CN102453821B

CN102453821B - Aluminium alloy plate

Info

Publication number: CN102453821B
Application number: CN201110314946.1A
Authority: CN
Inventors: 有贺康博; 常石英雅; 松本克史
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2010-10-19
Filing date: 2011-10-17
Publication date: 2016-12-14
Anticipated expiration: 2031-10-17

Abstract

Thering is provided a kind of it can be avoided that the new problems such as the reduction of bendability that causes of age-hardening under room temperature produce, the generation of SS trace is few, the Al Mg line aluminium alloy plate that extrusion molding is excellent.Manufacture by containing individual Mg, Cu when forming constituted Al Mg line aluminium alloy plate, periodically control the rate of cooling during Quenching Treatment after solid solution, and control additional anneal condition, this plate is measured by three-dimensional atom probe field ion microscope analysis, aggregation as specific Cu atom exists more than certain average density, Mg is difficult to spread, and serration is difficult to the tissue occurred, the generation of SS trace during suppression extrusion molding.

Description

Aluminium alloy plate

Technical field

The present invention relates to the Al-Mg line aluminium alloy plate having excellent formability.Aluminium alloy plate described in the present invention is hot rolled plate And cold-reduced sheet, refer to implement the quenched aluminium alloy plate of solutionizing process and annealing etc..Also aluminum is referred to as it addition, following Al。

Background technology

In recent years, from the viewpoint of considering earth environment etc., the light-weighted social desirability of the vehicles such as automobile carries day by day High.In order to tackle this requirement, as car panel, the particularly large-scale body panels such as hood, car door, roof is (inner panel, outer Plate) material, in addition to the ferrous materials such as steel plate, the application of aluminum alloy materials is also studied.

5000 line aluminium alloy plates of the JIS5052 alloy of Al-Mg system and JIS5182 alloy etc. are (hereinafter also referred to as Al-Mg It is alloy sheets) due to ductility and excellent strength, the most all the time by the extrusion molding as these large-scale body panels Former material uses.

But, as disclosed in patent documentation 1 grade, if carrying out tension test for these Al-Mg system alloys, then answering Near yield point on force-strain curve, there is the situation occurring surrender to extend, additionally in the strain that the comparison exceeding yield point is high Under amount (such as stretch percentage elongation more than 2%), also have on load-deformation curve, produce zigzag or stair-stepping jagged The situation of projection (serration) (vibration).Phenomenon on these load-deformation curves, in actual extrusion molding, is caused The generation of so-called elongation strain trace (following description is SS trace), this is special for the described large-scale body panels as formed products For not being the critically important outside plate of outward appearance, become the big problem of infringement commodity price.

This SS trace as known to the public, can be divided into irregular such as flamboyancy occurred in dependent variable than relatively low position The so-called irregular trace of banding apperance, about becomes 50 ° of such generations with the position higher in dependent variable relative to draw direction The parallel band (parallel band) of parallel banding apperance.The former irregular trace known is caused by yield point elongation, additionally The serration (vibration) that parallel band described later is fallen on described load-deformation curve by the preceding paragraph causes.

All the time, the method proposing to have these SS traces of various elimination.Such as, as main method, it is known to by Al- The crystal grain of Mg system alloy sheets is adjusted to the thickest method.But, the method for adjustment of such crystal grain, SS trace it In, invalid for the generation preventing the parallel band described in above-mentioned paragraph.If it addition, crystal grain becomes the thickest, then squeezing In pressing formation, surface can be produced on the contrary the other problemses such as Pericarpium Citri Reticulatae occur.

It addition, as other eliminate SS traces method, it is also known that have the O material (soft material) for Al-Mg system alloy sheets or T4 processes the quenched material of material etc., before extrusion molding is described large-scale body panels, is previously applied skin-pass processing or rectifys Some processing such as flat processing (preprocessing) give some strains (prestrain) in advance.But, even if taking such pre-add engineering method, When degree of finish is too high, the serration (vibration) being still susceptible on the load-deformation curve described in above-mentioned paragraph, During actual extrusion molding, still easily cause amplitude broad and obvious parallel band.Therefore, the degree of finish of preprocessing exists the biggest Restriction, reduce preprocessing time, then can not be stable against the generation of irregular trace.In this preprocessing method, because parallel Band prevents the optimal process degree prevented with irregular trace contrary, so both can not prevent simultaneously.

To this, in aforementioned patent literature 1, propose there is a kind of generation inhibiting irregular trace, and also inhibit width The preparation method that few Al-Mg system alloy sheets occurs of the SS trace of the generation of the parallel band of width.Specifically, it is that Al-Mg system is closed The milled sheet of gold is implemented with the solid solution/Quenching Treatment under the specified conditions cooled down rapidly, followed by as under specified conditions The cold working of preprocessing, then implement the final annealing under specified conditions.Then obtaining average crystal grain diameter is below 55 μm, and And the soleplate that the thick crystal grain that 150 is more than μm is created substantially absent.

Here, in the field of Al-Mg system alloy, may not directly mention the generation of suppression SS trace, it is also known that has, and passes through The position of the endothermic peak of the heating curves from room temperature that differential thermal analysis (DSC) is measured the thermal change of alloy sheets and obtained and Its height, in this, as the index of the extrusion molding raising of this plate.

Such as in patent documentation 2 propose, according to Al-Mg system alloy sheets differential thermal analysis (DSC) obtain from room temperature The endothermic peak height of ad-hoc location of heating curves, the index improved as extrusion molding.This differential thermal analysis (DSC), the cluster (intermetallic row) in influencing characterisitic can not differentiate or identify in the microstructure observations such as TEM, it is impossible to In the presence of directly proving it, with or without structural different difference such as clusters, just by the position of the characteristic of aforementioned heating curves Endothermic peak position and the most indirectly proving, and as index, therefore general in the field of aluminium alloy plate.

In patent documentation 2, cast continuously by double-roll type and the Mg that the manufactures Al-Mg system more than the high Mg of 8 mass % In alloy sheets, making the endothermic peak height between 50～100 DEG C of the heating curves from room temperature is 50.0 more than μ W, so that Extrusion molding improves.Its basis is that this endothermic peak height represents the Al-being referred to as β phase in Al-Mg system alloy sheets tissue The existing forms (solid solution, the stability of precipitation state) of Mg series intermetallic compound.

