Method for closing pores of alloy ingot blank

Abstract

The invention discloses a method for pore bridging of an alloy ingot blank, and relates to the technical field of alloy machining. The method for pore bridging of the alloy ingot blank comprises the following steps that the alloy ingot blank is compressed in the axial direction and then extruded, and pore bridging is completed; in the first stage, the compression temperature ranges from 200 DEG C to 500 DEG C, and the strain rate is larger than or equal to 0.4 s <-1 >; in the second stage, the compression temperature is 300-600 DEG C, and the strain rate is larger than or equal to 1.2 s <-1 > The specific compression process is combined with extrusion for pore bridging, the cost is low, the efficiency is high, pore bridging of the alloy ingot blank is effectively achieved, the elongation of the alloy is increased, and the fatigue life of the alloy is prolonged.

Description

Technical Field

[0001] This invention relates to the field of alloy processing technology, and in particular to a method for closing pores in alloy ingots. Background Technology

[0002] Compared to traditional smelting and metallurgical processes for producing ingots, spray forming is considered a superior method for producing aluminum alloy ingots due to its smaller grain size and fewer residual phases. However, during the preparation of spray-formed alloy ingots, rapid cooling can cause shrinkage cavities and gas mixing, resulting in porosity. The maximum size of these pores can reach over 100 μm, and the porosity (the percentage of pores in the total volume of the ingot) can exceed 2%. The large pore size and high porosity in the ingot increase the risk of cracking during subsequent hot working deformation. Furthermore, if these pores are not adequately sealed, their presence in the aluminum alloy product will severely reduce the alloy's elongation and fatigue life.

[0003] To close the porosity in spray-formed aluminum alloy ingots, methods such as hot isostatic pressing (HIP) or hot deformation are commonly used. HIP requires holding the ingot at high temperature (typically above 400°C) and high pressure (typically above 100 MPa) for an extended period (typically more than 24 hours), causing slow compression deformation. However, this method is demanding in terms of equipment, time-consuming, and costly, making it unsuitable for industrial production. Hot deformation methods mainly include extrusion and rolling. However, the porosity in the alloy after deformation is often difficult to completely close, especially the porosity distributed along the deformation direction, which severely damages the alloy's fatigue properties. Furthermore, these porosity are difficult to observe using conventional metallographic and electron microscopic methods, further increasing the risk of failure during the alloy's service life. Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of the present invention is to provide a method for pore filling in alloy ingots, which uses a specific compression process combined with extrusion to fill pores, resulting in low cost, high efficiency, and effective pore filling of alloy ingots, thereby improving the elongation and fatigue life of the alloy.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for closing pores in an alloy ingot includes the following steps: The alloy ingot is compressed along the axial direction and then extruded to complete the pore sealing. The compression is segmented compression, wherein: First stage: Compression temperature 200~500℃, strain rate ≥0.4s -1 ; Second stage: Compression temperature 300~600℃, strain rate ≥1.2s -1 .

[0006] Specifically, the compression is axial hot compression; during the extrusion process, the alloy ingot undergoes circumferential hot deformation.

[0007] Traditional hot deformation processes are ineffective at eliminating porosity in spray-formed ingots. Although small pores are difficult to observe using metallographic methods, they can still be observed along the deformation direction under synchrotron radiation CT scans. These pores severely reduce the elongation and fatigue performance of the alloy. This invention achieves the three-dimensional elimination of pores in the alloy ingot through a staged high-rate hot compression process combined with circumferential hot deformation during extrusion. This completely eliminates internal porosity in the resulting alloy, significantly improving the fatigue performance and elongation of the alloy material. This is beneficial for broadening the application range of spray-formed alloy materials in high-end manufacturing industries.

[0008] Specifically, the compression temperature of the first stage can be 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, or 500℃. The compression temperature of the second stage can be 300℃, 350℃, 400℃, 450℃, 500℃, 520℃, or 550℃.

[0009] Preferably, the compression temperature in the first stage is 300~500℃.

