Series network structure reinforced phase reinforced aluminum matrix composite material and preparation method thereof
Technical Field
The invention belongs to the field of ceramic reinforced aluminum matrix composite materials, and particularly relates to a series network structure reinforced phase reinforced aluminum matrix composite material and a preparation method thereof.
Background
The aluminum-based composite material has the excellent performances of high specific strength, good thermal stability, good wear resistance and the like, and has wide application prospect in the fields of aerospace and automobiles. At present, most of aluminum-based composite materials are reinforced based on single ceramics, and microstructure structural characteristics are not obvious. With the continuous improvement of the requirements of the modern industry on the material performance, single reinforced aluminum-based composite materials encounter bottlenecks due to the single reinforcing effect. The special structure is customized through the complex phase or multiphase reinforced aluminum-based composite material, so that a new thought is provided for improving the performance of the aluminum-based composite material, and the preparation of the customized reinforced structure can be realized by combining the advantages of different reinforced phases. Therefore, the complex phase reinforced aluminum-based composite material with the customized structure has important significance for the development and application of the aluminum-based composite material.
From the viewpoint of the processing technology, the traditional processing technology such as casting and forging, powder metallurgy and the like is easy to generate defects of uneven distribution of ceramic reinforcing phases, difficult control of size and shape, poor combination of ceramic reinforcing phases and matrix interfaces and the like due to the differences of components, crystal structures and physical and chemical properties between the ceramic phases and the metal matrix, so that the comprehensive performance of the aluminum-based composite material is poor. The laser powder bed melting technology is used as a novel laser additive manufacturing technology, and is a process for forming parts by using high-intensity laser as an energy source and melting powder layer by layer according to Computer Aided Design (CAD) data. Because of their high dimensional accuracy, higher cooling rates and the ability to customize certain complex structural components, are widely used. Under the action of high-energy laser beam, the powder particles are completely melted, so that the adjacent scanning tracks or interlayer metallurgical bonding is good, and the formability and performance of the aluminum-based composite material part are improved. Therefore, the laser powder bed melting technology is selected to form the aluminum-based composite material, and the aluminum-based composite material has great development potential.
Disclosure of Invention
The invention aims to: aiming at the defects of the prior art, the invention provides a series network structure reinforced phase reinforced aluminum-based composite material and a preparation method thereof, which aims to solve the problem that the existing aluminum-based composite material has limited reinforcing effect and realize the improvement of laser formability and mechanical properties.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a reinforced aluminium-base composite material with serially connected net structure and reinforced phase is composed of aluminium alloy matrix and Al uniformly dispersed in said matrix 11 X 3 And Al 3 A Ti series network reinforcing phase;
wherein the aluminum alloy matrix is aluminum-copper-lithium-nickel-zirconium alloy; x is selected from any one of Ce, la, nd and the like;
said Al 11 X 3 And Al 3 Reinforcing phase of Ti series network structure with Al 11 X 3 Is a main chain, al 3 Ti is a node, and the reinforcing phases with the series network structure are uniformly distributed in the aluminum alloy matrix.
Further, the invention also provides a preparation method of the series network structure reinforced phase reinforced aluminum matrix composite, which comprises the following steps:
(1) TiH is processed by 2 Metal powder, XB 6 Ceramic powder and aluminum alloy matrix powderUniformly mixing to obtain composite powder;
(2) Establishing a three-dimensional solid geometric model of a target part, slicing the model in layers, planning a laser scanning path, dispersing the three-dimensional solid into a series of two-dimensional data, and storing and guiding the series of two-dimensional data into laser powder bed fusion forming equipment;
(3) And (3) quickly melting and solidifying the composite powder in the step (1) layer by layer according to the file imported in the step (2) by using laser powder bed fusion forming equipment to obtain the composite powder.
Preferably, in step (1), the TiH 2 The grain size of the metal powder is distributed in the range of 2-5 mu m, and the purity is more than 99.5%.
Preferably, in step (1), the XB 6 The grain size of the ceramic powder is distributed in the range of 2-5 mu m, and the purity is more than 99.5%.
Further, in step (1), the TiH 2 Metal powder, XB 6 The mass ratio of the ceramic powder is 3:1-1:5, preferably 1:1; the TiH is 2 Metal powder, XB 6 The total mass of the ceramic powder accounts for 1-5 wt%, preferably 2 wt%, of the mass of the aluminum alloy matrix powder.
Preferably, in the step (1), the aluminum alloy matrix powder is an aluminum-copper-lithium-nickel-zirconium alloy, wherein the copper content is 3.0-4.2 wt.%, the lithium content is 0.6-1.7 wt.%, the nickel content is 0.15-0.90 wt.%, the zirconium content is 0.1-0.8 wt.%, and the balance is Al; the grain size distribution range of the aluminum alloy powder is 21-52 mu m, and the purity is more than 99.5%.