But, nearest described large-scale body panels, in the outside plate that particularly outward appearance is critically important, the requirement water of surface texture Flat more strict, in this patent documentation 1 or patent documentation 2, in the face of such requirement, the countermeasure that suppression SS trace occurs is not filled Point.Such as in patent documentation 1, it is to make the slight (ladder of the embodiment of patent documentation 1 of stair-stepping serration as far as possible Described in the explanation of the evaluation of shape serration), therefore, the parallel band as one of SS trace can not be suppressed completely.

In contrast, improve this point in patent documentation 3, it is proposed that a kind of inhibit SS trace, to car panel The Al-Mg line aluminium alloy plate having excellent formability of extrusion molding etc., it can suppress the generation of irregular trace simultaneously, also have flat The generation of row band.In same document, for Al-Mg line aluminium alloy plate, particularly make Zn contain 0.1～4.0%, improve further The critical strain (limiting strain amount) that serration occurs.I.e. containing and adding by third element such as Zn, make by Al With the formation amount of the cluster (ultra tiny intermetallic compound) that Mg is formed, increase as the cluster also containing Zn etc., more enter one Step improves the limiting strain amount brought by these clusters and increases effect.And, suppress serration, suppression thus to cause accordingly Parallel band, suppression SS trace generation.

Should be containing the size that cluster is below nanoscale of Zn etc., the microstructure at the FE-TEM etc. of about 100,000 times is seen Can not differentiate and identify in examining, it is impossible to directly prove that it exists.Therefore in this patent documentation 3, also same with aforementioned patent literature 2 Sample, for the structural difference with or without cluster etc., measures thermal change by differential thermal analysis (DSC), according to described heating song The endothermic peak position of the ad-hoc location of line and height, as the index of structural difference.Specifically, it is simply that will be containing Zn Deng Al-Mg cluster, thus it is speculated that for the endothermic peak between 100～150 DEG C of aforesaid DSC heating curves will be because of, this heat absorption Peak height is more than 200.0 μ W (microwatt).

[look-ahead technique document]

[patent documentation]

[patent documentation 1] Unexamined Patent 7-224364 publication

[patent documentation 2] JP 2006-249480 publication

[patent documentation 3] JP 2010-77506 publication

But, according to the understanding of the present inventors, in Al-Mg line aluminium alloy plate, contain in a large number as this patent documentation 3 When having Zn, it may occur that easily produce the such new problem of age-hardening under room temperature.This be presumably due to, as patent documentation Maximally effective means that 3 suppression SS traces occur and being allowed to produce, the cluster (ultra tiny intermetallic compound) that formed by Zn is held Easily at room temperature formed.That is, Zn content is the most, and the described cluster formed under room temperature more increases, and results presumption is under room temperature Age-hardening is excessively carried out.Generally, Al-Mg line aluminium alloy plate aluminium sheet manufacturer has manufactured, and is not to be shaped by automobile vendor at once For large-scale body panels etc., the interval generally having more than several weeks is the most universal.It is thus possible, for instance from plate manufacture after 1 month, then become When shape is large-scale body panels etc., age-hardening significantly advances, and can produce bendability and extrusion molding is the most hindered etc. Such new (other) problem.

As is it well known, compare Al-Zn-Mg system (7000 are) aluminium alloy plate of heat treatment type, generally, Al-Mg system aluminum Alloy sheets is difficult to the time effect under room temperature.But, such Al-Mg line aluminium alloy plate also as patent documentation 3, When increasing Zn content, identical with 7000 line aluminium alloy plates and demonstrate the age-hardening under room temperature.

Summary of the invention

In view of above-mentioned problem, it is an object of the invention to, it is provided that a kind of Al-Mg line aluminium alloy plate, it is it can be avoided that room The new problems such as the reduction of the bendability that the age-hardening under Wen causes produce, and suppress not advised by what described surrender extension caused simultaneously The then generation of trace and the generation of parallel band, suppresses SS trace, makes the extrusion molding towards car panel improve.

In order to reach this purpose, the main idea of the aluminium alloy plate of the present invention is, a kind of Al-Mg line aluminium alloy plate, with quality % Meter is containing Mg:2.0～6.0%, Cu: more than 0.3%, below 2.0%, surplus is made up of Al and inevitable impurity, its In, as the aggregation of the atom measured by three-dimensional atom probe field ion microscope, it is with 1.0 × 10⁴Individual/μm³Above Average density, containing the aggregation of following atom, the aggregation of this atom contain with among the distance of other adjacent Cu atoms The Cu atom that at least 1 is below 1.0nm reach more than 5.

The present inventors, as the element of the generation inhibition with SS trace, select Cu to substitute and easily produce room temperature Under the Zn of age-hardening.If this Cu, then will not produce age-hardening at room temperature as Zn, and there is SS trace There is inhibition.

But, even if containing Cu equally, also having the situation of the generation inhibition still lacking SS trace, the most also finding, phase With in the Al-Mg line aluminium alloy plate (hereinafter also referred to Al-Mg-Cu line aluminium alloy plate) of Cu content, the generation inhibition of SS trace There is also greatest differences.It is thus regarded that, do not contain only Cu, and existence (the tissue shape of the Cu in Al-Mg line aluminium alloy plate State) difference, also the generation state of SS trace can be produced significant impact.

The result studied further about the existence of this Cu, present inventor speculates, the generation inhibition of SS trace, also By among the fine cluster of various Cu, the amount of the fine cluster (the fine cluster based on Cu) of specific Cu with The significant impact whether existed.

But, the cluster of this specific Cu is the finest, in common structure observation, can not directly confirm that it is deposited ?.This Cu cluster is identical with the Al-Mg series intermetallic compound of aforementioned patent literature 2,3 etc., thus it is speculated that micro-for below nanoscale Little magnitude.Analysis method accordingly, as SEM and TEM of common structure observation method can not the cluster of this Cu specific.