[0010] More preferably, the compression temperature in the first stage is 350~500℃.

[0011] More preferably, the compression temperature in the first stage is 400~450°C.

[0012] Preferably, the compression temperature in the second stage is 350~550℃.

[0013] More preferably, the compression temperature in the second stage is 400~550℃.

[0014] More preferably, the compression temperature in the second stage is 400~500°C.

[0015] More preferably, the compression temperature in the second stage is 430~480℃.

[0016] Preferably, the strain rate in the first stage is 0.4~1.2 s⁻¹. -1 For example, the strain rate in the first stage is 0.4 s⁻¹. -1 0.5s -1 0.6s -1 0.8s -1 1s -1 1.1s-1 Or 1.2s -1 .

[0017] More preferably, the strain rate in the first stage is 0.5~1.2 s⁻¹. -1 .

[0018] More preferably, the strain rate in the first stage is 0.6~1s. -1 .

[0019] Preferably, the strain rate in the second stage is 1.2~3.5 s. -1 For example, the strain rate in the second stage is 1.2 s⁻¹. -1 1.3s -1 1.5s -1 1.6s -1 1.8s -1 2s -1 2.2s -1 2.5s -1 2.8s -1 3s -1 Or 3.5s -1 .

[0020] More preferably, the strain rate in the second stage is 1.2~3s. -1 .

[0021] More preferably, the strain rate in the second stage is 1.5~2.5 s. -1 .

[0022] Preferably, the total strain of the compression is 55% to 95%. For example, the total strain of the compression is 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%.

[0023] More preferably, the total strain of the compression is 60-90%.

[0024] More preferably, the total strain of the compression is 65-85%.

[0025] Preferably, the dependent variable in the first stage is 35% to 55%. For example, the dependent variable in the first stage is 35%, 40%, 45%, 50%, or 55%.

[0026] More preferably, the dependent variable in the first stage is 40-50%.

[0027] More preferably, the dependent variable in the first stage is 45-50%.

[0028] Preferably, the dependent variable in the second stage is 20% to 40%. For example, the dependent variable in the second stage is 20%, 25%, 30%, 35%, or 40%.

[0029] More preferably, the strain in the second stage is 25-35%.

[0030] Preferably, the actual strain in the first stage is 0.5 to 0.9.

[0031] More preferably, the actual strain in the first stage is 0.6 to 0.8.

[0032] More preferably, the actual strain in the first stage is 0.6 to 0.7.

[0033] Preferably, a die is placed around the alloy ingot during the compression process. Placing a die around the alloy ingot during compression helps to retain heat and prevent cracking.

[0034] More preferably, the temperature of the mold sleeve is 250~500℃. For example, the temperature of the mold sleeve is 250℃, 300℃, 350℃, 400℃, 450℃ or 500℃.

[0035] More preferably, the temperature of the mold sleeve is 300~500℃.

[0036] More preferably, the temperature of the mold sleeve is 350~450℃.

[0037] Preferably, the extrusion temperature is 300~500℃. For example, the extrusion temperature can be 300℃, 350℃, 380℃, 400℃, 410℃, 420℃, 430℃, 450℃ or 500℃.

[0038] More preferably, the extrusion temperature is 350~450℃.

[0039] More preferably, the extrusion temperature is 380~450°C.

[0040] More preferably, the extrusion temperature is 400~450℃.

[0041] Preferably, the extrusion ratio is 10 to 20. For example, the extrusion ratio can be 10, 12, 14, 15, 16, 17, 18 or 20.

[0042] More preferably, the extrusion ratio is 12 to 20.

[0043] More preferably, the extrusion ratio is 12 to 18.

[0044] More preferably, the extrusion ratio is 12 to 17.

[0045] Preferably, the extrusion speed is 1 to 6 mm / s. For example, the extrusion speed can be 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, or 6 mm / s.

[0046] More preferably, the extrusion speed is 2~5 mm / s.

[0047] More preferably, the extrusion speed is 2~3 mm / s.

[0048] Preferably, the diameter of the extruded bar obtained by extrusion is 10~200mm.