Specifically, in step (1), tiH 2 Metal powder, XB 6 The ceramic powder and the aluminum alloy matrix powder are subjected to ball milling and uniform mixing under the protection of inert gas by a planetary ball mill. The inert gas is preferably argon.
Preferably, the planetary ball mill adopts a QM series planetary ball mill, the ball-material ratio is 2:1, the ball milling speed is 150-250 rpm/s, and the ball milling time is 3-6 h.
Specifically, in the step (3), the laser powder bed fusion forming equipment comprises a YLR-500 type optical fiber laser, a laser forming chamber, an automatic powder spreading system, a protective atmosphere device, a computer control circuit system and a cooling circulation system; before forming, fixing the titanium alloy substrate subjected to sand blasting treatment on a workbench of a selective laser melting forming device, leveling, sealing a forming cavity through a sealing device, vacuumizing, and introducing inert gas for protection, so that the laser powder bed melting forming is carried out to obtain the required part.
Preferably, in the step (3), the laser power adopted by the laser powder bed fusion forming equipment is 375-475w, the laser scanning speed is 800-1400mm/s, the scanning interval is 60-100 μm, the powder spreading thickness is 30-50 μm, and the island-shaped scanning strategy is adopted.
The invention discovers for the first time that TiH is used in the laser forming process 2 And XB (XB) 6 The powder reacts in situ in the bath to form Al 11 X 3 Is a main chain and Al 3 Ti is a series network structure of nodes, and the structure can be used as heterogeneous nucleation points to promote the transformation of coarse columnar crystals of aluminum alloy into fine equiaxed crystals, can play roles in solid solution strengthening and fine crystal strengthening, and can realize remarkable improvement of laser formability and mechanical properties.
The beneficial effects are that:
(1) The invention adopts TiH 2 And XB (XB) 6 Powder reinforced aluminum-based composite material can generate Al in situ under the action of high-energy laser 11 X 3 Is a main chain and Al 3 The structure can be used as a heterogeneous nuclear point to promote the transformation of coarse columnar crystals of aluminum alloy to fine equiaxed crystals, can play a role in synergy of solid solution strengthening and fine crystal strengthening, and can realize remarkable improvement of laser formability and mechanical properties.
(2) According to the invention, the laser energy density can be adjusted by changing the laser power and the laser scanning speed, the thermodynamic and dynamic characteristics of a molten pool formed by the action of laser and the powder bed are changed along with the change of the laser energy input of the powder bed, and the series network structure reinforced phase reinforced aluminum matrix composite with excellent formability and mechanical property is obtained by reasonably selecting laser technological parameters, adjusting the laser energy input, reducing the generation of metallurgical defects such as cracks and pores.
(3) Compared with the method of directly adding nano particles, the method can obviously reduce the cost, has good economic benefit and obviously improves the mechanical property.
Drawings
The foregoing and/or other advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings and detailed description.
FIG. 1 is a schematic diagram of a reinforcing phase of a series network structure in a laser formed aluminum matrix composite.
Figure 2 example 1 laser additive manufacturing a shaped aluminum matrix composite optical microscope image.
FIG. 3 example 1 laser additive manufacturing formed aluminum matrix composite microstructure image and EDS composition analysis.
FIG. 4 example 1 laser additive manufacturing shaped aluminum matrix composite tensile properties curves.
Fig. 5 comparative example 1 laser additive manufacturing a shaped aluminum matrix composite optical microscope image.
FIG. 6 comparative example 1 laser additive manufacturing shaped aluminum matrix composite tensile property curves.
Fig. 7 comparative example 2 laser additive manufacturing a shaped aluminum matrix composite optical microscope image.
FIG. 8 comparative example 2 laser additive manufacturing shaped aluminum matrix composite tensile property curves.
Detailed Description
The invention will be better understood from the following examples.
In the following examples, aluminum-copper-lithium-nickel-zirconium alloy powders having a particle size of 21 to 52 μm were used, wherein the copper content was 3.0 to 4.2wt.%, the lithium content was 0.6 to 1.7wt.%, the nickel content was 0.15 to 0.90wt.%, the zirconium content was 0.1 to 0.8wt.%, and the balance Al, the purity was greater than 99.5%.
TiH used 2 The grain size distribution range of the metal powder is 2-5 mu m, and the purity is more than 99.5%.
XB used 6 The grain size distribution range of the ceramic powder is 2-5 mu m, and the purity is largeAt 99.5%.
