CN102400020B

CN102400020B - For the aluminum-copper-lithium alloys sheet material of the high-tenacity of airframe

Info

Publication number: CN102400020B
Application number: CN201110377207.7A
Authority: CN
Inventors: B·贝斯; H·赖比斯; C·希格里; T·华纳
Original assignee: Constellium France SAS
Current assignee: Constellium Issoire SAS
Priority date: 2005-06-06
Filing date: 2006-06-02
Publication date: 2015-10-28
Anticipated expiration: 2026-06-02
Also published as: CN102400020A; FR2889542B1; FR2889542A1

Abstract

The present invention relates to one and there is low-density aluminum base alloy, can be used for the sheet material of the airframe of aircraft structure, described aluminium alloy has high mechanical strength, high-tenacity and high corrosion resistance, comprises in % by weight: the MG of AG, 0.2-0.6 of LI, 0.1-0.8 of CU, 0.8-1.4 of 2.7-3.4 and be such as selected from a kind of element or its mixture of ZR, MN, CR, SC, HF and TI; The quantity of described element, in % by weight is: the MN of ZR, 0.05-0.8 of 0.05-0.13; The TI of CR and SC of 0.05-0.3, HF and 0.05-0.15 of 0.05-0.5.The amount of CU and LI is determined according to following formula: CU (in % by weight)+5/3LI (in % by weight) < 5.2.

Description

For the aluminum-copper-lithium alloys sheet material of the high-tenacity of airframe

Technical field

The present invention relates to alloy product in general, particularly relates to the product being applicable to aerospace industry and being applicable to apply in airframe.

Background technology

In current Civil Aviation Industry, when being particularly applied to airframe, in the urgent need to reducing weight and cost.Depend on stage (take off, fly, control, land ...) of operation and envrionment conditions (fitful wind, against the wind ...), the airframe in commercial transportation is subject to complicated combined stree.In addition, the different piece of airframe is subject to different stress.Although there are these complexcase, also can distinguish the major design criterion that some determine structural weight, some criterion has larger impact than other criterion for gross weight.

Such as, because the heaviest airframe wallboard stands such stress, therefore ultimate compression strength and slip resistance are extremely important design criterias.For the weight making type material can reduce the wallboard of these pressurizeds, described material should have elastic modulus, high to 0.2% yielding stress (for counter-bending) and low density.

Second main criteria is the residual resistive of longitudinal cracking (along airframe axis) wallboard.Aviation rules of permission specifies to consider in the design, to the tolerance of infringement, therefore usually can consider longitudinal direction large in airframe wallboard or circumference crackle, there will not be catastrophic fracture to prove to apply the stress of certain level.Determine that a kind of known material property of described design is the toughness under plane stress herein.But all known facts of critical stress intensity are all limited for the description given by toughness.Curve R test is a kind of method be widely known by the people for describing toughness performance.Curve R represents: under simple stress, along with effective crack growth, and the change of the critical effective stress intensity factor of crack propagation.It makes can measure the unstable critical load ruptured for all shapes directly relevant with the aircraft structure of splitting.The numerical value of effective stress intensity factor and effective crack growth factor is the numerical value defined according to standard A STM E561.The maximum crack growth of the curve of the length of curve R-namely-for the design of airframe is important parameter itself.The classical analysis commonly used is carried out in test for the wallboard with centre burst, and this analysis gives an apparent fracture stress intensity factor (kapp).This numerical value is not with the length noticeable change of curve R, particularly all the more so when slope close to the curve (stress application curve) relevant to the intensity factor being applied to crack length upper stress of the slope of curve R.But, in the structure of a practical structures element in---such as one comprises the wallboard of fixing strengthening rib---, time under a crack growth a to strengthening rib do not fractureed, because the bridging effect stress application curve of strengthening rib declines.In this case, for the crack length larger than the summation of Initial crack length and the crack growth under single load, the local minimum of stress application curve can be there is.In this case, for long curve R, before instability fracture, allow larger stress.So as adopted classical way determines, the same with identical critical stress intensity factor, have a longer curve R, this is favourable.

For the product with same mechanical performance, low density is obviously more useful for the weight of structural element.Therefore 3rd main criteria be the density of material.In addition, the intensity of loading that each major parts of airframe bears is different, and the weight of design is commonly referred to the restriction of the limit of " minimum thickness ".The concept of minimum thickness is corresponding to the minimum thickness that can be used for manufacturing (particularly the operation of wallboard) and repairing (riveted joint of repairing).The sole mode reducing weight is in the case the material using less density.

Other important criteria is the fatigue crack growth under following condition: under the stress of constant amplitude, or under the stress of variable amplitude (due to operation and blast, particularly in the vertical, but simultaneously around fin, in any direction).

At present, the sheet material that the major parts of civil aircraft fuselage is made up of alloy 2024,2056,2524,6013,6156 or 7475 alloy is formed, all with aluminium alloy---such as alloy 1050 or 1070---coating containing little alloying element on each surface.The object of coating alloy is to provide enough erosion resistances.Allow slight, large-scale or pitting corrosion, but corrosion should not penetrate can not corrode inner alloy.A kind of trend attempts using the material of some non-coating to design for airframe, to reduce cost.Therefore, the erosion resistance of airframe wallboard, particularly resistance to intergranular corrosion and anti-stress corrosiveness are the importances of its performance.

As mentioned above, in some cases, the unique method reducing weight is the density reducing the material used for aircraft structure.Aluminium-lithium alloy because its low density is as the effective workaround for reducing weight, for a long time to be widely known by the people.But different need---elastic modulus, high compressive strength, high damage tolerance and high corrosion resistance---as above is failed to meet by the aluminium-lithium alloy of prior art simultaneously.Having shown in specified range by these alloys acquisition high-tenacity is an insoluble problem.Such as, pula is spread, and people such as (Prasad) confirms (Sadhana, the 28th volume, the 1st & 2 part recently, in February, 2003/April, 209-246 page): " Al-Li alloy is the candidate material of first level of the aluminium alloy used for alternative tradition.Although Al-Li alloy has many advantageous properties, the low tensile toughness particularly on the direction of crossing thickness and not enough toughness are unfavorable for that they are that people accept ".At present, Al-Li alloy is limited to very special Military Application, such as, in the component of some helicopter component and some military airframe, as the high high thermal resistance in aerospace applications material, there is the material of the low-temperature toughness of improvement.

