Preparation method of in-situ TiC ceramic particle reinforced aluminum matrix composite material by additive manufacturing

Abstract

The present invention relates to a preparation method of an in-situ TiC ceramic particle reinforced aluminum matrix composite material by additive manufacturing, which is characterized by comprising the following steps: (1) Preparation of composite powder: introducing titanium element and carbon element into pure aluminum or aluminum alloy powder; for the powder obtained by introducing titanium element and carbon element into pure aluminum or aluminum alloy powder, dispersing the powder, and drying the dispersed powder; (2) Laser powder bed melting forming: using a 3D printer to form the powder dried in step (1) by the laser powder bed melting method, the 3D printing parameters are laser power of 150-500 W, laser scanning speed of 300-2000 mm / s, scanning line spacing of 80-110 μm, powder layer thickness of 20-80 μm, and laser interlayer rotation angle of 0°-90°.

Description

Technical Field

[0001] The present invention belongs to the field of preparing aluminum alloys and their composites by additive manufacturing, and particularly relates to a method for preparing an in-situ TiC ceramic particle-reinforced aluminum matrix composite by additive manufacturing. Background Art

[0002] As a new preparation technology, metal additive manufacturing technology has the characteristics of simplicity, high efficiency, and one-step forming, with high design freedom, and is suitable for the preparation and production of special-shaped complex components. Compared with traditional preparation processes such as casting and powder metallurgy, it shows unique advantages. Currently, the metals suitable for additive manufacturing are mainly materials with good weldability, such as steel and titanium alloys. Aluminum alloys, due to their low density, high specific strength, and specific stiffness, are important materials for promoting the lightweighting of the aerospace and automotive industries and have broad application prospects. However, due to the high laser reflectivity, high thermal conductivity, and high surface oxidation degree of aluminum alloys, it is difficult to form them by additive manufacturing. Currently, the commercially available aluminum alloys suitable for additive manufacturing are mainly Al-Si alloys, such as cast aluminum alloys like AlSi10Mg and AlSi12. However, the cast aluminum alloys suitable for additive manufacturing have a high content of Si element and are difficult to be regulated by heat treatment to achieve the effect of heat treatment strengthening, so they cannot reach better mechanical properties, which limits their application. Therefore, traditional commercially available heat-treatable high-strength aluminum alloys such as Al-Cu and Al-Zn-Mg are good choices for further improving the performance of additive manufacturing aluminum alloys. However, high-strength aluminum alloys have a wide solidification range and a high solidification shrinkage rate. The samples prepared by additive manufacturing have coarse columnar grains, a high volume fraction of thermal cracks and pores, and are difficult to form.

[0003] Aiming at the problems existing in heat-treatable high-strength aluminum alloys, they are improved by microalloying or introducing ceramic particles. Al3X (Sc, Zr, Ti, Ta) formed during the solidification process of additive manufacturing serves as a heterogeneous nucleating agent, promoting the transformation of columnar grains into equiaxed grains and inhibiting the formation of thermal cracks. However, the aluminum alloys introduced with Sc and Zr elements show uneven grain morphology, with a mixed microstructure of ultrafine grains, coarse columnar grains, and medium-sized equiaxed grains. Moreover, Sc, as an expensive rare earth metal, is difficult to be used on an industrial scale. By introducing ceramic particles such as TiN, TiC, and SiC, while eliminating defects and obtaining a fine equiaxed grain structure, the ceramic particles can improve the strength, wear resistance, and other properties of the composite material to obtain an aluminum matrix composite with excellent comprehensive mechanical properties.