Example 1
(1) 98wt.% aluminum-copper-lithium-nickel-zirconium alloy powder, 1wt.% TiH using a QM-series planetary ball mill 2 Metal powder, 1wt.% LaB 6 The ceramic powder is uniformly mixed. The ball-to-material ratio is 2:1, introducing argon into a ball milling tank as a protective gas, wherein the ball milling speed is 200rpm/s, the ball milling time is 4.5h, and the ball milling mode is set to stop for 10min every 20min of running so as to prevent the temperature from being too high;
(2) Models of 10mm×10mm×5mm and 70mm×10mm×5mm were respectively drawn in a computer using Creo modeling software, and the three-dimensional model was sliced hierarchically and laser processing parameters were set using Magics software, laser power was set to 425W, laser scanning speed was set to 1100mm/s, scanning pitch was 80 μm, powder layer thickness was 40 μm, scanning strategy was island scanning strategy, and the data was then imported into a laser additive manufacturing apparatus for subsequent laser shaping.
(3) The aluminum-based composite powder obtained above was shaped using an LPBF-150 laser powder bed melting apparatus equipped with a YLR-500 type optical fiber laser having a wavelength of 1070nm and a spot size of 70 μm, the aluminum-based composite material was placed in a powder chamber before shaping, an aluminum substrate was fixed in the shaping chamber, and argon gas was introduced into the apparatus as a shielding gas so that the oxygen content inside the apparatus was less than 50ppm, and then the desired part was obtained by a layer-by-layer powder-spreading-melting-solidifying process according to the above-mentioned slicing data.
(4) The formed specimens were cut from the substrate and blocks of 10mm x 5mm size were ground and polished according to standard metallographic procedures for subsequent OM microstructure characterization.
FIG. 1 is a schematic diagram of a reinforcing phase of a series network structure in a laser formed aluminum-based composite material of the present invention. The composite material comprises an aluminum alloy matrix and Al uniformly dispersed in the aluminum alloy matrix 11 X 3 And Al 3 Ti tandem network reinforcing phases.
Wherein the aluminum alloy matrix is aluminum-copper-lithium-nickel-zirconium alloy; x is selected from any one of Ce, la, nd and the like; al (Al) 11 X 3 And Al 3 Ti series network structureReinforcing phase with Al 11 X 3 Is a main chain, al 3 Ti is a node, and the reinforcing phases with the series network structure are uniformly distributed in the aluminum alloy matrix.
As shown in FIG. 2, the laser formed aluminum-based composite sample has no crack, only has a small amount of air holes, has a density of 99.8%, and is fine equiaxed grains with an average grain size of 3 μm. As shown in FIG. 3, by EDS component analysis, it was found that Al was used as a component 11 La 3 Is a main chain, al 3 Ti is a series network structure of nodes. The block samples with the dimensions of 70mm×10mm×5mm were cut into standard tensile pieces and then subjected to tensile test using a CMT5205 universal tester at a tensile rate of 2mm/min, and the resulting engineering stress-strain curve was shown in fig. 4, with a tensile strength of 300MPa and an elongation of 5.5%, which was 34% higher than that of the laser-formed aluminum-copper-lithium-nickel-zirconium alloy sample (224.6 MPa). The structure can be used as a heterogeneous nucleation point to promote the transformation of coarse columnar crystals of the aluminum alloy to fine equiaxed crystals, and can play a role in the synergistic effect of solid solution strengthening and fine crystal strengthening, so that the laser formability and the mechanical property can be obviously improved.
Example 2
(1) 99wt.% aluminum-copper-lithium-nickel-zirconium alloy powder, 0.5wt.% TiH using a QM-series planetary ball mill 2 Metal powder, 0.5wt.% LaB 6 The ceramic powder is uniformly mixed. The ball-to-material ratio is 2:1, introducing argon into a ball milling tank as a protective gas, wherein the ball milling speed is 250rpm/s, the ball milling time is 3h, and the ball milling mode is set to stop for 10min every 20min of running so as to prevent the temperature from being too high;
(2) Models of 10mm×10mm×5mm and 70mm×10mm×5mm were respectively drawn in a computer using Creo modeling software, and the three-dimensional model was sliced hierarchically and laser processing parameters were set using Magics software, laser power was set to 375W, laser scanning speed was set to 800mm/s, scanning pitch was 60 μm, powder layer thickness was 30 μm, scanning strategy was island scanning strategy, and the data was then imported into a laser additive manufacturing apparatus for subsequent laser shaping.
(3) The aluminum-based composite powder obtained above was shaped using an LPBF-150 laser powder bed melting apparatus equipped with a YLR-500 type optical fiber laser having a wavelength of 1070nm and a spot size of 70 μm, the aluminum-based composite material was placed in a powder chamber before shaping, an aluminum substrate was fixed in the shaping chamber, and argon gas was introduced into the apparatus as a shielding gas so that the oxygen content inside the apparatus was less than 50ppm, and then the desired part was obtained by a layer-by-layer powder-spreading-melting-solidifying process according to the above-mentioned slicing data.
