High strength aluminum alloys for rapid solidification.

Abstract

The method for producing an aluminum-based alloy and components having the alloy by additive manufacturing (AM) or other rapid solidification processes is based on an alloy having a composition of 2.01 to 15.0 wt. % manganese, 0.3 to 2.0 wt. % scandium, and the balance other than minor alloying elements and incidental impurities of aluminum.

Description

[Technology field]

[0001] The present invention relates to high strength aluminum alloys suitable for use in additive manufacturing processes, but is also applicable to other processes, particularly rapid solidification processes. [Background technology]

[0002] The term "additive manufacturing" (AM) has become popular in recent years due to the process's flexibility in producing geometrically complex parts and its versatility in many application fields. AM technology was developed in the 1980s with the aim of directly manufacturing parts and has developed rapidly during the intervening period. The unconventional nature of this attractive manufacturing process lies in the fact that components are manufactured additively, as opposed to traditional subtractive machining methods. All AM technologies developed for manufacturing metal parts are classified based on the material feedstock type into powder-bed-based technologies such as selective laser melting (SLM) and electron beam melting (EBM), flow powder technologies such as laser metal deposition (LMD) and laser direct deposition modeling (LENS), and technologies in which molded parts are made from wire, powder, metal ink, and other materials. Hereinafter, the term "additive manufacturing (AM)" is used in a broad sense to encompass these and other technologies. However, AM is not limited to these technologies. The present invention can be used not only for AM techniques, but also for other rapid solidification processes such as laser cladding (LC), thermal spraying (TS), spark plasma sintering (SPS), gas atomization (GA), and melt spinning (MS).

[0003] AM processes use a laser beam, electron beam, or electric arc as an energy source, precisely controlled by either a CNC drive system or a scanning galvanometer mirror system. Successive layers are built by moving the energy source point-by-point and step-by-step through the melting and solidification of material, each following a cross-sectional shape corresponding to a conceptual slice of the desired component to be produced. That is, the component is built by repeating the process layer-by-layer along the build direction and maintaining adhesion between successive layers.

[0004] In the AM process, melting and solidification are highly localized. As a result, very high cooling rates can be achieved within a single molten pool, on the order of 10 5 From 10 7 The cooling rate can be as low as 100 K / s or less. These cooling rates are such that the resulting components exhibit a fine microstructure and resulting superior properties compared to components produced by traditional casting processes. Along with the beneficial design freedom and manufacturing flexibility offered by AM processes, there is an increasing demand for significant weight reduction in components produced this way. High-performance aluminum alloys produced from AM techniques capable of operating at high temperatures (e.g., above 150°C) are also attracting interest in various industries because they have the potential to replace higher-density titanium alloys for parts required to operate in intermediate temperature regimes without losing their properties.

[0005] The selection of high-performance aluminum alloys suitable for AM processes is still very limited, limiting the potential application of AM processes to aluminum component manufacturing. Currently, the aluminum alloys widely used for AM processes are Al7SiMg, Al 2SiMg, and Al 3SiMg due to their good malleability and weldability. 12 Si, and Al 10Near-eutectic Al-Si alloys, such as SiMg, have reported tensile strengths below 400 MPa due to precipitation and / or coarsening of Si-containing particles, resulting in strengths below 300 MPa in the as-manufactured state and even lower strengths after residual stress relief treatment. These property levels do not meet current industrial design and application requirements, particularly for creating structural components with high load-bearing capacity. Furthermore, components made from these alloys require post-manufacturing solution processing to achieve the properties provided, which increases both lead time and costs for industrial production. Other high-strength aluminum alloys, such as the 2xxx and 7xxx series wrought alloys commonly used in the aerospace industry, cannot be easily produced by AM techniques due to their high susceptibility to solidification cracking during AM processing. The large amounts of copper, magnesium, and zinc present in this alloy system extend the solidification range, which in turn increases susceptibility to hot tearing. Additionally, no data has been reported on the high-temperature properties of aluminum alloys made by AM processes. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, the present invention seeks to provide a high strength aluminum alloy suitable for use in AM processes and applicable to other rapid solidification manufacturing processes. [Means for solving the problem]

[0007] According to a first aspect of the present invention, there is provided an Al-Mn-Sc alloy having 2.01 to 15.0 wt. % manganese, 0.3 to 2.0 wt. % scandium, the balance being other than alloying trace elements and the incidental impurity of aluminum.

