Forging forming process for high-performance aluminum alloy component

Abstract

The invention relates to the technical field of alloy materials, and discloses a high-performance aluminum alloy component forging forming technology which comprises the steps that after aluminum, lithium, magnesium, zirconium and rare earth elements are mixed and smelted, pouring, rough blank forging, precision forging, quenching and aging treatment are conducted in sequence, and a high-performance aluminum alloy component is obtained. By accurately controlling the key steps of smelting, preheating, forging, quenching, aging treatment and the like, the mechanical property of the aluminum alloy component is remarkably improved, the coarse grain problem is effectively eliminated, and industrial production is achieved. Compared with the prior art, the process provided by the invention not only improves the strength and toughness of the material, but also reduces the production cost.

Description

Technical Field

[0001] The invention relates to the technical field of alloy materials, and in particular to a forging process for a high-performance aluminum alloy component. Background Art

[0002] Aluminum alloys have become an indispensable material in many fields such as aerospace, automobile manufacturing, shipbuilding industry, and high-end equipment manufacturing due to their excellent specific strength, outstanding corrosion resistance, and excellent processing characteristics. The widespread application of this material is due to its unique advantages in lightweight, durability, and reliability. However, in the traditional forging process, aluminum alloy components are often prone to coarse grains, which not only reduces the strength of the material, but also leads to uneven mechanical properties, thus having a negative impact on the safety of use and the service life of the components. In addition, while traditional forging processes improve the strength of the material, it is often difficult to ensure that the material maintains good plasticity and ductility. This limitation greatly limits the application potential of aluminum alloys in high-load structural parts. At present, the solutions to the problem of coarse grains in aluminum alloys mainly focus on the following:

[0003] Grain refinement techniques: These include adding rare earth elements or implementing rapid cooling measures, however these methods have limited effectiveness and are costly.

[0004] Multiple heat treatment processes: such as repeated solution and aging treatments, although helpful for grain refinement, have a long production cycle and high energy consumption, and are therefore not suitable for large-scale production.

[0005] Traditional deformation control method: involves controlling deformation temperature and deformation amount, but due to the lack of systematic design, its effect is often not stable enough.

[0006] Therefore, there is an urgent need for a high-performance aluminum alloy component forging process that can eliminate coarse grains, improve mechanical properties and is suitable for industrial production to meet the demand for high-strength and excellent toughness materials in the high-end manufacturing field. Summary of the invention

[0007] In view of this, the present invention proposes a high-performance aluminum alloy component forging process, aiming to solve the above problems.

[0008] The present invention proposes a high-performance aluminum alloy component forging process, comprising:

[0009] Aluminum, lithium, magnesium, zirconium and rare earth elements are mixed and smelted at a smelting temperature of 740-760°C, a stirring time of 8-12 minutes, and a heat preservation time of 18-22 minutes; the smelted metal is poured to form an ingot; the ingot is heated to 490-510°C for preheating, and the preheated ingot is subjected to rough forging at 260-300°C to obtain a rough blank workpiece, with a deformation of 45%-55% and a reduction rate of 8-12 mm / s;

[0010] The rough blank workpiece is finely forged at a temperature of 190-210° C.; the forged workpiece is put into water for quenching at a water temperature of 10-15° C. for a quenching time of 12-18 seconds; and the quenched workpiece is subjected to aging treatment to obtain the high-performance aluminum alloy component.

[0011] Preferably, the weight ratio of aluminum, lithium, magnesium, zirconium and rare earth elements is 92-93:1.0-1.5:1.8-2.2:0.4-0.6:3.5-4.0.

[0012] Preferably, the rare earth elements include scandium, yttrium and cerium.

[0013] Preferably, the weight ratio of scandium, yttrium and cerium is 1.0-1.5:1.2-1.5:1.0-1.2.

[0014] Preferably, the deformation of the rough billet after forging is controlled at 50%-55%.

[0015] Preferably, the precision forging is performed in three steps, with each step causing a deformation of 10% to 12.5%.

[0016] Preferably, the transfer time of the workpiece during the quenching process does not exceed 5 seconds.

[0017] Preferably, the aging treatment includes a first stage and a second stage;

[0018] The first stage is kept at 130-140° C. for 7-9 hours, and the second stage is kept at 170-180° C. for 5-7 hours.

[0019] The present invention also proposes a high-performance aluminum alloy component, which is obtained by forging according to the above-mentioned high-performance aluminum alloy component forging forming process.

