3D-printed high strength aluminum alloy powder, alloy component and method for preparing the same

Abstract

The application relates to the field of additive manufacturing technology, in particular to a 3D printing high-strength and high-toughness aluminum alloy powder, an alloy component and a preparation method thereof. The 3D printing high-strength and high-toughness aluminum alloy powder comprises, in percentage by mass, Zn 5-8%, Mg 2-4%, Cu 1-2%, Ti 0.3-4%, Cr 0.1-0.3%, Mn 0.65-2% and C 0.01-0.3%, and the balance is Al and inevitable impurities. The application controls the content and proportion of Zn, Mg, Cu, Ti, Cr, Mn and C in the alloy, adjusts and controls the solidification behavior in the additive manufacturing process, obtains fine equiaxed crystals, has a large number of dispersed distribution precipitates, and can effectively improve the compactness, strength, crack propagation resistance and the like of the alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to a 3D printing high-toughness aluminum alloy powder, an alloy component and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy is an important material for lightweight and high-performance aerospace complex metal key components due to its light weight, high specific strength, good corrosion resistance and excellent thermal conductivity. Selective laser melting (SLM) is one of the most promising additive manufacturing technologies, which can quickly form fully metallurgical bonded and high-precision metal parts, and can provide an important technical approach for high-end equipment high-strength aluminum alloy complex component manufacturing. However, there are few types of commercially available additive manufacturing aluminum alloy powders at present, mainly AlSi10Mg, AlSi12 and other near-eutectic aluminum-silicon alloys, which have low mechanical properties (tensile strength less than 400 MPa, elongation less than 6%), limited load capacity, and cannot meet the demand for higher strength parts. On the other hand, traditional 2XXX, 6XXX and 7XXX series high-strength aluminum alloys are prone to form coarse columnar crystals during SLM forming, which easily leads to cracking, limiting their application.

[0003] Therefore, the present application is proposed. SUMMARY

[0004] The purpose of the present application is to provide a 3D printing high-toughness aluminum alloy powder, an alloy component and a preparation method thereof. By adjusting the element content and ratio in the alloy, the solidification behavior during additive manufacturing can be controlled, fine equiaxed crystals and a large number of dispersed distribution of precipitates can be obtained, and the density, strength and crack propagation resistance of the alloy can be improved.

[0005] In order to achieve the above purpose of the present application, the first aspect of the present application provides a 3D printing high-toughness aluminum alloy powder, which comprises, by mass percentage: Zn 5% to 8%, Mg 2% to 4%, Cu 1% to 2%, Ti 0.3% to 4%, Cr 0.1% to 0.3%, Mn 0.65% to 2%, C 0.01% to 0.3%, and the balance being Al and unavoidable impurities.

[0006] In the specific embodiment of the present application, the 3D printing high-toughness aluminum alloy powder comprises, by mass percentage: Zn 5% to 8%, Mg 2% to 4%, Cu 1% to 2%, Ti 0.8% to 2%, Cr 0.1% to 0.3%, Mn 0.65% to 1%, C 0.01% to 0.2%, and the balance being Al and unavoidable impurities.

[0007] In the specific embodiment of the present application, the mass percentage ratio of C element to Ti element in the 3D printing high-toughness aluminum alloy powder is 0.015-0.16.

[0008] The second aspect of the present application provides a preparation method of the 3D printing high-toughness aluminum alloy powder of the first aspect of the present application, comprising the following steps:

[0009] (a) using Al-Ti-C intermediate alloy, Al-Cr intermediate alloy, copper and aluminum as raw materials, after proportioning, melting is carried out; then magnesium, zinc and manganese are added in proportion, and after melting, heat preservation is carried out;

[0010] (b) after the melt prepared in step (a) is atomized to powder, screening and heat preservation treatment are carried out.

[0011] In the specific embodiment of the present application, in step (a), the temperature of the melting is 950-1050℃, and the time length of the melting is 5-20 min.

[0012] In the specific embodiment of the present application, in step (a), the melt after the melting is cooled to 800-900℃, and then magnesium, zinc and manganese are added in proportion. Further, in step (a), the time length of the heat preservation is 5-20 min.

[0013] In the specific embodiment of the present application, in step (b), in the atomization to powder, the melt is poured into a tundish preheated to 900-950℃. Further, in the atomization to powder, the atomization gas pressure is 1-5 MPa.

[0014] In the specific embodiment of the present application, the particle size range of the alloy powder after the screening is 15-53 μm.