(4) The formed specimens were cut from the substrate and blocks of 10mm x 5mm size were ground and polished according to standard metallographic procedures for subsequent OM microstructure characterization. A block specimen of dimensions 70mm by 10mm by 5mm was cut into standard tensile pieces and then subjected to tensile testing using a CMT5205 universal tester, with a tensile rate set at 2mm/min. The density of the final laser formed sample is 99.3%, the tensile strength is 293MPa, and the strength is improved by 30% compared with the strength of a laser formed aluminum-copper-lithium-nickel-zirconium alloy sample (224.6 MPa).
Example 3
(1) 95wt.% aluminum-copper-lithium-nickel-zirconium alloy powder, 2.5wt.% TiH using QM series planetary ball mill 2 Metal powder, 2.5wt.% LaB 6 The ceramic powder is uniformly mixed. The ball-to-material ratio is 2:1, introducing argon into a ball milling tank as a protective gas, wherein the ball milling speed is 150rpm/s, the ball milling time is 6h, and the ball milling mode is set to stop for 10min every 20min of running so as to prevent the temperature from being too high;
(2) Models of 10mm×10mm×5mm and 70mm×10mm×5mm were respectively drawn in a computer using Creo modeling software, and the three-dimensional model was sliced hierarchically and laser processing parameters were set using Magics software, laser power was set at 475W, laser scanning speed was set at 1400mm/s, scanning pitch was 100 μm, powder layer thickness was 50 μm, scanning strategy was island scanning strategy, and the data was then imported into a laser additive manufacturing apparatus for subsequent laser shaping.
(3) The aluminum-based composite powder obtained above was shaped using an LPBF-150 laser powder bed melting apparatus equipped with a YLR-500 type optical fiber laser having a wavelength of 1070nm and a spot size of 70 μm, the aluminum-based composite material was placed in a powder chamber before shaping, an aluminum substrate was fixed in the shaping chamber, and argon gas was introduced into the apparatus as a shielding gas so that the oxygen content inside the apparatus was less than 50ppm, and then the desired part was obtained by a layer-by-layer powder-spreading-melting-solidifying process according to the above-mentioned slicing data.
(4) The formed specimens were cut from the substrate and blocks of 10mm x 5mm size were ground and polished according to standard metallographic procedures for subsequent OM microstructure characterization. A block specimen of dimensions 70mm by 10mm by 5mm was cut into standard tensile pieces and then subjected to tensile testing using a CMT5205 universal tester, with a tensile rate set at 2mm/min. The density of the final laser formed sample is 99.5%, the tensile strength is 286MPa, and the strength is improved by 27% compared with that of the laser formed aluminum-copper-lithium-nickel-zirconium alloy (224.6 MPa).
Comparative example 1
This comparative example was conducted as in example step 1, except that in step (1), only 2wt.% of TiH was used 2 Metal powder is used as reinforcing phase to strengthen the aluminum-based composite material; the microstructure is shown in FIG. 5, and a large number of voids appear in the aluminum-based composite sample of comparative example 1. Due to the addition of TiH only 2 Powder, in situ forming Al only 3 Ti precipitates and fails to form a reinforcing phase having a network structure in series. TiH under the action of high-energy laser 2 The metal powder melts to generate hydrogen, thus resulting in increased porosity and reduced sample density to 92%; the resulting stress-strain curves are shown in FIG. 6, and the tensile strength is 234MPa and the elongation is 1.8%, which is reduced by 30% and 50% respectively compared to example 1, illustrating TiH alone 2 The powder has limited reinforcing effect.
Comparative example 2
This comparative example was conducted as in example step 1, except that in step (1), only 2wt.% of LaB was used 6 Metal powder is used as reinforcing phase to strengthen the aluminum-based composite material; the microstructure is shown in FIG. 7, and a large number of cracks appear in the aluminum-based composite material sample of comparative example 1. Due to the addition of only LaB 6 Powder, in situ forming Al only 11 La 3 The precipitated phase failed to form a reinforcing phase having a network structure in series. Due to the difference of thermophysical parameters between the ceramic powder and the aluminum alloy matrix, and fine Al 11 La 3 The precipitated phase is used as heterogeneous nuclear pointThe supercooling degree required by heterogeneous nucleation is high, so that the grain refining effect is weakened, the formation of thermal cracks cannot be inhibited, and the density of a sample is reduced to 95%; as shown in FIG. 8, the obtained stress-strain curve has a tensile strength of 201MPa and an elongation of 0.78%, which is reduced by 40% and 78% respectively compared with example 1, and particularly the elongation is significantly reduced, and the material is brittle-broken, indicating that LaB alone 6 The powder has limited reinforcing effect and causes an increase in brittleness of the aluminum-based material.
The invention provides a serial reticular structure reinforced phase reinforced aluminum matrix composite material, a method for preparing the same, and a method for realizing the technical scheme. The components not explicitly described in this embodiment can be implemented by using the prior art.