[0020] The present invention also proposes an application of the high-performance aluminum alloy component in the manufacture of structural parts.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a coarse grain elimination forging process for high-performance aluminum-lithium-rare earth alloy components, which achieves the following significant beneficial effects through precise temperature control, deformation design and synergistic effect of specific elements:

[0023] 1. Significantly improve mechanical properties

[0024] The tensile strength is increased to 520-550MPa, and the yield strength reaches 500-530MPa, which is more than 15% higher than the traditional process.

[0025] The elongation is increased to 10-12%, taking into account both high strength and excellent ductility, meeting the performance requirements of high-load structural parts such as aerospace.

[0026] 2. Effectively eliminate coarse crystals

[0027] Through preheating temperature control (466-555℃) and multi-stage deformation process, the grain size was successfully refined to 8-12μm, effectively eliminating the coarse grain problem caused by high temperature insulation in the traditional forging process and improving the uniformity and stability of the material.

[0028] 3. Synergistic effect of multiple reinforcement mechanisms

[0029] It adopts five strengthening mechanisms: solid solution strengthening, precipitation strengthening, fine grain strengthening, dislocation strengthening and rare earth element strengthening. Through the synergistic effect of lithium and rare earth elements, deep optimization of the microstructure is achieved.

[0030] Rare earth elements (such as cerium and yttrium) form stable rare earth oxides at the grain boundaries, inhibiting grain boundary embrittlement and improving corrosion resistance and fatigue life.

[0031] 4. The production process is stable and can be industrialized

[0032] The use of standardized temperature control and aging treatment processes facilitates large-scale production and reduces the energy consumption and time costs of multiple heat treatments.

[0033] The key process parameter ranges are clear, making implementation and quality control easier.

[0034] 5. Reduce production costs

[0035] By precisely controlling the holding time and deformation temperature, energy waste is reduced, and the material cost is further reduced due to the low amount of rare earth elements added.

[0036] 6. Wide range of applications

[0037] This process is applicable to 2xxx, 6xxx, and 7xxx series aluminum alloys, and is particularly suitable for the manufacture of aerospace structures, high-strength body parts, military equipment, and marine structures.

[0038] In summary, the present invention achieves significant improvements in the strength, toughness and microstructure of aluminum alloy components through innovative temperature and deformation control processes, and has outstanding industrial application value and promotion prospects. DETAILED DESCRIPTION

[0039] The exemplary embodiments of the present disclosure will be described in more detail below. Although the exemplary embodiments of the present disclosure are shown below, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0040] Example 1

[0041] A coarse grain elimination forging process for a high-performance aluminum-lithium-rare earth alloy component comprises the following steps:

[0042] 1. Raw material ratio (weight ratio)

[0043] Aluminum 92.5, lithium 1.2, magnesium 2.0, zirconium 0.5, rare earth elements (scandium 1.3, yttrium 1.5, cerium 1.0).

[0044] 2. Preparation Steps

[0045] (1) Melting

[0046] The above raw materials were put into a smelting furnace, melted at 750°C, stirred for 10 minutes to ensure uniform composition, then kept warm for 20 minutes and cast into an ingot with a diameter of 150 mm.

[0047] (2) Preheating

[0048] The ingot was heated to 500°C and kept at this temperature for 5 hours (calculated according to the holding time formula T = 2.0 min / mm).

[0049] (3) Rough blank

[0050] The ingot was preliminarily forged at a temperature of 280°C, with a deformation of 50% and a reduction rate of 10 mm / s.

[0051] (4) Precision forging

[0052] The rough-formed workpiece is heated to 200°C and forged three times, with a deformation of 10% each time.

[0053] (5) Quenching

[0054] The forged workpiece was immediately put into 20°C water for quenching for 15 seconds.

[0055] (6) Aging treatment

[0056] The first stage is to keep the temperature at 135°C for 8 hours; the second stage is to keep the temperature at 175°C for 6 hours, thereby obtaining aluminum alloy components that meet the technical requirements.

[0057] Example 2

[0058] A coarse grain elimination forging process for a high-performance aluminum-lithium-rare earth alloy component is basically the same as the steps in Example 1, but the key process parameters are adjusted:

[0059] 1. Raw material ratio (weight ratio)

[0060] Aluminum 92, lithium 1.5, magnesium 2.2, zirconium 0.4, rare earth elements (scandium 1.5, yttrium 1.2, cerium 1.2).

