CN101509091A - High-strength high-ductility Al-Zn-Mg-Cu-Sr alloy and production method - Google Patents

Abstract

An Al-Zn-Mg-Cu-Sr alloy with high strength and high toughness comprises the following components (weight percentage): Zn, Mg, Cu, Zr, Ti, Sr and Al being the balance. The preparation method comprises the following steps: mixing the components according to the weight percentage of each component; then heating the mixture up to 820-850 DEG C, refining the mixture with C2Cl6 after fully fusing, cooling and standing, pouring the mixture into a preheated mould; heating and rolling cast ingot after homogenization treatment, the rolling deformation being more than 80%; and then heating the rolled parts up to 450-500 DEG C and carrying out solid solution and water quenching; finally, carrying out artificial aging at 100-150 DEG C. The alloy is reasonable in component mixture ratio, easy in processing and manufacturing and simple in operating process, adopts Sr element alloying, effectively improves the aluminum alloy structure and the comprehensive mechanical property of the aluminum alloy, suits industrial application and provides a practical and feasible way for the improvement of the comprehensive mechanical property of Al-Zn-Mg-Cu high-strength aluminum alloy.

Description

A kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy and preparation method

Technical field

The invention discloses a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy and preparation method, belong to high performance structures material field.

Background technology

The Al-Zn-Mg-Cu series high-strength aluminum alloy is a kind of heat treatment reinforcement type alloy, because its age hardening ability preferably and higher intensity, is widely used in transportation and communication, military equipment, even on the spacecraft such as aircraft.What belong to this class alloy has 7005, its main chemical compositions is: 4.0%～5.0%Zn, 1.0%-1.8%Mg, 0.1%Cu, 0.20%～0.7%Mn, 0.05%Cr, 0.05%Ti, 0.08%～0.20%Zr, all the other are aluminium, its tensile strength is that 345MPa, yield strength are that 300MPa, elongation are 10%; The U.S. is used for 7039 aluminium alloys of armour material, its main chemical compositions is: 3.5%～4.50%Zn, 2.3%-3.3%Mg, 0.1%Cu, 0.10%～0.40%Mn, 0.15%～0.25%Cr, 0.10%Ti, all the other are aluminium, and its T64 attitude tensile strength, yield strength and elongation are respectively 450MPa, 380MPa and 13%; The main chemical compositions of 7050 aluminium alloys that intensity is higher is: 5.7%～6.7%Zn, 1.9%～2.6%Mg, 2.0%～2.6%%Cu, 0.10%Mn, 0.04%Cr, 0.08%～0.20%Zr, 0.06%Ti, the minimum mechanical property of its T73 attitude forging is tensile strength 490MPa, yield strength 470MPa, elongation 9%.Because of the intensity of 7005 and 7039 aluminium alloys is lower, though and 7050 intensity height, its sheet material prepares more complicated, is necessary further to improve the mechanical property that this is an alloy for this reason and simplifies its plate forming technology, makes its sheet alloy have higher mechanical property.At present still do not utilize the strontium element alloying process to improve the bibliographical information of the mechanical property of Al-Zn-Mg-Cu series high-strength aluminum alloy sheet material.

Summary of the invention:

The objective of the invention is to overcome the deficiencies in the prior art and a kind of reasonable mixture ratio of components is provided, processing and manufacturing is easy, operating procedure is simple, utilize Sr element alloyedly to improve aluminum alloy organization's structure, improve high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy of aluminium alloy comprehensive mechanical performance and preparation method thereof.

A kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy of the present invention (weight percent) composed of the following components:

Zn：5.0～8.0％

Mg：1.5～3.0％

Cu：1.5～2.5％

Zr：0.05～0.08％

Ti：0.04～0.08％

Sr：0.02～0.2％

Surplus is Al.

The preparation method of a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy of the present invention is:

A, by the weight percent of each component batching;

B, the raw material that step a is prepared are heated to 820 ℃～850 ℃, and fusing is cooled to 750 ℃～800 ℃ fully, leaves standstill 5～10min, uses C ₂Cl ₆Carry out refining, after melt leaves standstill, skims, be cast in the mould that is preheated to 200 ℃～250 ℃ in 730 ℃～750 ℃;

C, step b gained ingot casting is handled 15h～20h, air cooling in 450 ℃～500 ℃ homogenizing;

D, with step c products therefrom be heated to 400 ℃～450 ℃ rolling, rolling reduction is greater than 80%;

E, steps d gained rolled parts is heated to 450 ℃～500 ℃ solid solution 1h～3h, the shrend of coming out of the stove;

F, step e products therefrom is heated to 100 ℃～150 ℃, artificial aging 15h～30h.

Among the preparation method of a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy of the present invention, described mould is iron mould.