Accordingly, can the present inventors have studied the existence that prove this new specific Cu cluster.Then, utilization can be entered The three-dimensional atom probe field ion microscope that the row atomic structre less than 100 is analyzed, attempts carrying out containing Cu, and implements The analysis of the aggregation (cluster) of the atom of the atomic number about 10 of the quenched Al-Mg line aluminium alloy plate of specified conditions. That is, in the good and bad different Al-Mg line aluminium alloy plate containing Cu of SS trace inhibition, it is thus identified that the aggregation of atom each other The difference of existing forms (existence).

It, it was found that be able to confirm that the existence of the aggregation of the atom that present invention provide that, contains Cu atom according to this The existence of the aggregation of atom, other materials condition does not has difference each other, the SS trace suppression between Al-Mg line aluminium alloy plate Effect be very different.That is, finding that the density containing the aggregation of the atom of the Cu atom that present invention provide that is the most, SS trace presses down Effect processed is the biggest.Here, so-called other materials condition does not has difference, the meaning to be the SS mutually different plates of trace inhibition, its that This one-tenth is grouped into, and either by the structure observation of common TEM and SEM etc., or spreads out by extracting residua analysis and X-ray The analysis penetrated etc., does not the most all have difference.And, the meaning is only to contain the atom set body of the Cu atom that present invention provide that Existence is different.

So, in the Al-Mg line aluminium alloy plate containing Cu, three-dimensional atom probe field ion microscope that measure, The existence (average density) of the aggregation of the atom containing Cu atom, represents the tissue of impact (being correlated with) SS trace inhibition State (existence of new cluster).Therefore, the aggregation of the atom that should contain Cu atom (is the most also only called the collection of atom Fit) average density, become the index representing the relation with the extrusion molding representated by SS trace characteristic.

The present invention is thus by the Cu using the age-hardening being susceptible to unlike Zn under room temperature, it is possible to control Al- The tissue of Mg line aluminium alloy plate, prevents the movement of free Mg atom dispiration, becomes the tissue that Mg is difficult to spread, and makes zigzag dash forward Rising and be difficult to occur, SS trace is excellent.

Detailed description of the invention

Hereinafter, for embodiments of the present invention, specifically describe each important document.

(tissue)

It has been observed that in Al-Mg line aluminium alloy plate, if containing Cu, then there is the generation inhibition of SS trace, even if being Identical Cu content, the generation inhibition of SS trace there is also huge difference.This is presumed to, and does not contain only Cu, and Al- The structural state of Mg line aluminium alloy plate, the existing forms of the fine cluster i.e. generated by Cu, also can largely effect on sending out of SS trace Raw state.

But, the fine cluster (aggregation of atom) that present invention provide that, even if as maximum number by 100 atoms Composition, its size is the most onlyThe cluster that (angstrom Angstrom) left and right is small.The small cluster of such Cu, i.e. Make for speculating that the Al-Mg line aluminium alloy plate that it is contained, SS trace is inhibited carries out structure observation, be also not it is observed that 's.Specifically, use that the fine cluster for measuring in plate tissue is maximally effective, (transmission-type is electric for the FE-TEM of 100,000 times Sub-microscope) carry out structure observation, can not observe to the suppression of SS trace effectively, the fine cluster of new specific Cu.

It addition, such as measuring the solid solution capacity of addition element and the extraction residua analysis that precipitate amount is general, can not Observe the fine cluster of this new specific Cu.Extracting residua analysis is the filter utilizing minimum mesh size 0.1 μm, can To differentiate the being precipitate of fine sizes of below 0.1 μm, still more than the precipitate of coarse size of 0.1 μm.But, this Eventually or can not being differentiated by the aggregation of the atom of the atomic building less than 100 of bright regulation.

Even if these are true it is meant that order about mutually different plate good and bad for above-mentioned SS trace, carry out these TEM and The structure observation of SEM etc. or the analysis of extraction residua analysis and X-ray diffraction etc., in any case can not detect and present invention provide that The difference of existence of aggregation of atom.

But, otherwise these true also derive such supposition, i.e. can not by these TEM and SEM observe this Almost there is no the fine Cu cluster of too big difference with solid solution condition, influence whether that SS trace suppresses.If, such fine Cu cluster is not present in Al-Mg line aluminium alloy plate tissue, then whether be speculated as because of its deformation caused at extrusion molding Time prevent the diffusion of Mg, there is the inhibition that SS trace occurs.

(three-dimensional atom probe field ion microscope)

The aggregation of the atom of these new fine Cu clusters=present invention provide that, only uses known Three-dimensional atom to visit Pin field ion microscope (3DAP:3D Atom Probe Field Ion Microscope, hereinafter also referred to as 3DAP), when Time just can measure.

The analysis of this three-dimensional atom probe field ion microscope itself, always at magnetic recording film and the electronics of densification In the analysis of device etc. general.It addition, be also used for fabric analysis in steel field.Such as, in JP 2006-29786 public affairs In report, the kind of the element contained by carbon containing nano-precipitation that it is used in steel and quantitative analysis.It addition, in JP In 2007-254766 publication, its be also used for the sulfide in steel and Fe interface C amount, N quantitative analysis (atom/ nm²)。

It addition, in copper alloy field, the applicant itself proposes have one to refer to as JP 2009-263690 publication Mark, this characteristic evidences be just the use of this three-dimensional atom probe field ion microscope, for Cu-Fe-P series copper alloy plate The regulation of atom set body that improves of thermostability.That is, will at least contain any one of Fe atom or P atom, Fe atom or P are former The average density of the aggregation of the atom that distance is below 0.90nm between the atom that son is adjacent one another are is defined as, Cu atom, The total number of Fe atom and P atom is more than 15, less than 100.

(measuring principle of 3DAP and measuring method)

3DAP is to install time of-flight mass spectrometer on field ion microscope (FIM).It it is by this composition, it is possible to electricity consumption Each atom of metal surface observed by field ion microscope, identifies the partial analysis dress of these atoms with time of-flight mass spectrometer Put.It addition, 3DAP can analyze the kind of atom and position released from test portion simultaneously, therefore at the structure of aggregation of atom It is very effective means in analysis.Accordingly, as known technology, it has been observed that be used for magnetic recording film and electronic device or steel The fabric analysis etc. of material.

In this 3DAP, the ionizing of the test portion atom under the high electric field being known as field evaporation of utilization itself is existing As.If the high voltage required for test portion atom is used for field evaporation is applied to test portion, then atom is surface ionizing from test portion, It arrives detector through exploration hole.

