Part machined from aluminum alloy and its preparation process

Abstract

A machined aluminum alloy part and its preparation process, enabling, through optimization of the workpiece composition, its preparation by laser powder bed fusion, which forms a target metallographic phase. According to the invention, the machined aluminum alloy part comprises the following components, by mass fraction: 1.0% to 2.5% Fe, 1.5% to 3.0% Cu, 1.0% to 2.0% Cr, 0.5% to 1.1% Ti, 0.4% to 1.0% Zr, and Al for the remainder. The process yields an aluminum alloy material system with high strength and toughness at room temperature / at elevated temperatures for laser powder bed fusion, and extends the range of applications of laser powder bed fusion technology in the field of mesothermal end-use parts. Figure for the abstract: Figure 1

Description

Title of the invention: Worked part made of aluminum alloy and its preparation method Technical field

[0001] The present invention belongs to the technical field of additive manufacturing, and relates in particular to a worked part made of aluminum alloy and its preparation method. Background

[0002] In recent years, the aviation, aerospace, and automotive industries have developed rapidly. In the field of mesothermal end-use parts (200°C to 350°C), new materials and structural design techniques aimed at reduced weight and greater toughness can provide important supports for an energy-efficient sustainable development model. In the field of high-end equipment, there is an urgent need for the creation of complex aluminum alloy components resistant to high temperatures.Additive manufacturing technology based on laser powder bed fusion (LPBF) of complex aluminum alloy components has become a new research hotspot in the field of manufacturing, integrating structure and function, for metallic materials due to the irreplaceable advantages in material processing and structure design. However, due to the inherent high reflectivity of the laser and easy oxidation of the aluminum alloy, only two alloys, such as cast aluminum alloy ZL104 (AlSiioMg) and Al-Mg-Sc-Zr, developed by Airbus, can be used in LPBF for a long time. Preliminary research results show that although LPBF-processed Al-Si and Al-Mg-Sc-Zr alloys have excellent properties at room temperature, their tensile strengths are only about 70 MPa to 90 MPa and 30 MPa to 40 MPa respectively at 350°C, which cannot meet the requirements of mesothermal end parts.However, traditional Al-Cu alloys (2xxx series) with desirable temperature strength are prone to hot cracking during LPBF preparation during rapid directional solidification of the weld pool due to a wide solidification temperature range, resulting in inaccurate forming. Recently, research teams in the United States, Japan, and other countries have made some progress in the additive manufacturing of high-temperature aluminum alloys such as the Al-Fe and Al-Ce series, from the foundation of the casting process. However, due to the non-uniform distribution of a large number of intermetallic compounds in Al-Fe and . Al-Ce with low plasticity, there is always poor manufacturability and insufficient plasticity at room temperature, so it is impossible to directly prepare complex components by LPBF on a large scale. Summary

[0003] In order to overcome the disadvantages of the prior art, an objective of the present invention is to provide an aluminum alloy workpiece and a method for preparing the same. The present invention can avoid uneven distribution and poor room temperature plasticity of intermetallic compounds in the existing aluminum alloy system.

[0004] To achieve the above objective, the present invention adopts the following technical solutions.

[0005] The present invention provides an aluminum alloy workpiece comprising the following components, in mass fraction: 1.0% to 2.5% Fe, 1.5% to 3.0% Cu, 1.0% to 2.0% Cr, 0.5% to 1.1% Ti, 0.4% to 1.0% Zr, and the remainder Ai.

[0006] As a further improvement of the invention, the following embodiments are possible.

[0007] Preferably, the worked part made of aluminum alloy comprises less than 0.2%, in mass fraction, of elementary impurities.

[0008] Preferably, the aluminum alloy workpiece comprises more than 2.5% and less than 3.5%, by mass fraction, of Fe and Cr in total.

[0009] Preferably, the aluminum alloy workpiece comprises less than 2.0%, by mass fraction, of Ti and Zr in total.

[0010] Preferably, the aluminum alloy workpiece comprises less than 0.01%, by mass fraction, of oxygen.

[0011] Preferably, the aluminum alloy workpiece has a tensile strength greater than or equal to 500 MPa at room temperature.

[0012] Preferably, the aluminum alloy workpiece has an elastic limit greater than or equal to 400 MPa at room temperature.

