阅读说明：本技术 一种原位生成氮化铝增强铝基复合材料及其制备方法 (In-situ generated aluminum nitride reinforced aluminum-based composite material and preparation method thereof ) 是由 李森 张林杰 宁杰 张贵锋 程若亮 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种原位生成氮化铝增强铝基复合材料及其制备方法,由电弧熔丝增材制造工艺及搅拌摩擦加工工艺制备而成,所述电弧熔丝增材制造工艺中的保护气体为纯氮气或者氮气和氩气的混合气体；复合材料中的氮化铝强化相通过电弧增材制造过程中Al与N反应原位生成,并通过搅拌摩擦加工将氮化铝充分破碎得到,其中,复合材料中含有弥散分布的氮化铝颗粒,该复合材料具有较高的强度及良好的塑性,且制备方法较为简单。(The invention discloses an in-situ generated aluminum nitride reinforced aluminum-based composite material and a preparation method thereof, wherein the composite material is prepared by an arc fuse additive manufacturing process and a stirring friction processing process, and protective gas in the arc fuse additive manufacturing process is pure nitrogen or mixed gas of nitrogen and argon; the aluminum nitride strengthening phase in the composite material is generated in situ through the reaction of Al and N in the electric arc additive manufacturing process, and the aluminum nitride is fully crushed through stirring friction processing, wherein the composite material contains aluminum nitride particles which are dispersed, the composite material has high strength and good plasticity, and the preparation method is simple.)

1. The in-situ generated aluminum nitride reinforced aluminum-based composite material is characterized by being prepared by an arc fuse additive manufacturing process and a stirring friction processing process, wherein protective gas in the arc fuse additive manufacturing process is pure nitrogen or mixed gas of nitrogen and argon;

the aluminum nitride strengthening phase in the composite material is generated in situ through the reaction of Al and N in the electric arc additive manufacturing process, and the aluminum nitride is fully crushed through stirring friction processing, wherein the composite material contains aluminum nitride particles which are dispersed and distributed.

2. The in-situ generated aluminum nitride reinforced aluminum-based composite material as claimed in claim 1, wherein the content of the aluminum nitride particles in the composite material is adjusted by adjusting the content of nitrogen in the protective gas, so that the mass percentage A of the aluminum nitride in the composite material is 0.16-0.41%, wherein A is:

A＝-0.1597*B*B+0.7106*B-0.144

wherein B is the content of nitrogen in the mixed gas, and B is more than or equal to 50 percent.

3. The in-situ generated aluminum nitride reinforced aluminum matrix composite as claimed in claim 1, wherein the rotational speed of the stirring head in the friction stir processing is adjusted by adjusting R_FSPAnd a traveling speed V_FSPAnd controlling the maximum size C of the aluminum nitride after the friction stir processing, wherein C is as follows:

C＝500-17.668(R_FSP/V_FSP)+0.15434(R_FSP/V_FSP)*(R_FSP/V_FSP)。

4. a method for preparing an in-situ formed aluminum nitride reinforced aluminum matrix composite as claimed in claim 1, comprising the steps of:

1) determining the content and the maximum size of aluminum nitride in the composite material to be prepared;

2) taking a gas metal arc welding arc as a heat source, an aluminum alloy welding wire as a raw material, an aluminum alloy plate as a stacking substrate, pure nitrogen or mixed gas of nitrogen and argon as protective gas, and performing additive stacking through arc fuse additive manufacturing to form a deposition body, wherein the content of nitrogen in the protective gas is determined according to the content of aluminum nitride in the composite material to be prepared;

3) cutting off the stacked substrate, and leveling the surface of the deposition body to obtain a plate;

4) determining the rotating speed R of a stirring head in the friction stir processing technology according to the maximum size of the aluminum nitride in the composite material to be prepared_FSPAnd a traveling speed V_FSPAnd then, carrying out multi-pass friction stir processing on the plate by adopting a friction stir processing process to obtain the in-situ generated aluminum nitride reinforced aluminum matrix composite.