[0015] In the specific embodiment of the present application, in step (b), in the heat preservation treatment, the temperature is 95-105℃, and the time is 2-6 h.

[0016] The third aspect of the present application provides an alloy component containing the 3D printing high-toughness aluminum alloy powder provided by the first aspect of the present application.

[0017] The fourth aspect of the present application provides a preparation method of the alloy component of the third aspect of the present application, comprising the following steps: subjecting the 3D printing high-toughness aluminum alloy powder provided by the first aspect of the present application to selective laser melting forming to obtain an alloy component blank; and subjecting the alloy component blank to heat treatment.

[0018] In the specific embodiment of the present application, in the selective laser melting forming, the substrate preheating temperature is 0-200℃, the laser power is 200-450 W, the scanning speed is 500-1800 mm / s, and the powder layer thickness is 20-100 μm.

[0019] In the specific embodiment of the present application, the heat treatment comprises: water cooling after holding at 450-520℃ for 1-3h; and air cooling after holding at 100-180℃ for 6-32h.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] (1) By controlling the content and ratio of Zn, Mg, Cu, Ti, Cr, Mn, C and other elements in the alloy, the solidification behavior in the additive manufacturing process is controlled, fine equiaxed crystals are obtained, and a large number of dispersed precipitates are obtained, which can effectively improve the density, strength, crack propagation resistance and other properties of the alloy.

[0022] (2) In the preparation of the alloy powder of the present application, by means of step-by-step melting, Al-Ti-C intermediate alloy is used as raw material, TiC particles can be used as the core of Al3Ti, which can make the Al-Ti-C intermediate alloy melt and disperse better and precipitate more Al3Ti particles with smaller size, so that the alloy powder composition is more uniform, and the problem of difficult to obtain relatively high Ti content aluminum alloy powder in the prior art is solved.

[0023] (3) After the 3D printing high strength and toughness aluminum alloy powder of the present application is printed by selective laser melting technology, the alloy component obtained has a dense and uniform structure, no crack defects, high surface precision, wide forming process range and stable mechanical properties, which solves the problem of cracking of traditional deformed aluminum alloy 3D printing; after proper heat treatment, the tensile strength can be higher than 500MPa, and the elongation can be higher than 8%, which is significantly better than the mechanical properties of AlSi10Mg, and has great potential in aerospace load-bearing parts. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 The 3D printing high strength and toughness aluminum alloy powder provided for Example 1 of the present application is shown in the morphology diagram;

[0026] Figure 2 The longitudinal section metallographic micrograph of the alloy component additive manufactured by using the 3D printing high strength and toughness aluminum alloy powder of Example 1 of the present application is shown in the following figure:

[0027] Figure 3A cross-section metallographic micrograph of an alloy component additively manufactured using the 3D printed high strength and toughness aluminum alloy powder of Example 1 of the present application;

[0028] Figure 4 A longitudinal-section metallographic micrograph of an alloy component additively manufactured using the aluminum alloy powder provided in Comparative Example 1;

[0029] Figure 5 A cross-section metallographic micrograph of an alloy component additively manufactured using the aluminum alloy powder provided in Comparative Example 1. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described clearly and completely in the following with reference to the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, rather than all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts are within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0031] It is found that by adding a certain amount of transition metal elements to the base powder, a large number of heterogeneous nucleation sites can be formed in the early stage of additive manufacturing solidification, promoting the nucleation of grains and promoting the transformation of columnar crystals to equiaxed crystals, thereby inhibiting the formation of cracks. For example, Scalmalloy alloy is based on 5XXX series alloy (Al-Mg) adding a certain amount of Sc and Zr, and the structure is equiaxed crystal at the boundary of the molten pool and columnar crystal at the center of the molten pool, but the rare earth element Sc is expensive, resulting in high cost of Scalmalloy alloy, which seriously restricts large-scale engineering application. Compared with Al-Mg alloy, 7XXX series alloy (Al-Zn-Mg-Cu) with higher strength potential has a wider solidification interval, so it has a higher cracking tendency. In the case of adding the same amount of Sc and Zr, it is still difficult to completely inhibit the crack. Ti element has a high growth restriction factor, and the L12-Al3Ti generated in the aluminum melt has a small lattice mismatch with aluminum, which is the preferred addition element for promoting heterogeneous nucleation. Using Ti element instead of Sc can greatly reduce the cost. However, the solubility of Ti in aluminum is extremely low, and in the conventional atomization and melting process, Ti is prone to bottoming, resulting in low Ti content in the melt, making it difficult to atomize the powder with the required Ti content to eliminate cracks. By externally mixing pure Ti or TiB2 nanoparticles, an Al-Zn-Mg-Cu-Ti alloy without cracks can be obtained, which has a completely fine equiaxed crystal structure and excellent performance, but nanoparticles are prone to spontaneous combustion, difficult to transport, and difficult to mass produce and apply.

