CN101177750A - A high-strength heat-resistant heat-resistant aluminum alloy containing rare earth praseodymium and its preparation process - Google Patents

Abstract

The invention relates to a high-strength deformable heat-resistant aluminum alloy containing rare earth praseodymium and a preparation process thereof. It is used in the field of high-performance medium-temperature structural materials. The specific components and their weight percentages of the present invention are: Cu: 4-6.5%, Mg: 0.5-1.5%, Ag: 0.4-1.5%, Mn: 0.1-0.5%, Zr: 0.05-0.25%, Pr: 0.05- 0.40%, the balance is Al. The present invention adds a trace amount of rare earth praseodymium to the existing aluminum-copper-magnesium-silver-manganese-zirconium alloy, without changing the composition of the already formed alloy, but makes use of the effect of the trace amount of praseodymium to make the original cast structure of the aluminum-copper-magnesium-silver-manganese-zirconium alloy get refined. The refined as-cast structure is subjected to further deformation heat treatment, and aging treatment is carried out in the artificial aging process to obtain a better structure and make its performance in the best state.

Description

A high-strength heat-resistant heat-resistant aluminum alloy containing rare earth praseodymium and its preparation process

technical field

The invention belongs to the technical field of high-performance medium-temperature structural metal materials, and relates to a high-strength deformation heat-resistant aluminum alloy of Al-Cu-Mg-Ag-Mn-Zr system, and to an Al-Cu-Mg-Sg-Mn-Zr system high-strength deformation heat-resistant aluminum alloyed with rare earth praseodymium aluminum alloy.

Background technique

The Al-Cu-Mg series heat-resistant heat-resistant aluminum alloy is a typical age-hardening aluminum alloy. Its main alloying elements include Al, Cu, Mg, Mn, Zr, Ti, V, etc. It has good heat resistance and high specific strength, and is used as aerospace structure and automotive engine blade material. At present, the deformed heat-resistant aluminum alloy widely used in industry is 2618 aluminum alloy, and its typical composition is: 3wt% Cu ~ 1.6wt% Mg ~ 1.1wt% Fe ~ 1.0wt% Ni ~ 0.18wt% Si ~ 0.05wt% Ti, The remainder is Al, and its tensile strength σ _b at room temperature is 441MPa, σ _b is 321MPa at 200°C, and _60MPa at 300°C.

After literature search, it was found that Polmear added a small amount of Ag to the Al-Cu-Mg alloy to form an Al-Cu-Mg-Ag alloy, which was then hot-extruded into a rod (US Patent No-4772342; Materials Science Forum, 1996, Vols.217-222, P1759), its typical composition is 6.5wt% Cu ~ 0.48wt% Mg ~ 0.46wt% Ag ~ 0.3wt% Mn ~ 0.17wt% Zr ~ 0.07wt% Ti, the remainder is Al, the other The tensile strength σ _b at room temperature is 520MPa, and σ _b is 375MPa at 180°C. Through the analysis of the results of patents and publication reports, it is found that the high temperature heat resistance of Al-Cu-Mg-Ag alloys exceeds that of 2618 aluminum alloys, but the increase in the tensile strength at room temperature is not obvious, and the high temperature strength, especially 250 The high temperature strength above ℃ is far from meeting the requirements of practical applications. Therefore, it is necessary to further improve its mechanical properties so that the alloy has better room temperature and tensile strength. At present, there is no literature report on the use of praseodymium microalloying technology to promote the microstructure transformation and improve the heat resistance of Al-Cu-Mg-Ag alloys.

Contents of the invention

The purpose of the present invention is to provide a rare earth praseodymium microalloyed aluminum copper magnesium silver manganese zirconium high-strength heat-resistant aluminum alloy, which can refine the alloy grains through rare earth praseodymium microalloying. degree, refine the size of the aging precipitates, improve the thermal stability of the precipitates, to improve the overall strength and high temperature heat resistance of the alloy, so that the performance of the alloy exceeds the traditional 2618 aluminum alloy and Polmear alloy.

Another object of the present invention is to provide a preparation process for the above alloy.

The present invention is achieved through the following technical proposals. The Al-Cu-Mg-Sg-Mn-Zr alloy components and weight percentages of the present invention are: Cu: 4-6.5%, Mg: 0.5-1.5%, Ag: 0.4-1.5%, Mn: 0.1 to 0.5%, Zr: 0.05 to 0.25%, Pr: 0.05 to 0.40%, and the balance is Al. .