This detector is position sensitive detectors, according to the quality analysis of each ion (element as atomic species Identify), and measure the flight time of the detector to each ion, it is possible to determine its position detected (atom structure simultaneously Make position).Therefore, 3DAP can measure position and the atomic species of the atom of test portion front end simultaneously, can be three-dimensional so having Reconstruct, observe the speciality of the atomic structre of test portion front end.It addition, because field evaporation is sent out from the front end face order of test portion Raw, it is possible to investigate the atom from test portion front end in the distribution of depth direction with the resolving power of atomic energy level.

Because this 3DAP utilizes high electric field, so the test portion analyzed needs to be the test portion that the electric conductivity such as metal are high, Er Qieshi The shape of material is it is generally required to for superfine needle-like that point diameter is 100nm about φ or less.Therefore, from the Al-containing Cu The thickness of slab central parts of Mg line aluminium alloy plate etc. extract test portion, carry out cutting for this test portion with precision cutting device and electrolysis is ground Mill, makes the test portion with the superfine needle-like leading section analyzed.As measuring method, it such as uses Imago " LEAP3000 " of Scientific Instruments company, is configured to the aluminium alloy plate test portion of needle-like for its front end, The high pulse voltage of additional 1kV step (order), makes millions of atomizing/ionizings constantly from test portion front end.Ion is by position Putting sensitive detectors detection, according to from applying pulse voltage, each ion is after test portion front end flies out, to arriving flying of detector The row time, carry out the quality analysis (as the qualification of element of atomic species) of ion.

Additionally, utilizing field evaporation is the character that the front end face from test portion occurs the most regularly, arriving of display ion Reach place, two-dimensional map is suitably given the coordinate of depth direction, use and analyze software " IVAS ", carry out three-dimensional map (three-dimensional Under atomic structre: atom reflection construct).Thus, the Three-dimensional atom reflection of test portion front end is obtained.

Re-use definition belong to precipitate and cluster method, i.e. Maximum Separation Method, former for this Son this Three-dimensional atom reflection carries out the analysis of the aggregation (cluster) of atom.When carrying out this analysis, it is provided that the quantity of Cu atom, Distance (interval) between Cu atom adjacent one another are and to have the Cu of aforementioned specific narrow intervals (below 1.0nm) former The quantity of son is as parameter.Then, meet containing with among the distance of other adjacent Cu atom at least 1 be 1.0nm with Under Cu atom reach more than 5, the aggregation of such atom is defined as the aggregation of the atom of the present invention.Basis at this On, evaluate the aggregation of the atom meeting this definition, measuring test portion quantity is more than 3, by the number density of the aggregation of atom Equalization, as every 1 μm²Average density (individual/μm³) carry out measuring, quantification.

(detection efficiency of the atom of 3DAP)

But, the detection efficiency of the atom of this 3DAP, present situation is, about 50% among the atom of ionizing is Boundary, remaining atom can not detect.If the detection efficiency of the atom of this 3DAP will be improved etc. in future and occurs great Variation, then the mean number density (individual/μm of the aggregation of the atom that present invention provide that³) the measurement result from 3DAP have send out Change dynamic probability.Therefore, in order to make the measurement of the mean number density of the aggregation of this atom have repeatability, preferably The detection efficiency of the atom of 3DAP is approximately fixed is about 50%.

(definition of the aggregation of atom)

The aggregation (cluster) of the atom that what is called present invention provide that, is shown by three-dimensional atom probe electric field and ionic as such The aggregation of atom that micro mirror is measured, is to meet containing being 1.0nm with at least 1 among the distance of other adjacent Cu atoms Following Cu atom is the aggregation of 5 upper above atoms.

It addition, the aggregation of the described atom that present invention provide that, be not limited to only by Cu atomic building, except this Cu atom with Outward, also Al atom is contained with the highest probability.It addition, in addition to this Cu atom, as other elements, have the most especially containing The situation of Si atom etc..That is, if the aggregation of the described atom that present invention provide that meets the regulation of aforementioned Cu atom, the most additionally Containing which type of atom again can.

Additionally, be grouped into according to the one-tenth of the Al-Mg line aluminium alloy containing Cu, as alloying element and inevitable impurity The atom of Si, Fe, Mn, Cr, Zr, V, Ti or Zn etc. of containing is included in the aggregation of atom, necessarily occurs these other Atom by 3DAP analytical calculation in interior situation.But, even if these other atoms (from alloying element and impurity) are included in In the aggregation of atom, compared with the sum of Cu atom, it also it is little level.Therefore, such in aggregation containing its In the case of his atom, meet and the predetermined distance (interval) of other adjacent Cu atoms, and meet the Cu atom of this point Individual said conditions, also serve as the atom set body of the present invention, and only play in the same manner as the aggregation of the atom of Cu atomic building Function.

Therefore, containing in the case of other atoms in aggregation, in the aggregation of atom, if with adjacent its Among the distance of his Cu atom at least 1 is the Cu atom of below 1.0nm, then also serve as the aggregation meter of the atom of the present invention Including Suaning.So, when condition is not satisfied, such as close between Cu atom, do not include the aggregation of the atom of the present invention, no yet Count.

The regulation of the distance between the atom of the aggregation of the atom of the present invention, it has been observed that (constitute base relative to specific Accurate) Cu atom, other adjacent whole atomic distances each can also be not exclusively at below 1.0nm, on the contrary, it is also possible to each From being completely in below 1.0nm.In other words, other former beyond the distance other the Cu atom more than 1.0nm and Cu atom Son can also be adjacent, and around specific (constituting benchmark) Cu atom, other Cu meeting this predetermined distance (interval) are former Son is minimum 1.And, meet other the adjacent Cu atom of this predetermined distance when having 1, meet the condition of distance The quantity of inclusive Cu atom should contain specifically (constituting benchmark) Cu atom and become 2.Should it addition, meet When other the adjacent Cu atom of predetermined distance is 2, meet distance condition should the number of inclusive Cu atom Amount becomes 3 containing specific (constituting benchmark) Cu atom.