[0032] Based on this, the first aspect of the present application provides a 3D printing high-toughness aluminum alloy powder, comprising, in mass percentage: Zn 5% to 8%, Mg 2% to 4%, Cu 1% to 2%, Ti 0.3% to 4%, Cr 0.1% to 0.3%, Mn 0.65% to 2%, C 0.01% to 0.3%, and the balance being Al and unavoidable impurities.

[0033] The present application controls the content and ratio of elements such as Zn, Mg, Cu, Ti, Cr, Mn, and C in the alloy, regulates the solidification behavior in the additive manufacturing process, obtains fine equiaxed crystals, and has a large number of dispersed distribution of precipitates, which can effectively improve the density, strength, crack propagation resistance and other properties of the alloy.

[0034] Specifically, in the 3D printing high-toughness aluminum alloy powder of the present application, the addition of Ti element will precipitate a large number of submicron Al3Ti particles during SLM solidification, and the lattice mismatch with Al is only 0.24%, which can be used as an effective heterogeneous nucleation agent for Al, significantly improving the nucleation efficiency and promoting the transformation of columnar crystals to equiaxed crystals. Compared with columnar crystals, the formation of fine equiaxed crystals will significantly shorten the liquid film length in the late solidification, thereby achieving the effect of inhibiting cracks. However, excessive Ti will form coarse intermetallic compounds, reducing the plasticity of the alloy. In the 3D printing high-toughness aluminum alloy powder of the present application, the mass fraction of Ti element is controlled at 0.3% to 4%, which can balance the inhibition of cracks and ensure plasticity. In different embodiments, the mass fraction of Ti element can be 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or a range consisting of any two of them.

[0035] In the aluminum alloy powder of the present application, an appropriate amount of C element is added to form nanoscale TiC particles, which have good thermal stability and wear resistance, and can also be used as a strengthening phase to achieve dispersion strengthening and fine-grain strengthening, improving high-temperature performance and wear resistance; and TiC has a high melting point, which precipitates before Al3Ti, and can act as a nucleus for Al3Ti, increasing the number of Al3Ti particles and reducing their size. However, as the amount of C element increases, the rate of decrease in the size of Al3Ti particles gradually slows down, and excessive C element generates more TiC, resulting in a decrease in the actual precipitated Al3Ti phase. In the aluminum alloy powder of the present application, the mass fraction of C element is controlled at 0.01% to 0.3%, which can balance the improvement of high-temperature performance and wear resistance, and promote the formation of a large number of fine Al3Ti particles to effectively inhibit cracks. In different embodiments, the mass fraction of C element can be 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.15%, 0.18%, 0.2%, 0.25%, 0.3%, or a range consisting of any two of them.

[0036] In the aluminum alloy powder of the present application, an appropriate amount of Mn element is added to form a larger lattice distortion in Al, having excellent solid solution strengthening strength; and the diffusion coefficient of Mn in Al is low, which can be better solid-solved in the matrix under the condition of additive manufacturing rapid solidification, improving the strength of the aluminum alloy. However, when the amount of Mn element is too high, the Mn not solid-solved in the matrix will form intermetallic compounds with Al, resulting in poor material plasticity. In the aluminum alloy powder of the present application, the mass fraction of Mn element is controlled at 0.65% to 2%, so as to better balance the strength and plasticity of the aluminum alloy. For example, in different embodiments, the mass fraction of Mn element can be 0.65%, 0.7%, 0.75%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, or a range formed by any two of them.

[0037] The Zn element in the aluminum alloy powder of the present application is a forming element of the strengthening phase MgZn2, which has a significant strengthening effect on the alloy. When the content of MgZn2 increases from 0.5% to 12%, the tensile strength and yield strength can be significantly increased. Since Zn has a low saturated vapor pressure, it is easy to volatilize during laser selective melting, and more Zn content needs to be added in the powder. However, too high Zn content will increase the stress corrosion cracking tendency of the alloy. In the aluminum alloy powder of the present application, the mass fraction of Zn element is controlled at 5% to 8%, so as to balance the strength of the alloy and reduce the cracking tendency. For example, in different embodiments, the mass fraction of Zn element can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, or a range formed by any two of them.