5. The method for preparing in-situ formed aluminum nitride reinforced aluminum matrix composite according to claim 4, wherein in the step 2), when the stacking manner is single-pass multi-layer stacking, the stacking forms a wall-shaped deposition body;

when the adopted accumulation mode is single-layer multi-channel accumulation, the accumulation forms a thin block shape.

6. The method for preparing the in-situ generated aluminum nitride reinforced aluminum matrix composite material according to claim 4, wherein the current in the arc fuse additive manufacturing process is 90A-150A, the voltage is 16V-22V, the welding gun walking speed is 15 cm/min-50 cm/min, and the nitrogen flow is 10L/min-20L/min.

7. The method for preparing an in-situ generated aluminum nitride reinforced aluminum matrix composite according to claim 4, wherein in the step 3), the surface of the deposited body is milled and leveled to obtain a plate with a thickness of 4mm to 7 mm.

8. The method for preparing the in-situ generated aluminum nitride reinforced aluminum matrix composite material according to claim 4, wherein the multi-pass friction stir processing adopts an overlapping mode, the overlapping rate OR is 0-1, and the overlapping rate OR is:

OR＝(d_pi-l)/d_pi

wherein d is_piThe diameter of the stirring pin end is defined as the distance between the center lines of two successive stirring pins.

9. The method for preparing the in-situ generated aluminum nitride reinforced aluminum matrix composite material according to claim 4, wherein the rotating speed of the stirring head in the multi-pass friction stir processing is 700r/min to 2000r/min, and the walking speed of the stirring head is 15cm/min to 95 cm/min.

Technical Field

The invention belongs to the technical field of preparation of aluminum-based composite materials, and relates to an in-situ generated aluminum nitride reinforced aluminum-based composite material and a preparation method thereof.

Background

The existing preparation methods of the particle reinforced aluminum matrix composite material comprise stirring casting, extrusion casting, stirring friction processing, jet deposition and the like. However, in these methods, the strengthening particles are introduced into the aluminum alloy matrix by means of external addition, for example, when stirring and casting, the aluminum alloy matrix is heated to above the liquidus line, then the aluminum liquid is stirred, the particles are poured into the aluminum liquid, and the particles are dispersed by stirring the melt. However, the wettability between the reinforcing particles and the aluminum alloy matrix is poor, the reinforcing particles and the aluminum alloy matrix are difficult to be effectively combined, and the reinforcing particles are difficult to be uniformly and dispersedly distributed in the aluminum alloy matrix. The reason is that the prepared aluminum matrix composite material has low strength and poor plasticity.

This requires improvement of the current method, and requires that the strengthening phase be well wetted with the aluminum alloy matrix, and that the strengthening particles be uniformly distributed in the matrix, to prepare an aluminum matrix composite material having high strength and good plasticity.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an in-situ generated aluminum nitride reinforced aluminum-based composite material and a preparation method thereof.

In order to achieve the purpose, the in-situ generated aluminum nitride reinforced aluminum matrix composite is prepared by an arc fuse additive manufacturing process and a stirring friction processing process, wherein protective gas in the arc fuse additive manufacturing process is pure nitrogen or mixed gas of nitrogen and argon;

the aluminum nitride strengthening phase in the composite material is generated in situ through the reaction of Al and N in the electric arc additive manufacturing process, and the aluminum nitride is fully crushed through stirring friction processing, wherein the composite material contains aluminum nitride particles which are dispersed and distributed.

The content of the aluminum nitride particles in the composite material is adjusted by adjusting the content of nitrogen in the protective gas, so that the mass percent A of the aluminum nitride in the composite material is 0.16-0.41%, wherein A is:

A＝-0.1597*B*B+0.7106*B-0.144

wherein B is the content of nitrogen in the mixed gas, and B is more than or equal to 50 percent.

