JPH02194153A - Unrecrystalized thin film plain rolled product and preparation thereof - Google Patents

Abstract

PURPOSE: To produce an unrecrystallized thin and flat Al alloy sheet excellent in strength and fracture toughness by subjecting an Al alloy having a specified compsn. to rolling into the shape of a thin sheet, thereafter subjecting it to tilting annealing under specified conditions and furthermore executing solution treatment and aging treatment.

CONSTITUTION: At the time of producing a thin sheet of an Al alloy excellent in strength and fracture toughness as the structural member for aircraft, an ingot of an Al alloy as the stock contg., by weight, 1.0 to 12% Zn, 0.5 to 4.0% Mg, <3.0% Cu, <1.0% Mn, and Si, Fe, Cr, Ti, Zr, Sc and Hf respectively by ≤0.5% is rolled to form into a thin sheet shape. As for this Al alloy thin sheet, heating is started at 177 to 232°C, and it is heated at 390 to 454°C for about 2 to 8hr at a temp. rising rate of 1.1 to 55.6°C/hr and is subjected to tilting annealing. Next, the Al alloy thin sheet is subjected to solution treatment, rapid cooling and aging treatment to produce the Al alloy sheet with a substantially unrecrystallized structure having strength and fracture toughness on high levels.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to heat treatable alloys such as the AΔ2000, 6000 and 7000 series alloys, and more specifically the present invention relates to Or it relates to, for example, improving the strength and fracture toughness of a thin plate by thermal/mechanical treatment.

PRIOR ART AND PROBLEMS SOLVED BY THE INVENTION For many years, alloys in the 7000 series have been used in aerospace applications for their high strength and toughness. These alloys can be age-hardened to extremely high strength values under, for example, the heat treatment condition (1)6. Furthermore, the strength values of these alloys can be increased by increasing the concentration of solute. By increasing the strength of these alloys, designers can reduce the weight of aircraft by reducing the thickness of load-bearing components, such as the upper leg skin. Such parts must not only have high strength but also relatively high fracture toughness (even an absolute requirement).

According to some information, it has been found that plates with an unrecrystallized structure exhibit higher toughness values than plates with a recrystallized structure. Those skilled in the art will appreciate that by maintaining the rolling temperature at a high level, typically at a level of about 399°C (750″F), the aluminum alloy typically forms fine sub-grain boundaries of about 1-2 μm. It is a well-known fact that the dynamically recovered structure is difficult to recrystallize during subsequent solution treatment.
As strength and toughness increases permit the use of thinner plate thicknesses, it becomes impossible to produce such products with unrecrystallized structures using conventional manufacturing and thermo-mechanical techniques. come. This is because the rolling temperature tends to decrease as the plate thickness decreases.

Although the prior art teaches how to obtain a recrystallized grain structure, it does not teach how to obtain an unrecrystallized grain structure. Prior art US Pat. No. 4,092,181 discloses a method for imparting a fine-grained recrystallized structure to an aluminum alloy having precipitated components. This method is provided for imparting a fine grain structure to aluminum alloys with precipitated components. In this case, the alloy is first heated to solid solution temperature in order to dissolve the precipitated components within it. The alloy is then cooled below its solution temperature, preferably by water quenching, to form a precipitate by heating the alloy to a temperature above its precipitation hardening temperature but below its solution treatment temperature. Excessive aging.

Strain energy is introduced into the alloy by plastically deforming it at or below the overaging temperature. The alloy is then held at a recrystallization temperature, the overaged precipitates nucleating new grains, and the growth of these grains results in a fine recrystallized grain structure. Although this structure is useful for imparting superplastic properties, its toughness is inferior to that of an unrecrystallized structure.

SUMMARY OF THE INVENTION In contrast, the present invention provides flat rolled products, particularly thin plates and 7000 series aluminum alloy sheets, which provide the same with improved combined strength and fracture toughness. An improved thermal or thermo-mechanical processing technique is provided that allows the production of plates with substantially unrecrystallized textures imparted thereto.