[0008] According to a second aspect, the present invention provides a method for producing an aluminum-based alloy component, the method using AM or other rapid solidification process to produce the component by melting and then rapidly solidifying an aluminum-based alloy, the Al-Mn-Sc-based alloy having from 2.01 to 15.0% by weight manganese, 0.3 to 2.0% by weight scandium, the balance other than alloying trace elements and incidental impurities of aluminum.

[0009] In the first and second aspects of the invention, the manganese level is preferably between 2.5% and 8% by weight, more preferably between 3% and 5% by weight, and the scandium level is preferably between 0.4% and 1.5% by weight, more preferably between 0.6% and 1.2% by weight.

[0010] The Al-Mn-Sc alloy of the present invention, preferably in powder form of an appropriate grade, can be used to manufacture components by additive manufacturing or other rapid solidification manufacturing processes. The components may be directly age-hardened to simultaneously achieve optimized properties and relief of residual stresses generated during the manufacturing process. The starting material for the Al-Mn-Sc alloy has a higher manganese and scandium content than conventional aluminum alloys, and parts made from the alloy of the present invention can provide excellent mechanical properties under both room temperature and high temperature conditions. The alloy of the present invention preferably has 2.01 to 15.0 wt.% manganese and 0.3 to 2.0 wt.% scandium, and may also have additional alloying elements including up to 6.0 wt.% magnesium, up to 4.0 wt.% zirconium, and other elements that are substitutable for or complementary to any of the aluminum, manganese, scandium, magnesium, and zirconium, as well as combinations of two or more of the additional alloying elements.

[0011] The Al-Mn-Sc alloys of the present invention can be used to directly fabricate structural components for a wide range of industrial applications, either through AM processes or by using other rapid solidification manufacturing processes. Components fabricated from the alloys of the present invention can be directly subjected to a simple artificial aging treatment without solution treatment to achieve optimal properties. The components can exhibit high strength and thermal stability properties that can further enhance the potential applications for AM-fabricated aluminum parts.

[0012] As mentioned above, the Al-Mn-Sc material system based on 3xxx aluminum alloys has been investigated by researchers for forged / extruded product applications, primarily due to its favorable formability (see References 1-3). The purpose of adding scandium to 3xxx wrought alloys was primarily to improve recrystallization resistance and strengthen the alloy through dispersion hardening. However, in these studies, the amount of manganese was limited to 2 wt.% or less, typically 1.5 wt.% or less, and scandium was usually limited to 0.4 wt.% or less. This is due to the very limited solubility of manganese and scandium in traditional manufacturing processes, which limited the strengthening effect of the resulting materials.

[0013] In contrast to Al-Mn-Sc alloys based on the 3xxx aluminum alloy system, International Publication WO 2008 / 125092 and German Patent No. 102007018123 (assigned by Palm to EADS Deutschland GmbH) propose a method for producing structural components by a rapid prototyping process using an Al-Sc-based alloy with 0.41 to 2.0 wt.% scandium and 2.0 to 10 wt.% magnesium. This work devised an Al-Mg-Sc-based alloy powder system for use in the AM process, available under the trademark SCALMALLOY. By adding a percentage of scandium to an existing weldable 5xxx series wrought alloy, the alloy was effectively developed for AM. SCALMALLOY™ sought to further strengthen the base alloy by taking advantage of the high cooling rates of the AM process. However, a high magnesium content, due to its low melting point, can lead to severe evaporation and the so-called smoking phenomenon, resulting in the formation of highly porous structures and substantial property degradation in the finished AM product. Additionally, higher magnesium contents, typically above 3 wt.%, in 5xxx alloys can also cause corrosion problems due to intergranular impact from the precipitation of a continuous β-Mg5Al6 phase along grain boundaries when exposed to temperatures above 65°C, especially temperatures between 150°C and 200°C, for extended periods of time (see Reference 4). However, at aging temperatures above approximately 200°C, the β-Mg5Al6 phase is soluble, and higher magnesium contents can be tolerated if the application temperature is outside the critical range of approximately 65°C to 200°C. Nevertheless, magnesium contents above 6 wt.% are not recommended for alloys that are more susceptible to hot tearing (see Reference 5).