Patent US 5 032 359 (Martin Marietta) describes gang based on the alloy of Solder for Al-Cu Joint Welding-magnesium-silver alloys adding lithium in some specified ranges, and described alloy has resistance, high tenacity, extensibility, forging property and good weldability at a room temperature and a high temperature at a room temperature and a high temperature and natural aging response.Described embodiment describes some stamping products.Do not provide the information about toughness, fatigue property or erosion resistance.In a preferred embodiment, described alloy has following composition: the element of the selected among zirconium of the silver of the copper of 3.0-6.5%, the magnesium of 0.05-2.0%, 0.05-1.2%, the lithium of 0.2-3.1%, 0.05-0.5%, chromium, manganese, titanium, boron, hafnium, vanadium, TiB2 and their mixture.

Document US 5 122 339 (Martin Marietta) is the continuation application of aforementioned application.Which also describes the purposes of similar alloy as welding alloy.

Document US 5 211 910 (Martin Marietta) describes the aluminum base alloy comprising Cu, Li, Zn, Mg and Ag, these alloys have some favourable performances, as lower density, elastic modulus, the combination of high mechanical strength/toughness, there is or do not have the strong natural aging response of pre-cold forging distortion, and there is or do not have the elastic modulus of pre-cold forging distortion after tempering.Described alloy has following composition: a kind of following elements of Mg, 0.01-2%Ag, 0.01-2% of Zn, 0.05-3% of Li, 0.01-4% of Cu, 0.1-4% of 1-7%: described element is selected from Zr, Cr, Mn, Ti, Hf, V, Nb, B and TiB ₂, all the other are Al and inevitable impurity.This invention describe add Zn how can reduce in document US 5 032 359 propose alloy in Ag content to reduce cost.

Document US 5 455 003 (Martin Marietta) describes a kind of manufacture method of aluminum-copper-lithium alloys, and described alloy has cryogenic mechanical intensity and the toughness of improvement.By regulating described alloy composition, together with tempering, reach the low-temperature performance of improvement with processing parameter such as cold forging deflection.Described product is used for the low temperature storage tank in the launch vehicle of spatial emission.

Document US 5 389 165 (Reynolds) describes a kind of aluminum base alloy be used in aerospace device structure, and described alloy has low density, high mechanical strength and high-tenacity, and its empirical formula is: Cu _ali _bmg _cag _dzr _eal _balwherein a, b, c, d, e and bal (remaining sum) represent each alloying constituent quantity by weight percentage, and wherein 2.8 < a < 3.8,0.80 < b < 1.3,0.20 < c < 1.00,0.20 < d < 1.00 and 0.08 < e < 0.40.Preferably, regulate copper and lithium composition, make the content sum of copper and lithium remain on below solubility limit, to avoid toughness to lose upon exposure to high temperature.Relation between copper content and lithium content also should meet following relational expression:

Cu (by weight percentage)+1.5Li (by weight percentage) < 5.4.

Use the special conditions of contract of some restrained stretchings between 5 and 11%.Example is limited to the thickness of 19mm and is more than or equal to the zirconium content of 0.13% by weight.

Document US 2004/0071586 (Alcoa) discloses a kind of Al-Cu-Mg alloy, and described alloy comprises with weight note: the Li of Mg and 0.01-0.9% of Cu, 0.5-2% of 3-5%.According to this patent application, the alloy phase wherein adding 0.2-0.7 % by weight Li is not for comprising Li or comprising the similar alloy of Li of larger quantity, and toughness is significantly improved.

Need a kind of high mechanical strength, high-tenacity and particularly instability fracture before high crack growth, high corrosion resistance Al-Li alloy, be applied to aviation, be particularly applied to airframe sheet material.

Summary of the invention

Due to these and other reason, the present inventor completes the present invention relating to a kind of Solder for Al-Cu Joint Welding-lithium-magnesium-silver alloys, described alloy has the high crack growth before the instability fracture of high mechanical strength, high-tenacity and king-sized precrack wallboard, and high corrosion resistance.

An object of the present invention is a kind of method that manufacture has the aluminum base alloy sheet material of high-tenacity and high mechanical strength, wherein:

A) manufacture a metal pool (bain de m é tal liquide), described metal pool comprises following composition by weight: the Mg of Ag, 0.2-0.6% of Li, 0.1-0.8% of Cu, 0.8-1.4% of 2.7-3.4% and at least one are selected from the element of Zr, Mn, Cr, Sc, Hf and Ti; If select above-mentioned element, the quantity of described element by weight: the Ti of Cr and Sc of Mn, 0.05-0.3% of Zr, 0.05-0.8% of 0.05-0.13%, Hf and 0.05-0.15% of 0.05-0.5%,

All the other are aluminium and inevitable impurity,

Supplementary condition is: the amount of Cu and Li meets following formula:

Cu (by weight percentage)+5/3Li (by weight percentage) < 5.2;

B) with described metal pool for raw material is cast one block of plate;

C) plate 5-60 hour described in the temperature homogenisation between 490-530 DEG C;

D) described plate is rolled into the sheet material of final thickness between 0.8 and 12mm;

E) described sheet material carried out solution heat treatment and quench;

F) sheet material described in restrained stretching is to tension set 1-5%;

G) by within 5-30 hour, carrying out tempering to described sheet material 140-170 DEG C of heating.

Another object of the present invention be a kind of aluminium alloy make rolling, punching press and/or forging product, described aluminium alloy comprises following composition by weight: the Mg of Ag, 0.2-0.6% of Li, 0.1-0.8% of Cu, 0.8-1.4% of 2.7-3.4% and at least one are selected from the element of Zr, Mn, Cr, Sc, Hf and Ti; If select above-mentioned element, the quantity of described element by weight: the Ti of Cr and Sc of Mn, 0.05-0.3% of Zr, 0.05-0.8% of 0.05-0.13%, Hf and 0.05-0.15% of 0.05-0.5%,

All the other are aluminium and inevitable impurity,

Supplementary condition is: the amount of Cu and Li meets:

Cu (by weight percentage)+5/3Li (by weight percentage) < 5.2.