[0061] 2. Adjustment of preparation steps

[0062] The melting temperature is 760°C, the stirring time is 12 minutes, and the holding time is 22 minutes;

[0063] The preheating temperature is 510°C and the holding time is T=2.1min / mm (i.e. 5.25 hours);

[0064] The rough billet temperature is 300°C, the deformation is 55%, and the pressing rate is 12 mm / s;

[0065] The fine forging temperature is 210℃, and the deformation amount each time is 11.7%;

[0066] The quenching water temperature is 25°C and the time is 12 seconds;

[0067] The first stage of aging treatment is 140°C for 7 hours; the second stage is 180°C for 5 hours.

[0068] Example 3

[0069] A coarse grain elimination forging process for a high-performance aluminum-lithium-rare earth alloy component is basically the same as the steps in Example 1, but the key process parameters are adjusted:

[0070] 1. Raw material ratio (weight ratio)

[0071] Aluminum 93, lithium 1.0, magnesium 1.8, zirconium 0.6, rare earth elements (scandium 1.0, yttrium 1.5, cerium 1.1).

[0072] 2. Adjustment of preparation steps

[0073] The melting temperature is 740°C, the stirring time is 8 minutes, and the holding time is 18 minutes;

[0074] The preheating temperature is 490°C and the holding time is T=1.8min / mm (i.e. 4.5 hours);

[0075] The rough billet temperature is 260°C, the deformation is 45%, and the pressing rate is 8 mm / s;

[0076] The fine forging temperature is 190°C, and the deformation amount each time is 12.5%;

[0077] The quenching water temperature is 22°C and the time is 18 seconds;

[0078] The first stage of aging treatment is 130°C for 9 hours; the second stage is 170°C for 7 hours.

[0079] Comparative Example 1: No rare earth element added

[0080] 1. Raw material ratio (weight ratio)

[0081] Aluminum (Al): 98;

[0082] Lithium (Li): 1.2;

[0083] Magnesium (Mg): 0.8;

[0084] Zirconium (Zr): 0.5.

[0085] 2. Preparation Steps

[0086] Melting: carried out at 750°C, stirring for 10 minutes, keeping warm for 20 minutes, and then casting into ingots with a diameter of 150 mm.

[0087] Preheating: Keep at 500°C for 5 hours (T = 2.0 min / mm).

[0088] Rough billet: carried out at 280°C, with a deformation of 50% and a pressing rate of 10 mm / s.

[0089] Precision forging: carried out at 200°C, three forgings are performed, and the forging amount each time is 10%.

[0090] Quenching: Quenching in 10°C water for 15 seconds.

[0091] Aging treatment: 8 hours at 135°C; 6 hours at 175°C.

[0092] Comparative Example 2: Omitting the preheating step

[0093] 1. Raw material ratio (weight ratio)

[0094] Aluminum (Al): 92.5;

[0095] Lithium (Li): 1.2;

[0096] Magnesium (Mg): 2.0;

[0097] Zirconium (Zr): 0.5;

[0098] Rare earth elements (Sc1.3, Y1.5, Ce1.0).

[0099] 2. Preparation Steps

[0100] Melting: carried out at 750°C, stirring for 10 minutes, keeping warm for 20 minutes, and then casting into ingots with a diameter of 150 mm.

[0101] Rough billet: directly heated to 280℃ for deformation, with a deformation amount of 50%.

[0102] Precision forging: carried out at 200°C, three forgings are performed, and the forging amount each time is 10%.

[0103] Quenching: Quenching in water at 20°C for 15 seconds.

[0104] Aging treatment: 8 hours at 135°C; 6 hours at 175°C.

[0105] Comparative Example 3: Reducing the forging deformation

[0106] 1. Raw material ratio (weight ratio)

[0107] Aluminum (Al): 92.5;

[0108] Lithium (Li): 1.2;

[0109] Magnesium (Mg): 2.0;

[0110] Zirconium (Zr): 0.5;

[0111] Rare earth elements (Sc1.3, Y1.5, Ce1.0).

[0112] 2. Preparation Steps

[0113] Melting: carried out at 750°C, stirring for 10 minutes, keeping warm for 20 minutes, and then casting into ingots with a diameter of 150 mm.

[0114] Preheating: Keep at 500°C for 5 hours (T = 2.0 min / mm).

[0115] Rough billet: carried out at 280°C, with a deformation of 30% and a pressing rate of 10 mm / s.

[0116] Precision forging: carried out at 200°C, three forgings are performed, and the forging amount each time is 7%.

[0117] Quenching: Quenching in water at 20°C for 15 seconds.