[0049] It should be understood that the diameter of the extruded bar can be selected according to actual needs, such as 10mm, 20mm, 30mm, 35mm, 40mm, 50mm, 60mm, 80mm, 120mm, 150mm or 200mm. More preferably, the diameter of the extruded bar is 10~50mm.

[0050] Preferably, before extrusion, the compressed alloy ingot is cut.

[0051] Specifically, after compression and before extrusion, the compressed alloy ingot is cut into cylindrical shapes with an aspect ratio of 1 to 10.

[0052] More preferably, the length-to-diameter ratio of the cut alloy ingot is 4 to 8.

[0053] Adjusting the shape and length-to-diameter ratio of the cut alloy ingot helps to adjust the specifications of the extruded bar.

[0054] Preferably, the process after extrusion further includes solution treatment and aging steps; the solution treatment is a two-stage solution treatment, wherein: First stage of solution treatment: solution temperature 250~450℃, holding time 1~10h; Second stage of solution treatment: solution temperature 450~550℃, holding time 1~10h.

[0055] Specifically, the temperature of the first-stage solution treatment can be 250℃, 300℃, 350℃, 400℃, or 450℃; the temperature of the second-stage solution treatment can be 450℃, 460℃, 480℃, 500℃, or 550℃. The holding time for the first-stage solution treatment and the holding time for the second-stage solution treatment are independently 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, or 10h.

[0056] More preferably, the solution temperature of the first-stage solution is 300~450℃.

[0057] More preferably, the solution temperature of the first-stage solution is 350~450℃.

[0058] More preferably, the solution temperature of the first-stage solution is 400~450℃.

[0059] More preferably, the heat preservation time for the first stage of solid solution is 1 to 5 hours.

[0060] More preferably, the solution temperature of the second-stage solution is 450~520℃.

[0061] More preferably, the solution temperature of the second-stage solution is 450~500℃.

[0062] More preferably, the heat preservation time for the second-stage solution treatment is 1 to 5 hours.

[0063] Preferably, the aging process includes T6 aging treatment.

[0064] Preferably, the aging temperature is 100~200℃. For example, the aging temperature is 100℃, 120℃, 130℃, 150℃ or 200℃.

[0065] Preferably, the heat preservation time for aging is 10 to 60 hours. For example, the heat preservation time can be 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, or 60 hours, or other ranges composed of these values, such as 10 to 50 hours or 10 to 40 hours.

[0066] It should be understood that the product obtained after solution treatment and aging is an alloy.

[0067] Preferably, the alloy ingot is a spray-formed aluminum alloy ingot.

[0068] Preferably, the pore volume fraction of the alloy ingot is >2%; the maximum pore size of the alloy ingot is >100μm.

[0069] More preferably, the pore volume fraction of the alloy ingot is 2.05~5%; the maximum pore size of the alloy ingot is 110~150μm.

[0070] More preferably, the pore volume fraction of the alloy ingot is 2.1-3%; the maximum pore size of the alloy ingot is 110-140 μm.

[0071] Preferably, the alloy ingot comprises the following components by weight percentage: Zn: 4~10%, Mg: 0.5~3%, Cu: 0.5~3%, Zr: 0~0.3%, Ti: 0~0.3%, Mn: 0~0.3%, Zr+Ti+Mn+Sc≤0.4%, Fe+Si≤0.1%, balance is aluminum.

[0072] It is important to understand that Zr+Ti+Mn+Sc≤0.4% means that the sum of the mass percentages of Zr, Ti, Mn, and Sc in the alloy ingot is ≤0.4%; Fe+Si≤0.1% means that the sum of the mass percentages of Fe and Si in the alloy ingot is ≤0.1%.

[0073] More preferably, the alloy ingot comprises the following components by weight percentage: Zn: 6~9%, Mg: 1.5~2.5%, Cu: 1~2%, Zr: 0~0.2%, Ti: 0~0.1%, Mn: 0~0.2%, Fe: 0~0.1%, Si: 0~0.05%, Sc: 0~0.1%, balance being aluminum; wherein, Zr+Ti+Mn+Sc≤0.4%, Fe+Si≤0.1%.