In accordance with the present invention, there is provided an unrecrystallized thin-walled flat rolled product suitable for manufacturing into aircraft structural components, which product is comprised of an aluminum-based alloy selected from the 2000.6000 or 7000 series alloys. ing. 7000
For series series, this alloy basically contains 1.0-12 wt% ZN, 0.5-4.0 wt% MQ, maximum 3.0
Weight % Cu, maximum 1.0 weight % Mn1 each up to 0
, up to 5fwt% Si, Fe1Cr1Ti, Zr.

It can consist of Sc and Hf with residual aluminum and impurities.

Also provided is a method for producing an unrecrystallized, thin-walled, flat-rolled product, which method comprises hot working the alloy body into a thin-walled, flat-rolled product, which is then annealed. including exposure to a gradient anneal where the temperature is increased with the anneal time. This step is followed by solution treatment, quenching and aging to provide a substantially unrecrystallized product with improved levels of strength and fracture toughness.

There is also provided a method of manufacturing thin-walled flat rolled products of unrecrystallized aluminum-based alloys that includes the step of hot working the aluminum alloy bodies into final thickness flat rolled products. This thermal 1m processing step is followed by isothermal soaking, gradient annealing, solution annealing, quenching and aging to substantially improve the product with improved levels of strength and fracture toughness. Unrecrystallized product is provided.

Also, non-recrystallized AJ! includes a step of hot working the alloy body into a first product! - A method of manufacturing a Zn-Mq acid component thin flat rolled product is provided.

The first product is then reheated, cooled, heat treated and then rolled into a thin flat rolled product, such as a thin plank or sheet. The product is then solution treated, quenched, and aged to provide a substantially unrecrystallized product with improved levels of strength and fracture toughness.

EXAMPLES Aluminum-based alloys responsive to thermo-mechanical treatment in accordance with the present invention include the Aluminum Association (AA) No. 7000 series. Such an alloy is for example 7050
, 7150.7075.7475.7049 and 703
Contains 9.

Typically, these aluminum-based alloys are 1,0 to 1
2.0wt% Zn, 0.5-4.0wt% MO, up to 3.0wt% Cu1, up to 1.0wt% Mn, each up to 0.5wt% 3i.

Fe5Or, Ti, Zr, Sc and l-(f and residual aluminum, including incidental elements and impurities. These alloys are of the Al-Zn-11vll or AJ-Zn-Cu-MO type. can be called.

Alloys that are likely to respond readily to the thermo-mechanical treatment of the present invention contain higher levels of zinc, preferably 7.0-12.0% by weight Zn1, typically 8.0-1
Contains 1.0% by weight of 7n. When zinc is at these levels, magnesium content is between 0.2 and 3.5
, preferably in the range of 0.4 to 3.0% by weight. Also, copper at higher levels of zinc content is between 0.5 and 3.0% by weight, preferably between 1.0 and 3% by weight.
．． It can vary within the range of 0% heavy chain. Although the content of these alloying elements can be increased in some cases, the fracture toughness of the resulting alloy is reduced. In some cases, other ranges of alloying elements may be preferred. For example, ln is 7.0~9゜0% by weight, Mg is 1.5~
2.511%, cu is 1.9-2.7 flft%, z
A composition is possible in which r is 0.08-0.14% by weight and impurities such as Fe and Sl are less than 0.3Ti%. The Aluminum Association composition limits for 7050 and 7150 are 567 to 6.9 wt% Zn, 1.9 to
2.7 wt% MQ, 1.9-2.6 wt% Cu, 0
．． 05-0.15% by weight Zr, maximum 0.12% by weight
of Si, up to 0.15 wt% Fe, up to 0.10 wt% a
%Mn1 max 0.06wt% Ti max 0.04k
m% Cr1 residual aluminum and incidental elements and impurities.

Although the AA7000 series aluminum alloys have been described in detail, the present invention applies not only to other heat treatable alloys such as the AA2000 and 6000 series, but also to lithium-containing AA8 alloys such as 8090 and 8091.
It can also be applied to 000 alloy. Thus, typical applicable AA2000 series alloys include AA202
4.2124.2324.2219.2519.201
4.2618.2034.2090 and 2091, and AA6000 series platforms include 6061 and 60.
13 are included. Articles formed from these alloys have an oxygen content of less than 0.1% heavy chain. In history, for example, there are two types of products, such as flat-rolled products. The product has virtually no as-cast structure.