[0038] The Mg element in the aluminum alloy powder of the present application is also a forming element of the strengthening phase MgZn2. When Mg is excessive, it will produce a complementary strengthening effect. For every 1% increase of Mg in the alloy, the tensile strength increases by about 34 MPa. However, excessive Mg will increase the stress corrosion cracking tendency of the alloy. In the aluminum alloy powder of the present application, the mass fraction of Mg element is controlled at 2% to 4%, so as to balance the strength of the alloy and reduce the cracking tendency. For example, in different embodiments, the mass fraction of Mg element can be 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, or a range formed by any two of them.

[0039] The Cu element in the aluminum alloy powder of the present application has a certain solid solution strengthening effect, and the addition of an appropriate amount of Cu element can improve the stress corrosion resistance and tensile strength. However, when the content of Cu element is too high, not only the weight of the alloy will increase, but also the weldability and corrosion resistance of the alloy will decrease. For example, in different embodiments, the mass fraction of Cu element can be 1%, 1.2%, 1.5%, 1.8%, 2%, or a range formed by any two of them.

[0040] The addition of Cr element in the aluminum alloy powder of the present application can improve the stress corrosion resistance of the alloy, and increase the strength of the alloy in the quenched state and the artificial aging effect. However, excessive Cr will form intermetallic compounds with Al, reducing the plasticity of the alloy. In different embodiments, the mass fraction of Cr element can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, or a range consisting of any two of them.

[0041] The inevitable impurity content of the present application is controlled below 0.15wt%.

[0042] In a specific embodiment of the present application, the 3D printing high strength and toughness aluminum alloy powder comprises, by mass percentage: Zn 5%~8%, Mg 2%~4%, Cu 1%~2%, Ti 0.8%~2%, Cr 0.1%~0.3%, Mn 0.65%~1%, C 0.01%~0.2%, and the balance being Al and inevitable impurities.

[0043] In a specific embodiment of the present application, the mass percentage ratio of C element to Ti element in the 3D printing high strength and toughness aluminum alloy powder is 0.015~0.16.

[0044] TiC has a high melting point, and is precipitated before Al3Ti, which can act as a nucleus for the precipitation of Al3Ti, increasing the number of Al3Ti particles and reducing their size. However, as the amount of C element increases, the rate of decrease in the size of Al3Ti particles gradually slows down, and excessive C element generates more TiC, resulting in a decrease in the actual precipitation of Al3Ti phase. Controlling the mass percentage ratio of C element to Ti element to be 0.015~0.16 is more conducive to promoting the generation of a large number of fine Al3Ti particles. In different embodiments, the mass percentage ratio of C element to Ti element can be 0.015, 0.02, 0.025, 0.03, 0.04, 0.05, 0.06, 0.07, 0.075, 0.1, 0.12, 0.14, 0.16, or a range consisting of any two of them.

[0045] The second aspect of the present application provides a preparation method of the 3D printing high strength and toughness aluminum alloy powder of the first aspect of the present application, comprising the following steps:

[0046] (a) Al-Ti-C intermediate alloy, Al-Cr intermediate alloy, copper, and aluminum are used as raw materials, and after being proportioned, they are melted; then magnesium, zinc, and manganese are added in proportion, and after melting, they are kept warm;

[0047] (b) After the melt prepared in step (a) is atomized and powdered, it is sieved and kept warm.

[0048] The application takes Al-Ti-C intermediate alloy as raw material for introducing Ti and C elements, so that it is easier to melt and disperse in the smelting process. Moreover, by means of step-by-step smelting, Al-Ti-C intermediate alloy and the like are smelted at high temperature, so that Al3Ti particles are easier to melt and disperse, and the composition is more uniform; then magnesium, zinc, manganese and the like are added at low temperature, so that smoke and the like caused by evaporation and burn loss of these elements at high temperature is avoided.

[0049] In the specific embodiment of the application, in step (a), the temperature of smelting is 950-1050℃, and the time of smelting is 5-20min. For example, in step (a), the temperature of smelting can be 950℃, 980℃, 1000℃, 1020℃, 1050℃ or a range formed by any two of them, and the time of smelting can be 5min, 10min, 15min, 20min, etc.

[0050] In the specific embodiment of the application, in step (a), the melt after smelting is cooled to 800-900℃, for example, 800℃, 820℃, 850℃, 880℃, 900℃ or a range formed by any two of them, and then magnesium, zinc and manganese are added in proportion. Further, in step (a), the time of heat preservation is 5-20min, for example, 5min, 10min, 15min, 20min, etc.