[0004] The methods of introducing ceramic particles into the aluminum matrix are divided into two types: external addition and in-situ synthesis. The external addition method is to directly add ceramic particles into the aluminum matrix, while the in-situ synthesis method is to introduce them into the aluminum matrix through chemical reactions. Among them, the high-content ceramic particles added externally are prone to agglomeration and difficult to disperse evenly. The method of introducing ceramic particles through in-situ synthesis can effectively avoid this problem and thus improve the performance of aluminum matrix composites more efficiently. At present, the molten salt method can achieve the in-situ introduction of ceramic particles, but its complex preparation process is difficult to apply on a large scale. Therefore, a simple preparation process is needed for the production of in-situ ceramic particle-reinforced aluminum matrix composites by additive manufacturing. Summary of the Invention

[0005] In view of the above deficiencies in the technology, the present invention provides a preparation method for additive manufacturing of in-situ TiC ceramic particle-reinforced aluminum matrix composites. Starting from the perspective of in-situ reactions and combined with a simple preparation process, this method can effectively achieve the in-situ synthesis of TiC ceramic particles and their uniform dispersion in the aluminum matrix, obtaining a heat-treatable and high-strength aluminum matrix composite. To achieve the above object, the present invention is realized through the following technical solutions:

[0006] The present invention provides a preparation method for additive manufacturing of in-situ TiC ceramic particle-reinforced aluminum matrix composites, comprising the following steps:

[0007] (1) Preparation of composite powder

[0008] Titanium element and carbon element are externally introduced into pure aluminum or aluminum alloy powder, where the molar ratio of Ti:C is 1:(0.1 - 10); for the powder obtained by externally introducing titanium element and carbon element into pure aluminum or aluminum alloy powder, it is dispersed, and the dispersed powder is dried.

[0009] (2) Laser powder bed fusion forming

[0010] The dried powder in step (1) is formed by a 3D printer using the laser powder bed fusion method. The 3D printing parameters are as follows: laser power is 150 - 500W, laser scanning speed is 300 - 2000mm / s, scanning line spacing is 80 - 110μm, powder layer thickness is 20 - 80μm, and laser interlayer rotation angle is 0° - 90°.

[0011] Preferably, in step (1), the content of each element is Ti: 0.05 - 10wt.%; C: 0.05 - 10wt.%.

[0012] Preferably, in step (1), the content of each element is Ti: 1 - 3wt.%; C: 0.25 - 1.25wt.%.

[0013] Preferably, in step (1), the titanium element is from titanium powder; the carbon element is from graphite powder.

[0014] Preferably, in step (1), the uniformly dispersed powder is placed in a vacuum drying oven and dried at 100 °C for 2 - 4 h, and then cooled to room temperature.

[0015] Preferably, in step (2), the 3D printing parameters are as follows: the laser power is 225 - 325 W, the laser scanning speed is 800 - 1300 mm / s, the scanning line spacing is 90 - 100 μm, the powder layer thickness is 30 - 60 μm, and the laser interlayer rotation angle is 45° - 90°.

[0016] Preferably, the composite material sample formed by laser powder bed fusion is solution treated at 500 - 540 °C, and then aged to obtain the heat-treated composite material sample.

[0017] Compared with the prior art, the substantial features of the present invention are as follows:

[0018] (1) In the present invention, TiC ceramic particles are introduced into the aluminum matrix by in-situ reaction, which act as heterogeneous nucleating agents to promote grain refinement, improve the formability of the aluminum matrix, and obtain an aluminum matrix composite with high density.

[0019] (2) The present invention utilizes the interaction between the laser and the powder, and TiC ceramic particles are introduced into the aluminum matrix by in-situ reaction rather than by external addition. The in-situ formed TiC ceramic particles have a good interfacial bond with the aluminum matrix.

[0020] (3) The present invention combines in-situ reaction with heat treatment to achieve the synergistic strengthening effect of in-situ TiC reinforcement phase and precipitation phase.

[0021] (4) The present invention prepares an in-situ TiC ceramic particle reinforced aluminum matrix composite by additive manufacturing. By adjusting the ratio and content of titanium powder and graphite powder, and optimizing the process parameters in laser powder bed fusion, the in-situ TiC ceramic particle reinforced aluminum matrix composite prepared can achieve a large degree of grain refinement. No obvious cracks and pores are observed inside the composite material, improving the strength and plasticity, and having great application prospects. Description of the Drawings

[0022] Figure 1 It is the stress-strain curves of the composite materials prepared in Examples 1, 2, 3, and 4 of the present invention.