[0074] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a method for pore filling in alloy ingots. The invention employs a high-speed, large-deformation compression process, combined with circumferential thermal deformation of extrusion, to fill pores. This achieves pore filling in the alloy ingot in three dimensions, completely eliminating internal pores in the resulting alloy, thereby significantly improving the fatigue performance and elongation of the alloy material.

[0075] Specifically, this invention employs a two-stage compression process, involving hot compression with a total strain exceeding 55% under high strain rate conditions. The strain rate of the first stage compression is ≥0.4 s⁻¹. -1 This significantly reduces the volume fraction of pores and substantially decreases their axial dimensions. In the second stage, since the pores have been initially closed, the risk of cracking is reduced and the deformation capacity is enhanced; therefore, the strain rate is increased to 1.2 s⁻¹. -1 The above methods can significantly improve processing efficiency and reduce pore size under greater deformation conditions through compression. Subsequently, circumferential thermal deformation is performed using extrusion. Since the pore size has already been greatly reduced, a smaller extrusion ratio is needed to close the pores circumferentially, achieving complete pore elimination under synchrotron radiation CT scanning. This also significantly reduces the deformation resistance during processing, allowing extrusion speeds greater than 2 mm / s.

[0076] Therefore, through specific process design, the present invention achieves complete sealing of the pores in the spray-formed alloy ingot. Compared with materials prepared by traditional hot deformation processes, crack initiation points are less likely to form during deformation and fatigue loading, thereby significantly improving elongation and fatigue life. Attached Figure Description

[0077] Figure 1 This is a schematic diagram of the main process for filling the pores in the alloy ingot in Example 1.

[0078] Figure 2 This is a synchrotron radiation X-ray CT scan image of the alloy ingot formed by spraying in Example 1.

[0079] Figure 3 The image shown is an X-ray CT scan of the alloy ingot after hot compression in Example 1.

[0080] Figure 4 The image shown is an X-ray CT scan of the extruded alloy ingot in Example 1.

[0081] Figure 5 The image shows a metallographic image of the microcracks in the alloy ingot obtained in Example 11.

[0082] Figure 6 The image shows an X-ray CT scan of the alloy ingot obtained in Comparative Example 1. Detailed Implementation

[0083] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0084] Example 1 A method for filling pores in an alloy ingot, the main pore-filling process is as follows: Figure 1 As shown, the specific steps include: S1. Alloy ingot preparation: Al-Zn-Mg-Cu alloy ingots were prepared by spray forming. The composition of the alloy ingots by mass percentage was: Zn: 7.5%, Mg: 2.2%, Cu: 1.8%, Zr: 0.12%, Fe: 0.06%, Si: 0.04%, with the balance being Al. The volume fraction of pores in the alloy ingots was 2.4%, and the maximum pore size was 125 μm. S2. Hot Compression: The alloy ingot obtained in step S1 is compressed axially. During compression, a die sleeve is placed around the alloy ingot, and the die sleeve temperature is 420℃. The compression is performed in stages. In the first stage, the alloy ingot is heated to the compression temperature of 430℃ (i.e., Figure 1(In the "heating" step), the compression (strain) is 50%, the true strain is approximately 0.6, and the compressive strain rate is 0.8 s⁻¹. -1 The second stage compression temperature was 450℃, the compression amount (strain) was 30%, and the compression strain rate was 1.8s. -1 The total strain in the two stages of compression was 80%. S3. Cutting: The alloy ingot billet compressed in step S2 is wire-cut into a cylindrical shape with a length-to-diameter ratio of 6. S4. Extrusion: The alloy ingot blank cut in step S3 is extruded to achieve circumferential hot deformation; the extrusion temperature is 410℃, the extrusion ratio is 16, the extrusion speed is 2.5mm / s, and the diameter of the extruded bar is 35mm. S5. Solution treatment: Two-stage solution treatment is adopted. The first stage solution treatment temperature is 420℃ and the holding time is 2h; the second stage solution treatment temperature is 477℃ and the holding time is 2h; water quenching is performed after solution treatment. S6. Aging: The alloy material obtained by solution treatment and quenching in step S5 is subjected to T6 aging treatment at an aging temperature of 118℃ and a holding time of 31h to obtain the alloy.