Alloy ingredients according to the above proportions, smelting in a medium frequency induction resistance furnace, and refining with C ₂ Cl ₆ , after the melt was left to stand and slag removed, it was cast into a round billet through an iron mold, and the ingot was uniformly heated at 450-510°C Chemical treatment, and then machining, cut off the head and tail of the ingot and the surface layer, the processed ingot is hot extruded into a bar at 350-440 ° C, and then after solution quenching at 520-540 ° C, 150-210 ° C ℃ artificial aging treatment.

Compared with the prior art, the present invention has the advantages of:

The present invention has substantive features and remarkable effects. The present invention adds a small amount of rare earth praseodymium to the existing aluminum-copper-magnesium-silver-manganese-zirconium alloy, without changing the alloy composition already formed, but makes use of the effect of the trace amount of praseodymium to make aluminum-copper-magnesium-magnesium The original as-cast structure of the silver-manganese-zirconium alloy is refined. The refined as-cast structure is obtained through further deformation heat treatment and aging treatment in the artificial aging process to obtain a better structure and make its performance in the best state. The performance of the alloy is significantly better than the traditional 2618 aluminum alloy and Polmear alloy .

The preferred embodiment of the present invention is as follows:

Al-Cu-Mg-Sg-Mn alloy formed by adding 0.05% Pr, its composition and weight percentage are: 6.5% Cu, 0.8% Mg, 0.60% Ag, 0.10% Mn, 0.05% Zr, 0.05% Pr, and the rest is Al . The alloy is smelted in a medium-frequency induction resistance furnace, refined with C ₂ Cl ₆ , cast into a round billet through an iron mold, homogenized at 450°C, hot-extruded into a bar at 350°C, and then solid-solution quenched at 520°C , at 150 ° C for artificial aging treatment. Tensile strength σ _b of the alloy: room temperature ≥ 520MPa, 200°C ≥ 390MPa, 300°C ≥ 190MPa.

Al-Cu-Mg-Sg-Mn alloy formed by adding 0.10% Pr, its composition and weight percentage are: 6.0% Cu, 0.90% Mg, 1.0% Ag, 0.30% Mn, 0.15% Zr, 0.10% Pr, and the rest is Al . The alloy is smelted in a medium-frequency induction resistance furnace, refined with C ₂ Cl ₆ , and cast into a round billet through an iron mold. After homogenization treatment at 510°C, it is hot-extruded into a bar at 380°C, and then solid-solution quenched at 525°C. , at 210 ° C for artificial aging treatment. Tensile strength σ _b of the alloy: room temperature ≥ 540MPa, 200°C ≥ 410MPa, 300°C ≥ 220MPa.

Al-Cu-Mg-Sg-Mn alloy formed by adding 0.20% Pr, its composition and weight percentage are: 5.4% Cu, 1.0% Mg, 0.95% Ag, 0.45% Mn, 0.25% Zr, 0.20% Pr, and the rest is Al . The alloy is smelted in a medium-frequency induction resistance furnace, refined with C ₂ Cl ₆ , cast into a round billet through an iron mold, homogenized at 500°C, hot-extruded into a bar at 430°C, and then solid-solution quenched at 535°C , artificially aged at 185°C. Tensile strength σ _b of the alloy: room temperature ≥ 580MPa, 200°C ≥ 470MPa, 300°C ≥ 270MPa.

Al-Cu-Mg-Sg-Mn alloy formed by adding 0.40% Pr, its composition and weight percentage are: 5.3% Cu, 1.0% Mg, 0.8% Ag, 0.50% Mn, 0.20% Zr, 0.40% Pr, and the rest is Al . The alloy is smelted in a medium-frequency induction resistance furnace, refined with C ₂ Cl ₆ , cast into a round billet through an iron mold, homogenized at 520°C, hot-extruded into a bar at 410°C, and then solid-solution quenched at 530°C , artificially aged at 185°C. Tensile strength σ _b of the alloy: room temperature ≥ 550MPa, 200°C ≥ 420MPa, 300°C ≥ 240MPa.

Detailed ways

The following examples are intended to illustrate the present invention without further limiting the invention.