In addition to providing the alloy product with controlled spear alloying elements as described above, it is preferred that the alloy be made according to a specific process to provide the most desirable properties with respect to both strength and fracture toughness. Thus, the alloys described herein may be provided as ingots or billets and fabricated into suitable fabricated products by casting techniques currently employed for M-manufactured products, preferably continuous casting techniques. The ingot or billet can be pre-processed or shaped to provide a suitable shape for subsequent processing operations. Prior to the main processing operation, the alloy shape is preferably subjected to a homogenization step, preferably at an IfI of at least 1 hour at 472-566'C (850-1050°F).
) to dissolve soluble elements and homogenize the internal structure of the metal. A preferred time interval is about 20 hours or more in the homogenization humidity range.

Typically, the heating and homogenization treatment does not need to be carried out for more than 40 hours. However, longer periods of treatment are usually harmless.

It has been found that a treatment time of 20 to 40 hours at the homogenization temperature is reasonable.

In one aspect of the invention for producing an unrecrystallized flat rolled product, the ingot can be rolled into a final plate thickness product. The product is then subjected to an annealing process, referred to herein as gradient annealing, which increases the temperature by three degrees with increasing annealing time. Regarding annealing techniques, the starting temperature can be as high as 399°C (750°F) and ramped up to higher temperatures, such as 454°C (850°F), with annealing time. For high starting temperatures, a typical starting temperature is 388°C (730°F), and the temperature can then be increased over time to about 427°C (800T). When lower ramped annealing temperatures are used, the starting temperature typically does not exceed 288°C (550°), and more usually does not exceed 204°C (400°F).

Thus, typical starting temperatures are 177-232°C (350-232°C).
450°F) with an end temperature of 343-454°C (6
50-850°F). Typical finishing temperatures are 399-454°C (750-85°C) depending on alloy composition.
0°F). For inclined annealing, the temperature is 1.1 to 55.6°C/hour (2 to 100°F/hour), preferably 2.8 to 44.4°C/hour (5 to 80°F/hour).
The temperature can be increased at a rate of The time from start to finish of the ramp annealing can be from 3 to about 10 hours, with typical times ranging from 2 to 8 hours. A gradient annealing process can include a series of temperature increases with a temperature plateau (or series of plateaus). Additionally, the gradient annealing may include a continued increase in temperature followed by a decrease in temperature until a final terminal temperature is achieved. There may also be a holding plateau at one or more temperature levels. In some cases, as the annealing temperature increases, a separate solution treatment may not be necessary and this treatment may instead be included as part of the gradient annealing, as shown in Figures 1 and 2. be. Alternatively, the product may be cooled and subjected to separate solution treatment, quenching and aging treatments.

In a second aspect of the invention for producing an unrecrystallized product, said ingot is directly hot rolled into plates or sheets of final wall thickness before being subjected to isothermal soaking, and then tilted in accordance with the invention. You can do t@. Thus, in order to provide a sheet or board product, in particular a thin board product, according to the invention, the product is subjected to a warm temperature soaking treatment. Thus, the isothermal soak can be carried out at temperatures as low as 121°C (250°F), but is typically 152.8"
At temperatures above 275"F, typically 148
．． It is carried out at a temperature in the range of 9°C (300°F) to 260°C (500°F). The soaking step can be completed in a few hours, e.g. 3 hours, if the temperature is particularly high; Typically, the soaking time ranges from 4 to 20 hours.The flat-rolled product is then subjected to a ramp annealing in which the temperature is increased by one temperature with increasing annealing time. is carefully controlled until a higher end temperature is reached. Preferably, such end temperature is 343° C. (650° F.) or 37° C.
Within the range of 1°C (700°F) to 482°C (900°F). The starting temperature is around 37.8°C (100°F) (
or room temperature) to sometimes 399°C (750°F)
It is possible to maintain the temperature up to Typically, the onset temperature will be in the range of 250-730°F (121-388°C), with a preferred onset temperature of 300°F (149-260°F) or less, but usually 300-260°F (149-260°F). 500
°F). The temperature from the start temperature to the end temperature is controlled at a controlled rate, for example 1.1~b (2~12
5″F/hr), preferably 2.8-44.4°C/
(5-80°F/hour). The gradient annealing process can include a constant temperature section or a series of increasing temperature sections with a holding time at a series of constant temperature sections. Additionally, the gradient annealing may include a cycle portion in which the temperature is increased and then decreased until a final termination temperature is reached. There may also be a holding plateau at one or more temperature levels.