[0014] The Al-Mn-Sc alloy of the present invention has not previously been proposed or used for AM or other rapid solidification manufacturing processes. By eliminating magnesium or substantially reducing its content, the present invention effectively reduces the risk of evaporation and the problem of high porosity formation. The introduction of manganese into aluminum alloys does not have the existing corrosion or evaporation problems during AM or other rapid solidification manufacturing processes. Thanks to the high cooling rates derived from the manufacturing process, the use of large amounts of manganese and scandium is possible due to their greatly improved solubility. Manganese in the present alloy plays a major role in solid-solution strengthening, while scandium forms thermally stable L12-structured nano-sized precipitates after thermal post-treatment, which significantly strengthens the alloy and allows it to maintain improved mechanical properties up to high temperatures. It should be noted that manganese has a higher solid-solution strengthening effect than magnesium, on a weight percent basis (see Reference 6). The formation and decomposition of a large volume fraction of nano-sized Al3Sc precipitates during the aging treatment can significantly strengthen the present alloy. The Al3Sc precipitates have a face-centered cubic structure, maintain extremely low lattice mismatch and high coherency with the aluminum matrix, and the relative diffusion rate of scandium prevents the precipitates from coarsening at high temperatures. The high misfit strain and antiphase boundary energy of the Al3Sc precipitates contribute to the high strength of the alloys of the present invention by pinning grain boundaries and inhibiting dislocation migration. The alloys of the present invention have also been found to exhibit excellent corrosion resistance, weldability, thermal stability, and mechanical properties after AM or other rapid solidification processes.

[0015] The properties of the Al-Mn-Sc alloys of the present invention can be further improved by incorporating other substitutional or complementary alloying elements into the alloys of the present invention. For example, at least one of silicon, zinc, magnesium, copper, nickel, cobalt, iron, silver, chromium, lithium, vanadium, titanium, calcium, tantalum, zirconium, hafnium, yttrium, ytterbium, and erbium may be added to the alloys of the present invention. The benefits provided by one or more of these elements include (i) solid solution strengthening, (ii) a grain refinement effect, (iii) grain structure control, (iv) additional dispersion or precipitation strengthening, or (v) a combination of these effects. Typically, the content of these alloying elements is individually less than 4 wt. % and a maximum of 15 wt. % in total.

[0016] Additionally, depending on engineering and application requirements, alloying elements including at least one of chromium, vanadium, titanium, tantalum, zirconium, hafnium, and yttrium may be further added to the Al-Mn-Sc alloy of the present invention for improved high-temperature stability. These alloying elements have exceptionally low diffusion coefficients in aluminum. Therefore, low diffusion rates and high resistance to grain coarsening are expected at high temperatures. These alloying elements also have a high tendency to surround and isolate the Al3Sc precipitates to form a protective shell that can reinforce the Al3Sc precipitates from grain coarsening during exposure to high temperatures. Typically, the content of the above alloying elements should also be less than 4 wt.% individually and a maximum of 15 wt.% in total.

[0017] The Al-Mn-Sc alloys of the present invention can be used for the production of mechanical device components and may be used as base materials for producing composite admixtures of metallic or non-metallic materials through either in situ or ex situ reactions. In addition to fabricating components from the Al-Mn-Sc alloys of the present invention as starting materials, the alloys of the present invention can be made into powders, wires, and other types of semi-finished products for other manufacturing purposes.

[0018] To melt the starting raw materials, any possible energy source or combination thereof can be used, such as laser, electron beam source, plasma, and electric arc source, or conductive or induction processes associated with suitable chemical reactions or rapid solidification techniques. The cooling rate during the manufacturing process must be such that a supersaturated solid solution with respect to the main elements is achieved in order to maintain the properties of the fabricated component. A preferred cooling rate within the manufacturing process chain is 100 K / s or higher. The cooling properties during the process can be provided directly by the manufacturing process itself, such as AM techniques, or by other secondary processes, such as using water, liquid nitrogen, or other suitable cooling media.