[0085] Example 2 A method for filling pores in an alloy ingot, differing from Example 1, is as follows: In step S1, an Al-Zn-Mg-Cu alloy ingot is prepared by spray forming. The composition of the alloy ingot, by mass percentage, is: Zn: 7.8%, Mg: 2.3%, Cu: 1.7%, Mn: 0.18%, Ti: 0.08%, Sc: 0.05%, Fe: 0.06%, Si: 0.03%, with the balance being Al. The pore volume fraction in the alloy ingot is 2.5%, and the maximum pore size is 135 μm. The rest is the same as in Example 1.

[0086] Example 3 A method for filling pores in an alloy ingot, differing from Example 1, is as follows: In step S1, an Al-Zn-Mg-Cu alloy ingot is prepared by spray forming. The composition of the alloy ingot, by mass percentage, is: Zn: 7.0%, Mg: 1.8%, Cu: 1.2%, Fe: 0.06%, Si: 0.04%, with the balance being Al. The pore volume fraction in the alloy ingot is 2.1%, and the maximum pore size is 112 μm. The rest is the same as in Example 1.

[0087] Example 4 A method for closing pores in an alloy ingot, differing from Example 1, is as follows: in step S2, the die temperature during hot compression is 400°C; the first-stage compression temperature is 400°C, the compression amount is 40%, and the compression strain rate is 0.6 s⁻¹. -1The second stage compression temperature was 450℃, the compression rate was 35%, and the compression strain rate was 2.0 s⁻¹. -1 The total dependent variable for the two stages was 75%; the rest was the same as in Example 1.

[0088] Example 5 A method for closing pores in an alloy ingot, differing from Example 1, is as follows: in step S2, the die temperature during hot compression is 450°C; the first-stage compression temperature is 450°C, the compression amount is 50%, and the compression strain rate is 0.8 s⁻¹. -1 The second stage compression temperature was 460℃, the compression rate was 32%, and the compression strain rate was 2.5s. -1 The total dependent variable for the two stages was 82%; the rest was the same as in Example 1.

[0089] Example 6 A method for filling pores in an alloy ingot, which differs from Example 1 in that: in step S4, the extrusion temperature is 380°C, the extrusion ratio is approximately 12, the extrusion speed is 2 mm / s, and the diameter of the extruded bar is 180 mm; the rest is the same as in Example 1.

[0090] Example 7 The difference between this embodiment and embodiment 1 is that in S4, the cut billet is extruded at a temperature of 407°C, an extrusion ratio of 20, an extrusion speed of 2.5 mm / s, and an extruded bar diameter of 25 mm.

[0091] Example 8 A method for filling pores in an alloy ingot, which differs from Example 1 in that: in step S5, the first-stage solution temperature is 450℃ and the holding time is 1h; the second-stage solution temperature is 475℃ and the holding time is 4h; the rest is the same as in Example 1.

[0092] Example 9 A method for sealing the pores of an alloy ingot, which differs from Example 1 in that: no mold sleeve is used for protection during hot compression in step S2; the rest is the same as in Example 1.

[0093] In this embodiment, the alloy ingot does not use a die sleeve, and cracks occur when the compression reduction is approximately 78%.

[0094] Example 10 A method for sealing the pores of an alloy ingot, which differs from Example 1 in that the temperature of the mold sleeve during hot compression in step S2 is 200°C; the rest is the same as in Example 1.

[0095] In this embodiment, because the temperature of the die sleeve is low during compression, the temperature of the alloy ingot drops rapidly during the loading and compression process, resulting in weakened deformation energy and cracking when the reduction is about 69%.