Another object of the present invention is the structural element of the airframe that some obtain for raw material with described rolling, punching press and/or forging product, strengthening rib and wallboard.

Accompanying drawing explanation

Fig. 1: the curve R (test specimen CCT760) on T-L direction;

Fig. 2: the curve R (test specimen CCT760) on L-T direction;

Fig. 3: the change of the speed of splitting (vitesse de fissuration) when the changes in amplitude of stress intensity factor on T-L direction;

Fig. 4: the change of the speed of splitting when the changes in amplitude of stress intensity factor on L-T direction;

Fig. 5: the curve R on the T-L direction that sample of the present invention (test specimen CCT760) obtains, described sample has the distortion of different levels by stretching.

Embodiment

As illustrated without contrary, then the information of all relevant alloy compositions is all to represent based on the weight percent of alloy gross weight.The label of alloy is according to the regulation of the known ABAL (the Aluminium Association) of those skilled in the art.The definition of metallurgical state is as shown in European standard EN515.

Explanation as contrary in nothing, then measuring static mechanical properties according to the tension test of standard EN 10002-1---the namely yielding stress Rp0.2 of ultimate compression strength Rm, usual 0.2% elongation and extension at break A, standard EN-485-1 defines the direction of test specimen and test.

Speed of splitting (da/dN) measures according to standard A STM E647.The curve that stress intensity changes with crack growth, the curve R namely known, measures according to standard A STM E561.Critical stress intensity factor K _ceven if---intensity factor of crackle instability---calculates from curve R.Stress strength factor K _coalso can by starting Initial crack length to calculate owing to critical load from list-load.Test specimen for desired shape calculates this two values.K _apprepresent the factor K corresponding to the test specimen tested for curve R _co.K _effrepresent the factor K corresponding to the test specimen tested for curve R _c.Δ a _{eff (max)}represent the crack growth of last available point of curve R.As illustrated without contrary, then for M (T) type test specimen because of tired and the later stage flaw size in stage of rupturing in advance is W/3, wherein W be as in standard A STM E561 the width of test specimen that defines.It should be noted that the width of the test specimen used in curve R tests may have great impact for stress intensity measured in test.If the sheet material of airframe is large wallboard, then the result of the curve R obtained in enough large sample---such as has the sample of the width being more than or equal to 400mm---, and the evaluation for toughness is the most meaningful.Therefore, preferably use-testing sample CCT760 is in order to assess toughness, and the width of test sample CCT760 is 760mm.The length 2ao=253mm of initial crack.

Also test by means of fracture total energy (é nergie globale à rupture) E according to Cann (Kahn) _gin T-L Direction estimation toughness.Cann stress R _e(in MPa) equals the ultimate load F that test specimen can support _maxwith the ratio of the cross section of test specimen (thickness B and width W long-pending).R _ethe relative toughness of the sample that assessment of static mechanical property is different can not be supplied.Fracture total energy E _gin force-displacement curve with until test specimen fracture region measure, E _gdirectly related with toughness.Described test is at " the Cann type shearing experiment of aluminum alloy plate materials and cracking toughness " (" Kahn-type Tear Test and Crack Toughness of Aluminum Alloy Sheet ", be published in " investigation of materials and standard " magazine (Materials Research & Standards), in April, 1964,151-155 page) middle description.The test specimen that Cann toughness test uses such as is described in " metals handbook " (" Metals Handbook ", the 8th edition, the 1st volume, American Society of Metals (ASM), 241-242 page).

" sheet material ", a kind of rolled products being no more than 12mm thickness of this specification sheets middle finger.

Term " structural element " refers to a kind of element used in physical construction, and its static and/or dynamic mechanical properties is for the performance of physical construction and integrity particularly important, that the Structure Calculation of physical construction normally specifies or existing execution.It is usually directed to a mechanical part, and the inefficacy of described mechanical part may jeopardize described structure, its user, its user or other people safety.For flyer, these structural elements particularly comprise the composition element (such as aircraft fuselage skin, stringer, bulkhead, annular frame) of airframe, wing part (such as wingbox, stringer, rib, spar), empennage (such as level and vertical stabilizer) and ground stupefied crossbeam, seat rail, door etc.

Solder for Al-Cu Joint Welding-lithium-Yin-the magnesium alloy of one embodiment of the invention advantageously has following composition:

table 1

the scope (% by weight, all the other are Al) of alloy composition

	Cu	Li	Ag	Mg
					Wide	2.7-3.4	0.8-1.4	0.1-0.8	0.2-0.6
Preferably	3.0-3.4	0.8-1.2	0.2-0.5	0.2-0.6
					Most preferably	3.1-3.3	0.9-1.1	0.2-0.4	0.2-0.4

In order to obtain required toughness result, advantageously can obtain during solution heat treatment and almost dissolving completely, the decomposition of sosoloid can also be minimized at quenching.Contriver determines, and this can such as pass through limit the total amount of copper and lithium with following relationship and realize by guaranteeing---such as to use cold-water quench---in the sufficiently high speed of cooling of quenching:

Cu (by weight percentage)+5/3Li (by weight percentage) < 5.2.

For the preferred and most preferred composition in table 1, the relational expression between following copper and lithium is preferred:

Cu (by weight percentage)+5/3Li (by weight percentage) < 5.

Comprise at least one element, the one combination of such as Zr, Mn, Cr, Sc, Hf, Ti or these elements, so that refine grain size.Each element addition (by weight): Cr and Sc of Mn, 0.05-0.3% of Zr, 0.05-0.8% of 0.05-0.13% (preferably 0.09-0.13%), the Ti of Hf and 0.05-0.15% of 0.05-0.5%.When adding the element of these anti-recrystallizings multiple, summation can be limited by the appearance of first phase.

