CN104946923B - A kind of copper-based composite material and preparation method thereof - Google Patents

Abstract

The invention discloses a copper-based composite material and a preparation method thereof. Electron beam physical vapor deposition equipment is used to deposit a separation layer first, and then the copper ingot and the second phase material are respectively heated with an electron beam, wherein a constant beam is used for heating For the copper ingot, the second-phase material is heated with a periodically changing beam, the copper-based material is deposited on the separation layer, the temperature is lowered, and the copper-based composite material is obtained by separation. The prepared copper-based composite material contains second phase particles, the second phase particles are Mo, Nb, Al ₂ O ₃ or Y ₂ O ₃ , the volume content of the second phase particles is 0.4-2%, and the second phase The particle content in the copper-based composite material is periodically distributed along the thickness direction, and the particle size of the second phase is less than 50nm; the yield strength of the material R _p0.2 ≥ 460MPa, the tensile strength Rm ≥ 500MPa, the electrical conductivity ≥ 80% IACS, the elongation ≥6%. The invention can prepare nano particle reinforced copper base composite material with high strength and good conductivity.

Description

A kind of copper-based composite material and preparation method thereof

technical field

The invention relates to a copper-based composite material, in particular to a copper-based composite material in which the second phase particles change periodically along the thickness direction.

Background technique

Copper and copper alloy materials are important non-ferrous metal materials, which are widely used in industry due to their excellent physical and mechanical properties. However, the strength and heat resistance of pure copper are insufficient, and the tensile strength of the degenerated state is about 209MPa. After cold deformation, the strength of the material can reach 400MPa, but the elongation is low, and the cold working effect disappears quickly in the subsequent tempering process. Parts used at high temperatures cannot be satisfied. Dispersion-strengthened copper alloy is a copper-based composite material with nano-scale refractory metal particles or ceramic particles as the reinforcing phase. The diameter of the second phase particles is generally less than 100nm, which has little effect on the electrical conductivity of the alloy, and the fine second phase particles can prevent the movement of dislocations and the occurrence of recrystallization, and the alloy shows high strength and high softening temperature. The second phase particles generally include oxides, refractory metals, and the like.

At present, the methods for preparing such materials mainly include internal oxidation method, powder metallurgy method, mechanical alloying method and electron beam physical vapor deposition method. The internal oxidation method is a process that uses the selective oxidation of aluminum in copper-aluminum alloys under low oxygen conditions to form alumina second-phase particles. This process is currently the main process used to prepare Cu-Al ₂ O ₃ dispersion-strengthened composite materials. The performance of the material is good, but this process still has the disadvantages of complex process, long cycle and high cost. The powder metallurgy method is a process of mechanically mixing a certain proportion of copper powder and reinforcing particles, forming, sintering under vacuum or protective atmosphere conditions, repressing, and refiring to prepare materials. Although this process can prepare composite materials with enhanced particle distribution in various sizes, it still has the disadvantages of poor mechanical properties, many procedures, and high cost. The mechanical alloying method is to use a high-energy ball mill to mix copper powder and reinforcing particles evenly, then shape, sinter under vacuum or protective atmosphere conditions, repress, and refire to prepare materials. This process also has the disadvantages of poor mechanical properties, many steps and high cost. The electron beam physical vapor deposition process uses the electron beam as the heat source to heat the target material, evaporate it, deposit it on the substrate, cool it, separate it, and obtain a plate. Compared with the previous several processes, this process has the characteristics of simple process and low cost. At present, it has been reported in the literature that a copper-molybdenum carbide composite material has been prepared by electron beam physical vapor deposition process. Its tensile strength is 486 MPa, electrical conductivity is 82% IACS, but elongation is 3.9%. However, compared with the requirements for electrical contact materials of the increasingly developed electrical and electronic technology, the overall performance of the material is still not high enough, and the molybdenum carbide particles in the material are evenly distributed. Theoretical studies have shown that proper non-uniform distribution of second-phase particles can lead to materials with better properties. In view of this, the present invention prepares a copper-based composite material in which nanoparticles are periodically distributed along the thickness direction by controlling process parameters, and the material has more excellent comprehensive properties.

Contents of the invention

The object of the present invention is to provide a copper-based composite material with excellent mechanical properties and electrical properties.

In the copper-based composite material referred to in the present invention, the volume content of the second phase particles is 0.4-2%, the content of the second phase particles is periodically distributed in the matrix along the thickness direction, the size of the second phase particles is less than 50nm, and the second phase particles Including refractory metals, oxides, etc. Here, the refractory metals include Mo, Nb, etc., and the oxides include Al ₂ O ₃ , Y ₂ O ₃ , etc.