[0051] In the specific embodiment of the application, in step (b), in the atomization powder preparation, the melt is poured into a tundish preheated to 900-950℃. Further, in the atomization powder preparation, the atomization gas pressure is 1-5MPa, for example, 1MPa, 2MPa, 3MPa, 4MPa, 5MPa or a range formed by any two of them.

[0052] In the specific embodiment of the application, the particle size of the alloy powder after screening is 15-53μm.

[0053] In the specific embodiment of the application, in the heat preservation treatment, the temperature is 95-105℃, and the time is 2-6h.

[0054] In the specific embodiment of the application, the size of TiC phase in the Al-Ti-C intermediate alloy is 50-500nm, and the average size of TiC phase is 180-220nm, for example, 200nm; the size of Al3Ti phase is 0.5-20μm, and the average size of Al3Ti phase is 6-8μm, for example, 7μm. The Al-Ti-C intermediate alloy of the application has smaller Al3Ti phase, so that it is easier to melt and disperse in the smelting process.

[0055] The preparation method of the Al-Ti-C intermediate alloy of the application comprises:

[0056] The aluminum ingot is heated and melted in a medium-frequency induction furnace, and a covering agent is uniformly sprinkled on the surface; when the temperature of the melt is increased to 850 DEG C, the potassium fluotitanate powder and the nano graphite powder are uniformly mixed and then added into the aluminum melt, and the melt is kept for 1 h; the melt is stirred by a graphite rod for multiple times during the keeping process; after the surface scum of the melt is removed, the alloy liquid is poured and formed to obtain the Al-Ti-C intermediate alloy; the mass percentage ratio of the C element to the Ti element is 0.015-0.16; the component ratio of Ti to C of the Al-Ti-C alloy used in each specific embodiment of the present application is consistent with the designed component ratio of the aluminum alloy powder of the corresponding embodiment; and the proportion of Al is obtained according to the raw material and the designed component of the aluminum alloy powder.

[0057] The Al-Cr intermediate alloy of the present application is Al-5Cr.

[0058] The 3D printing high-strength and high-toughness aluminum alloy powder prepared by the preparation method of the present application has good sphericity and fluidity, and ensures uniform powder laying performance in the 3D printing process. The 3D printing high-strength and high-toughness aluminum alloy powder of the present application has stable preparation batches and can be produced on a large scale.

[0059] The third aspect of the present application provides an alloy component containing the 3D printing high-strength and high-toughness aluminum alloy powder provided by the first aspect of the present application.

[0060] In the specific embodiment of the present application, the microstructure of the alloy component is equiaxed crystal, and the average size is 0.5-5 μm, and the size range is 0.1-5 μm.

[0061] In the specific embodiment of the present application, the size of the precipitated Al3Ti phase in the alloy component is 50-500 nm, and the volume fraction is 2%-10%.

[0062] In the specific embodiment of the present application, the size of the un-melted Al3Ti phase in the alloy component is 0.5-10 μm, the average size is ≤5 μm, and the volume fraction is ≤0.5%.

[0063] The fourth aspect of the present application provides a preparation method of the alloy component of the third aspect of the present application, which comprises the following steps: subjecting the 3D printing high-strength and high-toughness aluminum alloy powder provided by the first aspect of the present application to selective laser melting forming to obtain an alloy component blank; and subjecting the alloy component blank to heat treatment.

[0064] In the specific embodiment of the present application, in the selective laser melting forming, the preheating temperature of the substrate is 0-200 DEG C, the laser power is 200-450 W, the scanning speed is 500-1800 mm / s, and the powder layer thickness is 20-100 μm.

[0065] As in different embodiments, in selective laser melting forming, the substrate preheating temperature can be 0℃, 20℃, 40℃, 60℃, 80℃, 100℃, 150℃, 200℃ or a range consisting of any two of them; the laser power can be 200W, 250W, 300W, 350W, 400W, 450W or a range consisting of any two of them; the scanning speed can be 500mm / s, 800mm / s, 1000mm / s, 1200mm / s, 1500mm / s, 1800mm / s or a range consisting of any two of them; the powder layer thickness can be 20μm, 30μm, 50μm, 80μm, 100μm or a range consisting of any two of them.

[0066] In the specific embodiment of the present application, the heat treatment comprises: water cooling after holding at 450-520℃ for 1-3h; and air cooling after holding at 100-180℃ for 6-32h.

