Aluminum alloy part and mixed manufacturing method

Abstract

The invention provides an aluminum alloy component and a hybrid manufacturing method, and relates to the technical field of hybrid manufacturing, and the method comprises the following steps: carrying out solid phase additive manufacturing on an aluminum alloy raw material to obtain an additive part; plastic processing treatment is conducted on the additive part, and the additive part subjected to plastic processing treatment is obtained; carrying out heat treatment on the additive part subjected to plastic processing treatment to obtain an aluminum alloy component; in the structure of the solid-phase additive component based on the aluminum alloy, the grain size is small, more grain boundary energy is stored, during solid solution heat treatment, abnormal grain growth is likely to happen, millimeter-scale grains appear in the structure, and the tensile property is damaged; strain energy is introduced into an additive structure through plastic processing treatment, so that during heat treatment, recrystallization nucleation and growth are promoted, and the effect of limiting growth of abnormal grains is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of manufacturing, and particularly relates to an aluminum alloy piece and a hybrid manufacturing method. BACKGROUND

[0002] Precipitation-strengthened aluminum alloys (Al-Cu series aluminum alloys, Al-Mg-Si series aluminum alloys, Al-Zn series aluminum alloys, Al-Li series aluminum alloys) have high specific strength, specific stiffness and fatigue resistance, and are applied to structural parts in the fields of aviation, aerospace, automobiles and the like. Additive manufacturing can manufacture parts by layer-by-layer accumulation of materials, and if additive manufacturing is applied to the preparation of precipitation-strengthened aluminum alloy components, the production cycle can be shortened and the cost can be reduced. However, defects such as pores and cracks often exist in the microstructure of the precipitation-strengthened aluminum alloy prepared by melting additive manufacturing, and it is difficult to apply it to load-bearing structural parts.

[0003] Solid-phase additive manufacturing technology represented by friction extrusion deposition can manufacture dense metal components without melting and solidification of materials during the additive process, and is expected to be applied to additive manufacturing of precipitation-strengthened aluminum alloys. However, the applicant found that at least the following problems exist when using solid-phase additive manufacturing technology to manufacture precipitation-strengthened aluminum alloy components: the precipitates of the lower layer material are significantly coarsened due to repeated additive thermal cycles during the additive process, resulting in a decrease in hardness and strength.

[0004] The prior art dissolves the coarsened precipitates by solid solution and aging heat treatment, and the precipitates are re-precipitated in the form of fine dispersion. However, due to the small grain size of the matrix phase in the solid-phase additive microstructure, the grain boundary energy is high, and abnormal grain growth easily occurs during solid solution heat treatment, resulting in a lower strength of the alloy after heat treatment than that of the fine-grained microstructure in the aging state. SUMMARY

[0005] Therefore, the present application provides an aluminum alloy piece and a hybrid manufacturing method, which can solve the problem of abnormal grain growth after heat treatment of the aluminum alloy solid-phase additive piece in the prior art.

[0006] To solve the above problems, the present application provides a hybrid manufacturing method of an aluminum alloy piece, comprising the following steps:

[0007] A step of preparing an additive piece: solid-phase additive manufacturing of an aluminum alloy raw material to obtain an additive piece;

[0008] A step of plastic processing treatment: plastic processing treatment of the additive piece to obtain a plastic processing treated additive piece;

[0009] A step of heat treatment: heat treatment of the plastic processing treated additive piece to obtain a hybrid manufactured aluminum alloy piece.

[0010] Further, in the step of preparing the additive part, the aluminum alloy raw material is a precipitation-strengthened aluminum alloy rod, including an Al-Cu series aluminum alloy rod, an Al-Mg-Si series aluminum alloy rod, an Al-Zn series aluminum alloy rod, and an Al-Li series aluminum alloy rod.

[0011] Further, in the step of plastic processing, the true strain of the plastic processing is ≥20%, preferably ≥40%, and further preferably 40%-200%; and / or

[0012] The plastic processing is one of rolling, forging, extrusion, and stamping; preferably, the plastic processing is rolling.

[0013] Further, the solid-phase additive manufacturing is in a friction extrusion deposition mode.

[0014] Further, the step of friction extrusion deposition specifically includes depositing the aluminum alloy rod raw material on the surface of the substrate layer by layer.

[0015] Preferably, the material of the substrate is an aluminum alloy.

[0016] Preferably, the thickness of the substrate is ≥5 mm.

[0017] Further, in the process of friction extrusion deposition, c·(2-5)·r 2 =v·t·a, and a>2.5r; wherein t is the thickness of a single additive layer, mm; a is the width of a single additive layer, mm; c is the feeding rate of the aluminum alloy raw material, mm / min; v is the travel rate of the friction extrusion deposition die, mm / min; and r is the radius of the aluminum alloy raw material, mm.

[0018] Preferably, the radius of the raw material is 5-20 mm; the rotation speed of the friction extrusion deposition die is 300-600 r / min; the feeding rate of the aluminum alloy raw material is 10-500 mm / min; the travel rate of the friction extrusion deposition die is 50-3000 mm / min; the thickness of a single additive layer is 0.5-2 mm; and the width of a single additive layer is 5-60 mm.

[0019] Further, the step of heat treatment specifically includes sequentially performing solid solution treatment and aging treatment on the additive part after the plastic processing.

[0020] Further, the temperature of the solid solution treatment is 440-500℃, and the holding time is 0.5-4 h. Further, the aging treatment includes artificial aging and natural aging.

[0021] The time of the natural aging treatment is ≥96 h.

[0022] The temperature of the artificial aging treatment is 100-200 DEG C, and the time is 6-48 hours.

[0023] In another aspect, the application provides an aluminum alloy part, the grain size of the aluminum alloy part is ≤200 μm; the nanoscale precipitates are dispersedly distributed in the grain of the aluminum alloy part; wherein, the width of the nanoscale precipitates is ≤20 nm; the average yield strength of the aluminum alloy part is ≥300 MPa, and the elongation after fracture is ≥8 %.

[0024] Preferably, the aluminum alloy part is obtained by the hybrid manufacturing method described in any one of the above.

[0025] The aluminum alloy part and the hybrid manufacturing method for preparing the aluminum alloy part provided by the application have the following beneficial effects:

[0026] 1. In one aspect, the grain size in the structure of the solid-phase additive component based on aluminum alloy is small, and more grain boundary energy is stored, and abnormal grain growth is prone to occur during solid solution heat treatment, resulting in the appearance of millimeter-level grains in the structure, which endangers the tensile properties; the application provides a hybrid manufacturing method for an aluminum alloy part, comprising the following steps: solid-phase additive manufacturing of an aluminum alloy raw material to obtain an additive part; plastic processing treatment of the additive part to introduce strain energy into the additive part, and obtaining the additive part after plastic processing treatment; heat treatment of the additive part after plastic processing treatment to obtain a hybrid manufactured aluminum alloy part; the application introduces more strain energy into the additive structure through plastic processing treatment, so as to promote recrystallization nucleation and growth during heat treatment, and achieve the effect of limiting abnormal grain growth.

[0027] 2. Further, in the process of friction extrusion deposition, the following formula can be used to ensure good forming of the additive sample, promote close interlayer interface bonding, and thus ensure good forming and effective accumulation of strain energy in the grains during rolling, and further avoid abnormal grain growth during heat treatment. The formula is as follows:

[0028] c·(2~5)·r 2 =v·t·a, and a>2.5r; wherein, t is the thickness of a single additive layer, mm; a is the width of a single additive layer, mm; c is the feeding rate of the aluminum alloy raw material, mm / min; v is the travel rate of the friction extrusion deposition die, mm / min; and r is the radius of the aluminum alloy raw material, mm.

[0029] 3. In another aspect, the application provides an aluminum alloy part obtained by the preparation method described above, the grain size of the aluminum alloy part is ≤200 μm; the nanoscale precipitates are dispersedly distributed in the grain of the aluminum alloy part; wherein, the width of the nanoscale precipitates is ≤20 nm; the average yield strength of the solid-phase additive aluminum alloy part is ≥300 MPa, and the elongation after fracture is ≥8 %.

[0030] 4. The present application uses friction extrusion deposition additive manufacturing technology in the manufacture of aluminum alloy parts. In the additive process, the material does not melt and solidify, and a dense metal component can be manufactured. The production cycle can be shortened, and the cost can be reduced. At the same time, the problem of pores, cracks and other defects often existing in traditional melting additive manufacturing of precipitation strengthened aluminum alloy can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. The drawings in the following description are only exemplary, and other embodiments can be derived from the provided drawings without creative labor for those skilled in the art.

[0032] Figure 1 Process schematic diagram of the additive part prepared in step 1 of Example 1;

[0033] Figure 2 Actual photograph of the additive part prepared in step 1 of Example 1;

[0034] Figure 3 Actual photograph of the aluminum alloy part prepared in Example 1;

[0035] Figure 4 Grain structure of the aluminum alloy part prepared in Example 1;

[0036] Figure 5 Precipitated phase of the aluminum alloy part prepared in Example 1;

[0037] Figure 6 Actual photograph of the aluminum alloy part prepared in Example 2;

[0038] Figure 7 Grain structure of the aluminum alloy part prepared in Example 2;

[0039] Figure 8 Precipitated phase of the aluminum alloy part prepared in Example 2;

[0040] Figure 9 Actual photograph of the aluminum alloy part prepared in Example 3;

[0041] Figure 10 Grain structure of the aluminum alloy part prepared in Example 3;

[0042] Figure 11 Precipitated phase of the aluminum alloy part prepared in Example 3;

[0043] Figure 12 Grain structure of the aluminum alloy part prepared in Comparative Example 1;

[0044] Figure 13 Grain structure of the aluminum alloy piece prepared for Comparative Example 2;

[0045] Figure 14 Actual figure of the additive piece prepared for Comparative Example 3;

[0046] Figure 15 Actual figure of the additive piece prepared for Comparative Example 4;

[0047] Figure 16 Actual figure of the additive piece prepared for Comparative Example 5. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. The accompanying drawings in the following description are merely exemplary, and other embodiments can be derived from the provided accompanying drawings without paying creative labor for those skilled in the art.

[0049] The present application provides a hybrid manufacturing method of an aluminum alloy piece, comprising the following steps:

[0050] The additive piece preparation step: solid-phase additive manufacturing is performed on an Al-Cu-Mg system aluminum alloy rod to obtain an additive piece;

[0051] Specifically, an aluminum alloy is used as a substrate, and after surface treatment (surface polishing and cleaning) and fixation, a precipitation strengthened aluminum alloy rod is deposited on the surface of the aluminum alloy substrate layer by layer by using a friction extrusion deposition method;

[0052] The thickness of the substrate is ≥5 mm; during the friction extrusion deposition process, c·(2~5)·r 2 =v·t·a, and a>2.5r; wherein t is the thickness of a single additive layer, in mm; a is the width of a single additive layer, in mm; c is the feeding rate of the aluminum alloy raw material, in mm / min; v is the travel rate of the friction extrusion deposition die, in mm / min; r is the radius of the aluminum alloy raw material, in mm; preferably, the radius of the raw material is 5-20 mm; the rotation speed of the friction extrusion deposition die is 300-600 r / min; the feeding rate of the aluminum alloy raw material is 10-500 mm / min; the travel rate of the friction extrusion deposition die is 50-3000 mm / min; the thickness of a single additive layer is 0.5-2 mm; and the width of a single additive layer is 5-60 mm.

[0053] The plastic processing treatment step: plastic processing treatment is performed on the additive piece to introduce strain energy into the additive piece, and an additive piece after plastic processing treatment is obtained;

[0054] The plastic processing treatment has a true strain of ≥20%, preferably a true strain of ≥40%, and more preferably a true strain of 40% to 200%. The plastic processing treatment is preferably rolling. The true strain, also referred to as "logarithmic strain", more accurately reflects the true deformation state of the material in the process of large deformation, and is obtained by integrating the ratio of "instantaneous deformation amount and instantaneous size".