In order to achieve the above object, the present invention adopts the following technical solutions.

A preparation method of copper-based composite material, said method comprising the following steps:

(1) Adopt electron beam physical vapor deposition equipment, put copper ingot and second phase material into two crucibles in vacuum chamber respectively, and put separation layer raw material on copper ingot; Described second phase material is Mo, _Nb , _Al2O3 or _{Y2O3 ;}

(2) Close the vacuum chamber and pump the vacuum; start the substrate rotating device to rotate the substrate, and heat the substrate so that the temperature of the substrate is 600-900°C (preferably 650-700°C);

(3) When the vacuum degree reaches below 1×10 ^-2 Pa, open the isolation baffle between the substrate and the crucible, turn on the electron gun, and the electron gun emits an electron beam to heat the raw material of the separation layer on the copper ingot and deposit it on the substrate get the separation layer;

(4) After the separation layer is deposited, the electron beam emitted by the electron gun heats the copper ingot and the second phase material respectively, wherein the copper ingot is heated with a constant beam, and the second phase material is heated with a periodically changing beam. Deposit copper-based material on the separation layer. When the thickness of the deposited layer reaches the required thickness, turn off the electron gun, pull up the isolation baffle, and stop the heating and rotation of the substrate;

(5) When the temperature of the substrate is cooled to below 200° C., the vacuum is stopped, the substrate is removed, and the deposited layer is separated to obtain the copper-based composite material.

In the step (1), the raw material of the separation layer is CaF ₂ or ZrO ₂ .

In the step (2), the rotation speed of the substrate is 2-40 rev/min, preferably 8-36 rev/min.

In the step (4), the second phase material is heated with a periodically changing beam current, and the periodically changing beam current means that the size of the beam current changes periodically according to the following steps:

A. The beam current gradually increases from 0A to MA; the range of M is 1-1.8;

B. The beam current gradually decreases from MA to 0.2A;

C. The beam current gradually increases from 0.2A to MA;

D. Repeat steps B to C;

The rate of increase or decrease is generally 0.5-4A/min

In the step (4), the copper ingot is heated with a constant beam current with a beam size of 1.4A.

In the step (4), the thickness and phase composition of the deposited material are generally controlled by changing the deposition time and the size of the electron beam.

The present invention also provides the copper-based composite material prepared according to the above method.

The copper-based composite material contains second phase particles, the second phase particles are Mo, Nb, Al ₂ O ₃ or Y ₂ O ₃ , the average volume content of the second phase particles is 0.4-2%, and the second phase The particle content in the copper matrix composite is periodically distributed along the thickness direction, and the particle size of the second phase is less than 50nm.

The volume content is determined by first measuring the mass content and then converting it into volume content, which is a detection method known to those skilled in the art.

The performance indexes of the copper-based composite material prepared by the invention are: tensile strength Rm≥500MPa, yield strength _{Rp0.2≥460MPa} , elongation≥6%, electrical conductivity≥80% IACS.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention uses periodically changing beams to heat and deposit the second phase material, so that the content of the second phase particles is periodically distributed along the thickness direction of the copper-based composite material, and the tensile strength of the obtained copper-based composite material is Rm≥500MPa, yielding Strength R _{p0.2 ≥} 460MPa, elongation ≥ 6%, electrical conductivity ≥ 80% IACS, while the room temperature yield strength of pure copper is 33MPa, and the tensile strength is 209MPa.

Description of drawings

Figure 1 is a TEM photo of the cross-section of the copper-based composite material prepared in Example 1.

Figure 2 is an enlarged view of A in Figure 1 .

detailed description

The technical solutions of the present invention will be further described through preferred embodiments below, but they should not be construed as limiting the protection scope of the present invention.