By adjusting the rotating speed R of the stirring head in the stirring friction processing technology_FSPAnd a traveling speed V_FSPAnd controlling the maximum size C of the aluminum nitride after the friction stir processing, wherein C is as follows:

C＝500-17.668(R_FSP/V_FSP)+0.15434(R_FSP/V_FSP)*(R_FSP/V_FSP)。

the preparation method of the in-situ generated aluminum nitride reinforced aluminum-based composite material comprises the following steps:

1) determining the content and the maximum size of aluminum nitride in the composite material to be prepared;

2) taking a gas metal arc welding arc as a heat source, an aluminum alloy welding wire as a raw material, an aluminum alloy plate as a stacking substrate, pure nitrogen or mixed gas of nitrogen and argon as protective gas, and performing additive stacking through arc fuse additive manufacturing to form a deposition body, wherein the content of nitrogen in the protective gas is determined according to the content of aluminum nitride in the composite material to be prepared;

3) cutting off the stacked substrate, and leveling the surface of the deposition body to obtain a plate;

4) determining the rotating speed R of a stirring head in the friction stir processing technology according to the maximum size of the aluminum nitride in the composite material to be prepared_FSPAnd a traveling speed V_FSPAnd then, carrying out multi-pass friction stir processing on the plate by adopting a friction stir processing process to obtain the in-situ generated aluminum nitride reinforced aluminum matrix composite.

In the step 2), when the adopted stacking mode is single-channel multi-layer stacking, wall-shaped deposition bodies are formed by stacking;

when the adopted accumulation mode is single-layer multi-channel accumulation, the accumulation forms a thin block shape.

The current in the process of manufacturing the arc fuse additive is 90A-150A, the voltage is 16V-22V, the walking speed of a welding gun is 15 cm/min-50 cm/min, and the flow of nitrogen is 10L/min-20L/min;

and 3) milling and leveling the surface of the sediment body to obtain a plate with the thickness of 4-7 mm.

The multi-pass friction stir processing adopts a lapping mode, the lapping rate OR is 0-1, and the lapping rate OR is:

OR＝(d_pi-l)/d_pi

wherein d is_piThe diameter of the stirring pin end is defined as the distance between the center lines of two successive stirring pins.

The rotating speed of the stirring head in the multi-pass stirring friction processing process is 700r/min-2000r/min, and the walking speed of the stirring head is 15cm/min-95 cm/min.

The invention has the following beneficial effects:

when the in-situ generated aluminum nitride reinforced aluminum-based composite material and the preparation method thereof are operated specifically, an aluminum nitride reinforced phase is generated through the reaction of Al and N in the arc fuse additive manufacturing process, the aluminum nitride generated through the in-situ reaction and an aluminum alloy matrix can be well wetted, a good combination is formed between the aluminum nitride and the aluminum alloy matrix, and the defect that the wetting of an external particle reinforced phase and the aluminum alloy matrix is poor is overcome. The sediment body is subjected to stirring friction processing, aluminum nitride generated in situ is fully crushed and homogenized, the defect that external reinforced particles cannot be uniformly distributed is overcome, and after the stirring friction processing, a large number of uniform and dispersed aluminum nitride particles are distributed in the matrix, so that the reinforcing effect of the matrix can be fully exerted, the composite material has higher strength and good plasticity, and the preparation method is simpler.

Furthermore, during preparation, the preparation parameters are controlled according to the quantity and the maximum size of the aluminum nitride in the composite material to be prepared, so that the prepared composite material has excellent comprehensive mechanical property, the strength of the composite material is far higher than that of a corresponding rolling state base metal, and the composite material has good plasticity.

