阅读说明：本技术 一种快速挤压高强度变形铝合金及其制备方法 (Rapid-extrusion high-strength wrought aluminum alloy and preparation method thereof ) 是由 吕正风 隋来智 程仁寨 隋信磊 马旭 肖栋 郑卓阳 王丹 任伟才 付凯 于 2019-09-23 设计创作，主要内容包括：本发明公开了一种快速挤压高强度变形铝合金,是由以下质量百分比的组分组成：Zn:7%-9%；Mg:1%-2%；Cu:1%-3%；Y:0.1-0.5%；余量为Al和不可避免的杂质元素；本发明还提供了高强度变形铝合金制备方法,采用快速挤压方法,操作简单、方便,便于推广应用。本发明通过快速挤压方法制备的Al-Zn-Mg-Cu-Y变形铝合金,在具有较高的强度的同时仍保持较好的延伸率,解决了现有的铝合金挤压加工制备方法中无法采用快速挤压工艺,型材缺陷多等问题,使其加工效率和成品率得以提高。(The invention discloses a rapid-extrusion high-strength wrought aluminum alloy which is composed of the following components in percentage by mass: 7% -9% of Zn; 1 to 2 percent of Mg; 1-3% of Cu; 0.1 to 0.5 percent of Y; the balance of Al and inevitable impurity elements; the invention also provides a preparation method of the high-strength wrought aluminum alloy, which adopts a rapid extrusion method, is simple and convenient to operate and is convenient to popularize and apply. The Al-Zn-Mg-Cu-Y wrought aluminum alloy prepared by the rapid extrusion method has higher strength and better elongation, solves the problems that the rapid extrusion process cannot be adopted in the existing aluminum alloy extrusion processing preparation method, the defects of the section bar are more, and the like, and improves the processing efficiency and the yield.)

1. The rapidly extruded high-strength wrought aluminum alloy is characterized by being an Al-Zn-Mg-Cu-Y wrought aluminum alloy, and comprising the following raw materials in percentage by mass: 7% -9% of Zn; 1 to 2 percent of Mg; 1-3% of Cu; 0.1 to 0.5 percent of Y; the balance of Al and inevitable impurity elements; the purity of the industrial pure magnesium, the industrial pure aluminum and the industrial pure zinc used for preparation is more than 99 percent.

2. The rapidly extruded, high strength wrought aluminum alloy according to claim 1, wherein the copper and yttrium are added as an intermediate alloy of Al-30wt.% Cu and Al-25wt.% Y.

3. A method of making a rapidly extruded, high strength wrought aluminum alloy according to claim 1, comprising the steps of:

(1) cleaning an alloying crucible, preheating the alloying crucible to 350-400 ℃, preheating the used raw materials to 180-200 ℃, putting industrial pure aluminum, zinc and magnesium into the alloying crucible, and melting the industrial pure aluminum, zinc and magnesium into alloy liquid at the temperature of 710-730 ℃;

(2) adding an aluminum-copper intermediate alloy and an aluminum-yttrium intermediate alloy into the alloy liquid obtained in the step (1) according to the mixture ratio of the raw materials, and melting the mixture into the alloy liquid at the temperature of 740-760 ℃;

(3) standing the alloy liquid obtained in the step (2) at 700-720 ℃ for 30-40min, fully stirring for 1-3min, and removing dross and oxide skin on the surface to obtain the alloy liquid;

(4) then taking out the alloy liquid, cooling to 700 ℃, pouring the alloy liquid into an iron mold preheated to 250-300 ℃ to prepare an ingot;

(5) homogenizing: keeping the ingot prepared in the step (4) at 300-330 ℃ for 8-10h, heating to 550-580 ℃ for 1h, keeping the temperature for 8-16h, and then performing water quenching to obtain a homogenized sample;

(6) extruding: placing the aluminum alloy ingot obtained after the homogenization treatment in the step (5) into a resistance furnace after turning the skin, preheating for 2h at 500-550 ℃, coating a lubricant on a die cavity and an ejector rod, and placing into an extruder at 500 ℃ of 400-; and obtaining the high-strength wrought aluminum alloy.

4. The method of claim 3, wherein the lubricant applied to the die cavity and the ejector pins is polyethylene wax.

5. The method of claim 3, wherein a direct heating rapid extrusion process is used, the extrusion ratio is 10:1, and the extrusion speed is 10 m/min.

Technical Field

The invention relates to the field of metal materials, in particular to a high-strength wrought aluminum alloy containing rare earth and a preparation method thereof.

Background

Aluminum is a lightweight, metallic structural material that is increasingly used in automobiles. The automobile adopts the aluminum alloy, so that the weight can be reduced, and the exhaust emission is reduced, so that the research and development of the aluminum alloy have important significance for saving energy and inhibiting environmental pollution. However, the poor strength and heat resistance of aluminum alloy seriously hinder the application of aluminum alloy in aerospace, military industry, automobiles and other industries, so the improvement of the strength and heat resistance of aluminum alloy is an important subject for developing aluminum alloy materials.