In some cases, as the annealing temperature increases, a separate solution treatment may not be necessary, and it may instead be included as part of a gradient anneal, as shown in Figure 3, or the product may be cooled and a separate solution treatment performed. Treatment, quenching operations, and aging operations can also be carried out. The time from start to end temperature of the ramp annealing can vary from as short as 2 hours or less to as long as 20 hours or more. It has been found that times in the range of 3 to 10 hours are highly preferred, with 4 to aim being useful.

The use of isothermal soaking and ramp annealing as described herein has been found to be extremely advantageous because the process is independent of the type of technique used to process the ingot.

In some alloys, to obtain unrecrystallized products,
It may be desirable to combine these processes. That is, inclined annealing can be used in addition to precipitation heat treatment in intermediate processing steps, and such combinations are within the scope of the present invention.

It is thus possible to produce unrecrystallized thin plate or sheet products according to the third aspect of the invention.

The term unrecrystallized means that there are no fully developed grains, and a highly worked structure containing recovered sub-grain boundaries and retaining the as-worked crystallographic structure is present. There is. This means that at least 60% of the plates or sheets do not have well-developed grains and retain the as-processed structure. In this process, the thermomechanical steps should be carefully controlled. Thus, when the ingot is hot-rolled (at a temperature in the range of 260-482°C) into slab dimensions after soaking, depending on the slab sheet composition) 3
Temperatures within the range of 43-482°C (650-900°F), preferably 343°C (650°F) or 371°C (7
00°F) to 427°C (800°F) to melt or partially melt particles that were precipitated during the previous thermal-mechanical operation. Reheating can be carried out at a temperature for a short period of time, such as 1/4 or 1/2 hour, but can also be extended to 4 hours or more. However, long periods of time are usually not required.

The slab is then subjected to cold fIO at a rate that keeps the dissolved elements in solution. Preferably, the slab is cold water quenched or rapidly cooled. The slab is then subjected to a precipitation heat treatment at high temperatures for controlled particle precipitation. Precipitation heat treatment is performed at 93.3-288℃ (
200-550°F), preferably 177-260°C (
350-500°F), typically 204-260°C (
It can be carried out at temperatures within the range of 400-500°F. The precipitation heat treatment time at this temperature can be from 5 to 20 hours or more, with 9 to 15 hours being very suitable. After precipitation heat treatment, the slab is processed or rolled into thin plates or sheets. A meat plate is at least 3.2 am (0.125 in.), typically 6.2 am (0.125 in.) thick.
This refers to a board with a thickness of 4a (0.25 inches) or more. The thickness is 12.7am (0,
5 inches) or more, e.g. 19,1 m
(0.75 inches) or 25.4am (1.0 inches)
Or it can extend up to 31.8 rin (1.25 inches).

Although the slab can be cold rolled in these thicknesses, it is preferred that the slab be rolled using warm rolling techniques to the final thickness product, such as a thin plate or sheet. Thus, warm rolling is carried out at 288°C (550°
). Furthermore, preferably,
The temperature at which warm rolling begins should not fall below 93°C (200°F). Typically, the warm rolling may begin at a precipitation heat treatment temperature. Preferably, the warm rolling temperature should not exceed the precipitation heat treatment temperature.