The aggregation of the Cu atom of present invention mentioned above, thus it is speculated that be by by the solutionizing of hot rolled plate and cold-reduced sheet and Quenching Treatment, and the fire of bringing down a fever for a long time it persistently carried out under low temperature quenched (aftermentioned) that be combined and generate.

(average density of the aggregation of atom)

In the present invention, make defined above, and analyzed the aggregation of the atom measured by 3DAP, with 1.0 × 10⁴Individual/μ m³Above average density, is present in the Al-Mg line aluminium alloy plate tissue containing Cu.That is, as by three-dimensional atom probe electricity The aggregation of the atom that field ion microscope is measured, meets and contains and at least 1 among the distance of other adjacent Cu atom The individual Cu atom for below 1.0nm reaches more than 5, makes the aggregation of such atom, with 1.0 × 10⁴Individual/μm³Above is average Density, is present in the Al-Mg line aluminium alloy plate tissue containing Cu.Further, in the present invention, the aggregation of atom is the closeest Degree higher limit be not particularly limited, if but from manufacture on boundary etc., then be set as 1.0 × 10⁶Individual/μm³Left and right.

Hereby it is possible to positively suppress sending out of the SS trace of the extrusion molding as the Al-Mg line aluminium alloy plate containing Cu Raw.That is, the aggregation of atom is the most, more can block (capture) Al-Mg line aluminium alloy plate containing Cu with the aggregation of atom Atomic vacancy.The existence in the hole of atom, thus it is speculated that can promote that the jagged projection on load-deformation curve causes parallel The generation of band and propagation.Therefore, if atomic vacancy is blocked by the aggregation of atom, then generation and the propagation of SS trace is inhibited. It addition, can also suppress to be extended by surrender the generation of the irregular trace caused, the also generation of parallel band accordingly simultaneously. According to the invention it is thus possible to synthetically suppress the generation of SS trace, it is possible to make extrusion molding improve.

In contrast, the aggregation of this atom is less than 1.0 × 10⁴Individual/μm³Average density time, the aggregation mistake of atom Few, it is impossible to make Cu spread and block (capture) in the atomic vacancy of the Al-Mg line aluminium alloy plate containing Cu.Therefore, atom is empty Cave the most directly remains, it is impossible to prevent the SS trace generation that this atomic vacancy brings and the facilitation propagated, it is impossible to fully suppress The generation of SS trace.

Here, the aggregation of the atom of the present invention, why meet containing with among the distance of other adjacent Cu atoms At least 1 Cu atom at below 1.0nm reach more than 5, be due to its number less than 5 time, the chi of the aggregation of atom Very little too small, blocking (capture) effect of atomic vacancy is little.On the other hand, in the set of atom originally, the number of this Cu atom is 100 Individual above majority, it is oversize, and the inhibition that SS trace occurs diminishes.Therefore, the number of this Cu atom be preferably 5 with Above, the scope less than 100.

(irregular trace prevents)

In the present invention, it is also possible to prevent among SS trace, the generation of the irregular trace caused is extended due to surrender. Therefore, it is not required that in order to prevent the generation of this irregular trace, and apply the countermeasure of existing prestrain (preprocessing).Change speech It, even if not applying existing prestrain (preprocessing), it is also possible to is adequately suppressed in dependent variable than relatively low position generation Irregular trace, and the generation of the elongation strain trace (SS trace) of the parallel band these two aspects occurred at the position that dependent variable is higher.

The present invention as car panel with former material plate, particularly requirement to surface texture in the outer panels that outward appearance is important When level is the strictest, it is also possible to suppress to be extended, by surrender, the generation of irregular trace caused simultaneously, and with described stress- The generation of the parallel band that the serration on strain curve is associated.Its result is car panel can be significantly increased with former The performance of material plate.

(chemical composition composition)

The chemical composition composition of aluminium alloy plate of the present invention, is substantially equivalent to the JIS 5000 as Al-Mg system alloy The aluminium alloy of system.Further, represent that the % of the content of each element is entirely the meaning of quality %.

The present invention, needs to meet extrusion molding, intensity, weldability, corrosion resistant with former material plate especially as car panel Many characteristics such as erosion property.Therefore the hot rolled plate of the present invention, is in 5000 line aluminium alloys, in terms of quality % possibly together with Mg:2.0～ 6.0%, Cu: more than 0.3% below 2.0%, the Al-Mg line aluminium alloy plate that surplus is made up of Al and inevitable impurity. Further, constituent content is entirely quality %.

Additionally, as the Zn of impurity element, it has been observed that it becomes the age-hardening under generation room temperature and makes bendability and squeeze The reason that pressing formation reduces, therefore does one's utmost not comprise.If it addition, contain, also specifying below 1.0% in terms of quality %, It is preferably less than 0.6%, more preferably less than 0.1%.

Mg:2.0～6.0%

Mg improves work hardening capacity, it is ensured that the intensity needed with former material plate as car panel and durability.It addition, its Make material occur homogeneous plastic deformation to make the fracture crack limit improve, make formability improve.The content of Mg is less than 0.5% Time, intensity and durability are insufficient.On the other hand, if the content of Mg is more than 7.0%, then the manufacture difficulty of plate, and in extruding Being susceptible to intercrystalline failure during shaping on the contrary, extrusion molding significantly reduces.Therefore, the content of Mg is 2.0～6.0%, preferably It it is the scope of 2.4～5.7%.

Cu: more than 0.3%, below 2.0%

Cu forms the aggregation (fine cluster) of the aforesaid atom based on Cu, and different from Zn, it will not make plate send out Raw room-temperature aging hardening, thus it is speculated that the generation of SS trace when can suppress extrusion molding.Cu very few and less than 0.3% time, based on Cu The growing amount of the cluster of body is not enough, and the generation inhibition of SS trace during extrusion molding plays insufficient.On the other hand, if Cu Content more than 2.0 mass %, the generation quantitative change of the thickest crystal and precipitate is many, easily becomes the starting point of destruction, instead And make extrusion molding reduce.In the content of Cu is the scope more than 0.3%, below 2.0%, preferably 0.5～1.5% In the range of.

Cu/Mg:0.05～1

Here, for the described additive effect playing Cu, Cu is for the ratio of the content of Mg: Cu/Mg is preferably 0.05～1. This than higher limit and lower limit, according between higher limit and the lower limit of described content each other or preferably higher limit and under Ratio between limit value calculates, in the range of preferably 0.08～0.8.