[0013] Preferably, the aluminum alloy workpiece has an elongation greater than or equal to 8% at room temperature.

[0014] Preferably, the aluminum alloy workpiece has a tensile strength greater than or equal to 200 MPa at 350°C.

[0015] Preferably, the aluminum alloy workpiece has an elastic limit greater than or equal to 160 MPa at 350°C.

[0016] Preferably, the aluminum alloy workpiece has an elongation greater than or equal to 8% at 350°C.

[0017] The present invention also provides a method of preparing the part worked in aluminum alloy, including the following steps:

[0018] Step 1: drawing a three-dimensional diagram of a part to be prepared, and formulating the process parameters during printing; and

[0019] Step 2: Printing using configured aluminum alloy powder baked in a laser powder bed fusion (LPBF) printer to produce the aluminum alloy workpiece.

[0020] Preferably, in step 1, the process parameters include laser power, scanning speed, spacing between scan lines, rotation angle, lamination thickness, oxygen content, and substrate preheating temperature.

[0021] Preferably, in step 2, the particle size distribution of the aluminum alloy powder comprises: a D10 powder having a particle size of 10 pm to 25 pm, a D50 powder having a particle size of 30 pm to 45 pm, and a D90 powder having a particle size of 50 pm to 60 pm.

[0022] Preferably, in step 2, the aluminum alloy powder is baked at a temperature of 100°C to 120°C for 2 hours to 4 hours.

[0023] The present invention has the following beneficial effects over the existing art:

[0024] The present invention provides an aluminum alloy workpiece. In the aluminum alloy workpiece, by optimizing the content of each element, the aluminum alloy workpiece has a heterogeneous structure in the final metallographic phase, a combination of columnar grains and equiaxed grains, and has excellent strengthening by an intermetallic compound. Therefore, the aluminum alloy workpiece has excellent tensile strength, high temperature stability, and room temperature strength, so that the alloy has desirable mechanical properties at room temperature and high temperatures, exhibiting high strength, excellent crack resistance, and desirable plasticity.

[0025] The present invention further provides a method for preparing an aluminum alloy workpiece. By optimizing the composition of the aluminum alloy workpiece, the aluminum alloy workpiece can be prepared by LPBF in the preparation process, thereby forming a target metallographic phase. The preparation method overcomes the problem that the composition of a high-strength and high-temperature resistant aluminum alloy designed on the basis of a traditional casting and forging process cannot go hand in hand with LPBF, and makes full use of the rapid cooling of LPBF. By establishing a composition system of the aluminum alloy workpiece combined with the rapid cooling of LPBF, an alloy composition of aluminum having a target crystalline phase is prepared by the method. The preparation method combines the composition of the aluminum alloy with LPBF to achieve mutual promotion, thereby forming a target part, so that an aluminum alloy having high strength and toughness at room temperature / high temperature can be prepared by LPBF. The preparation method results in a material system of the aluminum alloy having high strength and toughness at room temperature / high temperature for LPBF, and expands the application range of LPBF technology in the field of mesothermal final parts.

[0026] Furthermore, the alloy powder used in the LPBF of the invention achieves lower cost during preparation. Brief description of the drawings

[0027] [Fig.l] [Fig.l] shows a flowchart of the invention;

[0028] [Fig.2] [Fig.2] shows a state diagram of a powder and its particle size in Example 1;

[0029] [Fig.3a] [Fig.3a] shows a microphotograph of a finished product prepared in Example 1, where (a) is an optical microscope image of a part formed by LPBF; and

[0030] [Fig.3b] [Fig.3b] shows a microphotograph of a finished product prepared in Example 1, where (b) is a microstructure of the part formed after etching; and

[0031] [Fig.4a] [Fig.4a] shows a performance test result of the alloy prepared in Example 1, where (a) is a performance diagram at room temperature;

[0032] [Fig.4b] [Fig.4b] shows a performance test result of the alloy prepared in Example 1, where (b) is a performance diagram at an elevated temperature. Detailed Description of Embodiments

[0033] The present invention will be further explained in detail below with reference to the accompanying drawings.