Such temperatures range from approximately 177°C (350°F) to 260°C
℃ (500″F). This warm rolling technique requires significantly higher rolling temperatures, typically around 399°C.
This is in contrast to the prior art which teaches that the angle should be greater than or equal to (750°).

Optionally, said plate or sheet product is subjected to a solution treatment and then subjected to a cooling action by cold water quenching.

The solution treatment is preferably carried out at 427-566°C (800°C
-1050°F) to produce an unrecrystallized grain structure. - In membranes, relatively short processing times at the relevant temperatures are sufficient, for example 5 minutes or less, for sheet thicknesses. 12.7as+(0,
For thin plates (5 inches), the processing time at the temperature can be from 1/4 to 5 hours, typically 2 hours.

To further provide the desired strength and fracture toughness needed for the final product and the process to form the product, the product should be rapidly quenched to prevent uncontrolled precipitation of reinforcing phases. Thus, when practicing the present invention, the quench rate is at least 111°C/second (200°F) from the solution temperature to a temperature of about 93°C (200°F) or less.
°F/sec). The preferred quench rate is from 482°C (900°) or higher to 93°C (20°
at least 111°C/second (200°F/second) over a temperature range of up to 0°F (0°F) or below. Approximately 93 metals
Once a temperature of 200° F. is reached, the metal can then be air cooled.

Once the alloy product of the present invention has been quenched, the copper product is subjected to an aging operation to achieve the fracture toughness and strength properties so highly desired for aircraft components. Artificial aging involves heating sheets or plates or molded products at 66-204℃ (
This can be achieved by further increasing the yield point by exposure to temperatures in the range of 150 to 400 degrees Fahrenheit.

By artificially aging some of the components of this alloy product, yield strengths as high as 7001" (100 ksi) can be obtained. However, useful strength values range from 49 to 63 phantom f/2 (70 ksi). ~90 ksi) and the corresponding fracture toughness values are within 1 inch (25,
4m) 9r/m2 (20-50
kis). Preferably, artificial aging is accomplished by treating the alloy article at a temperature within the range of 135-191°C (275-375°F) for a period of at least 30 minutes. Appropriate aging conditions include approximately 163°C (325°
F) for about 8 to 24 hours.

Additionally, the alloy products of the present invention can be subjected to any of the typical overaging or underaging treatments known in the art, including natural aging. However, it is currently believed that natural aging has little advantage.

Also, although only a single aging stage has been described here, multiple aging stages are contemplated, such as two or three aging stages, and stretching or equivalent processing may be performed prior to or prior to part of such multiple aging stages. It can be used even afterwards.

Although the present invention has been described in terms of sheets and plates, the application of the present invention is not necessarily limited thereto. That is, the process can be applied to extrusions and forgings that have the alloying components mentioned herein or that have components that are responsive to these treatments.

Unlike rolling, in extrusion it is not critical to hold the ingot at am, but doing so is uneconomical due to the low extrusion speed. The extrudate therefore has a recrystallized structure in terms of curvature. To provide an unrecrystallized extrudate according to the present invention, the process will include two or more extrusion stages. That is,
Once an ingot temperature of about 700 to 800 degrees Fahrenheit is obtained, the ingot is extruded into intermediate cross-section specimens having, for example, a 75% reduction in area. Thereafter, the partially extruded material is subjected to reheating, for example under the same conditions as previously described for the slab. The same material may also be subjected to elevated temperature precipitation treatments, such as those previously described for slabs. Thereafter, the partially extruded article is
For example, it is further processed or extruded into a product shape under the same conditions as described above for the slab rolled into the final Negishi product. Thereafter, the extrudate can be solution treated, rapidly cooled, and aged to produce an unrecrystallized aluminum alloy extrudate. Since the process of forming forgings is often repeated, a forging operation can be carried out including the procedure described above for the flat rolled product, thereby producing an unrecrystallized aluminum alloy forged product. I can do it. Unrecrystallized products can be produced by combining rolling, extrusion or forging steps.