[0067] As in different embodiments, in the first step of the heat treatment, the holding temperature can be 450℃, 460℃, 480℃, 500℃, 520℃ or a range consisting of any two of them, and the holding time can be 1h, 2h, 3h, etc.; in the second step of the heat treatment, the holding temperature can be 100℃, 120℃, 140℃, 160℃, 180℃ or a range consisting of any two of them, and the holding time can be 6h, 10h, 16h, 20h, 24h, 32h, etc.

[0068] The 3D printing high-strength and high-toughness aluminum alloy powder of the present application, the alloy component formed by SLM technology, after the above heat treatment, the tensile strength can be higher than 500MPa, and the elongation can be higher than 8%, completely solving the cracking problem of the 3D printing alloy component of the deformed aluminum alloy.

[0069] Example 1

[0070] The present embodiment provides a 3D printing high-strength and high-toughness aluminum alloy powder, which comprises the following elements in mass percentage: Zn 6.98%, Mg 2.90%, Cu 1.54%, Ti 1.80%, Cr 0.21%, Mn 0.87%, C 0.15%, and the balance being Al and unavoidable impurities (the total content of the unavoidable impurities <0.15%).

[0071] The preparation method of the 3D printing high-strength and high-toughness aluminum alloy powder of the present embodiment comprises:

[0072] (1) Put the Al-Ti-C and Al-Cr intermediate alloy and pure copper and aluminum ingots into the crucible after proportioning, and melt in vacuum, the melting temperature is 960℃, and the melting time is 10min;

[0073] (2) The melt after refining in step (1) is cooled to 850℃, and then magnesium, zinc and manganese are put in proportionally by wrapping with aluminum foil, and after melting, the temperature is kept for 10 min;

[0074] (3) The melt after refining in step (2) is poured into a tundish preheated to 920℃, and atomized to powder at an atomization gas pressure of 2.5 MPa, and then the powder is sieved, the powder with a particle size of 15-53 μm is collected, and kept at 100℃ for 4 h to obtain the 3D printing high strength and toughness aluminum alloy powder.

[0075] The preparation method of the alloy component in this embodiment includes: using the 3D printing high strength and toughness aluminum alloy powder to be additively manufactured by selective laser melting technology, and then heat treated. The parameters of selective laser melting are: laser power 360 W, scanning speed 1400 mm / s, powder layer thickness 30 μm, substrate preheating temperature 100℃, and argon gas is used as the protective gas during the forming process. The heat treatment includes: keeping at 490℃ for 1 h, and then water cooling; and then keeping at 120℃ for 24 h, and then air cooling.

[0076] Example 2

[0077] This embodiment provides a 3D printing high strength and toughness aluminum alloy powder, which includes the following elements in percentage by mass: Zn 5.01%, Mg 2.03%, Cu 1.14%, Ti 0.64%, Cr 0.21%, Mn 0.66%, C 0.10%, and the balance is Al and unavoidable impurities (the total content of the unavoidable impurities <0.15%).

[0078] The preparation method of the 3D printing high strength and toughness aluminum alloy powder in this embodiment includes:

[0079] (1) Al-Ti-C and Al-Cr intermediate alloy, pure copper and aluminum ingot are proportioned and put into a crucible for vacuum melting, and the melting temperature is 980℃, and the melting time is 10 min;

[0080] (2) The melt after refining in step (1) is cooled to 820℃, and then magnesium, zinc and manganese are put in proportionally by wrapping with aluminum foil, and after melting, the temperature is kept for 10 min;

[0081] (3) The melt after refining in step (2) is poured into a tundish preheated to 920℃, and atomized to powder at an atomization gas pressure of 3.2 MPa, and then the powder is sieved, the powder with a particle size of 15-53 μm is collected, and kept at 100℃ for 4 h to obtain the 3D printing high strength and toughness aluminum alloy powder.

[0082] The preparation method of the alloy component in this embodiment is referred to Example 1, and the only difference is that the 3D printing high strength and toughness aluminum alloy powder in Example 1 is replaced by the 3D printing high strength and toughness aluminum alloy powder prepared in this embodiment.