[0034] The present invention provides an aluminum alloy workpiece, comprising the following components, in mass fraction: 1.0% to 2.5% of Fe, 1.5% to 3.0% of Cu, 1.0% to 2.0% of Cr, 0.5% to 1.1% of Ti, 0.4% to 1.0% of Zr, and the balance being Ai. In the alloy system, the elements Al and Fe can form a reinforcing phase of intermetallic compound Al6Fe, which improves tensile strength and high temperature stability. The elements Al, Cu, Cr, and Fe can form two quasicrystalline reinforcing phases, Al-Fe-Cr and Al-Cu-Fe-Cr, and simultaneously precipitate reinforcing nanophases such as 0-Al2 Cu. Elemental Ti-Al3Ti can improve the high temperature stability of the quasicrystalline phase and refine the size of the quasicrystalline phase. Zr elements and Al generate Al3Zr particles that can be used as heterogeneous nucleation cores of a-Al grains, refining the grains and realizing the transformation of columnar grains into equiaxed grains, so as to improve the plasticity of the alloy system. In addition, the Al3Zr phase can also improve the high-temperature stability of the overall system. Furthermore, Ti and Zr elements can introduce Ll2-type Al3(Zr,Ti) particles existing at the melt boundary during LPBF forming, with a size of 100 nm to 800 nm. Due to a small lattice mismatch with a-Al, the particles can serve as heterogeneous nucleation cores to promote the transformation of columnar grains into equiaxed grains. Eventually, a heterogeneous structure is formed, consisting of columnar crystals within the melt and equiaxed crystals at the melt boundary.Under the action of strengthening the residual internal stresses, the room temperature strength and toughness of the alloy are each further improved.

[0035] Preferably, the total content of elemental Fe and Cr is greater than 2.5% and does not exceed 3.5%. The total content of elemental Ti and Zr is greater than 0.9% and does not exceed 2.0%.

[0036] More preferably, in one example, the elemental impurity content is less than 0.2%. Specifically, the elemental impurities are alloying element impurities, in the form of alloying impurities that are inevitably introduced due to the process or by the introduction of raw materials during the preparation of the alloy; in the example, the oxygen content is less than 0.01%. Limiting the elemental impurity and oxygen content can prevent the generation of unnecessary brittle metal oxides or intermetallic compounds, thereby preventing grain formation from being affected and the overall aluminum alloy content from being affected.

[0037] In one example of the invention, it is defined that there is a tensile strength greater than or equal to 500 MPa at room temperature, a yield strength greater than or equal to 400 MPa at room temperature, and an elongation greater than or equal to 8% at room temperature.

[0038] In an example of the invention, the properties of the aluminum alloy workpiece at 350°C are defined, specifically the tensile strength is greater than or equal to 200 MPa at 350°C, the yield strength is greater than or equal to 160 MPa at 350°C, and the elongation is greater than or equal to 8% at 350°C.

[0039] In the present invention, the above tensile strength, yield strength and elongation can be obtained in these two examples mainly through the design of the composition system, and the formation of strengthening phases at various scales in the alloy system can improve in combination the strength and ductility of alloys. Elemental Al and Fe can form strengthening phases into intermetallic compounds Al6Fe and Al3Fe4, which improves the tensile strength and high-temperature stability. Elemental Al, Cu, Cr, and Fe can form two quasicrystalline strengthening phases, Al-Fe-Cr and Al-Cu-Fe-Cr. Elemental Ti can improve the high-temperature stability of the quasicrystalline phase and refine the size of the quasicrystalline phase. Elemental Zr and Al generate Al3Zr particles, which can be used as heterogeneous nucleation cores of a-Al grains, refining the grains and realizing the transformation from columnar grains to equiaxed grains, so as to improve the plasticity of the alloy system. In addition, the Al3Zr phase can also improve the high-temperature stability of the whole system.In addition, the introduced elemental Ti and Zr can also lead to a heterogeneous microstructure composed of equiaxed grains at the melt boundary and columnar grains in the melt. Under the effect of further strengthening of residual internal stresses, the alloy can achieve strength-toughness synergy at room temperature. This property can further expand the use of the alloy system in both room temperature and high temperature fields, and can be applied to high-temperature petroleum pipelines, filter elements, engine pistons, and other components.