Drawings

FIG. 1a is a diagram of a 5356 aluminum alloy deposit for nitrogen protected arc fuse additive manufacturing;

FIG. 1b is a profile of the deposition body after milling;

FIG. 2 shows the shape and the sampling position of a tensile sample after friction stir processing of a 5356 aluminum alloy deposit manufactured by nitrogen-protected arc fuse additive manufacturing when the overlap ratio OR is 0;

fig. 3 is a structural morphology diagram of the 5356 aluminum alloy deposit after friction stir processing in nitrogen-protected arc fuse additive manufacturing when the overlap ratio OR is 0, and fig. 3 is a morphology diagram after corrosion, in which black pits are corrosion pits;

FIG. 4 is a graph showing the tensile strength of an aluminum nitride reinforced aluminum matrix composite material and a 5083 base material prepared at an overlap ratio OR of 0;

FIG. 5 shows the shape of the aluminum alloy deposit 5356 produced by nitrogen-protected arc fuse additive manufacturing after friction stir processing and the sampling position of a tensile sample when the overlap ratio OR is 0.5;

fig. 6 is a structural morphology diagram of the aluminum alloy deposition body 5356 produced by nitrogen-protected arc fuse additive manufacturing after friction stir processing when the overlap ratio OR is 0.5, wherein fig. 6 is a morphology diagram after corrosion, and black pits are corrosion pits;

fig. 7 is a graph showing the tensile strength of an aluminum nitride reinforced aluminum matrix composite material and a 5083 base material prepared at an overlap ratio OR of 0.5.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

The in-situ generated aluminum nitride reinforced aluminum-based composite material is prepared by an arc fuse additive manufacturing process and a stirring friction processing process, wherein a protective gas in the arc fuse additive manufacturing process is pure nitrogen or a mixed gas of nitrogen and argon;

the aluminum nitride strengthening phase in the composite material is generated in situ through the reaction of Al and N in the electric arc additive manufacturing process, and the aluminum nitride is fully crushed through stirring friction processing, wherein the composite material contains aluminum nitride particles which are dispersed and distributed.

The content of the aluminum nitride particles in the composite material is adjusted by adjusting the content of nitrogen in the protective gas, so that the mass percent A of the aluminum nitride in the composite material is 0.16-0.41%, wherein A is:

A＝-0.1597*B*B+0.7106*B-0.144

wherein B is the content of nitrogen in the mixed gas, and B is more than or equal to 50 percent.

By adjusting the rotating speed R of the stirring head in the stirring friction processing technology_FSPAnd a traveling speed V_FSPAnd controlling the maximum size C of the aluminum nitride after the friction stir processing, wherein C is as follows:

C＝500-17.668(R_FSP/V_FSP)+0.15434(R_FSP/V_FSP)*(R_FSP/V_FSP)。

the preparation method of the in-situ generated aluminum nitride reinforced aluminum-based composite material comprises the following steps:

1) determining the content and the maximum size of aluminum nitride in the composite material to be prepared;

2) taking a gas metal arc welding arc as a heat source, an aluminum alloy welding wire as a raw material, an aluminum alloy plate as a stacking substrate, pure nitrogen or mixed gas of nitrogen and argon as protective gas, and performing additive stacking through arc fuse additive manufacturing to form a deposition body, wherein the content of nitrogen in the protective gas is determined according to the content of aluminum nitride in the composite material to be prepared;

3) cutting off the stacked substrate, and leveling the surface of the deposition body to obtain a plate;

4) determining the rotating speed R of a stirring head in the friction stir processing technology according to the maximum size of the aluminum nitride in the composite material to be prepared_FSPAnd a traveling speed V_FSPAnd then, carrying out multi-pass friction stir processing on the plate by adopting a friction stir processing process to obtain the in-situ generated aluminum nitride reinforced aluminum matrix composite.

In the step 2), when the adopted stacking mode is single-channel multi-layer stacking, wall-shaped deposition bodies are formed by stacking; when the adopted accumulation mode is single-layer multi-channel accumulation, the accumulation forms a thin block shape.