[0019] Thermal post-treatment is usually required to release residual stresses generated in components manufactured by AM or other rapid solidification processes and achieve optimal properties. The present invention includes a post-SLM thermal post-treatment in which components manufactured by AM processes using the Al-Mn-Sc alloy of the present invention are preferably subjected to a heat treatment in a single heat treatment process at a temperature range between 200°C and 500°C for a cumulative time between 0.10 and 100 hours. However, heat treatments with similar temperature correction times, multi-step processes, or special environmental treatments are also applicable. This may include hot isostatic pressing (HIP) under appropriate pressure. A simple direct aging process without a separate solution treatment is most preferred, which is another point that differs from other age-hardening systems. After heat treatment, there are no necessary restrictions on subsequent cooling and cooling control, and cooling can range from slow furnace cooling to rapid water quench cooling. Residual stresses generated due to the high cooling rates during AM manufacturing processes can be effectively released by heat treatment. Also, the decomposition of the supersaturated solid solution resulting from high cooling rates produces the precipitation of large volume fractions of nano-sized particles or other dispersions, thereby improving the mechanical properties of components produced by AM processes.

[0020] For the AM manufacturing process, several other beneficial control aspects are preferred using the Al-Mn-Sc based alloy of the present invention, such as carefully adjusting the parameters in the AM technique (e.g., laser type, laser parameters, scanning strategy, substrate temperature, etc.) to maintain an appropriate cooling rate and better workability, using a protective gas environment to protect the fabricated parts from oxygen, eliminating so-called smoke or spatter generation during the AM process, or any other control over the AM technique and other rapid solidification techniques is expected to further improve product properties.

[0021] <References> 1. Forbord B, Hallem H, Ryum N, Marthinsen K: “Precipitation and recrystallization in Al-Mn-Zr with and without Sc”, Materials Science and engineering A (2004), 387-389, 936-939 2. Forbord B, Hallem H, Royset J, Marthinsen K: “Thermal stability of Al3(Scx,Zr1-x)-dispersoids in extruded aluminum alloys”, Materials Science and Engineering A (2008), 475, 241-248 3. Forbord B, Auran L, Lefebvre W, Hallem H, Marthinsen K: “Rapid precipitation of dispersoids during extrusion of an Al-0.91 wt.% Mn-0.13 wt.% Zr-0.17 wt.% Sc-alloy”, Materials Science and Engineering A (2006), 424, 174-180 4. Rowe, J., “Advanced materials in automotive engineering”, Woodhead Publishing Limited, UK, ISBN 978-1-84569-561-3. Bloeck, M., Chapter 5 “Aluminum sheet for automotive applications”, 92-93 5. Li RD, Wang MB, Yuan TC, Song Bo, Chen C, Zhou KC, Cao P: “Selective laser melting of a novel Sc and Zr modified Al-6.2 Mg alloy: Processing, microstructure, and properties”, Powder Technology 319 (2017) 117-128 6. JR Davis, “Alloying: Understanding the Basics.” ASM International Publishing, 2001, USA, ISBN978-0-87170-744-4. Chapter 16, “Aluminum and Aluminum alloys,” p. 368

[0022] The performance of the first and second Al-Mn-Sc based alloy samples produced in Example 1 is illustrated in the accompanying Figures 1 and 2, and the performance of the sample according to Example 2 is shown in Figures 3 and 4. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a BSE image showing the indentation hardness in a sample of the second Al—Mn—Sc based alloy. [Figure 2] FIG. 2 is a plot showing the evolution of hardness with aging time for each of the first and second Al—Mn—Sc based alloys. [Figure 3] FIG. 3 is a schematic diagram of the tensile sample geometry according to ASTM E8M. [Figure 4] Figure 4 shows the engineering stress / strain curves of the non-heat-treated and heat-treated samples produced by SLM fabrication. DETAILED DESCRIPTION OF THE INVENTION