[0040] The present invention further provides a method for preparing the aluminum alloy workpiece. The aluminum alloy workpiece can be prepared by LPBF in the preparation method. For an Al-Fe-Cu-Cr-Ti-Zr alloy target, rapid solidification of LPBF is adopted, which has rapid cooling, and has obvious non-uniform distribution of temperature gradient and solidification rate on the scale of a single melt. Therefore, LPBF is advantageous for forming a reinforced Al-based composite having an Al-Fe-Cr quasicrystal, metastable phases of Al-Cu and Al-Fe, and Al3 Ti and Al3Zr as reinforcing phases in different regions of the melt.The composite structure is mainly manifested by: structural features of a duplex microstructure with equiaxed and columnar grains of a-Al grains on the 100 pm scale, heterogeneous distribution of Al-Fe-Cr quasicrystal and Al-Fe phase at the melt edge and center on the 1 pm to 10 pm scale, and enhanced precipitation of Al3Ti, Al3Zr, and Al2Cu phases on the nanoscale. As a result, by combining the above composite strengthening mechanisms, the alloy at room temperature and high temperatures has significantly improved composite strength, which is suitable for more severe environments. The preparation process specifically includes the following steps: .

[0041] Step 1, a three-dimensional diagram of a part is drawn, and a scanning strategy is formulated; in step 1, the formulated scanning strategy specifically consists of the process parameters of LPBF, including important parameters such as laser power, scanning speed, spacing between scanning lines, rotation angle, lamination thickness, oxygen content, and substrate preheating temperature.For the alloy composition in this example, specific process parameters include: a laser power of 325 W to 400 W, a scanning speed of 1000 mm / s to 1400 mm / s, a scan line spacing of 100 pm to 140 pm, a rotation angle of 17° to 67°, a lamination thickness of 0.025 mm to 0.03 mm, an oxygen content of less than 200 ppm, and a substrate preheating temperature of 150°C to 195°C, with the residual stress of the part being reduced by heating the substrate.

[0042] Step 2, an aluminum alloy powder is prepared according to a target composition, and the aluminum alloy powder is dried.

[0043] Preferably, the aluminum alloy powder is prepared by gas atomization in a suitable ratio of the elementary raw materials. The composition and proportions of the aluminum alloy powder are as follows:

[0044] Table 1 - Composition of aluminum alloy powder

[0045] [Tables 1] Element Fe Cu Cr Ti Zr Al Content (wt%) 1.0 to 2.5 1.0 to 3.0 1.0 to 2.0 0.5 to 1.1 0.4 to 1.0 The remainder

[0046] The impurity content of the master alloy is less than 0.2%, and the oxygen content is less than 0.01%.

[0047] Furthermore, the particle size distribution and flowability requirements of the powder are as follows:

[0048] Table 2 - Particle size distribution requirements

[0049] [Tables2] DIO / pm D50 / pm D90 / pm Indicator requirements (%) 10 to 25 30 to 45 50 to 65

[0050] The aluminum alloy powder has a bulk density greater than 1.36 g / cm2 and a Hall flow rate less than 80 s / 50 g.

[0051] As one of the preferred solutions, a powder having a particle size of 15 pm to 53 pm is dried under vacuum at a temperature of 100°C to 120°C for 2 hours to 4 hours.

[0052] Step 3, the baked aluminum alloy powder is printed on a printer LPBF according to the established process parameters, so that a quasi-crystalline reinforced Al-based composite is prepared to obtain high-strength aluminum alloy parts.

[0053] The present invention will be further described in detail with reference to specific examples, which are intended to illustrate and not to limit the present invention.

[0054] Example 1

[0055] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 17° and a layer thickness of 0.03 mm.

[0056] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.0% Fe, 2.0% Cu, 1.0% Cr, 1.0% Ti, 1.0% Zr, and the remainder being Ai; the aluminum alloy powder had a particle size state shown in [Fig.2]. The powder exhibited desirable sphericity, where most of the powder particles had a smooth surface, and a small portion had a certain proportion of satellite powder. The particles with the largest size were less than 70 pm, while there were fewer small-sized powders, and the majority of the particles had a particle size distribution of 10 pm to 60 pm, suitable for LPBF. The powder with a particle size of 15 pm to 53 pm was baked at 110°C for 3 hours.

[0057] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 375 W, a scanning speed of 1400 mm / s, a spacing between scanning lines of 140 pm, and a substrate preheating temperature of 150°C.