The electron beam physical vapor deposition equipment used in the embodiment of the present invention is Gekont L-5

Example 1:

Put the copper ingot and the molybdenum ingot into two crucibles in the vacuum chamber respectively, put 5g CaF ₂ on the copper ingot; close the vacuum chamber and start vacuuming; start the rotating device to rotate the substrate at a speed of 10rev/min , and turn on the substrate heating device, heat the substrate temperature to make it stable at 700°C; when the vacuum degree reaches 1×10 ^-2 Pa, open the isolation baffle between the substrate and the crucible, turn on the electron gun, and deposit the separation layer CaF ₂ ; then Constantly heat the copper ingot with a beam of 1.4A, and heat the molybdenum ingot with a beam size of 0.2-1.2A. During deposition, the beam of molybdenum fixed material is gradually increased from 0A to 1.2A, and then gradually decreased from 1.2A to 0.2A, then gradually increase from 0.2A to 1.2A, repeat the above process until the end of the preparation process, the increased or decreased beam rate is 2A/min. After 1 hour of deposition, turn off the electron gun, pull up the baffle, turn off the heating device, and turn off the substrate rotation device; when the temperature of the substrate drops below 200°C, open the vacuum chamber, remove the substrate, and separate to obtain copper with a thickness of 0.3mm and a diameter of 1000mm base composite material. The average volume content of molybdenum in the prepared composite material is 1.2vol%. According to the national standard GB/T228.1-2010, the final product is tested for mechanical properties, and its yield strength R _p0.2 = 470MPa, tensile strength Rm = 530MPa, Elongation 12%. The electrical conductivity of the material was detected by the four-probe method, and the electrical conductivity was 82% IACS. Figure 1 is a TEM photo of the cross-section of the prepared copper-based composite material, and Figure 2 is an enlarged view of A in the figure. It can be seen that there is a periodic structure in the thickness direction of the material. The Mo particles are large and the content is large at the black linear positions, and the Mo particles are small and low in the black linear positions, and the Mo particle size is less than 50nm.

Example 2:

Put the copper ingot and the niobium ingot into two crucibles in the vacuum chamber respectively, put 5g CaF ₂ on the copper ingot; close the vacuum chamber and start vacuuming; start the rotating device to rotate the substrate at a speed of 20rev/min , and turn on the substrate heating device, heat the substrate temperature to make it stable at 700°C; when the vacuum degree reaches 1×10 ^-2 Pa, open the isolation baffle between the substrate and the crucible, turn on the electron gun, and deposit the separation layer CaF ₂ ; then Constantly heat the copper ingot with a beam of 1.4A, and heat the niobium ingot with a beam size of 0.2-1.5A. During deposition, the beam for heating the niobium ingot gradually increases from 0A to 1.5A, and then gradually decreases from 1.5A to 0.2A, then gradually increase from 0.2A to 1.5A, repeat the above process until the end of the preparation process, the increased or decreased beam rate is 4A/min. After 1 hour of deposition, turn off the electron gun, pull up the baffle, turn off the heating device, and turn off the substrate rotation device; when the temperature of the substrate drops below 200°C, open the vacuum chamber, remove the substrate, and separate to obtain copper with a thickness of 0.3mm and a diameter of 1000mm base composite material. The average volume content of niobium in the prepared composite material is 1.3vol%. According to the national standard GB/T228.1-2010, the mechanical properties of the final product are tested, and its yield strength R _p0.2 = 490MPa, tensile strength Rm = 560MPa, Elongation 10%. The electrical conductivity of the material was detected by the four-probe method, and the electrical conductivity was 85% IACS.

Example 3:

Put the copper ingot and the yttrium oxide ingot into two crucibles in the vacuum chamber respectively, put 5g CaF ₂ on the copper ingot; close the vacuum chamber and start vacuuming; start the rotating device to rotate the substrate at a speed of 8rev/min , and turn on the substrate heating device, heat the substrate temperature to make it stable at 650°C; when the vacuum degree reaches 1×10 ^-2 Pa, open the isolation baffle between the substrate and the crucible, turn on the electron gun, and deposit the separation layer CaF ₂ ; then Constantly heat the copper ingot with a beam of 1.4A, heat the yttrium oxide ingot with a beam size of 0.2-1A, and gradually increase the beam of the yttrium oxide ingot from 0A to 1A during deposition, and then gradually decrease from 1A to 0.2 A, then gradually increase from 0.2A to 1A, repeat the above process until the end of the preparation process, the increased or decreased beam rate is 1A/min. After 1 hour of deposition, turn off the electron gun, pull up the baffle, turn off the heating device, and turn off the substrate rotation device; when the temperature of the substrate drops below 200°C, open the vacuum chamber, remove the substrate, and separate to obtain copper with a thickness of 0.3mm and a diameter of 1000mm base composite material. The average volume content of the prepared composite material yttrium oxide is 0.4vol%. According to the national standard GB/T228.1-2010, the final product is tested for mechanical properties, and its yield strength _Rp0.2 =470MPa, tensile strength Rm=530MPa, Elongation 15%. The electrical conductivity of the material was detected by the four-probe method, and its electrical conductivity was 90% IACS.