[0024] Example 1 The production of Al-Mn-Sc alloy components according to the present invention by the AM process was simulated using two alloy compositions: the first having a composition of Al-4.18Mn-2Mg-0.9Sc-0.18Zr (by weight), and the second having a composition of Al-3Mn-1.5Mg-1Sc-0.05Zr (by weight). These alloys were simulated by melting master alloys of the compositions Al-60Mn, Al-50Mg, Al-2Sc, and Al-10Zr (all by weight) in a resistance-heated furnace at 800°C, casting the resulting continuous melt, and then melting the alloys to approximately 1000°C. 3 The alloys were produced by cooling the castings at a solidification cooling rate of 1000 K / s. The cast alloys were cut into 5 mm thick samples, which were then polished using sandpaper to maintain the same surface roughness.

[0025] The thus-prepared samples were placed on the substrate of a commercially available EOSINT M280 SLM machine for laser scanning. A total of 30 laser scans were performed on the polished sample surface to generate parallel adjacent melt pools without additional powder, yielding a scan area of ​​approximately 3 mm every 18 mm. The laser scanning process was performed with a laser power of 370 W, a scanning speed of 500 mm / s, a spot size of 0.1 mm, and a hatch distance of 0.1 mm. After laser scanning, the samples were aged in a salt bath at 300 °C for various times up to 168 h. The samples were then sectioned using a low-speed saw and mounted to expose the cross-sectional melt pool for subsequent examination. Samples for manufacturing observation and microhardness testing were prepared according to standard metallographic sample preparation methods. Vickers hardness was measured within the cross-sectional area of ​​the melt pool using a Duramin A300 hardness tester with a 0.5 kg load for 10 seconds. Backscattered electron micrographs of cross-sectional areas were obtained with a JEOL 7001 FEG scanning electron microscope (SEM). The following characteristics were obtained: a) After ageing at 300°C for 10 hours, the maximum hardness achieved by the first alloy Al-4.18Mn-2Mg-0.9Sc-0.18Zr was 186.3±2 HV0.5. b) After ageing at 300°C for 24 hours, the maximum hardness achieved by the second alloy Al-3Mn-1.5Mg-1Sc-0.05Zr was 170.6±2 HV0.5.

[0026] <Example 2> Prism-shaped samples were fabricated by SLM fabrication from gas-atomized powder with a weight percent composition of Al-4.52Mn-1.32Mg-0.79Sc-0.74Zr. Samples were fabricated using a commercially available EOSINT M290 SLM machine with a laser power of 370 W, a scanning speed of 1000 mm / s, a hatch distance of 0.1 mm, and a layer thickness of 30 μm. Samples were constructed on 6061 aluminum alloy substrates, from which they were removed by electrical discharge machining (EDM). Some samples were salt-bath heat-treated at 300 ± 2°C for 5 hours. All samples, both heat-treated and untreated, were then machined into tensile specimens with the geometry shown in Figure 3 according to ASTM E8M. Tensile tests were performed using a 100 kN Instron 5500R / 4505 screw-drive machine with a constant crosshead travel speed of 0.48 mm / min. The resulting tensile engineering stress / strain curve is shown in Figure 4, and other properties were as follows: 1) Tensile properties of non-heat-treated SLM-produced samples Yield strength = 427 MPa, ultimate tensile strength = 453 MPa, elongation = 12.0% 2) Tensile properties of SLM-fabricated samples after heat treatment at 300±2°C for 5 hours Yield strength = 577 MPa, ultimate tensile strength = 588 MPa, elongation = 11.3%

[0027] Figure 1 shows a backscattered electron microscope (BSE) image of a sample cut surface of the second Al-Mn-Sc alloy exposed by metallographic preparation. The lower region of the image shows the microstructure of the second alloy as cast, while the upper region shows the microstructure of the rapidly solidified melt pool produced by remelting the alloy via laser scanning. As shown, hardness measurements were performed on the upper remelted region. Figure 1 clearly shows that the upper region resulting from the laser-remelted melt pool differs from the initial cast region in that no white, needle- or rod-shaped primary Al6Mn or Al3Sc-type precipitates are observed. This clearly indicates that manganese and scandium are successfully trapped within the aluminum matrix after the extremely fast cooling laser remelting process, and a supersaturated state is achieved.