The technique of inclined annealing is suitable for many applications. That is, the technique can be successfully used independent of previous thermo-mechanical techniques. For example, the same technique has been used for thin plate, where the slab is reheated, quenched, heat treated, and warm rolled into the previously described plate products to produce a completely unrecrystallized product. (See Example 3).

Basically, in weight%, Zn is 10, MO is 1.8, 1,
An aluminum alloy consisting of Cu of 5, zr of 0.12 and the balance essentially aluminum and impurities was cast into an ingot suitable for rolling. The ingot was homogenized and hot rolled at about 427° C. (800° F.) into a 38.1 mm (1.5 inch) thick slab. The slab was cut into several pieces and was heated to 399-471℃ (750-880℃).
390°C (750°F) and then approximately 390°C (750°F).
) from a starting temperature of 7.6 mm + (0.3 inch) thick plate. 388°C (730°F) for the sample
A ramp annealing was performed starting at 427°C (800°F) and ending at 800°F. The heating rate here is approximately 5.6°C/hour (10°
After annealing, these samples, along with the unannealed samples, were heated to 471°C (880°F) and subjected to solution treatment at this temperature for 1 hour, and then the samples shown in FIG. The microstructures showed that the degree of recrystallization of the tilt-annealed samples was significantly reduced compared to the microstructures of samples that were not annealed in this way.

Example 2 7,6M (with the composition of Example 1 and prepared as in Example 1)
A sample of 0.3 in.) was subjected to a gradient annealing starting at 204°C (400T) and ending at 427°C (800°F) with a temperature increase of 4 hours (see Figure 2). . These samples were solution treated in the same manner as in Example 1. The microscopic structure basically showed an unrecrystallized grain structure.

Example 3 This sample (7.6 mm) had the same composition and processing as Example 2, except that it was heated at 390°C (750°F) for approximately 0.5 hours prior to hot rolling into a 7.6m thick plate. ), water quenched and subjected to a 12 hour precipitation heat treatment at 204°C (400°F), followed by hot rolling at a temperature of 204°C (400°F), with a thickness of 7.6°. The microscopic structure of this sample showed that it was a completely unrecrystallized grain structure.

9-A Basically, in weight percent, 10 Zn, 1.8 Mg, 1.
An aluminum alloy consisting essentially of aluminum and impurities with 5 parts Cu and 0.12 parts Zr1 balance was cast into an ingot suitable for rolling. The ingot was homogenized and rolled into 38.1 mm shore slabs. The slab was cut into several pieces, and the pieces were made at 399-471°C (
Annealed at a temperature of 750-880°F) and
, 3 inches) into sheets. After that, the above 7
．． The six-metal plate was thermostatically soaked at 204°C (400°F) for 16 hours, then started at 204°C (400°F), and heated at 42°C (400°F).
It was subjected to a ramp annealing that terminated at 7°C (800°F). The heating process in this case was accomplished over 4 hours. 7 above.
The 6 m plate was then solution treated at 471° C. (880° F.) for 1 hour and then quenched with cold water. Microscopic examination of the structure revealed that it was an unrecrystallized structure. This indicates that constant temperature soaking and inclined annealing are effective in preventing recrystallization.

Example 5 Nominal weight percent 10 Zn, 1.8 Mg, 1.5 C
An aluminum alloy consisting of U and 0.12 Zr, the remainder essentially aluminum and impurities was cast into an ingot suitable for rolling.

The ingot is homogenized and then heated to approximately 427°C (800°F).
) into 38.1 mm (1.5 inch) thick slabs. The slab was then heated to 390°C (750″
F) for 30 minutes and quenched with cold water. The slab was then subjected to a precipitation heat treatment at 204°C (400°F) for 12 hours. The slab was then heated to approximately 204°C and 7.6am (
0.3 inch) thick plate and then heated to 471 °C (8
Solution treated for 1 hour at 80″F) and quenched with cold water.