In another favourable embodiment of the present invention, the refining of crystal grain realizes because adding following composition (by weight): the Ti of Hf and 0.05-0.15% of Cr, 0.05-0.5 of Mn, 0.05-0.3% of the Sc of Zr, 0.02-0.3% of 0.05-0.13% and optional (i.e. selectivity and non-mandatorily) 0.05-0.8%.

In some cases, the particularly hot rolled plate of thickness between 4 and 12mm, the content that advantageously can limit Mn is 0.05% by weight, is preferably 0.03% by weight.Contriver notices for such thickness, and the existence of Mn makes the more difficult control of the structure of crystal grain, and may affect mechanical property and toughness simultaneously.

Fe and Si affects toughness performance usually.The content of Fe preferably should be restricted to 0.1% by weight, and the content of Si preferably should be restricted to 0.1% (most preferably being 0.05% by weight) by weight.Other element any similarly should preferably be restricted to 0.1% (being most preferably 0.05% by weight) by weight.

If contriver find the content of copper be greater than by weight 3.4% in some cases toughness performance may decline rapidly.For some embodiment of the present invention, the content of copper is recommended not exceed 3.3% by weight.Preferably, the content of copper is greater than 3.0% by weight, or 3.1%.

Contriver notices that the content of Zr is greater than 0.13% by weight and may causes low toughness performance in some cases.The reason no matter toughness declines why, and contriver finds that high Zr content will cause first phase Al ₃the formation of Zr.In this case, the pouring temperature of rising can be used to avoid the formation of first phase, but in impurity and gas content, just cause the quality of liquid metal poorer like this.This is why the present inventor thinks that Zr advantageously by weight can not more than 0.13%.

If contriver finds that the content of Li is less than 0.8% or even 0.9% by weight, the improvement of physical strength is very little.In some cases, advantageously the content of Li by weight can > 0.9%.In addition, because the content of Li is less, the minimizing of alloy density is also very little.For be greater than by weight 1.4% be even greater than 1.2% or be greater than 1.1% Li content, toughness can significantly reduce.In addition, this high Li content has multiple shortcoming, particularly relevant to raw-material thermostability, castability and cost shortcoming.

The interpolation of Ag is principal feature of the present invention.The alloy not comprising silver can not reach the mechanical property and toughness performance observed by contriver usually.Contriver thinks: during natural aging or artificial aging, form the sclerosis phase time comprising copper, silver plays effect, and silver makes it possible to particularly form thinner phase and these phases that more uniformly distribute.The advantageous effects of Ag is observed when the content of Ag is greater than 0.1% by weight and is preferably greater than 0.2%.For the cost of Ag is added in restriction, advantageously Ag can be no more than 0.5% or even 0.4% by weight.

The interpolation of Mg improves mechanical property and decreases density.But add excessive Mg, for toughness, there is deleterious effects.In a favourable embodiment of the present invention, Mg content is restricted to by weight 0.4%.Contriver thinks that being added between cupric phase Formation period of Mg also plays effect.

Then the metal pool with the present invention's composition casts.The invention enables and can obtain a kind of rolling, punching press and/or forging product, the thickness benefits of described product ground between 0.8 and 12mm, preferably between 2 and 12mm.

According to a favourable embodiment of the present invention, the alloy casting with regulated alloying element amount is plate shape.Described plate is then 490 to 530 DEG C of homogenizing 5 to 60 hours.Contriver notices that the homogenization temperature being greater than 530 DEG C may cause reducing toughness performance in some cases.

Before hot rolling, described plate was 490 to 530 DEG C of heating 5 to 30 hours.Carry out hot rolling to obtain the thickness between 4 and 12mm.For the thickness of about 4mm or lower, if needed, cold rolling step can be increased.Obtain sheet metal thickness preferably between 0.8 and 12mm, the present invention for thickness be 2 to the 12mm even sheet material of 2 to 9mm advantageously, for thickness be the sheet material of 3 to 7mm advantageously.Then described sheet material carry out solution treatment, such as, to pass through at 490 to 530 DEG C thermal treatment 15 minutes to 2 hours, then by room temperature water or preferred cold-water quench.

Then described product carries out 1-5% and the restrained stretching of preferred 2.5-4%.The cold forging distortion of this level also can obtain by the following method: cold rolling, leveling, forging or the combination of these methods and restrained stretching.Advantageously, total after quenching cold forging distortion is between 2.5-4%.Particularly, when when quenching and carry out flattening operation between restrained stretching and do not carry out other cold deformation any, can advantageously restrained stretching distortion between 1.7-3.5%.Contriver notices that toughness is tending towards reducing when restrained stretching distortion is greater than 5%.In addition, for the tension set being greater than 5%, Cann test-results particularly Eg is tending towards reducing.This is the reason of recommending tension set to be no more than 5%.In addition, if stretched be greater than 5%, industrial difficulty may be run into, such as, process operation increase and difficult forming, which increase product cost.

Tempering is carried out 5 to 30 hours at 140 to 170 DEG C, and this makes it possible to acquisition state T8.In some cases, particularly when preferred composition and the most preferred composition of table 1, tempering is most preferably carried out 10 to 30 hours at 140 to 155 DEG C.Low tempering temperature is conducive to high-tenacity usually.In one embodiment of the invention, tempering step is divided into two steps: the pre-tempering step before welding operation, and the finished heat treatment of welded construction element.Within the scope of the invention, mixed friction welding (soudage par friction-malaxage) is a kind of preferred welding technique.

Sheet material of the present invention has favourable characteristic for the microstructure of recrystallize, non-recrystallize or mixed crystallization (namely comprising recrystallize region and non-recrystallize region).In some cases, contriver notices and can advantageously avoid mixed crystallization microstructure: for the sheet material of thickness between 4 and 12mm, and advantageously microstructure can be complete non-recrystallize.

The performance of the sheet material that the present invention obtains is state T8:

-in the l-direction, usual yielding stress R _p0.2preferably at least 440MPa, more preferably at least 450MPa or even at least 460MPa.