The existing aluminum alloy mainly starts from limiting dislocation movement and strengthening grain boundaries, and achieves the purposes of improving the heat resistance and high-temperature creep resistance of the aluminum alloy by means of introducing a second phase with high thermal stability, reducing the diffusion rate of elements in an aluminum matrix or improving the structure state and the structure form of the grain boundaries and the like through proper alloying. Currently, among all alloying elements, Rare Earth (RE) is the most effective alloying element for improving the properties of aluminum alloys. Most of rare earth elements have larger solid solubility limit in aluminum, and the solid solubility is sharply reduced along with the temperature reduction, so that larger supersaturation can be obtained, and dispersed and high-melting-point rare earth compound Al is precipitated in the subsequent aging process_xAnd (4) an RE phase. The rare earth elements can also refine crystal grains and improve the room temperature strength, and the dispersed high-melting point rare earth compounds which are distributed in the crystal and in the crystal boundary are mainly the crystal boundary can pin the crystal internal dislocation and the crystal boundary sliding at high temperatureAnd the diffusion rate of the rare earth element in the aluminum matrix is low, so that the aluminum alloy added with the rare earth is suitable for long-term operation in a high-temperature environment. The rare earth aluminum alloy is an important aluminum alloy system and has higher high-temperature strength and excellent creep resistance.

China is the first major country of rare earth resources, researches on rare earth aluminum alloys are continuously increased and deepened in recent years, and the successful research and development of the rare earth aluminum alloys can help us to utilize the advantages. The main defects of the existing commercial heat-resistant aluminum alloy are that the performance is not stable enough, the strength is reduced more at high temperature, and the higher requirement of the commercial heat-resistant aluminum alloy on the strength stability when the commercial heat-resistant aluminum alloy is used in a wider operation temperature range in the aerospace industry, the military industry, the automobile industry and other industries can not be completely met.

Disclosure of Invention

Aiming at the defects, the invention provides a rapid extrusion high-strength wrought aluminum alloy and a preparation method thereof, and the rapid extrusion high-strength wrought aluminum alloy is realized by the following technical scheme:

a rapid extrusion high-strength wrought aluminum alloy is an Al-Zn-Mg-Cu-Y wrought aluminum alloy, and comprises the following raw material components in percentage by mass: 7% -9% of Zn; 1 to 2 percent of Mg; 1% -2% of Cu; 0.1 to 0.5 percent of Y; the balance of Al and inevitable impurity elements; the purity of the industrial pure aluminum, magnesium and zinc used for preparation is more than 99 percent.

Preferably, the copper and yttrium are measured in mass fractions and added as an Al-30wt.% Cu and Al-25wt.% Y master alloy.

The preparation method of the rapidly extruded high-strength wrought aluminum alloy comprises the following steps:

(1) cleaning an alloying crucible, preheating the alloying crucible to 350-400 ℃, preheating the used raw materials to 180-200 ℃, putting industrial pure aluminum, zinc and magnesium into the alloying crucible, and melting the industrial pure aluminum, zinc and magnesium into alloy liquid at the temperature of 710-730 ℃;

(2) adding an aluminum-copper intermediate alloy and an aluminum-yttrium intermediate alloy into the alloy liquid obtained in the step (1) according to the mixture ratio of the raw materials, and melting the mixture into the alloy liquid at the temperature of 740-760 ℃;

(3) standing the alloy liquid obtained in the step (2) at 700-720 ℃ for 30-40min, fully stirring for 1-3min, and removing dross and oxide skin on the surface to obtain the alloy liquid;

(4) then taking out the alloy liquid, cooling to 700 ℃, pouring the alloy liquid into an iron mold preheated to 250-300 ℃ to prepare an ingot;

(5) homogenizing: keeping the ingot prepared in the step (4) at 300-330 ℃ for 8-10h, heating to 550-580 ℃ for 1h, keeping the temperature for 8-16h, and then performing water quenching to obtain a homogenized sample;

(6) extruding: placing the aluminum alloy ingot obtained after the homogenization treatment in the step (5) into a resistance furnace after turning the skin, preheating for 2h at 500-550 ℃, coating a lubricant on a die cavity and an ejector rod, and placing into an extruder at 500 ℃ of 400-; and obtaining the high-strength wrought aluminum alloy.

Preferably, the lubricant applied to the mold cavity and ejector pin is polyethylene wax.

Preferably, a direct heating rapid extrusion process is adopted, the extrusion ratio is 10:1, and the extrusion speed is 10 m/min.

Drawings

FIG. 1: the gold phase diagram of the extruded alloy prepared in example 2.

FIG. 2: the gold phase diagram of the extruded alloy prepared in comparative example 1.

Advantageous effects

1. The Al-Zn-Mg-Cu-Y alloy provided by the invention is a novel rare earth-containing aluminum alloy, and the adopted alloying elements are all low-cost metals. In the Al-Zn-Mg-Cu alloy system, the strengthening phases are AlZnMgCu and MgZn₂Al6Cu6Y and Al are also formed after rare earth Y is added₃The addition of Y phase, and therefore alloying elements, has a dual effect of solid solution strengthening and second phase strengthening of the alloy. The aluminum alloy section with higher strength is prepared after hot extrusion.

2. The invention adopts a simpler processing technology of rapid extrusion, realizes rapid extrusion processing with large extrusion ratio by reasonably regulating and controlling the preheating temperature and the extrusion temperature, has the highest extrusion speed of 10m/min and the average extrusion ratio of 10:1, and has flat and smooth surface of the extruded section without obvious defects and cracks and high density. The resulting extruded alloy strength exceeded most 7 series wrought aluminum alloys.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.