[0118] Aging treatment: 8 hours at 135°C; 6 hours at 175°C.

[0119] Test Example 1

[0120] The aluminum-lithium-rare earth alloy components prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to quality tests of mechanical properties and microstructures. The sample size was a standard tensile specimen (according to GB / T 228.1-2010), with a diameter of 10 mm and a gauge length of 50 mm.

[0121] 1. Test items and reference standards:

[0122] Tensile strength (MPa): GB / T 228.1-2010 "Tensile test of metal materials".

[0123] Yield strength (MPa): GB / T 228.1-2010.

[0124] Elongation(%): GB / T 228.1-2010.

[0125] Microstructure grain size (μm): GB / T 13298-2015 "Methods for testing metal microstructures".

[0126] 2. Testing process

[0127] Sample preparation: 10 tensile specimens were prepared by standard machining, and each group was measured 5 times to obtain the average value.

[0128] Tensile test: stretch at a rate of 2 mm / min until fracture, and record the tensile strength, yield strength and elongation after fracture.

[0129] Microstructure testing: After polishing and etching, the grain size was determined using an optical microscope and image analysis software.

[0130] Repeatability: Each group of samples was tested 5 times, the average value was taken, and the fluctuation range was recorded.

[0131] 3. Test results

[0132] The test results are shown in Table 1.

[0133] Table 1

[0134]

[0135] According to Table 1, we can see that:

[0136] (1) Tensile strength and yield strength

[0137] The tensile strength (512.1-538.6 MPa) and yield strength (487.3-502.7 MPa) of Examples 1-3 are significantly higher than those of the comparative example (the highest tensile strength is only 489.5 MPa).

[0138] Since no rare earth element is added to Comparative Example 1, its strength is significantly reduced, and the tensile strength decreases by about 14%.

[0139] (2) Elongation

[0140] The elongation of Examples 1-3 is all above 10.8%, meeting the plasticity requirement of high-strength alloys.

[0141] The elongation of the comparative samples is generally lower than 9%, with the lowest being only 7.2%, showing a trend of increasing brittleness.

[0142] (3) Microstructure

[0143] The grain size of Examples 1-3 is controlled between 9.2 and 11.0 μm, and the grain distribution is uniform and fine.

[0144] Due to the lack of rare earth elements and sufficient preheating, the grain size of Comparative Example 1 is relatively large, reaching 21.4 μm, and the grains are coarse and unevenly distributed.

[0145] (4) Defect rate

[0146] The defect rate of Examples 1-3 is controlled below 2.6%, which is significantly better than the comparative example (the defect rate is as high as 5.7%).

[0147] 4. Discussion

[0148] (1) Solid solution strengthening

[0149] Principle: Lithium (Li) elements are introduced into the aluminum matrix, and Li atoms dissolve in the aluminum matrix to form a solid solution. Due to the difference between the atomic radius of Li atoms (152pm) and aluminum (143pm), local distortion is introduced into the lattice. This distortion increases the resistance of the slip system and limits the movement of dislocations, thereby improving the yield strength and tensile strength of the material.

[0150] Microscopic manifestations: lattice distortion and stress concentration points appear; slip resistance of crystal dislocations increases.

[0151] (2) Precipitation strengthening (second phase strengthening)

[0152] Principle: During the aging treatment stage, metastable Al3Li, Al3RE (RE is a rare earth element, such as cerium, yttrium, etc.) nano-scale precipitates are formed in the aluminum-lithium-rare earth alloy. These precipitates act as obstacles inside the crystal, hindering the slip of dislocations, thereby further enhancing the strength of the material.

[0153] Microscopic manifestations: Nanoscale dispersed Al3Li phase and Al3RE phase particles; these particles act as dislocation pinning points, hindering the movement of the slip system; mainly affecting the yield strength.

[0154] (3) Grain refinement strengthening (Hall-Petch effect)

[0155] Principle: By adopting optimized forging and preheating processes, the grain size of aluminum alloy is effectively refined, and the average grain size is reduced to between 9-11μm. According to the Hall-Page formula:

[0156]

[0157] Among them, σy is the yield strength; σ0 is the intrinsic strength of the material; k is the material constant; d is the grain size.

[0158] The reduction in grain size leads to an increase in the total length of grain boundaries, so that more grain boundaries hinder the expansion of dislocations and significantly improve the strength.

[0159] Microscopic manifestations: finer and more uniform equiaxed grain distribution; dislocation accumulation at grain boundaries; mainly improve yield strength and tensile strength.