[0028] In Figure 2, Al-Mn-Sc alloys have a hardness value of 170 to 186 HV. 0.5 These properties are similar to those of high-strength 7xxx series alloys, but the thermal stability is greatly improved, with high hardness levels maintained even after 168 hours at 300°C. Laser-treated or cast aluminum alloys cannot typically achieve these properties, especially compared to aluminum alloys currently widely used for additive manufacturing. Conventional age-hardening of aluminum alloys begins with exposure to 300°C for several minutes to overage and soften them. Furthermore, the results demonstrated by the examples of this invention demonstrate that further improvements can be achieved with higher cooling rates and other benefits of the additive manufacturing process. In summary, the Al-Mn-Sc-based alloys of this invention exhibit very promising properties and great potential for applications in a wide range of structural, industrial, engineering, aerospace, and transportation components produced by additive manufacturing or other rapid solidification manufacturing processes.

[0029] Figure 3 shows a properly manufactured tensile sample from which the stress / strain curves of Figure 4 were derived. The significantly enhanced yield strength of 577 MPa for the heat-treated sample highlights the potential for the alloy of the present invention, but the yield strength of 427 MPa for the as-fabricated (unheat-treated) sample itself is also excellent. In contrast, the most favorable yield strength cited for heat-treated SCALMALLOY™ is believed to be in the range of 459 to 479 MPa (see www.citim.de / en / metal-additive-manufacturing).

[0030] The results shown in Examples 1 and 2 and Figures 1 through 4 highlight a number of important points regarding the alloys of the present invention. The alloys benefit from the slow diffusion rates described above for both scandium and manganese, along with other additive elements such as zirconium. These slow rates promote the alloy's ability, after high cooling rates from thermal cycling, to experience precipitation effects due to the precipitation of thermally stable nano-sized precipitates or dispersoids. With regard to manganese, a useful lower limit of 2.01 wt.% is possible, up to a relatively high upper limit of 15.0 wt.%, without the undesirable precipitate coarsening that tends to occur at manganese addition levels above 15 wt.%.

[0031] The alloy is also characterized by enhanced property development achievable based on simple heat treatment without the need for solution treatment, as is the complex heat treatment regime required for other precipitation-hardened aluminum alloys. The simple heat treatment, preferably involving only a single-stage operation, is doubly effective as a stress-relief step and a precipitation-hardening heat treatment. In the case of the use of AM rapid solidification processes, such as those based on SLM, the heat treatment can be performed before or after the resulting component produced by the process is cut from the build platform on which it is constructed.

[0032] While the alloys of the present invention are well suited for use in AM processes such as SLM and other rapid solidification processes, Example 1 and Figures 1 and 2 demonstrate the suitability of the alloy for use in alternative rapid solidification processes. Specifically, for components made by subtractive manufacturing processes, such as any range of casting processes, the component may be scanned with an energy source, such as a laser or electron beam, to achieve melting of a scanned area of ​​the component's surface, after which the body of the component provides a heat sink that is heated to rapid solidification to enhance the alloy's properties in the scanned surface area. This includes surface treatments such as laser cladding or repair of components using Al-Mn-Sc-based alloys of the present invention as part of the component and / or deposited surface materials. [Prior art documents] [Patent documents]

[0033] [Patent Document 1] International Publication No. WO2008 / 125092 [Patent Document 2] German Patent No. 102007018123 [Non-patent literature]

