditions can be for a time period of at least about 1, at least about 2, at least about 3, at least about 4 or at least about 5 h at a temperature between about 450 to about 600° C., about 500 to about 600° C., about 550 to about 590° C. or about 560 to about 580° C. In some embodiments, the aluminum product is an extrusion billet.

The strength and ductility of aluminum alloys can be determined with various suitable methods. However, the elongation to failure during a tensile test is not a useful parameter for predicting crash performance. On the other hand, the ductility of extrusions can be assessed by the bend testing of the German Association of the Automotive Industry (VDA 238-100) in the extrusion direction or transverse to the extrusion direction. Such bend testing can simulate the bending applied during folding in axial or lateral crush or strains applied during mechanical joining such as self piercing riveting. True fracture strain measured in a tensile test (Ln(initial cross section/final fracture area)) is a useful measure of ductility for such applications.

In some embodiments, the aluminum product of the present disclosure has an Ultimate Tensile Strength (UTS) of at least 290, at least 295, at least 300, at least 305, at least 310, at least 315, at least 320, at least 325, at least 330 or at least 335 MPa. In some embodiments, the aluminum product of the present disclosure has a yield strength of at least 260, at least 265, at least 270, more than 275, at least 280, at least 285, at least 290, at least 295, at least 300, or at least 305 MPa. In some embodiments, the aluminum product of the present disclosure has a longitudinal VDA bend angle longitudinal of at least 50, at least 55, at least 60, or at least 65°. In some embodiments, the aluminum product of the present disclosure has a transverse VDA bend angle of at least 25, 26, 27, 28, 29, or 30° for a thickness of 2.5 mm. In some embodiments, the aluminum product of the present disclosure has a true fracture strain of at least 0.40, at least 0.41, at least 0.42, or at least 0.43 for a thickness of 2.5 mm.

The present disclosure will be more readily understood by referring to the following example.

The alloy compositions listed in Table 1 were direct chill cast (DC cast) as 101 mm diameter billets. A 5% Ti-1% B grain refiner was added prior to casting. In some cases, additional Ti was added in the furnace to augment the grain refiner. Alloys A-D, H and I were homogenised for 2 h/580° C., whereas alloys F, G and J were homogenised for 3 h/560° C. due to their lower solidus. After homogenisation, all alloys were forced air cooled at 450° C./h between 500° C. and 200° C. Alloys E and K, corresponding to typical commercial AA6082 and AA6061 alloy variants, were given industrial homogenisation cycles. The billets were extruded into a 50×20×2.5 mm hollow box profile using a billet preheat temperature of 500° C., at extrusion exit speeds of 10-11 m/min. The die was constructed to position the extrusion welds on the 20 mm faces of the profile such that property evaluation could be conducted on the wide 50 mm face away from any extrusion welds. After exiting the die, the profile was water spray quenched at a rate of 150° C./sec between 500° C. and 300° C. The quench rate was measured using a clip-on contact thermocouple attached to a waterproof high frequency logger with a WiFi transmitter. The cooled profiles were stretched to give a permanent set of 0.5% and aged for 8 h/177° C. after a room temperature delay of 24 h. Tensile testing was conducted in the longitudinal direction according to ASTM E8, and the fracture area projected in the tensile direction was measured using an image analysis technique to permit calculation of the true fracture strain using the expression Ln(initial cross-section area/final fracture area). A higher value of fracture strain is indicative of superior bendability and ductility. VDA bend testing was conducted in the longitudinal (bend axis perpendicular to extrusion direction) and transverse (bend axis parallel to extrusion direction) orientations using a punch radius of 0.4 mm, a roller spacing of 2× the material thickness, i.e. 5 mm and a load drop of 60 N. The complementary bend angle was measured after the load was removed, such that an increasing bend angle is indicative of superior ductility or bendability.

The compositions in Table 1 are grouped into increasing Mg concentrations. Alloys A, B and D conformed with the AA6008 composition range, which is an alloy developed and widely used for automotive applications. These contained a deliberate addition of vanadium required by the AA6008 specification. Alloy C is similar to AA6008 but did not contain a deliberate addition of V. Alloys F and G correspond to the widely used AA6005A composition range. Alloys H, I and J have increased levels of Cu and controlled additions of Mn and Cr.

The microstructures of the extrusions were assessed metallographically. Typical grain structures, as revealed by Barkers electro-etching and viewing under polarised light, are shown in. The commercial alloy AA6082 (alloy E) had a mainly non-recrystallised grain structure with a coarse grain recrystallised surface layer. In contrast, the remaining alloys all exhibited a fully recrystallised grain structure which is desirable for this type of product to avoid problems associated with coarse surface grains and for improved local ductility at extrusion weld lines. Examples of recrystallised structures for alloys K (AA6061) and J are shown in, andB.

Table 2 presents the mechanical property results for each composition where VDA-L is the longitudinal bend angle test, VDA-T is the transverse bend angle test, El is the elongation, Ef is the true fracture strain, YS is the yield strength and UTS is the ultimate tensile strength.

is a plot of longitudinal VDA bend angle in function of yield strength after artificial ageing. The points are labelled with the alloy I.D.s from Table 1. The AA6008 (A,B,D), the V-free AA6008 (C) and AA6005A (F,G) variants along with the commercial AA6061 (K) gave strength-ductility combinations in a band labelled “baseline strength and ductility” where ductility decreased near linearly with increasing yield strength. In contrast, alloys H, I and J with controlled additions of Cu, Mn and or Cr gave improved strength/ductility combinations compared to the baseline and also gave equivalent or improved performance compared to the non-recrystallised commercial AA6082 alloy (E).shows a similar plot for transverse VDA angle in function of yield strength. The transverse results exhibited a similar separation between the inventive compositions and the baseline materials. The bend angle measured transverse to the extrusion direction is typically lower than that measured in the longitudinal direction, as shown by comparison of. Non-recrystallised grain structures, such as observed for the commercial AA6082 (Alloy E), typically exhibit a superior transverse bend angle compared with recrystallised materials. However, the inventive alloys H, I and J again exhibited a superior strength ductility/combination to the baseline alloys when tested in the transverse direction and also gave similar strength and ductility to alloy E.

presents a plot of the third measure of ductility, true fracture strain from a tensile test, in function of yield strength. Similar to the longitudinal VDA results, the baseline AA6008, AA6005A and AA6061 compositions displayed a trend of decreasing fracture strain with increasing yield strength. The inventive alloys H, I and J exhibited superior strength and fracture strain combinations to the baseline and similar performance to the non-recrystallised commercial AA6082 (E).

While the present disclosure has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations including such departures from the present disclosure as come within known or customary practice within the art and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims.