WO2021035771A1

WO2021035771A1 - Light metal composite material with rare earth oxide as reinforcement

Info

Publication number: WO2021035771A1
Application number: PCT/CN2019/104185
Authority: WO
Inventors: 乐启炽; 任良; 李小强; 宝磊; 程春龙; 周伟阳
Original assignee: 东北大学
Priority date: 2019-08-29
Filing date: 2019-09-03
Publication date: 2021-03-04
Also published as: CN110423935A; CN110423935B

Abstract

Provided is a light metal composite material with a rare earth oxide as a reinforcement. The component chemical formula of the material is Mg-X-REmOn, Mg-Li-X-REmOn, Al-X-REmOn or Al-Li-X-REmOn. The material contains, by mass percentage, no greater than 10 percent of X and contains, by volume percentage, 0.1-30 percent of REmOn, wherein when the chemical formula is Mg-Li-X-REmOn, the material contains, by mass percentage, 0.1-30 percent of Li, and when the chemical formula is Al-Li-X-REmOn, the material contains, by mass percentage, 0.1-10 percent of Li.

Description

Light metal composite material with rare earth oxide as reinforcement

Technical field

The invention relates to the technical field of composite materials, in particular to a light metal composite material with rare earth oxide as a reinforcement.

Background technique

At present, magnesium alloys and aluminum alloys are the most widely used in light metals. They have the advantages of low density, specific rigidity, and high specific strength. They are widely used in aerospace, automobile manufacturing and other industries and have broad prospects; but with the development of light metals In large-scale use, the mechanical properties and other comprehensive properties of magnesium alloys and aluminum alloys need to be further improved; therefore, in order to expand the application range of light alloys, it is urgent to research and design light metal composite materials.

Compared with traditional magnesium, aluminum and their alloys, composite materials not only have excellent mechanical properties, but also have some special properties and other good comprehensive properties. When the reinforcement is added to the metal material, it is generally stable and does not react with the base alloy; at the same time, the reinforcement can be used as the second phase to achieve the effect of refining the metal material, thereby improving its mechanical properties; finally, different reinforcements give the composite The special properties of different materials expand the application range of metal composite materials.

At present, reinforcements are roughly divided into three types: whiskers, fibers, and particles; such as rare earth oxide particles, silicon carbide whiskers, and carbon fibers. Among them, the cost of fiber reinforcement is high, and it will form a strong texture, which makes the composite material performance poor. Whiskers and particle-reinforced composite materials have the advantages of easy processing and dimensional stability. The rare earth oxide reinforcement has a high melting point and will not melt when added to the light alloy melt, and will not chemically react with the matrix at the same time. If it can exist uniformly in the matrix and reduce the segregation of interstitial impurities at the grain boundary, the strength of the grain boundary can be improved; in addition, the rare earth oxide can pin the dislocations and hinder the movement of the dislocations, thereby making the composite The strength of the material is improved, and the plasticity will not drop too much; my country's rare earth content ranks among the top in the world, and the preparation of rare earth oxides has a simple process and low cost. Therefore, the research of light metal composite materials with rare earth oxides as reinforcements is of great significance.

Summary of the invention

technical problem

The solution to the problem

Technical solutions

The purpose of the present invention is to provide a light metal composite material with rare earth oxides as reinforcements. Rare earth oxides are used as reinforcements to be evenly distributed in the light metal matrix, so as to solve the limitations of the mechanical properties and special properties of light alloys, and improve Mechanical properties.

The composition chemical formula of the light metal composite material with rare earth oxide as the reinforcement of the present invention is Mg-X-RE _m O _n , Mg-Li-X-RE _m O _n , Al-X-RE _m O _n or Al-Li- X-RE _m O _n, containing in percentage by mass X≤10%, by volume percent containing _{_{RE m O n 0.1 ~ 30%}} ; wherein when the formula _{Mg-Li-X-RE m} O n, Li-containing mass percent 0.1～30%; when the chemical formula is Al-Li-X-RE _m O _n , the content of Li is 0.1～10% by mass percentage; when the chemical formula is Mg-X-RE _m O _n or Mg-Li-X-RE _m When O _n , X is one or more of aluminum, zinc, manganese, rare earth, zirconium, and silicon; when the chemical formula is Al-X-RE _m O _n or Al-Li-X-RE _m O _n , X It is one or more of copper, zinc, manganese, rare earth, magnesium, silicon, and titanium.

The aforementioned RE _m O _n is La ₂ O ₃ , CeO ₂ and/or Y ₂ O ₃ .

The preparation method of the light metal composite material with rare earth oxide as the reinforcement of the present invention is carried out according to the following steps:

(1) Prepare magnesium ingots or aluminum ingots as raw materials according to the target composition, prepare salt flux and reinforcement RE _m O _n ; when the target composition is Al-Li-X-RE _m O _n or Mg-Li-X-RE _m O _{When n} , prepare metal lithium; when the content of X in the target component is not 0, prepare a component containing X, the component containing X is a metal ingot, compound or alloy containing element X; when the target component is Mg-X-RE _{When m} O _n , the salt flux is a mixture of barium chloride, magnesium chloride, sodium chloride and calcium chloride, in which barium chloride accounts for 35-50% of the total mass of the salt flux, and magnesium chloride accounts for 10-20% of the total mass of the salt flux Sodium chloride accounts for 10-20% of the total mass of the salt flux, the rest is calcium chloride and impurities, and the impurities account for ≤1% of the total mass of the salt flux; when the target component is Al-X-RE _m O _n , the salt flux is A mixture of potassium chloride, sodium chloride and cryolite, in which potassium chloride accounts for 20-50% of the total mass of the salt flux, sodium chloride accounts for 20-50% of the total mass of the salt flux, and cryolite accounts for 20-50% of the total mass of the salt flux 20-60%; when the target component is Al-Li-X-RE _m O _n or Mg-Li-X-RE _m O _n , the salt flux contains 65-85% of lithium chloride and 15% of lithium fluoride by mass percentage. ～35%, lithium bromide ≤20%; the amount of reinforcement is 1.1 to 1.4 times the theoretical requirement of the target component; the reinforcement is 1-50% of the total volume of the salt flux; the amount of metal lithium is based on the theoretical requirement of the target component 1.2～1.6 times;

(2) Put the salt flux in a clay crucible or a graphite crucible and heat it to form a salt flux melt; add the reinforcement into the salt flux melt, stir to make the reinforcement uniformly dispersed, and make a liquid-solid mixture;

(3) Pour the liquid-solid mixture into a clay crucible or graphite crucible at room temperature, and cool to room temperature to obtain a precursor;

(4) Preheat the smelting crucible to 473～523K, then place the raw materials in the smelting crucible, the raw materials are melted to form a raw material melt; when the content of X in the target component is not 0, put the X-containing components in the iron crucible together Together to form a raw material melt; among them, when magnesium ingots are used as raw materials, the smelting crucible is an iron crucible, and when aluminum ingots are used as a raw material, the smelting crucible is a graphite crucible;

(5) When the target component is Mg-Li-X-RE _m O _n or Al-Li-X-RE _m O _n , put the metal lithium wrapped in tin foil into the raw material melt, stir and mix evenly, and then add Precursor, continue to stir and mix uniformly; then stand still to separate the impurity components and composite material components to form scum and composite material melt;

(6) Remove the scum on the surface of the composite material melt, then lower the temperature of the composite material melt to 983±5K, and cast it into a light metal composite material with rare earth oxide as the reinforcement.

The purity of the aluminum ingot is greater than or equal to 99.8%, the purity of the magnesium ingot is greater than or equal to 99.85%, and the purity of the metal lithium is greater than or equal to 99.8%.

The shape of the above-mentioned reinforcement is fiber, particle or whisker, wherein the particle diameter is 300nm-20μm; the whisker diameter is 0.1-1μm, the whisker length is 10-100μm; the fiber diameter is 5-20μm, and the continuous length is 10~ 70mm.

In the above step (5), the precursor is first crushed to a particle size ≤ 5 cm, and then put into the raw material melt.

In the above step (2), the stirring speed is 100-200r/min, and the time is 2-20min.

In the above step (5), the stirring speed is 100-300 r/min, and the time is 2-20 min.

In the above step (2), when the reinforcement is added to the salt flux melt, all the reinforcements are added in 3 to 5 times, and the addition amount each time is less than 50% of the total mass of the reinforcement.

In the above step (5), before standing, use argon for degassing, the argon pressure is 0.1-0.7 MPa, and the degassing time is 2-5 min.

In the above step (5), the standing time is 10-20 minutes.

In the above step (1), when the chemical formula of the target component is Mg-X-RE _m O _n or Mg-Li-X-RE _m O _n , and when the content of X in the target component is not 0, the The X-containing component is metallic aluminum, zinc ingot, manganese chloride, magnesium rare earth alloy, magnesium zirconium alloy and/or magnesium silicon alloy.

In the above step (1), when the chemical formula of the target component is Al-X-RE _m O _n or Al-Li-X-RE _m O _n , and when the content of X in the target component is not 0, the The X-containing component is aluminum copper alloy, zinc ingot, aluminum manganese alloy, aluminum rare earth alloy, metallic magnesium, aluminum silicon alloy and/or aluminum titanium alloy.

The beneficial effects of the invention

Beneficial effect

The present invention is characterized in that: for light metals, the content range of alloyed metals and rare earth oxides is wide, and there are many kinds of additions; the salt flux can improve the surface wettability of the reinforcement, so that the bonding strength of the reinforcement and the alloy is greatly improved to achieve dispersion. Strengthening effect. From the perspective of metal and rare earth oxide reinforcements, the raw material cost is low, and the selection range is large; from the method of preparing composite materials, the process cost is low, the process is simple, and it is suitable for large-volume and automated production; the prepared product can increase the light metal composite The application of materials has an important impact on industrial production.

Invention embodiment

Embodiments of the present invention

The invention will be described in detail below in conjunction with embodiments.

In the embodiment of the present invention, a thermocouple is used to detect temperature to ensure the accuracy of temperature measurement.

In the embodiment of the present invention, the purity of the aluminum ingot is greater than or equal to 99.8%, the purity of the magnesium ingot is greater than or equal to 99.85%, and the purity of the metal lithium is greater than or equal to 99.8%.

The purity of the metallic aluminum and zinc ingots in the embodiment of the present invention is 98.9% to 99.9%.

The magnesium rare earth alloy, magnesium zirconium alloy and magnesium silicon alloy of the present invention are collectively referred to as magnesium master alloy, and the rare earth, zirconium and silicon in the magnesium master alloy respectively account for 10-40% of the total mass of the magnesium master alloy.

The aluminum-manganese alloy, aluminum-rare-earth alloy, aluminum-copper alloy, aluminum-titanium alloy and aluminum-silicon alloy of the present invention are collectively referred to as aluminum master alloys. The manganese, rare earths, copper, titanium and silicon in the aluminum master alloys account for 10% of the total mass of the aluminum master alloys. ~40%.

The shape of the reinforcement in the embodiment of the present invention is fiber, particle or whisker; the particle diameter is 300nm-20μm; the whisker diameter is 0.1-1μm and the length is 10-100μm; the fiber diameter is 5-20μm, and the continuous length is 10μm. 70mm.

In the embodiment of the present invention, argon gas is used to degas the materials in the melting crucible before standing. The argon gas pressure is 0.1-0.7 MPa, and the degassing time is 2-5 minutes.

In the embodiment of the present invention, the recovery rate of the reinforcement in the light metal composite material with the rare earth oxide as the reinforcement is 70-90%.

Example 1

The composition chemical formula of the light metal composite material with rare earth oxide as the reinforcement is Mg-X-La ₂ O ₃ , which contains 10% of X by mass and 5% by volume of La ₂ O ₃ ; X is Al+Mn, Al The mass ratio to Mn is 2;

The method is;

Prepare magnesium ingots as raw materials according to the target composition, prepare salt flux and reinforcement RE _m O _n ; prepare manganese chloride and metal aluminum; salt flux is a mixture of barium chloride, magnesium chloride, sodium chloride and calcium chloride, which is chlorinated Barium occupies 40% of the total mass of the salt flux, magnesium chloride occupies 15% of the total mass of the salt flux, sodium chloride occupies 15% of the total mass of the salt flux, and the rest is calcium chloride and impurities; the amount of reinforcement is based on the theoretical required amount of the target component 1.2 times of that; the reinforcement is 20% of the total volume of the salt flux;

Put the salt flux in the clay crucible and heat it to make the salt flux melt; add the reinforcement into the salt flux melt, stir to make the reinforcement uniformly dispersed, and make a liquid-solid mixture; stirring speed 100r/min, time 20min;

Pour the liquid-solid mixture into a clay crucible at room temperature, and cool it to room temperature to obtain the precursor; when adding the reinforcement to the salt flux melt, all reinforcements are added in 3 times, and the amount of each addition is equal to the total mass of the reinforcements. Less than 50%;

Preheat the smelting crucible to 473K, then put the raw materials, manganese chloride and metallic aluminum in the smelting crucible, the raw materials are melted to form a raw material melt; the smelting crucible is an iron crucible;

Crush the precursor to a particle size ≤ 5cm, then put it into the raw material melt, continue to stir and mix evenly; then stand for 15 minutes to separate the impurity components and composite material components to form scum and composite material melt; stirring speed 100r/min , Time 20min;

The scum on the surface of the composite material melt is removed, and then the temperature of the composite material melt is reduced to 983±5K, and the light metal composite material with rare earth oxides as the reinforcement is made by casting.

Example 2

The composition chemical formula of the light metal composite material with rare earth oxide as the reinforcement is Mg-Li-XY ₂ O ₃ , containing 8% X by mass percentage, _{15% Y 2} O ₃ by volume percentage, and 10% Li by mass percentage ; X is Al+Zn, the mass ratio of Al and Zn is 3;

The method is the same as in Example 1, the difference is:

(1) Prepare metallic lithium; prepare zinc ingot; the salt flux contains 70% lithium chloride, 20% lithium fluoride, and 10% lithium bromide by mass percentage; the amount of reinforcement is 1.3 times the theoretical required amount of the target component; the reinforcement is 15% of the total volume of the salt flux; the amount of lithium metal is 1.5 times the theoretical required amount of the target component;

(2) Stirring speed 200r/min, time 2min;

(3) When the reinforcement is added to the salt flux melt, all the reinforcements are added in 5 times;

(4) Preheat the smelting crucible to 523K, and then put the raw materials, aluminum ingots and zinc ingots in the smelting crucible to melt to form a raw material melt;

(5) Put the metal lithium wrapped in tin foil into the raw material melt, stir and mix evenly; put the precursor again; let it stand for 20 minutes; stirring speed 300r/min, time 2min.

Example 3

The composition chemical formula of the light metal composite material with rare earth oxide as the reinforcement is Al-X-La ₂ O ₃ , containing 6% by mass and RE _m O _n 20% by volume; X is Mg+Cu, Mg The mass ratio with Cu is 1;

The method is the same as in Example 1, the difference is:

(1) Prepare aluminum ingots according to the target composition as raw materials; prepare metallic magnesium and aluminum-copper alloys; in the salt flux, potassium chloride accounts for 30% of the total mass of the salt flux, sodium chloride accounts for 40% of the total mass of the salt flux, and cryolite 30% of the total mass of the salt flux; the amount of reinforcement is 1.4 times the theoretical required amount of the target component; the reinforcement is 35% of the total volume of the salt flux;

(2) Put the salt flux in a graphite crucible and heat it to make the salt flux melt; stirring speed 150r/min, time 10min;

(3) Pour the liquid-solid mixture into a graphite crucible at room temperature to cool;

(4) Preheat the smelting crucible to 493K, then place the raw materials, magnesium metal and aluminum-copper alloy in the smelting crucible, and the raw materials are melted to form a raw material melt; the smelting crucible is a graphite crucible;

(5) Let stand for 10 minutes; stirring speed 200r/min, time 0min.

Example 4

The composition formula of the light metal composite material with rare earth oxide as reinforcement is Al-Li-X-CeO ₂ , which contains 9% by mass of X, _{25% by volume of CeO 2 and} 7% by mass; X It is Si+Cu+Zn, Si:Cu:Zn=1:5:10;

The method is the same as in Example 1, the difference is:

(1) Prepare aluminum ingots as raw materials according to the target composition, prepare metal lithium; prepare aluminum-silicon alloy, aluminum-copper alloy and zinc ingot; salt flux contains 80% lithium chloride and 20% lithium fluoride according to mass percentage; 1.1 times the theoretical required amount of the target component; the reinforcement is 50% of the total volume of the salt flux; the amount of metal lithium is 1.6 times the theoretical required amount of the target component;

(2) Put the salt flux in a graphite crucible and heat it to make the salt flux melt; stirring speed 150r/min, time 12min;

(4) Preheat the melting crucible to 503K, and then place the raw materials, aluminum-silicon alloy, aluminum-copper alloy and zinc ingot in the melting crucible; the melting crucible is a graphite crucible;

(5) Put the metal lithium wrapped in tin foil into the raw material melt, stir and mix uniformly; then crush the precursor to a particle size ≤ 5cm, then put it into the raw material melt, continue to stir and mix evenly; then let it stand for 20 minutes; The stirring speed is 200r/min, and the time is 15min.

Claims

A light metal composite material with rare earth oxide as a reinforcement, characterized in that the chemical formula of the composition is Mg-X-RE m O n , Mg-Li-X-RE m O n , Al-X-RE m O n or Al -Li-X-RE m O n , containing in percentage by mass X≤10%, by volume percent containing RE m O n 0.1 ~ 30% ; wherein when the formula Mg-Li-X-RE m O n, by mass The percentage contains Li 0.1-30%; when the chemical formula is Al-Li-X-RE m O n , the mass percentage contains Li 0.1-10%; when the chemical formula is Mg-X-RE m O n or Mg-Li -X-RE m O n , X is one or more of aluminum, zinc, manganese, rare earth, zirconium, and silicon; when the chemical formula is Al-X-RE m O n or Al-Li-X-RE m when O n, X is copper, zinc, manganese, rare earths, magnesium, silicon, titanium, one or more.
The light metal composite material with rare earth oxide as a reinforcement according to claim 1, wherein the RE m O n is La 2 O 3 , CeO 2 and/or Y 2 O 3 .
A method for preparing a light metal composite material with a rare earth oxide as a reinforcement according to claim 1, characterized in that it is carried out according to the following steps;

(1) Prepare magnesium ingots or aluminum ingots as raw materials according to the target composition, prepare salt flux and reinforcement RE m O n ; when the target composition is Al-Li-X-RE m O n or Mg-Li-X-RE m O When n , prepare metal lithium; when the content of X in the target component is not 0, prepare a component containing X, the component containing X is a metal ingot, compound or alloy containing element X; when the target component is Mg-X-RE When m O n , the salt flux is a mixture of barium chloride, magnesium chloride, sodium chloride and calcium chloride, in which barium chloride accounts for 35-50% of the total mass of the salt flux, and magnesium chloride accounts for 10-20% of the total mass of the salt flux Sodium chloride accounts for 10-20% of the total mass of the salt flux, the rest is calcium chloride and impurities, and the impurities account for ≤1% of the total mass of the salt flux; when the target component is Al-X-RE m O n , the salt flux is A mixture of potassium chloride, sodium chloride and cryolite, in which potassium chloride accounts for 20-50% of the total mass of the salt flux, sodium chloride accounts for 20-50% of the total mass of the salt flux, and cryolite accounts for 20-50% of the total mass of the salt flux 20-60%; when the target component is Al-Li-X-RE m O n or Mg-Li-X-RE m O n , the salt flux contains 65-85% of lithium chloride and 15% of lithium fluoride by mass percentage. ～35%, lithium bromide ≤20%; the amount of reinforcement is 1.1 to 1.4 times the theoretical requirement of the target component; the reinforcement is 1-50% of the total volume of the salt flux; the amount of metal lithium is based on the theoretical requirement of the target component 1.2～1.6 times;

(2) Put the salt flux in a clay crucible or a graphite crucible and heat it to make a salt flux melt; add the reinforcement into the salt flux melt, stir to make the reinforcement uniformly dispersed, and make a liquid-solid mixture;

(3) Pour the liquid-solid mixture into a clay crucible or graphite crucible at room temperature, and cool to room temperature to obtain a precursor;

(4) Preheat the smelting crucible to 473～523K, then place the raw materials in the smelting crucible, the raw materials are melted to form a raw material melt; when the content of X in the target component is not 0, put the X-containing components in the iron crucible together Together to form a raw material melt; among them, when magnesium ingots are used as raw materials, the smelting crucible is iron crucible, and when aluminum ingots are used as raw materials, the smelting crucible is graphite crucible;

(5) When the target component is Mg-Li-X-RE m O n or Al-Li-X-RE m O n , put the metal lithium wrapped in tin foil into the raw material melt, stir and mix evenly, and then add Precursor, continue to stir and mix uniformly; then stand still to separate the impurity components and composite material components to form scum and composite material melt;

(6) Remove the scum on the surface of the composite material melt, then lower the temperature of the composite material melt to 983±5K, and cast it into a light metal composite material with rare earth oxide as the reinforcement.
A method for preparing a light metal composite material with rare earth oxide as a reinforcement according to claim 3, wherein in step (1), when the chemical formula of the target component is Mg-X-RE m O n or Mg-Li-X-RE m O n , and when the content of X in the target component is not 0, the X-containing component is metallic aluminum, zinc ingot, manganese chloride, magnesium rare earth alloy, magnesium Zirconium alloy and/or magnesium silicon alloy.
The method for preparing a light metal composite material with rare earth oxide as a reinforcement according to claim 3 according to claim 1, characterized in that in step (1), when the chemical formula of the target component is Al-X-RE m O n or Al-Li-X-RE m O n , and when the content of X in the target component is not 0, the X-containing component is aluminum copper alloy, zinc ingot, aluminum manganese alloy, aluminum rare earth alloy, Metal magnesium, aluminum silicon alloy and/or aluminum titanium alloy.