Other elements

Other elements, illustrate and have Fe, Si, Mn, Cr, Zr, Ti etc..These elements, as fused raw material, are as aluminium alloy Amount of waste (relative to the ratio of aluminum substrate metal) increases and contains the impurity element that quantitative change is many.That is, from the circulation profit of Al alloy sheets From the viewpoint of with, as fused raw material, it is more than using highly purified aluminum substrate metal, is alloy and other Al conjunction with 5000 When gold waste material, low-purity Al parent metal etc. are used for melting raw material, the mixed volume (content) of these elements necessarily increases. These elements are reduced to consciously the such as the following practice of such as detectable limit and can raise manufacturing cost, it is therefore desirable to allow with The common specification (upper limit amount) of 5000 line aluminium alloys contains with degree.Based on this point, described aluminium alloy plate also allow for Quality % meter containing from below Fe:0.5%, below Si:0.5%, below Mn:0.5%, below Cr:0.1%, Zr:0.1% with Under, select within below Ti:0.05% one or more.It addition, allow the scope at the content less than Ti to contain appearance The B (boron) easily adhering to Ti and be mixed into.

(manufacture method)

Manufacture method below for the plate of the present invention is specifically described.

In the present invention, to reaching the rolling process before solution treatment, 5182,5082,5083,5056 etc. containing Mg are The plate of about 4.5%, it is possible to use the manufacture method of manufacturing process based on shaping Al-Mg system alloy manufactures.That is, warp Casting (DC casting and continuous casting process), the heat treatment that homogenizes, common each manufacturing process of hot rolling manufacture, and become plate Thickness is the aluminum alloy hot rolling band of 1.5～5.0mm.This stage can be as sheet, additionally can also be before cold rolling or cold rolling Midway optionally while carrying out once or twice above intermediate annealing, carry out cold rolling again, be 1.5mm as thickness of slab The sheet of following cold-reduced sheet.

Solution treatment (final annealing)

In order to become the plate of the tissue with the present invention, for these hot rollings having required thickness of slab obtained in the above-described manner Plate or cold-reduced sheet, first carried out with instant heating and the solutionizing Quenching Treatment that cools down rapidly.Carry out this solid solution Changing the material of Quenching Treatment, so-called T4 processes material compared with the batch annealing material with the heating and cooling of comparing mitigation Relatively, the balance of intensity and formability is more excellent.It addition, in time carrying out Quenching Treatment after solutionizing processes, atomic vacancy is imported into.

Although here, the appropriate value of solid solution temperature can be different according to concrete alloy composition, but needing In the scope of more than 450 DEG C less than 570 DEG C.Additionally the holding under solutionizing treatment temperature need 180 seconds (3 minutes) with In.When solid solution temperature is less than 450 DEG C, the solid solution of alloying element is insufficient, and intensity, ductility etc. are likely to decrease.Another Aspect, if solutionizing treatment temperature is more than 570 DEG C, then excessive grain coarsening, the Pericarpium Citri Reticulatae when reduction of formability and shaping Become problem.If it addition, the retention time under solutionizing treatment temperature was more than 180 seconds, then produce excessive grain There is the problems such as Pericarpium Citri Reticulatae during the shaping that coarsening is brought.

Quenching Treatment

During Quenching Treatment after solution treatment, the temperature of plate needs the rate of cooling with more than 20 DEG C/sec from solid solubility temperature Continuous coo1ing is to low-temperature anneal temperature speed.When rate of cooling is less than 20 DEG C/sec, cooling generates thick precipitate, even if Its after-applied process annealing and become final plate, the growing amount of the aggregation (fine cluster) of atom is still not enough and SS trace occurs. These process with instant heating and the solution hardening cooled down rapidly, it is possible to use continuous annealing line (CAL) etc. enters continuously OK, or can also hanker using salt bath etc. adding, cooling use water quenching, oil hardening, forced air-cooling etc. enter with batch-type OK.During here, implement the solution treatment/quenching using CAL, room temperature～the general heating of solid solution temperature and the speed of cooling Degree is about 5～100 DEG C/sec.

Process annealing

After this Quenching Treatment (chilling), be carried out continuously less than 100 DEG C more than 50 DEG C scope keep 24 hours with On process annealing.To this end, the temperature of plate during the scope of less than 100 DEG C, stops the cold of Quenching Treatment (chilling) more than 50 DEG C But, directly plate (volume) is kept more than 24 hours in this temperature range of more than 50 DEG C less than 100 DEG C.If here, less than 50 Within retention time at DEG C is 200 seconds, then between Quenching Treatment and process annealing, plate can also be less than 50 DEG C.

So, after solution hardening, carry out process annealing continuously, as the plate of the present invention, this for 1.0 × 10⁴Individual/μm³Above average density, the aggregation aspect containing following atom is critically important, and the aggregation of this atom contains and phase The Cu atom that at least 1 is below 1.0nm among the distance of other adjacent Cu atoms reaches more than 5.

These stress relief annealed 50～100 DEG C of such temperature, compared with usual higher Precipitation temperature, for significantly Low temperature.This is because, low temperature thermal oxidation one side, the super saturated solid solution degree after solution hardening processes is big, the most ultramicrofine cluster It is stably formed.If this low-temperature anneal temperature too high and more than 100 DEG C, the precipitate low-density dispersion of the thickest Mg-Cu system, Therefore, containing reaching more than 5 with the Cu atom that at least 1 is below 1.0nm among the distance of other adjacent Cu atoms The aggregation of atom, does not reaches 1.0 × 10⁴Individual/μm³Above average density.It addition, crystal grain boundary etc. containing Mg and Cu with The second phase particles generation coarsening of outer alloy addition element, causes the reduction of ductility, formability and corrosion resistance.

It addition, this low-temperature anneal temperature is less than 50 DEG C, or, even if such as the temperature range of appropriate 50～100 DEG C, But if the retention time was less than 24 hours, then the diffusion of atom is insufficient.Therefore, in the case of any one, ultramicrofine cluster Formation amount is the most insufficient, and process annealing is not sufficiently effective.