[0023] Figure 2 It is the stress-strain curves of the composite materials prepared in Examples 2, 3, and 6 within the preferred parameter range of the present invention.

[0024] Figure 3Stress-strain curves of the composite materials prepared in Examples 1, 4, 5, and 7 within the non-preferred parameter range of the present invention.

[0025] Figure 4 Stress-strain curves of the composite materials prepared in Examples 8 and 9 within the preferred parameter range after heat treatment of the present invention.

[0026] Figure 5 XRD pattern of the composite material prepared in Example 6 of the present invention.

[0027] Figure 6 SEM image of the composite material prepared in Example 2 of the present invention.

[0028] Figure 7 SEM image of the tensile fracture surface of the composite material prepared in Example 2 of the present invention. Detailed implementation manners

[0029] We provide a preparation process for TiC ceramic particle-reinforced aluminum matrix composites by in-situ synthesis using the laser powder bed fusion method by designing the doping of titanium and carbon elements in pure aluminum or aluminum alloy powder to form TiC ceramic particles in-situ.

[0030] Reaction mechanism: In laser powder bed fusion forming, due to the interaction between the laser and the powder, the local temperature of the molten pool reaches above 2000 °C. Under the action of high temperature, the pure aluminum or aluminum alloy powder, the added titanium powder, and graphite powder in the molten pool are completely melted and the uniform distribution of aluminum, titanium, and carbon elements is achieved. Due to the short existence time of the molten pool, under the action of a fast laser scanning speed and a high cooling rate, the in-situ synthesized TiC ceramic particles are of nanometer size.

[0031] Reaction equation: Ti + C → TiC

[0032] The present invention will be further described below in conjunction with specific embodiments. The following embodiments illustrate the present invention but do not limit the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0033] Example 1

[0034] Weigh 8 g of titanium powder, 2 g of graphite powder, and 990 g of 2024 aluminum alloy powder into a 5-L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 250 W, the laser scanning speed is 800 mm / s, the scanning line spacing is 90 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 1 wt.%.

[0035] Example 2

[0036] Weigh 16 g of titanium powder, 4 g of graphite powder, and 980 g of 2024 aluminum alloy powder into a 5-L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 300 W, the laser scanning speed is 1300 mm / s, the scanning line spacing is 100 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 2 wt.%.

[0037] Example 3

[0038] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5-L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 250 W, the laser scanning speed is 900 mm / s, the scanning line spacing is 90 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%.

[0039] Example 4

[0040] Weigh 32 g of titanium powder, 8 g of graphite powder, and 960 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 250 W, the laser scanning speed is 800 mm / s, the scanning line spacing is 100 μm, the powder layer thickness is 30 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 4 wt.%.

[0041] Example 5

[0042] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 250 W, the laser scanning speed is 1600 mm / s, the scanning line spacing is 100 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%.

[0043] Example 6

[0044] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 300 W, the laser scanning speed is 1100 mm / s, the scanning line spacing is 90 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%.

[0045] Example 7

[0046] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 300 W, the laser scanning speed is 1500 mm / s, the scanning line spacing is 100 μm, the powder layer thickness is 40 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%.

[0047] Example 8

[0048] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 300 W, the laser scanning speed is 1100 mm / s, the scanning line spacing is 90 μm, the powder layer thickness is 30 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%. Then perform a solution treatment on the composite material sample at 520 °C for 2 h, and then carry out an aging treatment by keeping it at 120 °C for 18 h to obtain a heat-treated composite material sample.