[0096] Example 11 A method for closing pores in an alloy ingot, differing from Example 1, in that the deformation rate used in the first stage of hot compression in step S2 is 1.5 s. -1 The rest is the same as in Example 1.

[0097] Because the alloy ingot has many initial pores and large pore sizes, the high speed in the first stage of this embodiment will cause microcracks to be generated inside the alloy ingot.

[0098] Example 12 A method for filling pores in an alloy ingot, which differs from Example 1 in that: the first stage compression temperature during hot compression in step S2 is 250°C; the rest is the same as in Example 1.

[0099] Because the alloy ingot has many initial pores and large pore sizes, the compression temperature used in the first compression stage in this embodiment is relatively low. The alloy ingot has poor deformation ability and is prone to stress concentration at low temperatures, which leads to the formation of microcracks inside.

[0100] Example 13 A method for closing pores in an alloy ingot, differing from Example 1, in that: in step S3, the strain rate used in the second stage of hot compression is 4s. -1 The rest is the same as in Example 1.

[0101] Due to the higher strain rate in the second stage, although the porosity of the alloy ingot has been further reduced after the first stage of compression, local stress concentration will still occur during the second stage of compression, resulting in microcracks inside.

[0102] Example 14 A method for filling pores in an alloy ingot, which differs from Example 1 in that the extrusion ratio in step S3 is 5; the rest is the same as in Example 1.

[0103] Because the extrusion ratio is small, the pores cannot be fully closed, resulting in a small number of pores, which significantly reduces the elongation and fatigue cycle count of the resulting alloy.

[0104] Example 15 A method for filling pores in an alloy ingot, which differs from Example 1 in that: in step S2, the compression amount in the first stage of hot compression is 30%, the compression amount in the second stage is 20%, and the total strain is 50%; the rest is the same as in Example 1.

[0105] Because the total deformation during the compression stage is relatively small, the pore size is still relatively large and is not completely closed during the subsequent extrusion process, resulting in a significant reduction in the elongation and fatigue cycle count of the alloy.

[0106] Comparative Example 1 A method for filling pores in an alloy ingot, which differs from Example 1 in that step S2 is omitted; the rest is the same as in Example 1.

[0107] Since this comparative example did not undergo staged hot compression, the resulting alloy contained obvious pores distributed along the extrusion direction, resulting in a significant reduction in elongation and fatigue cycle count.

[0108] Result detection The alloy ingots and the resulting alloys obtained by the methods of the above embodiments and comparative examples are then tested.

[0109] The porosity characteristics of the alloy ingot and the alloy were tested at the CT scanning beamline of the Shanghai Synchrotron Radiation Facility. The images were reconstructed using three-dimensional image analysis software, and the porosity characteristics (size and volume fraction) were directly read out. The tensile strength and elongation were tested in accordance with the GB / T 16865-2023 standard. The fatigue performance was tested in accordance with the fatigue performance of the ISO 12106 standard.

[0110] The results are shown in Tables 1 and 2 below.

[0111] Table 1. Test results of alloy ingots and alloys in Example 1 and Comparative Example 1.

[0112] In Table 1, a maximum pore size of 0 after extrusion indicates no pores; the initial pore volume fraction and the initial maximum pore size are the same as the pore volume fraction and maximum pore size of the alloy ingot.

[0113] As can be seen from Table 1, compared with Comparative Example 1 which did not undergo hot compression, the alloy obtained in Example 1 of the present invention is free of pores under CT scanning with a radiation source, achieving complete elimination of pores. Furthermore, while ensuring the strength of the alloy, the elongation is increased by 35% compared with Comparative Example 1, and the number of cyclic fatigue cycles is increased by 45%.

[0114] Furthermore, the present invention optimizes the process parameters during the pore-filling process through different embodiments to further ensure the successful pore-filling process and improve the performance and quality of the alloy.

[0115] As shown in Table 2, Table 2 presents the test results of the alloy ingots and alloys of Examples 1 to 15.