As a result of the examination, it was found that the microscopic structure was essentially an unrecrystallized structure. For comparison, 39 cases without statute of limitations
An identical sample hot rolled into 7.6 ms+ plate immediately after annealing at 0°C (750°F) showed a high degree of recrystallization. Thus, the thermal/mechanical treatment according to the present invention is Aj!
It will be appreciated that unrecrystallized thin plate or sheet products can be made of aluminum alloys of the -Zn-MO or Al-Zn-fvl-Cu types.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing inclined annealing according to the present invention, FIG. 2 is a diagram showing inclined annealing according to the present invention, and FIG. FIG. 4 is a schematic diagram illustrating the steps in a process for manufacturing thin-walled unrecrystallized plates in accordance with the present invention.

Claims (1)

[Scope of Claims] (1) A method for producing an unrecrystallized aluminum-based thin-wall flat-rolled heat-treated product with improved levels of strength and fracture toughness, comprising: (a) a heat-treatable aluminum-based thin-walled flat-rolled heat-treated product; (b) processing the alloy body into a fabricated product; (c) providing an alloy body;
(d) solution annealing, quenching and aging said final wall thickness flat rolled product to provide substantially improved levels of strength and fracture toughness; and providing an unrecrystallized product. (2) The method of claim 1, wherein the annealing temperature is one of the following: (1) the annealing begins at a temperature not exceeding 390°C (750°F); (3) annealing begins at a temperature not exceeding 204°C (400°F);
(4) annealing terminated at a temperature within the range of 177-232°C (350-450°F);
3 within a period of approximately 2 to 8 hours.
increased to a temperature within the range of 90-454°C (750-850°F) and/or in annealing at a temperature of 1.1°C/hour (2°F/hour) to 55.6°C. °C/hour (
100°F/hour). 3. The method according to claim 1, wherein the product is subjected to isothermal soaking prior to exposing the product to the gradient annealing. (4) In the method according to claim 1, the processing includes: (1) thermally processing the alloy body into a first wrought product; and (2) reheating the first wrought product. (3)
(4) heat treating the first wrought product; and (5) further processing the first wrought product to produce a second wrought product. A method characterized by: (5) A method of making an unrecrystallized aluminum-based wrought alloy product with improved levels of strength and fracture toughness, the method comprising: (a) providing a heat treatable aluminum-based alloy body; (b) processing the alloy body into a wrought product; and (c)
) subjecting said product to constant temperature soaking; (d) then subjecting said product to gradient annealing in which the annealing temperature is increased during annealing; and (e) solution treating, quenching, and aging said product. and providing a substantially unrecrystallized wrought product having improved strength and fracture toughness levels. (6) In the method according to claim 5, the gradient annealing temperature is (1) a final temperature of 343 to 482°C (650 to 900°C).
(2) the starting temperature is 149°C (300°F) or less;
The terminal temperature is 371-482°C (700-900°F) and/or the temperature is 1.1-69.4°C/hour (2-69.4°C/hour)
125°F/hour), preferably 2.8 to 44.4°C/hour (5 to 80°F/hour). (7) The method of claim 5, wherein the isothermal soak is at a temperature within the range of 149-260°C (300-500°F) and/or the duration of the soak is (149-260°C). ) at least 3 hours; (2) at least 4 hours; (3) within the range of 4 to 24 hours. (8) with improved levels of strength and fracture toughness;
A method of making a heat-treatable, unrecrystallized wrought aluminum-based product, the method comprising the steps of: (a) providing a heat-treatable aluminum-based alloy body; and (b) heat-treating the alloy body into a first wrought product. (c) reheating the first forged product; (d)