The following examples are provided in conjunction with the method of the present invention:

The most preferred embodiment of the present invention is in aluminum-copper-magnesium-silver-manganese-zirconium alloy (Cu: 4～6.5%, Mg: 0.5～1.5%, Ag: 0.4～1.5%, Mn: 0.1～0.5%, Zr: 0.05～0.25% %, Pr: 0.05～0.40%, the balance is Al) adding different contents of praseodymium to the ingredients, and five alloys are designed, whose composition is different from 2618 aluminum alloy, 2219 aluminum alloy and Polmear alloy (as shown in Table 1 and 2 ). The alloy is smelted in a SG-12-13 medium frequency induction resistance furnace, refined with C ₂ Cl ₆ , cast into a round billet through an iron mold, the ingot is homogenized, hot extruded, extruded into a bar, and solid After solution quenching, aging treatment is carried out. The tensile strength at room temperature and high temperature is significantly higher than that of 2618 aluminum alloy and Polmear alloy (shown in Table 3 and 4). Specific embodiments are described as follows:

Example 1:

Add 0.05% Pr to the aluminum-copper-magnesium-silver-manganese alloy. Master alloy, Al-2Pr master alloy) is melted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ , after standing still, slag removal, casting into round billet through iron mold, 450℃ uniform After chemical treatment, it is hot-extruded into rods at 350°C, then solution quenched at 525°C, and then artificially aged at 185°C. The composition and weight percentage of the alloy are 4.0% Cu, 1.5% Mg, 1.5% Ag, 0.50% Mn, 0.15% Zr, 0.05% Pr, and the rest is Al.

Example 2:

Add 0.05% Pr to the aluminum-copper-magnesium-silver-manganese alloy. The master alloy, Al-2Pr master alloy) is smelted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ , after standing still, slag removal, casting into round billet through iron mold, 480℃ uniform After chemical treatment, it is hot-extruded into rods at 430°C, then solution quenched at 520°C, and then artificially aged at 150°C. The composition and weight percentage of the alloy are 6.5% Cu, 0.80% Mg, 0.60% Ag, 0.10% Mn, 0.05% Zr, 0.05% Pr, and the rest is Al.

Example 3:

Add 0.10% Pr to the aluminum-copper-magnesium-silver-manganese alloy. The intermediate alloy, Al-2Pr intermediate alloy) is melted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ , after standing still, slag removal, casting into round billet through iron mold, 510℃ uniform After chemical treatment, it is hot-extruded into rods at 380°C, then solution quenched at 525°C, and then artificially aged at 210°C. The composition and weight percentage of the alloy are 6.0% Cu, 0.90% Mg, 1.0% Ag, 0.30% Mn, 0.15% Zr, 0.10% Pr, and the rest is Al.

Example 4:

Add 0.20% Pr to the aluminum-copper-magnesium-silver-manganese alloy. Master alloy, Al-2Pr master alloy) is melted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ , after standing still, slag removal, casting into round billet through iron mold, 500℃ uniform After chemical treatment, it is hot-extruded into rods at 430°C, then solution quenched at 535°C, and then artificially aged at 185°C. The composition and weight percentage of the alloy are 5.4% Cu, 1.0% Mg, 0.95% Ag, 0.45% Mn, 0.25% Zr, 0.20% Pr, and the rest is Al.

Example 5:

Add 0.20% Pr to the aluminum-copper-magnesium-silver-manganese alloy. The master alloy, Al-2Pr master alloy) is smelted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ , after standing still, slag removal, casting into round billet through iron mold, 490 ℃ uniform After chemical treatment, it is hot-extruded into rods at 410°C, then solution quenched at 525°C, and then artificially aged at 185°C. The composition and weight percentage of the alloy are 5.0% Cu, 1.2% Mg, 0.8% Ag, 0.25% Mn, 0.10% Zr, 0.20% Pr, and the rest is Al.

Embodiment 6:

Add 0.40% Pr to the aluminum-copper-magnesium-silver-manganese alloy. The master alloy, Al-2Pr master alloy) is smelted in SG-12-13 medium frequency induction resistance furnace, and refined with C ₂ Cl ₆ . After chemical treatment, it is hot-extruded into rods at 410°C, then solution quenched at 530°C, and then artificially aged at 185°C. The composition and weight percentage of the alloy are 5.3% Cu, 1.0% Mg, 1.0% Ag, 0.50% Mn, 0.20% Zr, 0.40% Pr, and the rest is Al.