[0160] (4) Rare earth element strengthening mechanism

[0161] Principle: Rare earth elements (cerium, yttrium, lanthanum) have multiple strengthening effects in aluminum alloys:

[0162] ① Grain boundary cleaning effect: Rare earth elements have extremely strong oxide affinity and can react with impurity elements (such as oxygen, sulfur, etc.) to generate stable oxides (such as Ce2O3), reducing the grain boundary weakening effect.

[0163] ② Grain refinement: Rare earth elements segregate at grain boundaries during solidification to form tiny rare earth compound particles, which inhibit grain growth and thus achieve grain refinement.

[0164] ③ Second phase strengthening: forming rare earth-aluminum compounds (such as Al3Ce), which can be used as nano-precipitation phase strengthening matrix.

[0165] Microscopic manifestations: distribution of rare earth oxides at grain boundaries; finer grain structure; distribution of rare earth-aluminum compound particles.

[0166] (5) Dislocation strengthening (work hardening)

[0167] Principle: During the forging process, due to the high degree of deformation, a large number of dislocations accumulate inside the material. The increase in dislocation density forms dislocation cross-slip and dislocation accumulation, which further hinders the movement of the slip system and increases the strength of the material.

[0168] Microscopic manifestations: A large number of dislocations are interlaced inside the crystal; dislocation pile-up is obvious; mainly improves yield strength.

[0169] (6) Micro-comprehensive mechanism analysis

[0170] ①Improvement of yield strength

[0171] It mainly depends on the combined effects of solid solution strengthening, precipitation strengthening, grain refinement strengthening and dislocation strengthening.

[0172] ②Improved tensile strength

[0173] It is mainly affected by grain refinement and precipitation strengthening, while work hardening further improves the tensile strength during the tensile stage.

[0174] ③Elongation optimization

[0175] Grain boundary cleaning and a fine grain structure reduce the risk of brittle fracture, thereby increasing elongation.

[0176] (7) Summary

[0177] Through the synergistic effect of multiple strengthening mechanisms such as solid solution strengthening, precipitation strengthening, grain refinement strengthening, rare earth element strengthening and dislocation strengthening, the high-performance aluminum alloy in the embodiment of the present invention has higher tensile strength, yield strength and good ductility, which is significantly better than the comparative sample.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A high-performance aluminum alloy component forging process, characterized in that: include: Aluminum, lithium, magnesium, zirconium and rare earth elements are mixed and smelted at a smelting temperature of 740-760°C, a stirring time of 8-12 minutes, and a heat preservation time of 18-22 minutes; the smelted metal is poured to form an ingot; the ingot is heated to 490-510°C for preheating, and the preheated ingot is subjected to rough forging at 260-300°C to obtain a rough blank workpiece, with a deformation of 45%-55% and a reduction rate of 8-12 mm / s; The rough blank workpiece is finely forged at a temperature of 190-210° C.; the forged workpiece is put into water for quenching at a water temperature of 10-15° C. for a quenching time of 12-18 seconds; and the quenched workpiece is subjected to aging treatment to obtain the high-performance aluminum alloy component.

2. The forging process according to claim 1, characterized in that: The weight ratio of aluminum, lithium, magnesium, zirconium and rare earth elements is 92-93: 1.0-1.5：1.8-2.2：0.4-0.6：3.5-4.0。 3. The forging process according to claim 1 or 2, characterized in that: The rare earth elements include scandium, yttrium and cerium.

4. The forging process according to claim 3, characterized in that: The weight ratio of scandium, yttrium and cerium is 1.0-1.5:1.2-1.5:1.0-1.

2.

5. The forging process according to claim 1, characterized in that: The deformation of the rough billet after forging is controlled at 50%-55%.

6. The forging process according to claim 1, characterized in that: The precision forging is divided into three forgings, and the deformation amount of each forging is 10%-12.5%.

7. The forging process according to claim 1, characterized in that: The transfer time of the workpiece during quenching does not exceed 5 seconds.

8. The forging process according to claim 1, characterized in that: The aging treatment includes a first stage and a second stage; The first stage is kept at 130-140° C. for 7-9 hours, and the second stage is kept at 170-180° C. for 5-7 hours.

9. A high performance aluminum alloy component, characterized in that: The high-performance aluminum alloy component is obtained by forging according to the forging forming process according to any one of claims 1 to 8.

10. Use of the high-performance aluminum alloy component according to claim 9 in the manufacture of structural parts.

Images