The current in the process of manufacturing the arc fuse additive is 90A-150A, the voltage is 16V-22V, the walking speed of a welding gun is 15 cm/min-50 cm/min, and the flow of nitrogen is 10L/min-20L/min;

and 3) milling and leveling the surface of the sediment body to obtain a plate with the thickness of 4-7 mm.

The multi-pass friction stir processing adopts a lapping mode, the lapping rate OR is 0-1, and the lapping rate OR is:

OR＝(d_pi-l)/d_pi

wherein d is_piThe diameter of the stirring pin end is defined as the distance between the center lines of two successive stirring pins.

The rotating speed of the stirring head in the multi-pass stirring friction processing process is 700r/min-2000r/min, and the walking speed of the stirring head is 15cm/min-95 cm/min.

Example one

The preparation method of the in-situ generated aluminum nitride reinforced aluminum-based composite material comprises the following steps:

1) preparing an aluminum matrix composite material with the nitride content of 0.4% and the maximum size of 2 mu m;

2) adopting nitrogen protection to carry out arc fuse additive manufacturing to prepare a deposition body;

in the step 2), 5356 aluminum alloy welding wires with the diameter of 1.2mm are used as raw materials, 5083 aluminum alloy is used as a substrate, the thickness of the substrate is 3mm, MIG electric arc is used as a heat source, and pure nitrogen (99.99% N) is used as protective gas₂) The accumulation mode is single-channel multi-layer accumulation, the material increase parameters are current 102A, voltage 16.6V, the welding gun walking speed is 30cm/min, and the protective air flow rate is 13L/min. In the accumulation process, a steel brush is adopted to clean the surface of a weld bead in each accumulation pass to expose the metal luster, and then the accumulation of the next weld bead is carried out until the accumulation is finished.

3) Cutting off the substrate of the sediment body by adopting linear cutting, and then milling the rugged part on the surface of the sediment body by adopting a milling machine to change the rugged part into a flat plate, wherein the thickness of the milled plate is 5.5 mm;

4) and carrying out multi-pass stirring friction processing on the flat plate to obtain the aluminum nitride reinforced aluminum matrix composite.

In the step 4), the size of the stirring head adopted for the multi-pass friction stir processing is as follows: the diameter of the shaft shoulder is 24mm, the length of the stirring pin is 3.5mm, and the diameter of the end part of the stirring pin is 5 mm; the parameters of the stirring friction processing are as follows: the rotating speed of the stirring head is 1180r/min, and the walking speed of the stirring head is 23.5 cm/min. The multi-pass friction stir processing adopts a lap joint mode, the lap joint rate OR is 0, namely the distance between the central lines of two friction stir processing passes is 5mm, and each part of the plate is ensured to be processed by the stirring needle.

The nitrogen-protected arc fuse additive manufacturing of the deposition body is shown in fig. 1a, and due to the way of layer-by-layer accumulation of the deposition body, the surface is uneven, and a very flat plate is formed after milling, as shown in fig. 1 b. When the overlap ratio OR is 0, the surface topography of the deposit body by multi-pass friction stir processing is shown in fig. 2. The structure of the aluminum nitride reinforced aluminum-based composite material obtained by subjecting the sediment body to multi-pass friction stir processing is shown in fig. 3, fine nitride particles are uniformly distributed in an aluminum alloy matrix, the tensile property is shown in fig. 4, the tensile strength of the aluminum nitride reinforced aluminum-based composite material is 343MPa, the elongation is 24%, the tensile strength of a 5083 aluminum alloy substrate similar to the components of the aluminum nitride reinforced aluminum-based composite material in the market is 295MPa, and the elongation is 31%, so that the strength of the aluminum-based composite material prepared by the method is far higher than that of a commercially available material similar to the components of the aluminum-based composite material, and the aluminum-based composite material has excellent plasticity.