[0083] Embodiment 3

[0084] The 3D printing high-toughness aluminum alloy powder of the present embodiment comprises the following elements in percentage by mass: Zn 7.68%, Mg 3.53%, Cu 1.94%, Ti 3.18%, Cr 0.23%, Mn 0.97%, C 0.15%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0085] The preparation method of the 3D printing high-toughness aluminum alloy powder of the present embodiment comprises:

[0086] (1) Put the Al-Ti-C and Al-Cr intermediate alloy, pure copper and aluminum ingot in the crucible after proportioning, and melt in vacuum at a temperature of 1010℃ for 10 min;

[0087] (2) Cool the melt after refining in step (1) to 830℃, then put magnesium, zinc and manganese in proportion into the melt by wrapping with aluminum foil, and keep the melt at temperature for 10 min after melting;

[0088] (3) Pour the melt after refining in step (2) into a tundish preheated to 925℃, and atomize the melt to powder at an atomization gas pressure of 1.9 MPa, then sieve the powder, collect the powder with a particle size of 15-53 μm, and keep the powder at 100℃ for 4 h to obtain the 3D printing high-toughness aluminum alloy powder.

[0089] The preparation method of the alloy component of the present embodiment refers to that of Embodiment 1, except that the 3D printing high-toughness aluminum alloy powder of Embodiment 1 is replaced by the 3D printing high-toughness aluminum alloy powder prepared in the present embodiment.

[0090] Embodiment 4

[0091] The present embodiment refers to the 3D printing high-toughness aluminum alloy powder and the preparation method thereof and the preparation method of the alloy component of Embodiment 1, except that the element composition of the 3D printing high-toughness aluminum alloy powder is different.

[0092] The 3D printing high-toughness aluminum alloy powder of the present embodiment comprises the following elements in percentage by mass: Zn 6.95%, Mg 2.95%, Cu 1.52%, Ti 1.82%, Cr 0.22%, Mn 0.85%, C 0.025%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0093] Embodiment 5

[0094] The embodiment of the 3D printing high-toughness aluminum alloy powder, by mass percent, comprises the following elements: Zn 6.92%, Mg 2.97%, Cu 1.53%, Ti 1.79%, Cr 0.20%, Mn 0.83%, C 0.295%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0095] The embodiment of the 3D printing high-toughness aluminum alloy powder, by mass percent, comprises the following elements: Zn 6.92%, Mg 2.97%, Cu 1.53%, Ti 1.79%, Cr 0.20%, Mn 0.83%, C 0.295%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0096] Comparative Example 1

[0097] The aluminum alloy powder of Comparative Example 1 comprises, by mass percent, the following elements: Zn 5.21%, Mg 2.61%, Cu 1.53%, Ti 0.033%, Cr 0.20%, Mn 0.069%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0098] The preparation method of the aluminum alloy powder of Comparative Example 1 comprises:

[0099] (1) zinc ingot, magnesium ingot, copper plate, titanium ingot, Al-Cr intermediate alloy and aluminum ingot are proportioned and placed in a crucible for vacuum melting, the melting temperature is 850°C, and the melting time is 10 min;

[0100] (2) the melt refined in step (1) is poured into a tundish preheated to 900°C, and the powder is prepared by atomization at a gas pressure of 2.4 MPa, then the powder is sieved, the powder with a particle size of 15-53 μm is collected, and the powder is kept at 100°C for 4 h to obtain a 3D printing high-toughness aluminum alloy powder.

[0101] The preparation method of the alloy component of Comparative Example 1 refers to Example 1, and the difference is only that the 3D printing high-toughness aluminum alloy powder of Example 1 is replaced by the aluminum alloy powder prepared in Comparative Example 1.

[0102] Comparative Example 2

[0103] Comparative Example 2 refers to the 3D printing high-toughness aluminum alloy powder and its preparation method and the preparation method of the alloy component of Example 1, and the difference is only that the element composition of the aluminum alloy powder is different.

[0104] The aluminum alloy powder of Comparative Example 2 comprises, by mass percent, the following elements: Zn 6.94%, Mg 2.92%, Cu 1.52%, Ti 1.82%, Cr 0.21%, Mn 0.42%, C 0.16%, and the balance of Al and inevitable impurities (the total content of inevitable impurities <0.15%).

[0105] Comparative Example 3

[0106] Comparative Example 3 refers to the preparation method of the 3D printing high strength and toughness aluminum alloy powder and the preparation method of the alloy member of Example 1, and the difference is only that the element composition of the aluminum alloy powder is different, and when the aluminum alloy powder is prepared, the Al-Ti alloy is used instead of the Al-Ti-C intermediate alloy.

[0107] The aluminum alloy powder of Comparative Example 3 comprises the following elements in mass percentage: Zn 6.92%, Mg 2.95%, Cu 1.56%, Ti 1.79%, Cr 0.23%, Mn 0.86%, and the balance is Al and unavoidable impurities (the total content of the unavoidable impurities <0.15%).