-in the l-direction, ultimate compression strength Rm preferably at least 470MPa, more preferably at least 480MPa or even at least 490MPa.

-use the toughness performance of test specimen CCT760 (2ao=253mm) as follows:

K on T-L direction _apppreferably at least more preferably at least or even at least

K on L-T direction _appat least preferably at least

K on T-L direction _effat least preferably at least

K on L-T direction _effat least or even at least preferably at least

Δ a _{eff (max)}, the crack growth of the last available point of curve R on T-L direction, preferably at least 30mm, more preferably at least 40mm.

Δ a _{eff (max)}, the crack growth of the last available point of curve R on L-T direction, preferably at least 50mm.

The shaping of sheet material of the present invention can be carried out advantageous by following technology: deep stamping, drawing, spinning, roll extrusion or grinding, and these technology are known by those of ordinary skill in the art.

When mounting structure component, if needed, any be applicable to aluminium alloy known and possible riveted joint and welding technique can use.Described sheet material can by riveting or be welded and fixed to strengthening rib or framework.If contriver finds to select welding, preferably can use low-temperature bounding method, the region that described low-temperature bounding method contributes to guaranteeing to be influenced by heat is little as much as possible.For this reason, laser welding and friction mixing welding provide gratifying especially result usually.Within the scope of the invention, friction mixing welding is preferred welding process.Weld by friction mixing the weld of sheet material of the present invention advantageously obtained to have and be greater than 70% and the effectiveness coefficient being preferably greater than the weld of 75%.Before or after welding operation, carry out tempering and obtain this favourable result.

By the structural element of at least one product formation of the present invention, particularly by sheet material of the present invention and strengthening rib or framework---these strengthening rib or framework are preferably made up of the punching press section bar---structural element formed, may be used for the wallboard particularly manufacturing airframe, and wherein this performance is favourable other purposes any.

According to the present invention, structural element, strengthening rib and/or airframe wallboard can be that raw material manufactures with the rolling obtained, punching press and/or forging product.Contriver finds that sheet material of the present invention has particularly advantageous static mechanical properties and high toughness.For the product that some are known, the sheet material of high-tenacity has low yielding stress and ultimate compression strength usually.For sheet material of the present invention, high-mechanical property is conducive to industrially applying to airplane structural parts, and the yielding stress of described sheet material and ultimate compression strength are the features directly considered for computation structure size.Comprise the structural element of sheet material of the present invention and/or strengthening rib, the particularly wallboard of airframe, relative to the calculation result of structural element of comparable performance of sheet material only with the prior art be made up of alloy 2024,2056,2098,7475 or 6156, demonstrate the possibility that weight reduces.Such weight reduces normally 1-10%, in some cases, can reach even larger weight reduction rates.

Such as, in the component of given shape and size,---structural element size does not change with the improvement of mechanical features---can reduce weight and be about 3-3.5% simply to replace alloy 2024 with one alloy of the present invention.

The high-mechanical property of alloy of the present invention makes it possible to the product developing smaller szie and less shape, this also make it possible to reach weight minimizing 10% or even weight reduce by more than 10%.

During peripheral operation surperficial in normally used process aircraft structure, sheet material of the present invention can not cause any special problem usually.

The resistance to intergranular corrosion of sheet material of the present invention improves usually; Such as when metal carries out corrosion test, usually only detect some points.In a preferred embodiment of the invention, sheet material of the present invention can be used and without coating.

Below will explain these aspects in more detail by means of nonrestrictive exemplary embodiment, and other side of the present invention.

Embodiment

Embodiment 1

In order to compare (reference symbol A to E), provide multiple known materials related to the present invention.Described material comprises alloy 2024,2056,7475,6156 and 2098 respectively.Embodiments of the invention are labeled as F to I.Give the chemical constitution of various beta alloy in table 2.

table 2

chemical constitution (by weight percentage)

The density of different beta alloy displayed in Table 3.Sample F to I shows the minimum density of different beta alloy.

table 3

the density of beta alloy

The method that manufacture reference coupon A to D uses is common commercial run, and these reference coupon are by coating.The last metallurgical state of A, B, C and D is T3, T3, T76 and T6 according to standard EN 573 respectively.The method manufacturing sample E and F and use is shown in table 4.In some cases, between quenching and restrained stretching, screed step is carried out.In order to compare, the most common conditional transition of sample E, the most common described condition comprises the restrained stretching operation of extending between 5 and 10%.Sample E#3 before carrying out solution heat treatment anneal to improve toughness.The increase of the cost that the concrete grammar used sample E#3---comprises a replenish step---is correlated with due to step therewith and be unfavorable for industrial application.Other is used to the sample of alloy E, do not carry out annealing steps.

table 4

the condition of continuous conversion step

For reference symbol G, H, I and J, the composition accurately selected can dissolve completely, remains on one significantly lower than the temperature of the solution heat treatment of solidus curve simultaneously.

After tempering, sample is cut into required size.Table 5 gives reference symbol and their size of various sample.

Test described sample in order to measure their static mechanical properties and their toughness.Yielding stress R is given in table 6 _p0.2, ultimate compression strength R _mwith extension at break (A).

table 5

the final size of sample

table 6

the mechanical property of sample

The static mechanical properties of sample of the present invention is very high compared with common resistant to damage series alloy 2xxx, even having with reference symbol is the rank that the sample C of 7475T76 is the same, and the physical strength of sample of the present invention is slightly less than the physical strength that reference symbol is the alloy of E.Contriver thinks that the low copper content of sample of the present invention and low zirconium content affect little on their physical strength.