In order to, after solution hardening processes, not make plate be cooled to room temperature, but carry out this process annealing, plate temperature continuously Stop forced air-cooling or spraying etc. when 50～100 DEG C and force cooling (chilling), or be immersed in the warm water that bath temperature is 50～100 DEG C Groove or oil groove cool down (chilling).And afterwards, in plate or volume are directly promptly moved to stove or carry out covering to keep temperature, Will plate reheat after move to stove in or carry out covering to keep temperature, implement this process annealing the scopes of 50～100 DEG C.

Further, after this solution treatment Quenching Treatment, in order to the shape of plate controls and removes residual stress, it is also possible to enter Row skin-pass, or carry out tension level(l)er threading.Thereafter additional anneal or Ageing Treatment, go out from SS trace generation inhibition Send out and need not, do not carry out.

By such solution treatment/Quenching Treatment and stress relief annealed special combination, it is possible to make the Al-Mg containing Cu The tissue of line aluminium alloy plate becomes the aggregation of the atom that present invention provide that.That is, containing the distance with other adjacent Cu atoms Among the Cu atom that at least 1 is below 1.0nm reach the aggregation of atom of more than 5, it is possible to 1.0 × 10⁴Individual/μm³With On average density contain.Then, hereby it is possible to the limiting strain amount improving the Al-Mg line aluminium alloy plate containing Cu increases effect, Jagged projection on suppression load-deformation curve, the parallel band that suppression thus causes, the generation of suppression elongation strain trace. It addition, also be able to the generation preventing being extended the irregular trace caused among SS trace by surrender.

Hereinafter, enumerate embodiment and further illustrate the present invention, but the present invention is not limited by following embodiment certainly, Can meet and front and back state the scope of objective and also can suitably be changed enforcement, these are all contained in the technical scope of the present invention.

[embodiment]

It follows that explanation embodiments of the invention.Manufacture the Al-Mg system of each composition of the example shown in table 1, comparative example Alloy sheets, quenched with the condition shown in table 2 (continued 1), manufacture after, measure respectively, evaluate this quenched after the tissue of plate, machinery Characteristic.Its result displays that in table 2.Further, the "-" statement of the constituent content in table 1, represent that the content of this element is in inspection Survey below boundary.

Each manufacture method (condition) of hot rolled plate and cold-reduced sheet, each example is all carried out with identical common condition.That is, with 480 DEG C the ingot casting that the 50mm that cast by book mold (book mold) is thick is carried out to the heat treatment that homogenizes of 8 hours, thereafter, with 400 DEG C start hot rolling.Become the hot rolled plate that thickness of slab is 3.5mm.This hot rolled plate is carried out cold rolling until after the thickness of slab of 1.35mm, Carry out 400 DEG C, the intermediate annealing of 10 seconds with niter oven, then carry out cold rolling and become the thick cold-reduced sheet of 1.0mm.

For these cold-reduced sheets, as shown in table 2, each condition is carried out all changes and carry out at solution treatment, quenching Reason and the annealing of continuous low temperature thereafter.This process annealing is to be immersed in bath temperature 50～the oil groove of 100 DEG C after Quenching Treatment In carry out, plate temperature arrives after 50～100 DEG C, does not make plate be cooled to room temperature, but in moving to be maintained at the stove of 50～100 DEG C and protect Hold temperature, implement this process annealing.Further, do not carry out after solution treatment and Quenching Treatment, as the cold rnning applying prestrain The temper rolling of work and room-temperature aging process thereafter, artificial aging process etc..

Cut test film (1mm is thick) plate after these process annealings process, (can neglect there is no room-temperature aging impact Depending on), process annealing process after within (make soleplate after) 24 hours, carry out this test film (plate after quenched) 3DAP measures, and measures respectively, evaluates tissue, the characteristic of machinery.

(tissue that 3DAP is carried out is measured)

By using three-dimensional atom probe field ion microscope and analyzing the measuring method of parsing software (in above-mentioned paragraph Detailed measuring method), measure the average density of the aggregation of the atom that present invention provide that.

(characteristic of machinery)

As the investigation of the mechanical characteristic of described plate, carry out tension test, measure tensile strength elongation percentage respectively.Test Condition is, extracts No. 5 test films (25mm × 50mmGL × thickness of slab) relative to the JISZ2201 that rolling direction is right angle orientation, Carry out tension test.Tension test, based on JISZ2241 (1980) (Tensile Testing Method of Metallic Materials), is entered at room temperature 20 DEG C Row test.At this moment, crosshead speed is that 5mm/ divides, and carries out with fixing speed, until test film fracture.

(characteristic of the plate after the rheological parameters' change with time under room temperature)

It addition, in order to evaluate the rheological parameters' change with time (impact of room-temperature aging hardening) when keeping with room temperature, carry out described quenched After processing (manufacture), above-mentioned each test film is kept 1 month with room temperature, carries out tension test with same condition afterwards, try to achieve The increments (room-temperature aging hardening capacity) of the tensile strength after described modifier treatment (manufacture).

(SS trace is evaluated)

Equally, in order to carry out keeping the SS trace of extrusion molding of plate after 1 month to comment as described room temperature Valency, investigates the surrender elongation percentage (%) during the tension test after described room temperature keeps 1 month, and on described load-deformation curve Jagged serration occur dependent variable (critical strain: %).Incidentally, in the present embodiment, actually (straight Ground connection) cannot confirm as the SS trace (generation of SS trace) of the plate of extrusion molding, but this serration occur critical should Variable is the most relevant to the SS trace during extrusion molding of reality.Therefore, in the present invention, as representing described aluminum The index of the SS trace (formability) of alloy sheets, the serration on the load-deformation curve of the most described aluminium alloy plate is sent out Raw critical strain is more than 8%.The critical strain that this serration occurs is the highest more good, advises the most especially Its upper limit fixed.But, if from the manufacture boundary of described aluminium alloy plate, then the upper limit of this critical strain is about 20% left side Right.

(extrusion molding evaluation)

As the evaluation of the stretch forming becoming problem in outer panels, carry out stretch forming test.Stretch forming is tested, It is making after soleplate after one month, use the spherical stretching convex die of diameter 101.6mm, at long 180mm, wide 110mm On test film, make antirust cleaning oil R-303P as lubricant applying スギ system ラ chemistry (strain), with forming speed 4mm/S, folding Wrinkle loading 200kN, stroke 20mm carry out stretch forming test, the generation state of visual observations crackle.Then, complete during extrusion molding Complete there is not crackle be evaluated as zero, even if some occur crackle be also evaluated as ×.