[0049] Example 9

[0050] Weigh 24 g of titanium powder, 6 g of graphite powder, and 970 g of 2024 aluminum alloy powder into a 5 L stainless steel tank respectively, and uniformly disperse the powders. Place the uniformly dispersed powders in a vacuum drying oven, dry them at 100 °C for 3 h, and then cool them to room temperature. Use a 3D printer to form the dried powders by laser powder bed fusion method, where the laser power is 300 W, the laser scanning speed is 1100 mm / s, the scanning line spacing is 90 μm, the powder layer thickness is 30 μm, and the laser interlayer rotation angle is 67°. Obtain an in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite by additive manufacturing, where the theoretical content of TiC ceramic particles is 3 wt.%. Then perform a solution treatment on the composite material sample at 520 °C for 2 h, and then carry out an aging treatment by keeping it at 120 °C for 24 h to obtain a heat-treated composite material sample.

[0051] Figure 1 This is the stress-strain curve of the composite materials prepared in Examples 1, 2, 3, and 4 of the present invention. Figure 2Stress-strain curves of the composite materials prepared in Examples 2, 3, and 6 within the preferred parameter range of the present invention. Figure 3 Stress-strain curves of the composite materials prepared in Examples 1, 4, 5, and 7 outside the preferred parameter range of the present invention. Figure 4 Stress-strain curves of the composite materials prepared in Examples 8 and 9 within the preferred parameter range of the present invention after heat treatment. In the present invention, by adjusting the ratio and content of titanium powder and graphite powder added, and optimizing the process parameters during the laser powder bed fusion process, the in-situ TiC ceramic particle-reinforced 2024 aluminum matrix composite materials prepared in the examples within the preferred parameter range have good strength-ductility matching. After T6 heat treatment, the composite materials have a significant heat treatment strengthening effect, with a tensile strength of 530 MPa, realizing the synergistic strengthening effect between the in-situ TiC reinforcement phase and the precipitation phase.

[0052] Figure 5 XRD pattern of the composite material prepared in Example 6 of the present invention. Figure 5 It can prove the in-situ synthesis of TiC ceramic particles in the aluminum matrix by additive manufacturing. Figure 6 SEM image of the composite material prepared in Example 2 of the present invention. From Figure 6 fine equiaxed microstructures can be observed. The bright white nanoparticles are in-situ synthesized TiC ceramic particles, which are uniformly distributed inside the grains. Figure 7 SEM image of the tensile fracture surface of the composite material prepared in Example 2 of the present invention. Figure 7 Obvious tearing ridges and dimples are shown, indicating the ductile fracture of the composite material and good plasticity. The in-situ TiC ceramic particle-reinforced aluminum matrix composite material prepared by the additive manufacturing method of the present invention. During the 3D printing process, an in-situ reaction occurs between titanium powder and graphite powder to form TiC ceramic particles. Due to the extremely high cooling rate, the coarsening of TiC ceramic particles is restricted, and nano-sized TiC ceramic particles are obtained. The TiC ceramic particles formed by the in-situ reaction are mainly distributed inside the grains and have a good strengthening effect.

Claims

1. A preparation method of an in-situ TiC ceramic particle reinforced aluminum matrix composite by additive manufacturing, characterized in that, It includes the following steps: (1) Preparation of composite powder Introduce titanium element from titanium powder and carbon element from graphite powder into 2024 aluminum alloy powder externally, where the molar ratio of Ti:C is 1:(0.1~10), Ti: 1~3 wt.%; C: 0.25~1.25 wt.%; for the powder obtained by externally introducing titanium element and carbon element into 2024 aluminum alloy powder, disperse it, and dry the dispersed powder; (2) Laser powder bed fusion forming Use a 3D printer to form the powder dried in step (1) by laser powder bed fusion method. The 3D printing parameters are as follows: laser power is 225~325 W, laser scanning speed is 800~1300 mm / s, scanning line spacing is 90~100 μm, powder layer thickness is 30~60 μm, and laser interlayer rotation angle is 45°~90°.

2. The preparation method of an in-situ TiC ceramic particle reinforced aluminum matrix composite material for additive manufacturing according to claim 1, characterized in that, Perform solution treatment on the composite material sample formed by laser powder bed fusion at 500~540 °C, and then perform aging treatment to obtain a heat-treated composite material sample.

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