Some sample of the present invention and reference coupon E provide respectively in fig. 1 and 2 at the curve R in T-L and L-T direction.Fig. 1 clearly illustrates: with regard to crack growth (the Δ a of the last available point of curve R _{eff (max)}), sample of the present invention is much larger than sample E#1, E#2, E#31 and E#4.This parameter at least with numerical value K _appequally crucial, this is because as the description in prior art part, the length of curve R is an important parameter for the design of airframe.Fig. 2 shows same trend, although L-T direction gives in fact better result.Owing to reaching the ultimate load of machine, sample F#3 fails to measure at the curve R in L-T direction.Table 7 summarises the result of toughness test.For sheet material of the present invention, K on T-L direction _appnumerical value be greater than even be greater than and for the reference coupon E that alloy 2098 is made, the K on T-L direction _appnumerical value be less than except the sample E#3 carrying out special annealing steps before solution heat treatment.

table 7

the result of toughness test

The result from curve R has been concentrated in table 8.The crack growth of the last available point of the curve R of sample of the present invention is greater than reference coupon.Therefore, on T-L direction, all samples of the present invention all reach the crack growth of at least 30mm and even at least 40mm, but the maximum extension of the crackle of reference coupon is less than 40mm.Contriver thinks can provide many reasons to explain this performance, as minimum Cu content, and/or minimum Zr content.

table 8

the data of curve R

Fig. 3 and 4 shows on T-L and L-T direction and splits speed da/dN (mm/ circulation) respectively about the change of the stress intensity factor (Δ K) of different levels.The width of sample is 400mm (test specimen CCT 400) and R=0.1.Very big-difference is not found between sample E and F.What the speed of splitting of sample F obtained usually at alloy 2056 (sample B) splitting in the same range of speed, and is less than the velocity range of splitting that alloy 6156 (sample D) obtains.

Resistance to intergranular corrosion is tested according to standard A STM G110.For all samples of the present invention, be not measured to intergranular corrosion.The reference coupon (E#1 to E#4) that alloy 2098 is made is not measured to intergranular corrosion.For sample B (to it except de-plating), observe the intergranular corrosion of the mean depth of 120 μm, for sample D (to sample D except de-plating), observe the intergranular corrosion of the mean depth of 180 μm.Therefore the resistance to intergranular corrosion of sample of the present invention is very high.

Embodiment 2

In the present embodiment, have studied the impact of drawing deformation for test grade sample.From foundry goods H and six samples being processed into the sheet material of thickness 5mm according to the described condition in table 4, be out of shape by the restrained stretching of permanent set between 1 and 6%, then 155 DEG C of tempering 18 hours.Test described sample to measure their static mechanical properties and their toughness.Yielding stress R is given in table 9 _p0.2, ultimate compression strength Rm and extension at break (A).

table 9

the mechanical property of the test sample of different permanent sets

When restrained stretching, static mechanical properties increases along with permanent set.Permanent set for 3% obtains main increase.Therefore, permanent set increases 1-3%, Rm (L) and increases by 7%, and permanent set increase 4-6%, Rm (L) only increases by 3%.By Cann test method assessment toughness, give described result in table 10.

table 10

the Cann test-results of the test sample of different permanent sets

Fracture total energy E _gwith the relation between toughness is directly proportional, although fracture total energy E _gvalue can not in order to predict the result of the curve R of wide sample, reason is that the geometrical shape of sample is different.E can be noticed _gslow reduction, until the tension set of 5%, and for 6% tension set, reduce rapidly.

Embodiment 3

In the present embodiment, some Industrial sample have studied the impact of the permanent set obtained by restrained stretching.From foundry goods J, two samples being processed into the sheet material of 5mm thickness according to the condition shown in table 4, be leveled and carry out the restrained stretching of permanent set of 1.8 and 3.4%.Described sample carries out static mechanical properties and their toughness of testing to measure them.Yielding stress R is given in 11 _p0.2, ultimate compression strength Rm and extension at break (A).

The mechanical property of the Industrial sample of the different permanent set of table 11

The curve R that two samples obtain on T-L direction is shown in Fig. 5.Table 12 summarises the result of curve R.The sample standing the tension set of 1.8% demonstrates less physical strength than the sample of the tension set standing 3.4%.In addition, very high toughness all observed by described two samples.

the toughness test result of the Industrial sample of the different permanent set of table 12

Embodiment 4

In the present embodiment, to evaluate between sheet material of the present invention or with reference to the physical strength of weld between sheet material.Sheet material from the 3.2mm thickness of foundry goods D (6156), E and I is welded together by friction mixing welding.Welding machine carry out.Welding setting is based on the test and Selection of preliminary study.Result according to microstructural observations and grinding test carries out Selecting parameter.For the sheet material from foundry goods E and I, be connected with the welding speed of 300mm/min with the instrument speed of rotation of 800tpm (revolution of per minute).For the sheet material from foundry goods D, be connected with the welding speed of 900mm/min with the instrument speed of rotation of 510tpm (revolution of per minute).

Tempering was carried out before or after being welded to connect by friction mixing.Described result is given in table 13.Below the performance of the weld obtained with sheet material of the present invention, two aspects are satisfactory especially.The first, for sheet material of the present invention, the effectiveness coefficient of weld---ratio between the ultimate compression strength of weld and the ultimate compression strength of non-welded blank---is greater than 70% and is even greater than 75%.In some cases, this coefficient even reaches 80%.This result is better than the result obtained with the sheet material from foundry goods E.The second, described result is little by the impact of the position (before welding or afterwards) of tempering step, and this makes method flexible.On the contrary, for the sheet material obtained for raw material by foundry goods D (6156), the impact observing the position of tempering step is very large.

the mechanical property of table 13 weld

Embodiment 5

In this embodiment, the impact of Zr and Mn content for static mechanical strength and toughness is assessed.

According to cast to two kinds of alloys about the condition of sample G, H and I in table 4 and be processed into the sheet material of 6mm thickness.The composition of these alloys is given in table 14.

table 14

comprise the chemical constitution (by weight percentage) of the alloy of Mn

Test described sample to measure their static mechanical properties and their toughness.Yielding stress R is given in table 15 _p0.2, ultimate compression strength Rm and extension at break (A), and in table 16, give toughness test result.

table 15

comprise the mechanical property of the sample of the alloy of Mn

table 16

comprise the toughness test result of the alloy of Mn

Sample L and M reaches the mechanical property of the present invention to state T8.In addition, the static mechanical properties of sample L---it comprises Mn and low Zr content---and the sample of toughness Performance Ratio other embodiments of the invention low.Contriver think the lowest performance of sample L with particularly exist recrystallize region and non-recrystallize region (mixing microstructure) is feature, the microstructure with less advantageous property is relevant.