[0034] [Non-Patent Document 1] Forbord B, Hallem H, Ryum N, Marthinsen K: “Precipitation and recrystallization in Al-Mn-Zr with and without Sc”, Materials Science and engineering A (2004), 387-389, 936-939 [Non-patent document 2] Forbord B, Hallem H, Royset J, Marthinsen K: “Thermal stability of Al3(Scx,Zr1-x)-dispersoids in extruded aluminum alloys”, Materials Science and Engineering A (2008), 475, 241-248 [Non-patent document 3] Forbord B, Auran L, Lefebvre W, Hallem H, Marthinsen K: “Rapid precipitation of dispersoids during extrusion of an Al-0.91 wt.% Mn-0.13 wt.% Zr-0.17 wt.% Sc-alloy”, Materials Science and engineering A (2006), 424, 174-180 [Non-patent document 4] Rowe, J., “Advanced materials in automotive engineering”, Woodhead Publishing Limited, UK, ISBN 978-1-84569-561-3. Bloeck, M., Chapter 5 “Aluminum sheet for automotive applications”, 92-93 [Non-Patent Document 5] Li RD, Wang MB, Yuan TC, Song Bo, Chen C, Zhou KC, Cao P: Paper entitled “Selective laser melting of a novel Sc and Zr modified Al-6.2 Mg alloy: Processing, microstructure, and properties”, Powder Technology 319 (2017) 117-128 [Non-patent document 6] "Alloying: Understanding the Basics" by JR Davis. ASM International Publishing, 2001, USA, ISBN978-0-87170-744-4. Chapter 16, "Aluminum and Aluminum alloys", p.368

Claims

1. 1. An Al-Mn-Sc system powder alloy of a grade that allows for the production of heat treatable components by additive manufacturing processes or other rapid solidification processes, said Al-Mn-Sc system powder alloy comprising: 2.5% to 8% by weight manganese; 0.3% to 2.0% by weight of scandium; 0 to 6.0% by weight magnesium; 0 to 4.0 wt. % zirconium; Equipped with the Al-Mn-Sc system powder alloy having a balance of aluminum and incidental impurities; The Al-Mn-Sc system powder alloy optionally comprises at least one alloying element selected from silicon, zinc, copper, nickel, cobalt, silver, chromium, lithium, vanadium, titanium, calcium, tantalum, hafnium, yttrium, and erbium, present in an amount of less than 4 wt.-% individually and up to 15 wt.-% in total to provide at least one of: (i) solid solution strengthening; (ii) grain refinement; (iii) grain structure control; (iv) additional dispersion or precipitation strengthening; and (v) improved high temperature stability in the case of any of chromium, vanadium, titanium, tantalum, hafnium, and yttrium; The Al-Mn-Sc powder alloy is a nano-sized Al ３ The heat treatable component can be strengthened by Sc precipitates. The Al-Mn-Sc powder alloy is characterized in that

2. 2. The Al-Mn-Sc powder alloy according to claim 1, further comprising at least one of magnesium having an upper limit of 6.0 wt. % and zirconium having an upper limit of 4.0 wt. %.

3. 3. The Al-Mn-Sc powder alloy according to claim 1, wherein the manganese content is between 3 and 5% by weight.

4. 4. The Al-Mn-Sc powder alloy according to claim 1, wherein the scandium content is 0.4 to 1.5% by weight.

5. The Al-Mn-Sc powder alloy according to claim 4, characterized in that the scandium content is 0.6 to 1.2 wt %.

6. 6. A method for manufacturing an aluminium-based alloy component, the method using an additive manufacturing process or other rapid solidification process to manufacture the component by melting and then rapidly solidifying an aluminium-based powder alloy, the aluminium-based powder alloy comprising an Al-Mn-Sc-based powder alloy according to any one of claims 1 to 5.

7. The method of claim 6 , wherein the component is age hardened after the additive manufacturing process or other rapid solidification process.

8. 8. The method of claim 6 or 7, wherein the cooling rate during the additive manufacturing process or other rapid solidification process is such that a supersaturated solid solution for the manganese and scandium is achieved.

9. 10. The method of claim 8, wherein the cooling rate is greater than 100 K / s and is achieved during the additive manufacturing process or other rapid solidification process or from an auxiliary process using water, liquid nitrogen or other coolant.

10. 10. The method of any one of claims 6 to 9, further comprising performing a thermal post-treatment of the component manufactured by the additive manufacturing process or other rapid solidification process by exposing the component to heat in a single heat treatment process in a temperature range between 200°C and 500°C for a cumulative time between 0.10 and 100 hours.

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