Such as table 1, example 1～9, it is limited to, containing Cu, without Zn, meet the Al-Mg line aluminium alloy composition rule of the present invention Fixed.It addition, such as table 2, with aforesaid solution treatment/Quenching Treatment and the preferably fabricated condition system of stress relief annealed special combination Make.As a result of which it is, the aggregation of the atom being organized as present invention provide that of the Al-Mg line aluminium alloy plate containing Cu can be become. That is, containing reaching more than 5 former with the Cu atom that at least 1 is below 1.0nm among the distance of other adjacent Cu atoms The aggregation of son, it is possible to 1.0 × 10⁴Individual/μm³Above average density contains.

Thus, the increments (room-temperature aging hardening capacity) of the tensile strength after modifier treatment (manufacture) described in each example Little, excellent at interior extrusion molding containing SS trace characteristic.That is, the jagged projection on the load-deformation curve of aluminium alloy plate The critical strain occurred is more than 8%, high more than 10%, in described stretch forming test, crackle does not the most occur.And, The SS trace characteristic of these excellences can be made, reach what 5000 line aluminium alloy plates of JIS5052 alloy and JIS5182 alloy etc. had The characteristic levels of the excellent machinery of tensile strength and elongation percentage etc., will not make this level reduce and will not generation chamber warm hardening Hardening.

But, although it is allowance, but Zn contains the example 9 reaching 0.6% more, with poor 0.02% Example 5 compare with without another example of Zn, although in allowed band, but room-temperature aging hardening capacity is bigger.

On the other hand, comparative example 10～14 is the alloy composition identical with example 3, and simultaneously such as table 2, quenched condition is respectively Depart from preferred scope.

Comparative example 10 solid solution temperature is too low.

The rate of cooling of the chilling in comparative example 11 Quenching Treatment is too low.

Comparative example 12 low-temperature anneal temperature is too low.

Comparative example 13 low-temperature anneal temperature is too high.

The comparative example 14 stress relief annealed retention time is too short.

As a result of which it is, the aggregation that comparative example 10～14 is containing the Cu atom that present invention provide that only be less than lower limit (1.0 × 10⁴Individual/μm³) average density.Therefore, although characteristic and the example difference of the present invention of the machinery of intensity and elongation percentage etc. are little, but It is that the critical strain that jagged projection on the load-deformation curve of aluminium alloy plate occurs is low, for less than 8%, SS trace characteristic Significantly reduce compared with example.That is, for the described incidental tissue of jagged projection.

Comparative example 15～18 such as table 1,2, although quenched condition is in preferred scope, but alloy composition departs from invention model Enclose.Comparative example 15 is without Cu, and its Cu content of comparative example 16 is very few.Its Mg content of comparative example 17 is too much.Its Zn content of comparative example 18 Too much.

As a result of which it is, the comparative example 15,16 of the effect of Cu can not be played, although with solution treatment/Quenching Treatment and low temperature The optimum condition manufacture of the combination of annealing, but the aggregation without the Cu atom that present invention provide that, or with less than lower limit (1.0 ×10⁴Individual/μm³) average density contain.Therefore, although room-temperature aging hardening is few, but intensity is the lowest, answering of aluminium alloy plate The critical strain that jagged projection on force-strain curve occurs is low, and for less than 8%, SS trace characteristic is aobvious compared with example Write and reduce.That is, for the described incidental tissue of jagged projection.

Comparative example 17, although room-temperature aging hardening is few, but intensity is too high, and elongation percentage is low, cracks during extrusion molding, squeezes Pressing formation is lower than present invention example.

Comparative example 18 is because Zn is too much, so room-temperature aging hardening capacity exceedes allowed band greatly, produces during extrusion molding Crackle, extrusion molding is lower than present invention example.

Be may certify that by above enforcement, each important document of the present invention or preferably manufacturing condition etc., make SS trace characteristic being used for With the meaning that the characteristic etc. of extrusion molding or machinery has both the criticality being had.

[table 1]

[table 2]

Industrial applicability

As described above, in accordance with the invention it is possible to provide the new of the curvature reduction etc. that the age-hardening under room temperature causes Problem will not produce, it is possible to suppress to be extended the generation of the irregular trace caused and sending out of parallel band by described surrender simultaneously Raw, suppress SS trace, make the Al-Mg line aluminium alloy plate improved towards the extrusion molding of car panel.As a result of which it is, towards right In plate extrusion molding a large amount of purposes of described automobile etc. of being used, expand the application of Al-Mg line aluminium alloy plate.

Claims

1. the aluminium alloy plate having excellent formability, it is characterised in that be Al-Mg line aluminium alloy plate, containing Mg in terms of quality %: 3.8～6.0%, Cu:1.0～2.0%, surplus is Al and inevitable impurity, wherein, as by three-dimensional atom probe electric field The aggregation of the atom that ion microscope is measured, with 1.0 × 10⁴Individual/μm³Above average density contains the collection of following atom Zoarium, the aggregation of this atom contain more than 5 with at least 1 distance among the distance of other adjacent Cu atoms be The Cu atom of below 1.0nm.

The aluminium alloy plate having excellent formability the most according to claim 1, wherein, described aluminium alloy plate also contains in terms of quality % Have from below Fe:0.5%, below Si:0.5%, below Mn:0.5%, below Cr:0.1%, below Zr:0.1%, Ti: One or more the element selected in less than 0.05%.

The aluminium alloy plate having excellent formability the most according to claim 1 and 2, wherein, described aluminium alloy plate is in terms of quality % Possibly together with below Zn:1.0%.

The aluminium alloy plate having excellent formability the most according to claim 1 and 2, wherein, as representing described aluminium alloy plate On the load-deformation curve of the described aluminium alloy plate of the index of formability occur serration critical strain be 8% with On.

The aluminium alloy plate having excellent formability the most according to claim 3, wherein, as the shaping representing described aluminium alloy plate Property index described aluminium alloy plate load-deformation curve on occur serration critical strain be more than 8%.