Claims

1. manufacture has a method for the aluminum base alloy sheet material of high-tenacity and high mechanical strength, wherein:

Manufacture a metal pool, described metal pool comprises one of following composition by weight:

(1) Si 0.02, Fe 0.04, Cu 3.3, Mn 0.01, Mg 0.31, Zr 0.12, Li 0.96, Ag0.32, Ti 0.02, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, carry out homogenizing 8 hours at 500 DEG C and carry out homogenizing 36 hours at 526 DEG C, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm, cold-rolling thickness <4mm, carry out solution heat treatment 1 hour at 517 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, tempering is carried out 14 hours at 155 DEG C,

(2) Si 0.05, Fe 0.06, Cu 3.2, Mn 0.01, Mg 0.31, Zr 0.11, Li 0.93, Ag0.32, Ti 0.03, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, homogenizing is carried out 12 hours, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm at 505 DEG C, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, carries out tempering 14 hours at 155 DEG C;

(3) Si 0.05, Fe 0.06, Cu 3.3, Mn 0.02, Mg 0.31, Zn 0.06, Zr 0.11, Li0.96, Ag 0.34, Ti 0.02, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, homogenizing is carried out 12 hours at 505 DEG C, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, tempering is carried out 14 hours at 155 DEG C,

(4) Si 0.05, Fe 0.06, Cu 3.2, Mn 0.01, Mg 0.31, Zr 0.11, Li 0.94, Ag0.33, Ti 0.03, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, homogenizing is carried out 12 hours, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm at 505 DEG C, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, carries out tempering 14 hours at 155 DEG C;

(5) Si 0.03, Fe 0.04, Cu 3.2, Mg 0.31, Zr 0.11, Li 0.98, Ag 0.33, Ti0.02, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, carry out homogenizing 12 hours at 505 DEG C, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, carries out tempering 14 hours at 155 DEG C;

(6) Si 0.03, Fe 0.04, Cu 3.3, Mn 0.00, Mg 0.31, Zr 0.11, Li 0.97, Ag0.34, Ti 0.03, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, carry out homogenizing 8 hours at 500 DEG C and carry out homogenizing 36 hours at 526 DEG C, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm, cold-rolling thickness <4mm, carry out solution heat treatment 1 hour at 517 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, tempering is carried out 14 hours at 155 DEG C,

(7) Si 0.03, Fe 0.05, Cu 3.3, Mn 0.31, Mg 0.32, Zr 0.05, Li 0.99, Ag0.32, Ti 0.02, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, homogenizing is carried out 12 hours, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm at 505 DEG C, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, carries out tempering 14 hours at 155 DEG C;

(8) Si 0.03, Fe 0.05, Cu 3.3, Mn 0.30, Mg 0.33, Zr 0.11, Li 0.98, Ag0.35, Ti 0.02, all the other are aluminium and inevitable impurity, with described metal pool for raw material is cast one block of plate, homogenizing is carried out 12 hours, preheating 20 hours before 520 DEG C are carried out hot rolling, hot rolled thickness >4mm at 505 DEG C, cold-rolling thickness <4mm, carry out solution heat treatment 30 minutes at 505 DEG C and quench, described in restrained stretching, sheet material is to tension set 1-5%, carries out tempering 14 hours at 155 DEG C.

2. aluminum alloy plate materials, is produced by the method for claim 1, it is characterized in that being in T8 state:

A () comprises composition (1) and the sheet material that thickness is 3.0mm, 5.0mm, 6.7mm extends 0.2% yielding stress recorded in the l-direction is respectively 469MPa, 470MPa, 481MPa,

Comprise composition (2) and the sheet material that thickness is 3.8mm extends 0.2% yielding stress recorded in the l-direction is 470MPa,

Comprise composition (3) and thickness is 5.0mm that to extend 0.2% yielding stress recorded in the l-direction be 478MPa; Comprise composition (3), thickness is 5.0mm and the sheet material that permanent set is 1%, 2%, 3%, 4%, 5%, 6% extends 0.2% yielding stress recorded in the l-direction is respectively 436MPa, 469MPa, 493MPa, 501MPa, 514MPa, 524MPa

Comprise composition (4) and the sheet material that thickness is 5.0mm extends 0.2% yielding stress recorded in the l-direction is 458MPa,

Comprise composition (5), thickness is 5.0mm and the sheet material that permanent set is 1.8%, 3.4% extends 0.2% yielding stress recorded in the l-direction is respectively 465MPa, 499MPa,

Comprise composition (6) and the sheet material that thickness is 2.0mm extends 0.2% yielding stress recorded in the l-direction is 481MPa,

Comprise composition (7) and the sheet material that thickness is 6.0mm extends 0.2% yielding stress recorded in the l-direction is 447MPa,

Comprise composition (8) and the sheet material that thickness is 6.0mm extends 0.2% yielding stress recorded in the l-direction is 464MPa, and

B () comprises composition (1) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 5.0mm, 6.7mm _appt-L direction is respectively the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (2) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 3.8mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (3) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 5.0mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (4) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 5.0mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (5), thickness is 5.0mm and the toughness K that records on CCT760 type test specimen of the sheet material that permanent set is 1.8%, 3.4% _appt-L direction is respectively the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (6) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 2.0mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (7) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 6.0mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen,

Comprise composition (8) and the toughness K that records on CCT760 type test specimen of the sheet material that thickness is 6.0mm _appt-L direction is the length 2ao=253mm of the initial crack of described CCT760 type test specimen, and

The crack growth Δ a of the last available point of (c) its curve R on T-L direction _{eff (max)}at least 30mm.