[0116] Table 2. Test results of alloy ingots and alloys in Examples 1-15

[0117] In Table 2, a maximum pore size of 0 after extrusion indicates no pores; the initial pore volume fraction and the initial maximum pore size are the same as the pore volume fraction and maximum pore size of the alloy ingot.

[0118] In Table 2, Examples 1-3 used aluminum alloy ingots with different compositions, and all of them were able to achieve pore filling, improve the elongation and fatigue performance of the alloy. This shows that the pore filling method of the present invention is applicable to alloy ingots with different compositions, has good universality, and can completely eliminate pores in spray-formed aluminum alloy ingots.

[0119] In Examples 1 and 4-15, by adjusting the process parameters of hot compression and extrusion, the effect of improving the elongation and fatigue performance of the alloy can be optimized, while avoiding problems such as incomplete pore filling or cracking and microcracks during compression.

[0120] Figure 2 The image shown is a synchrotron radiation X-ray CT scan result of the alloy ingot formed by spraying in Example 1. It can be seen that the maximum pore size in the alloy ingot is 125 μm.

[0121] Figure 3 The image shown is an X-ray CT scan of the alloy ingot after hot compression in Example 1. It can be seen that the maximum pore size in the compressed alloy ingot is 22 μm.

[0122] Figure 4 The image shown is an X-ray CT scan of the extruded alloy ingot in Example 1. It can be seen that there are no pores in the extruded alloy ingot, so the final alloy has high elongation and fatigue cycle life.

[0123] Figure 5 The image shown is a metallographic photograph of the microcracks in the alloy ingot obtained in Example 11. It can be seen that fine cracks appeared in the alloy. The microcrack characteristics in Examples 12 and 13 are similar.

[0124] Figure 6 The image shown is an X-ray CT scan of the alloy ingot in Comparative Example 1 after direct extrusion without hot compression. It can be seen that a small number of pores are still distributed in the extruded alloy ingot, and its elongation and fatigue cycle life are low.

[0125] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method of porosity healing of an alloy ingot, characterized by, The method comprises the following steps: The alloy ingot is compressed along the axial direction, and then extruded to complete the pore closure; The compression is segmented compression, wherein: First stage: compression temperature is 200-500°C, strain rate is ≥0.4s -1 ; Stage 2: compression temperature 300-600°C, strain rate > 1.2 s -1 .

2. The method of claim 1, wherein, The first stage of straining has a rate of 0.4 to 1.2 s -1 ; and / or the second stage has a strain rate of 1.2 to 3.5 s -1 .

3. The method according to claim 1 or 2, characterized in that, The total strain of the compression is 55-95%.

4. The method of claim 3, wherein, The strain of the first stage is 35-55%; And / or, the strain of the second stage is 20-40%.

5. The method of claim 1, wherein, A die sleeve is placed around the alloy ingot during the compression; and / or, the temperature of the die sleeve is 250-500 DEG C.

6. The method of claim 1, wherein, The temperature of the extrusion is 300-500 DEG C; And / or, the extrusion ratio of the extrusion is 10-20; And / or, the speed of the extrusion is 1-6 mm / s.

7. The method according to claim 1 or 6, characterized in that, The compressed alloy ingot is cut before the extrusion.

8. The method of claim 1, wherein, The extrusion further comprises the steps of solid solution and aging; the solid solution is two-stage solid solution, wherein: The first-stage solid solution has a solid solution temperature of 250-450 DEG C and a holding time of 1-10 h; The second-stage solid solution has a solid solution temperature of 450-550 DEG C and a holding time of 1-10 h.

9. The method of claim 1, wherein, The alloy ingot is a spray-formed aluminum alloy ingot.

10. The method according to claim 1 or 9, characterized in that, The alloy ingot comprises the following components in percentage by mass: Zn: 4-10%, Mg: 0.5-3%, Cu: 0.5-3%, Zr: 0-0.3%, Ti: 0-0.3%, Mn: 0-0.3%, Zr+Ti+Mn+Sc≤0.4%, Fe+Si≤0.1%, and the balance being aluminum.

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