Example 4:

Put the copper ingot and the alumina ingot into two crucibles in the vacuum chamber respectively, put 5g of CaF ₂ on the copper ingot; close the vacuum chamber and start vacuuming; start the rotating device to rotate the substrate at a speed of 36rev/min , and turn on the substrate heating device, heat the substrate temperature to make it stable at 700°C; when the vacuum degree reaches 1×10 ^-2 Pa, open the isolation baffle between the substrate and the crucible, turn on the electron gun, and deposit the separation layer CaF ₂ ; then Constantly heat the copper ingot with a 1.4A beam, heat the alumina ingot with a beam size of 0.2-1.8A, and gradually increase the beam of the aluminum oxide ingot during deposition from 0A to 1.8A, and then gradually decrease from 1.8A As small as 0.2A, then gradually increase from 0.2A to 1.8A, repeat the above process until the end of the preparation process, the increased or decreased beam rate is 0.5A/min. After 1 hour of deposition, turn off the electron gun, pull up the baffle, turn off the heating device, and turn off the substrate rotation device; when the temperature of the substrate drops below 200°C, open the vacuum chamber, remove the substrate, and separate to obtain copper with a thickness of 0.3mm and a diameter of 1000mm base composite material. The average volume content of alumina in the prepared composite material is 2vol%, and the mechanical properties of the final product are tested according to the national standard GB/T 228.1-2010. The yield strength R _p0.2 = 500MPa, the tensile strength Rm = 540MPa, and the extension Rate 6%. The electrical conductivity of the material was detected by the four-probe method, and the electrical conductivity was 80% IACS.

Claims (6)

1. a kind of Cu-base composites are it is characterised in that described Cu-base composites contain Second Phase Particle, described second phase Grain is mo, nb, al₂o₃Or y₂o₃, the average external volume content of Second Phase Particle is 0.4-2%, and Second Phase Particle content is multiple in cuprio Condensation material through-thickness is in periodic distribution, and Second Phase Particle is smaller in size than 50nm；

The preparation method of described Cu-base composites comprises the following steps:

(1) adopt electro beam physics vapour deposition equipment, copper ingot material and the second phase material are respectively put into indoor two of vacuum In crucible, and put stratum disjunctum raw material on copper ingot material；Described second phase material is mo, nb, al₂o₃Or y₂o₃；

(2) vacuum chamber, evacuation are shut；Starting substrate rotating device makes substrate rotate, and heats substrate, makes the substrate temperature be 600-900℃；

(3) when vacuum reaches 1 × 10^-2During below pa, open the isolation baffle plate between substrate and crucible, open electron gun, electricity Sub- rifle launching electronics line, the stratum disjunctum raw material above Heated Copper ingot, on substrate, deposition obtains stratum disjunctum；

(4) after stratum disjunctum deposition finishes, electronic beam current respectively Heated Copper ingot and second phase material of electron gun transmitting, wherein with Constant line Heated Copper ingot, heats the second phase material with periodically variable line, deposits copper-based material in stratum disjunctum, when When deposit thickness reaches desired thickness, close electron gun, pull on isolation baffle plate, stop substrate heating and rotate；

(5) when substrate temperature is cooled to less than 200 DEG C, stop evacuation, take off substrate, separate and obtain sedimentary, as described Cu-base composites.

2. Cu-base composites as claimed in claim 1 are it is characterised in that in described step (1), described stratum disjunctum raw material is caf₂Or zro₂.

3. Cu-base composites as claimed in claim 1 are it is characterised in that in described step (2), the rotary speed of substrate is 2-40rev/min.

4. Cu-base composites as claimed in claim 1 are it is characterised in that in described step (4), described with cyclically-varying Line heat the second phase material, described periodically variable line refer to line size according to the following steps cycle period change:

A, line are gradually increased to ma from 0a；The scope of m is 1～1.8；

B, line gradually decrease to 0.2a from ma；

C, line are gradually increased to ma from 0.2a；

D, repeat step b～c.

5. Cu-base composites as claimed in claim 4 it is characterised in that described line increase or reduce speed be 0.5～ 4a/min.

6. Cu-base composites as claimed in claim 1 are it is characterised in that the performance indications of described Cu-base composites are: anti- Tensile strength rm >=500mpa, yield strength r_p0.2>=460mpa, elongation percentage >=6%, electrical conductivity >=80%iacs.