3. aluminum alloy plate materials according to claim 2, is characterized in that:

Comprise composition (1) and thickness is sheet material K on L-T direction of 5.0mm, 6.7mm _appbe respectively

Comprise composition (2) and thickness is sheet material K on L-T direction of 3.8mm _appfor

Comprise composition (3) and thickness is sheet material K on L-T direction of 5.0mm _appfor

Comprise composition (6) and thickness is sheet material K on L-T direction of 2.0mm _appfor

4. aluminum alloy plate materials according to claim 2, is characterized in that:

Comprise composition (1) and thickness is sheet material K on T-L direction of 5.0mm, 6.7mm _efffor

Comprise composition (2) and thickness is sheet material K on T-L direction of 3.8mm _efffor

Comprise composition (3) and thickness is sheet material K on T-L direction of 5.0mm _efffor

Comprise composition (4) and thickness is sheet material K on T-L direction of 5.0mm _efffor

Comprise composition (5), thickness be 5.0mm and permanent set be 1.8%, 3.4% sheet material K on T-L direction _effbe respectively

Comprise composition (6) and thickness is sheet material K on T-L direction of 2.0mm _efffor

Comprise composition (7) and thickness is sheet material K on T-L direction of 6.0mm _efffor

Comprise composition (8) and thickness is sheet material K on T-L direction of 6.0mm _efffor

5. aluminum alloy plate materials according to claim 2, is characterized in that:

Comprise composition (1) and thickness is sheet material K on L-T direction of 5.0mm, 6.7mm _effbe respectively

Comprise composition (2) and thickness is sheet material K on L-T direction of 3.8mm _efffor

Comprise composition (3) and thickness is sheet material K on L-T direction of 5.0mm _efffor

Comprise composition (6) and thickness is sheet material K on L-T direction of 2.0mm _efffor

6. aluminum alloy plate materials according to claim 2, is characterized in that:

Comprise composition (1) and thickness be the sheet material of 3.0mm, 5.0mm, 6.7mm in the l-direction, ultimate compression strength R _mbe respectively 490MPa, 498Mpa, 514Mpa,

Comprise composition (2) and thickness be the sheet material of 3.8mm in the l-direction, ultimate compression strength R _mfor 507MPa,

Comprise composition (3) and thickness be the sheet material of 5.0mm in the l-direction, ultimate compression strength R _mfor 517MPa; Comprise composition (3), thickness be 5.0mm and permanent set be the sheet material of 1%, 2%, 3%, 4%, 5%, 6% in the l-direction, ultimate compression strength R _mbe respectively 495MPa, 515MPa, 529MPa, 534MPa, 542MPa, 550MPa,

Comprise composition (4) and thickness be the sheet material of 5.0mm in the l-direction, ultimate compression strength R _mfor 493MPa,

Comprise composition (5), thickness be 5.0mm and permanent set be the sheet material of 1.8%, 3.4% in the l-direction, ultimate compression strength R _mfor 510MPa or 534MPa,

Comprise composition (6) and thickness be the sheet material of 2.0mm in the l-direction, ultimate compression strength R _mfor 508MPa,

Comprise composition (7) and thickness be the sheet material of 6.0mm in the l-direction, ultimate compression strength R _mfor 479MPa,

Comprise composition (8) and thickness be the sheet material of 6.0mm in the l-direction, ultimate compression strength R _mfor 494MPa.

7. aluminium alloy make rolling, punching press and/or a forging product, described aluminium alloy comprises one of following composition by weight:

(1) Si 0.02, Fe 0.04, Cu 3.3, Mn 0.01, Mg 0.31, Zr 0.12, Li 0.96, Ag0.32, Ti 0.02, all the other are aluminium and inevitable impurity;

(2) Si 0.05, Fe 0.06, Cu 3.2, Mn 0.01, Mg 0.31, Zr 0.11, Li 0.93, Ag0.32, Ti 0.03, all the other are aluminium and inevitable impurity;

(3) Si 0.05, Fe 0.06, Cu 3.3, Mn 0.02, Mg 0.31, Zn 0.06, Zr 0.11, Li0.96, Ag 0.34, Ti 0.02, all the other are aluminium and inevitable impurity;

(4) Si 0.05, Fe 0.06, Cu 3.2, Mn 0.01, Mg 0.31, Zr 0.11, Li 0.94, Ag0.33, Ti 0.03, all the other are aluminium and inevitable impurity;

(5) Si 0.03, Fe 0.04, Cu 3.2, Mg 0.31, Zr 0.11, Li 0.98, Ag 0.33, Ti0.02, all the other are aluminium and inevitable impurity;

(6) Si 0.03, Fe 0.04, Cu 3.3, Mn 0.00, Mg 0.31, Zr 0.11, Li 0.97, Ag0.34, Ti 0.03, all the other are aluminium and inevitable impurity;

(7) Si 0.03, Fe 0.05, Cu 3.3, Mn 0.31, Mg 0.32, Zr 0.05, Li 0.99, Ag0.32, Ti 0.02, all the other are aluminium and inevitable impurity;

(8) Si 0.03, Fe 0.05, Cu 3.3, Mn 0.30, Mg 0.33, Zr 0.11, Li 0.98, Ag0.35, Ti 0.02, all the other are aluminium and inevitable impurity.

8. structural element, comprises the aluminum alloy plate materials of at least one claim 2 or the product of claim 7, or is obtained by this aluminum alloy plate materials or product.

9. the structural element of claim 8, comprises the product of at least one claim 7, or is obtained by this product, it is characterized in that: it is a kind of strengthening rib or framework.

10. structural element according to claim 8, is characterized in that: comprise a welded construction, and described welded construction is welded together by friction mixing welding.

11. structural elements according to claim 8, is characterized in that: it is a kind of wallboard of airframe.

12. structural elements according to claim 11, described airframe wallboard weight at least has comparable performance airframe wallboard weight than one reduces 1-10%, described in there is the airframe wallboard of comparable performance sheet material be the alloy being selected from alloy 2024,2056,2098,7475 and 6156.

13. structural elements according to claim 8, its weight at least has the structural element of comparable performance weight than one reduces 1-10%, described in there is the structural element of comparable performance sheet material be the alloy being selected from alloy 2024,2056,2098,7475 and 6156.