[0058] Step 4, a printed experimental block was separated from the substrate by wire cutting for preparation of a metallographic sample and density measurement. The finished product is shown in [Fig.3a] and [Fig.3b], where (a) is an optical microscope image of the LPBF-treated part, and it is seen that the formed sample has a high density and no obvious defects; and (b) is a post-corrosion microstructure image of the LPBF-treated part, and it is seen that a single melt has a width of 100 pm to 150 pm and a depth of 20 pm to 40 pm. In addition, the reinforced particles have a non-uniform distribution in different regions of the melt.

[0059] Step 4, the mechanical properties of the part were determined with the optimal process parameters. Referring to [Fig.4a] and [Fig.4b], the aluminum alloy powder of this example had a density of not less than 99% with LPBF forming; from (a), it is seen that the as-deposited samples have a tensile strength of 500 MPa or more, an upper yield strength of or equal to 400 MPa, and an elongation greater than or equal to 8% at room temperature; it is seen from (b) that the as-deposited samples have a tensile strength greater than or equal to 200 MPa, a yield strength greater than or equal to 160 MPa, and an elongation greater than or equal to 8% at 350°C.

[0060] Example 2

[0061] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 50° and a layer thickness of 0.025 mm.

[0062] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 1% Fe, 2.0% Cu, 1.8% Cr, 0.8% Ti, 0.6% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 115°C for 3 hours.

[0063] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 350 W, a scanning speed of 1200 mm / s, a spacing between scan lines of 120 pm, and a substrate preheating temperature of 155°C.

[0064] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0065] Example 3

[0066] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 63° and at a layer thickness of 0.03 mm.

[0067] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 1.8% Fe, 2.5% Cu, 1.5% Cr, 1.1% Ti, 0.8% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 120°C for 2 hours.

[0068] Step 3, the fired powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 400 W, a scanning speed of 1300 mm / s, a spacing between scanning lines of 130 pm, and a substrate preheating temperature of 150°C.

[0069] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0070] Example 4

[0071] Step 1, a three-dimensional diagram of an experimental block with parameters optimized process parameters were plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 43° and at a layer thickness of 0.027 mm.

[0072] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.5% Fe, 1.5% Cu, 1.4% Cr, 0.9% Ti, 0.9% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 120°C for 2 hours.

[0073] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 360 W, a scanning speed of 1250 mm / s, a spacing between scanning lines of 125 pm, and a substrate preheating temperature of 160°C.

[0074] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0075] Example 5

[0076] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 37° and at a layer thickness of 0.03 mm.

[0077] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.5% Fe, 1.8% Cu, 2% Cr, 0.8% Ti, 0.6% Zr, and the remainder being Al. The powder having a particle size of 30 pm to 45 pm was fired at 120°C for 3.5 hours.

[0078] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 365 W, a scanning speed of 1350 mm / s, a spacing between scanning lines of 135 pm, and a substrate preheating temperature of 170°C.

[0079] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0080] Example 6

[0081] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 23° and at a layer thickness of 0.029 mm.

[0082] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.3% Fe, 2.2% Cu, 1.7% Cr, 0.75% Ti, 0.5% Zr, and the remainder being Ai. The powder having a particle size of 15 pm to 53 pm was baked at 115°C for 2.5 hours.

[0083] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 355 W, a scanning speed of 1400 mm / s, a spacing between scanning lines of 140 pm, and a substrate preheating temperature of 180°C.

[0084] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0085] Example 7

[0086] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 67° and at a layer thickness of 0.03 mm.

[0087] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.2% Fe, 3% Cu, 2% Cr, 0.6% Ti, 0.4% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 120°C for 4 hours.

[0088] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 340 W, a scanning speed of 1000 mm / s, a spacing between scanning lines of 100 pm, and a substrate preheating temperature of 190°C.

[0089] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0090] Example 8

[0091] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 45° and at a layer thickness of 0.025 mm.

[0092] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.4% Fe, 2.5% Cu, 1.2% Cr, 0.7% Ti, 0.8% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 115°C for 4 hours.

[0093] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 325 W, a scanning speed of 1300 mm / s, a spacing between scan lines of 130 pm, and a substrate preheating temperature of 160°C.