The main chemical composition (percentage by weight) of the alloy of the present invention in table 1

Alloy Cu Mg Ag Mn Zr Yb Al Example 1 4.0 1.50 1.5 0.50 0.15 0.05 Surplus Example 2 6.5 0.80 0.60 0.10 0.05 0.05 Surplus Example 3 6.0 0.90 1.0 0.30 0.15 0.10 Surplus Example 4 5.4 1.0 0.95 0.45 0.25 0.20 Surplus Example 5 5.0 1.2 0.80 0.25 0.10 0.20 Surplus Example 6 5.3 1.0 1.0 0.50 0.20 0.40 Surplus

Table 2 compares the main chemical composition (weight percent) of the alloy

Alloy Cu Mg Ag Mn Zr Ti Fe Ni V Si Al 2618 aluminum alloy bar 2.3 1.6 - - - 0.05 1.1 1.0 - 0.18 Surplus Polmear Alloy Rods 6.5 0.48 0.46 0.3 0.17 0.07 - - - 0.07 Surplus

Table 3 Tensile properties of alloy rods of the present invention

Alloy Test temperature, ℃ tensile properties _σb , MPa δ,% Example 1 25 482 10.1 200 345 13.5 300 138 21.4 Example 2 25 521 9.7 200 395 12.8 300 190 19.5 Example 3 25 548 9.2 200 410 11.3 300 223 16.3 Example 4 25 584 8.5 200 476 10.7 300 272 14.6 Example 5 25 531 9.0 200 523 11.8 300 225 18.5 Example 6 25 553 8.8 200 426 11.6 300 230 15.4

Table 4 Tensile properties of comparative alloys

Alloy Test temperature, ℃ tensile properties _σb , MPa δ,% 2618 aluminum alloy bar twenty four 400 12 200 234 20 300 72 38 Polmear Alloy Rods twenty four 520 10.0 180 375 14.5

Claims (6)

1. the high-strength deformation thermostable aluminum alloy of a praseodymium-containing, contain Cu, Mg, Ag, Mn, Zr, it is characterized in that also contain the trace rare-earth praseodymium, the weight percent of each component is: Cu:4～6.5%, Mg:0.5～1.5%, Ag:0.4～1.5%, Mn:0.1～0.5%, Zr:0.05～0.25%, Pr:0.05～0.40%, surplus are Al.

2. the high-strength deformation thermostable aluminum alloy of praseodymium-containing according to claim 1 is characterized in that, the weight percent of each component is: 6.5%Cu, and 0.8%Mg, 0.60%Ag, 0.10%Mn, 0.05%Zr, 0.05%Pr, all the other are Al.

3. the high-strength deformation thermostable aluminum alloy of praseodymium-containing according to claim 1 is characterized in that, the weight percent of each component is: 6.0%Cu, and 0.90%Mg, 1.0%Ag, 0.30%Mn, 0.15%Zr, 0.10%Pr, all the other are Al.

4. the high-strength deformation thermostable aluminum alloy of praseodymium-containing according to claim 1 is characterized in that the weight percent of each component is: 5.4%Cu, and 1.0%Mg, 0.95%Ag, 0.45%Mn, 0.25%Zr, 0.20%Pr, all the other are Al.

5. the aluminium-copper-magnesium-silver-manganese system high-strength deforming heat-stable aluminium alloy of praseodymium microalloying according to claim 1 is characterized in that, the weight percent of each component is: 5.3%Cu, and 1.0%Mg, 0.8%Ag, 0.50%Mn, 0.20%Zr, 0.40%Pr, all the other are Al.

6. the technology for preparing the high-strength deformation thermostable aluminum alloy of the described a kind of praseodymium-containing of claim 1, it is characterized in that, press Cu:4～6.5%, Mg:0.5～1.5%, Ag:0.4～1.5%, Mn:0.1～0.5%, Zr:0.05～0.25%, Pr:0.05～0.40%, surplus are the alloying ingredient of Al, are cast into billet by the melting of Medium frequency induction resistance furnace again, ingot casting is handled through 450～510 ℃ of homogenizing then, adopt the mode of 350～440 ℃ of hot extrusions to be squeezed into bar, bar through after 520～540 ℃ of solution hardening, carries out ageing treatment again under 150～210 ℃ of artificial agings.