[0108] Experimental Example

[0109] Figure 1 The morphology diagram of the 3D printing high strength and toughness aluminum alloy powder prepared in Example 1 of the application is shown in the figure, and it can be seen from the figure that the powder has good sphericity. The microstructure of the alloy member of different examples and comparative examples is observed, Figures 2-3 The longitudinal section metallographic micrograph and the transverse section metallographic micrograph of the alloy member (before heat treatment) of the 3D printing high strength and toughness aluminum alloy powder of Example 1 of the application are shown in the figure, Figures 4-5 The longitudinal section metallographic micrograph and the transverse section metallographic micrograph of the alloy member of the 3D printing high strength and toughness aluminum alloy powder of Example 1 of the application are shown in the figure,

[0110] Table 1 Longitudinal section microstructure of different alloy members

[0111]

[0112] Further, the tensile properties of the alloy members of different examples and comparative examples after heat treatment are tested, and the test results are shown in Table 2.

[0113] Table 2 Tensile properties of different alloy members

[0114]

[0115] From the test results, it can be seen that after the 3D printing high-toughness aluminum alloy powder of the application is printed by using selective laser melting technology, the obtained alloy component has a compact and uniform structure, no crack defects, and high surface precision, and the problem of cracking of traditional deformed aluminum alloy 3D printing is solved; after proper heat treatment, the tensile strength is higher than 500MPa, and the elongation is higher than 8%, which is significantly better than the mechanical properties of AlSi10Mg, and has great potential in aerospace load-bearing parts.

[0116] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A 3D printing high-strength and high-toughness aluminum alloy powder, characterized in that, Composed of the following elements as a percentage by mass Composition: Zn 5%~8%, Mg 2%~4%, Cu 1%~2%, Ti 0.3%~4%, Cr 0.1%~0.3%, Mn 0.65%~2%, C 0.03%~0.2%, balance Al and unavoidable impurities; The mass percentage ratio of C to Ti is 0.025 to 0.

16.

2. The 3D printing high-strength and high-toughness aluminum alloy powder according to claim 1, characterized in that, Composed of the following elements as a percentage by mass Composition: Zn 5%~8%, Mg 2%~4%, Cu 1%~2%, Ti 0.8%~2%, Cr 0.1%~0.3%, Mn 0.65%~1%, C 0.03%~0.2%, with the balance being Al and unavoidable impurities.

3. The method for preparing 3D-printed high-strength and high-toughness aluminum alloy powder according to any one of claims 1 to 2, characterized in that, Includes the following steps: (a) Using Al-Ti-C master alloy, Al-Cr master alloy, copper and aluminum as raw materials, after mixing them in proportion, they are smelted; then magnesium, zinc and manganese are added in proportion, and the mixture is kept at a constant temperature after melting. (b) After atomizing the melt obtained in step (a) into powder, the melt is sieved and kept warm.

4. The preparation method according to claim 3, characterized in that, It has at least one of the following characteristics: (1) In step (a), the melting temperature is 950-1050°C and the melting time is 5-20 min; (2) In step (a), the melt after smelting is cooled to 800-900°C, and then magnesium, zinc and manganese are added in proportion; (3) In step (a), the heat preservation time is 5 to 20 minutes.

5. The preparation method according to claim 3, characterized in that, It has at least one of the following characteristics: (1) In step (b), during the atomization powdering process, the melt is poured into an intermediate ladle preheated to 900-950°C; (2) In the atomization powder making process, the atomization gas pressure is 1-5 MPa; (3) The particle size range of the alloy powder after sieving is 15-53 μm; (4) In step (b), the temperature during the heat preservation treatment is 95-105℃ and the time is 2-6h.

6. An alloy component, characterized in that, It contains the 3D printing high-strength and tough aluminum alloy powder as described in any one of claims 1 to 2.

7. The method for preparing the alloy component according to claim 6, characterized in that, Selective laser melting is performed on the 3D printing high-strength and tough aluminum alloy powder according to any one of claims 1 to 2 to obtain an alloy component blank; the alloy component blank is then heat-treated.

8. The method for preparing the alloy component according to claim 7, characterized in that, In the selected area laser melting forming process, the substrate preheating temperature is 0-200℃, the laser power is 200-450W, the scanning speed is 500-1800mm / s, and the powder layer thickness is 20-100μm.

9. The method for preparing the alloy component according to claim 7, characterized in that, The heat treatment includes: holding at 450–520°C for 1–3 hours, followed by water cooling; then holding at 100–180°C for 6–32 hours, followed by air cooling.

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