[0094] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0095] Example 9

[0096] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 55° and at a layer thickness of 0.03 mm.

[0097] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.4% Fe, 2.2% Cu, 1.3% Cr, 0.5% Ti, 0.9% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 113°C for 3.5 hours.

[0098] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 330 W, a scanning speed of 1150 mm / s, a spacing between scan lines of 120 pm, and a substrate preheating temperature of 180°C.

[0099] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0100] Example 10

[0101] Step 1, a three-dimensional diagram of an experimental block with optimized process parameters was plotted, and layer slicing was performed using a scanning strategy with a rotation angle between adjacent layers of 35° and at a layer thickness of 0.027 mm.

[0102] Step 2, an aluminum alloy powder to be fired was prepared, and the aluminum alloy powder comprised the following components: 2.2% Fe, 1.9% Cu, 1.6% Cr, 0.8% Ti, 0.7% Zr, and the remainder being Al. The powder having a particle size of 15 pm to 53 pm was fired at 112°C for 4 hours.

[0103] Step 3, the baked powder was printed in a powder feed chamber of an LPBF printer, where LPBF was performed at a laser power of 335 W, a scanning speed of 1150 mm / s, a spacing between scan lines of 135 pm, and a substrate preheating temperature of 195°C.

[0104] Step 4, a printed experimental block was separated from the substrate by wire cutting for the preparation of a metallographic sample and the measurement of density and mechanical properties.

[0105] The above described constitutes purely preferred embodiments of the invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should all fall within the scope of protection of the invention.

Claims

Claims

1. An aluminum alloy workpiece comprising the following components, in mass fraction: 1.0% to 2.5% Fe, 1.5% to 3.0% Cu, 1.0% to 2.0% Cr, 0.5% to 1.1% Ti, 0.4% to 1.0% Zr, and the remainder Ai.

2. An aluminum alloy workpiece according to claim 1, comprising less than 0.2%, by mass fraction, of elemental impurities.

3. An aluminum alloy workpiece according to any one of claims 1 or 2, comprising more than 2.5% and less than 3.5%, by mass fraction, of Fe and Cr in total.

4. An aluminum alloy workpiece according to any one of claims 1 to 3, comprising less than 2.0%, by mass fraction, of Ti and Zr in total.

5. An aluminum alloy workpiece according to any one of claims 1 to 4, comprising less than 0.01%, by mass fraction, of oxygen.

6. An aluminum alloy workpiece according to any one of claims 1 to 5, having a tensile strength greater than or equal to 500 MPa at room temperature.

7. An aluminum alloy workpiece according to any one of claims 1 to 6, having a yield strength greater than or equal to 400 MPa at room temperature.

8. An aluminum alloy workpiece according to any one of claims 1 to 7, having an elongation greater than or equal to 8% at room temperature.

9. An aluminum alloy workpiece according to any one of claims 1 to 8, having a tensile strength greater than or equal to 200 MPa at 350°C.

10. An aluminum alloy workpiece according to any one of claims 1 to 9, having a yield strength greater than or equal to 160 MPa at 350°C.

11. An aluminum alloy workpiece according to any one of claims 1 to 10, having an elongation greater than or equal to 8% at 350°C.

12. A method of preparing the aluminum alloy workpiece according to any one of claims 1 to 11, comprising the steps following: step 1: drawing a three-dimensional diagram of a part to be prepared, and formulating the process parameters during printing; and step 2: printing a configured and baked aluminum alloy powder in a laser powder bed fusion (LPBF) printer to obtain the aluminum alloy workpiece.

13. A method of preparing an aluminum alloy workpiece according to claim 12, wherein, in step 1, the process parameters include laser power, scanning speed, spacing between scanning lines, rotation angle, lamination thickness, oxygen content, and substrate preheating temperature.

14. A method for preparing an aluminum alloy workpiece according to any one of claims 12 to 13, wherein, in step 2, the particle size distribution of the aluminum alloy powder is characterized by a D10 value of 10 pm to 25 pm, a D50 value of 30 pm to 45 pm, and a D90 value of 50 pm to 60 pm.

15. A method of preparing an aluminum alloy workpiece according to any one of claims 12 to 14, wherein, in step 2, the aluminum alloy powder is baked at a temperature of 100°C to 120°C for 2 hours to 4 hours.

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