Example two

The preparation method of the in-situ generated aluminum nitride reinforced aluminum-based composite material comprises the following steps:

1) preparing an aluminum matrix composite material with the nitride content of 0.4 percent and the maximum size of 2 mu m;

2) adopting nitrogen protection to carry out arc fuse additive manufacturing to prepare a deposition body;

in the step 2), 5356 aluminum alloy welding wires with the diameter of 1.2mm are used as raw materials, 5083 aluminum alloy is used as a substrate, the thickness of the substrate is 3mm, and MIG electric arcs are used as heat sources. The protective gas adopts pure nitrogen (99.99 percent N)₂). The stacking mode is single-layer multi-channel stacking, and the additive parameters are as follows: the current is 102A, the voltage is 16.6V, and the welding gun walking speed is 30 cm/min; in the accumulation process, a steel brush is adopted to clean the surface of a weld bead in each accumulation pass to expose the metal luster, and then the accumulation of the next weld bead is carried out until the accumulation is finished.

3) Cutting off the substrate of the sediment body by adopting linear cutting, and then milling the rugged part on the surface of the sediment body by adopting a milling machine to change the rugged part into a flat plate, wherein the thickness of the milled plate is 5.5 mm;

4) and carrying out multi-pass stirring friction processing on the flat plate to obtain the aluminum nitride reinforced aluminum matrix composite.

Step 4), the size of a stirring head adopted by multi-pass friction stir processing is as follows: the diameter of the shaft shoulder is 24mm, the length of the stirring pin is 3.5mm, and the diameter of the end part of the stirring pin is 5 mm. The friction stir processing parameters obtained by calculation are as follows: the rotating speed of the stirring head is 1180r/min, and the walking speed of the stirring head is 23.5 cm/min. The multi-pass friction stir processing adopts an overlap joint mode, the overlap joint ratio OR is 0.5, namely the distance between the central lines of two friction stir processing passes is 2.5mm, and each part of the plate is ensured to be processed by the stirring pin.

The surface morphology of the deposit body after multi-pass friction stir processing is shown in fig. 5 when the overlap ratio OR is 0.5; the structure of the aluminum nitride reinforced aluminum-based composite material obtained by subjecting the deposition body to multi-pass friction stir processing is shown in fig. 6, and fine nitride particles are uniformly distributed in the aluminum alloy matrix; as shown in FIG. 7, the tensile strength of the aluminum nitride reinforced aluminum matrix composite is 351MPa, the elongation is 27%, the tensile strength of a 5083 aluminum alloy substrate similar to the aluminum nitride reinforced aluminum matrix composite in components on the market is 295MPa, and the elongation is 31%, so that the aluminum matrix composite prepared by the invention has the strength far exceeding that of a commercially available material similar to the aluminum nitride reinforced aluminum matrix composite in components, and has excellent plasticity.

Finally, the invention combines the electric arc fuse wire additive manufacturing technology with the stirring friction processing technology, and fully utilizes the advantages of the electric arc fuse wire additive manufacturing technology and the stirring friction processing technology to prepare the aluminum-based composite material. Meanwhile, the quantity and the size of the nitride in the aluminum matrix composite material can be regulated and controlled. The aluminum nitride in the aluminum-based composite material is obtained by reacting Al and N in the process of manufacturing the arc fuse additive. Because the aluminum nitride is generated in situ in the aluminum alloy matrix, the aluminum nitride can be well wetted with the aluminum alloy matrix, and the aluminum nitride and the aluminum alloy matrix are effectively combined. However, the aluminum nitride exists in the aluminum alloy matrix in a lamellar shape, and has a large size, the length of which can reach 500 μm, and the large-size aluminum nitride cannot effectively play a role in strengthening. Therefore, the invention adopts the stirring friction processing mode to process the sediment body, and the aluminum nitride in the sediment body is crushed, so that the aluminum nitride can be more uniformly distributed in the aluminum alloy matrix. After the stirring and friction processing, the shape of the aluminum nitride is changed into particles, the size is greatly reduced, and the maximum size is only a few microns, so that the aluminum nitride reinforced aluminum matrix composite material with high strength and excellent plasticity is prepared.