Compared with prior art, the invention has the advantages that:

The present invention adds strontium element in existing aluminium zinc-magnesium copper zirconium titanium alloy, do not change the optimizing components design of established alloy, but the strontium that utilizes and the electronegativity and the atomic radius difference of aluminium atom can make alloy form a kind of Al that contains rare earth Sr in the process of solidifying _xThe Sr particle, this particle can play the effect that the refinement alloy casting state is organized crystal grain, makes original as-cast structure grain refining.The cast alloy that obtains refinement is by further thermal processing distortion, particularly in the solid solution process, and Al _xBut Sr particle pinning crystal boundary suppresses recrystal grain and grows up, thereby obtains the grain structure of refinement, after artificial aging is handled, to obtain better tissues and performance.The present invention can effectively improve the overall tensile strength of alloy, yield strength and elongation, wherein: tensile strength of alloys can improve that 25MPa, yield strength can improve 20MPa, elongation can improve 5.0%, and the performance that makes alloy surpasses the same alloy constituent content but do not contain the alloy of Sr.In sum, reasonable mixture ratio of components of the present invention, processing and manufacturing is easy, operating procedure is simple, utilize Sr element alloyed, effectively improve aluminum alloy organization's structure, improve the aluminium alloy comprehensive mechanical performance, be suitable for industrial applications, for the improvement of Al-Zn-Mg-Cu series high-strength aluminum alloy comprehensive mechanical performance provides a kind of practicable approach.

Description of drawings

(a) be not for containing the Al-Zn-Mg-Cu series high-strength aluminum alloy as-cast structure metallograph of strontium element in the accompanying drawing 1.

(b) is for containing the Al-Zn-Mg-Cu series high-strength aluminum alloy as-cast structure metallograph of strontium element in the accompanying drawing 1.

(a) organizes metallograph for the Al-Zn-Mg-Cu series high-strength aluminum alloy solid solution attitude that does not contain strontium element in the accompanying drawing 2.

(b) organizes metallograph for the Al-Zn-Mg-Cu series high-strength aluminum alloy solid solution attitude that contains strontium element in the accompanying drawing 1.

Comparative drawings figs 1,2 as can be known, the crystal grain that contains the alloy casting state of strontium and solid solution attitude is obviously thinner than the crystal grain of the alloy that does not contain strontium.

Embodiment:

The specific embodiment of the present invention describes in detail below in conjunction with embodiment:

The present invention has provided four kinds of concrete alloys (composition is wt%) as embodiment, wherein:

Alloy 1: composition is: 6.5%Zn-2.4%Mg-2.0%Cu-0.06%Zr-0.07%Ti; Do not contain strontium element;

Alloy 2: composition is: 6.5%Zn-2.4%Mg-2.0%Cu-0.06%Zr-0.07%Ti-0.02%Sr;

Alloy 3: composition is: 6.5%Zn-2.4%Mg-2.0%Cu-0.06%Zr-0.07%Ti-0.06%Sr;

Alloy 4: composition is: 6.5%Zn-2.4%Mg-2.0%Cu-0.06%Zr-0.07%Ti-0.2%Sr;

The present invention is placed on respectively and is heated to 850 ℃ of meltings in the Medium frequency induction resistance furnace by above-mentioned four kinds of alloying constituent proportionings, then, is cooled to 780 ℃ and leaves standstill 5～10min, uses C ₂Cl ₆Refining, melt are left standstill the back in 740 ℃ of swages that are cast in 200 ℃ of preheatings, and ingot casting is handled through 470 ℃ of 7/18h homogenizing, 420 ℃ rolling after being incubated 2h, rolling reduction is 85%, hot-rolled sheet is in 470 ℃ of solid solution 1.5h shrend, 120 ℃ of artificial aging 24h; Under the normal temperature, the tensile mechanical properties that detects four kinds of alloys of gained sees Table 1.

As known from Table 1: alloy contains the mechanical property of alloy of strontium apparently higher than the alloy that does not contain strontium after melting and casting, homogenizing, machining, hot rolling, solid solution, ageing treatment, and strength of alloy, yield strength and elongation that its alloy that adds 0.06%Sr does not add Sr improve respectively: 25MPa, 20MPa and 5.0%.

Table 1

Claims (5)

1, a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy, (weight percent) composed of the following components:

Zn：5.0～8.0％；

Mg：1.5～3.0％；

Cu：1.5～2.5％；

Zr：0.05～0.08％；

Ti：0.04～0.08％；

Sr：0.02～0.2％；

Surplus is Al.

2, a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy according to claim 1 is characterized in that: described Sr content is: 0.06～0.16%.

3, a kind of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy according to claim 1 is characterized in that: described Sr content is: 0.1%.

4, a kind of manufacturing method of high-strength high-ductility Al-Zn-Mg-Cu-Sr alloy according to claim 1 comprises following step:

A, by the weight percent of each component batching;

B, the raw material that step a is prepared are heated to 820 ℃～850 ℃, and fusing is cooled to 750 ℃～800 ℃ fully, leaves standstill 5～10min, uses C ₂Cl ₆Carry out refining, after melt leaves standstill, skims, be cast in the mould that is preheated to 200 ℃～250 ℃ in 730 ℃～750 ℃;

C, step b gained ingot casting is handled 15h～20h, air cooling in 450 ℃～500 ℃ homogenizing;

D, with step c products therefrom be heated to 400 ℃～450 ℃ rolling, rolling reduction is greater than 80%;

E, steps d gained rolled parts is heated to 450 ℃～500 ℃ solid solution 1h～3h, the shrend of coming out of the stove;

F, step e products therefrom is heated to 100 ℃～150 ℃, artificial aging 15h～30h.

5, method according to claim 4 is characterized in that: described mould is iron mould.

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