(e) heat treating the first wrought product; and (f) further processing the first wrought product to produce a second wrought product. (g) solution treating, quenching, and aging said second wrought product to provide a substantially unrecrystallized product with improved levels of strength and fracture toughness. The way you are. (9) In the method according to claim 8, the reheating temperature is any of the following temperatures, i.e. (1) 260 to
(2) a temperature of 650-800°F (343-427°C); (3) a temperature of 700-800°F (371-427°C); and/or or a method characterized in that said reheating is carried out for at least 1/4 hour, preferably for 1/4 to 4 hours. (10) The method of claim 8, wherein the heat treatment of the first wrought product comprises: (1) 93-288°C (200-550°F);
177-260°C (350-500°F), (3) 20
A process characterized in that it is carried out at a temperature between 4 and 260C (400 and 500F) and/or that the duration of the heat treatment is between 5 and 20 hours, preferably between 9 and 15 hours. (11) The method according to any one of claims 1 to 10, wherein the alloy contains 1.0 to 12% by weight.
Zn, 0.5-4.0 wt% Mg, up to 3.0 wt% Cu, up to 1.0 wt% Mn, up to 0.5 wt% each of Si, Fe, Cr, Ti, Zr , Sc and Hf residual aluminum and impurities. (12) The method according to any one of claims 1 to 10, wherein the alloy contains 7.0 to 9.0% by weight of Zn, 1.5 to 2.5% by weight of Mg, 1.9-2.
7% by weight Cu, 0.08-0.14% by weight Zn, up to 0.5% by weight each of Si, Fe, Cr, Ti, Zr, S
c and Hf, residual aluminum and impurities. (13) An unrecrystallized thin-wall flat-rolled product suitable for fabrication into aircraft structural components, which product basically consists of 7.
0-9.0 wt% Zn, 1.5-2.5 wt% Mg
, 1.9-2.7 wt.% Cu, 0.08-0.14 wt.% Zr, max. 0.12 wt.% Si, max. 0.15
wt% Fe, max. 0.10 wt.% Mn, max. 0.0
The product has an aluminum base alloy consisting of 6 wt.% Ti, up to 0.04 wt.% Cr, the remainder aluminum and incidental elements and impurities;
．． Products with a thickness within the range of 1 mm (0.1 to 0.75 inches). (14) An unrecrystallized thin-walled flat-rolled product suitable for manufacturing into aircraft structural parts, which basically has a 5.7
~6.9% by weight Zn, 1.9-2.7% by weight Mg,
1.9-2.6 wt% Cu, 0.05-0.15 wt% Zr, max 0.12 wt% Si, max 0.15 wt% Fe, max 0.10 wt% Mn , maximum 0.06
% Ti, up to 0.04% Cr, the remainder aluminum and incidental elements and impurities, the product having a weight ratio of 2.5 to 19.
Products with a thickness within the range of 1 mm (0.1 to 0.75 inches). (15) An unrecrystallized thin-walled flat-rolled product suitable for manufacturing into aircraft structural parts, which basically has a 5.7
~6.9% by weight Zn, 1.9-2.7% by weight Mg,
1.9-2.6 wt% Cu, 0.05-0.15 wt% Zr, max 0.12 wt% Si, max 0.15 wt% Fe, max 0.10 wt% Mn , maximum 0.06
having an aluminum-based alloy consisting of wt% Ti, up to 0.04 wt% Cr, balance aluminum and incidental elements and impurities, said product is substantially free of cast structure and has a 6.4-12. 7mm (0.25-0.5 inch)
Products with a thickness within the range of . (16) An unrecrystallized thin-walled flat-rolled product suitable for manufacturing into aircraft structural parts, which is basically 1.0
~12 wt% Zn, 0.5-4.0 wt% Mg, up to 3.0 wt% Cu
, up to 1.0 wt% Mn, each up to 0.5 wt% Si
, Fe, Cr, Ti, Zr, Sc and Hf, less than 0.1% by weight O_2, the remainder aluminum and incidental elements and impurities, said product having a substantially cast structure. 6.4-12.
Products with a thickness within the range of 7 mm (0.25 to 0.5 inches). (17) An unrecrystallized thin-walled flat-rolled product suitable for manufacturing into aircraft parts, which is basically 7.0 to 9
．． 0 wt% Zn, 1.5-2.5 wt% Mg, 1.
9-2.7 wt.% Cu, 0.08-0.14 wt.% Zr, max. 0.12 wt.% Si, max. 0.15 wt.%
of Fe, up to 0.10% by weight Mn, up to 0.06% by weight Ti, up to 0.04% by weight Cr, the remainder aluminum and incidental elements and impurities; The product has virtually no cast structure,
Products having a thickness within the range of 0.25 to 0.5 inches (6.4 to 12.7 mm).