[0055] The heat treatment step includes: after the plastic processing treatment, the additive part is kept at 440-500°C for 0.5-4h, then quenched to obtain a solid solution treated hybrid manufacturing part, and then the solid solution treated hybrid manufacturing part is aged to obtain an aluminum alloy part.

[0056] It should be noted that the microstructure of the solid-phase additive component of the aluminum alloy has small matrix grain size, stores a large amount of grain boundary energy, and only a small amount of strain energy, about 0.6-1.2 MJ / m³. During solid solution heat treatment, abnormal grain growth is easy to occur, resulting in the presence of millimeter-level grains in the microstructure, which is harmful to the tensile properties. Based on the above method, more strain energy is introduced into the additive microstructure through plastic processing treatment (the strain energy in the additive part after plastic processing treatment is 1.5-2 times that before plastic processing treatment), so that during heat treatment, recrystallization nucleation and growth are promoted, and the effect of limiting abnormal grain growth is achieved. During plastic processing treatment, a true strain of not less than 20% can effectively inhibit abnormal grain growth. In addition, through plastic processing treatment, a high-density low-angle grain boundary + high-dislocation density microstructure can be formed in the grain, and this kind of microstructure has high intracrystalline strain energy and high recrystallization driving force.

[0057] The process of friction extrusion deposition refers to feeding raw materials into the inner sleeve, and the raw materials soften and are extruded to form an additive layer after friction with the rotating friction extrusion die.

[0058] During the above friction extrusion deposition process, the aluminum alloy raw material is fed into the friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, causing local softening of the raw material. With the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die. With the movement of the die, the extruded material forms an additive layer on the substrate. After the solid-phase additive is completed, an additive part is obtained.

[0059] Specifically, the upper end of the friction extrusion deposition die has an opening, and the lower end has an extrusion hole; here, the raw material part (aluminum alloy raw material) is fed into the lower end of the friction extrusion die through a feeding mechanism; the raw material part rubs with the inner wall (especially the bottom) of the rotating friction extrusion deposition die during the feeding process, causing the rubbed part of the raw material to soften and be extruded from the extrusion hole.

[0060] Wherein, since the residual stress of the aluminum alloy is large during the additive manufacturing, the thickness of the substrate is required to be at least 5mm to avoid the warping deformation;

[0061] Since the plasticity of the precipitation-strengthened aluminum alloy is poor, the forming difficulty during the additive manufacturing is large, and defects such as holes and cracks are prone to occur, during the friction extrusion deposition, c·(2~5)·r 2 =v·t·a, and a>2.5r, at this time, the temperature and flowability of the extruded material during the additive manufacturing can be controlled, so as to ensure the formability of the Al-Cu-Mg aluminum alloy, and at the same time, the proper material extrusion amount is ensured (if the extrusion amount is too large, the friction heat and the plastic deformation heat are too much, which causes the defects such as holes and peeling on the surface of the additive layer; if the extrusion amount is too small, the material is insufficient, and the incomplete additive layer is formed), so as to avoid the occurrence of macroscopic defects;

[0062] In addition, by using the formula, the heat input during the additive manufacturing can be controlled, and at the same time, the forming of the additive manufacturing process is controlled. The control of the heat input can avoid the grain size being too small in the additive structure. When the grain size is too small, the stored grain boundary energy in the structure is large, and the strain is difficult to accumulate in the grain, which causes the effect of plastic deformation to inhibit the abnormal grain growth to decrease; if the rotation speed of the friction extrusion deposition die is too high, the heat generated is too much, which causes the defects such as peeling and holes on the surface of the additive layer. If the rotation speed of the friction extrusion deposition die is too low, the temperature is too low, and the material flowability is insufficient, which causes the forming to be poor.

[0063] In some embodiments, before the step of plastic processing treatment, the step of cutting off the unbound area of the edge of the additive part is further included to avoid the defects generated in the plastic processing; after the aging treatment, the substrate and / or the excess material on the additive part need to be cut off.

[0064] Since the precipitated phase of the precipitation-strengthened aluminum alloy will be coarsened after being heated, the strengthening effect is weakened and the hardness and strength are decreased. Therefore, the previous additive layer will be softened due to the heating by the subsequent additive layer, which causes the strength to decrease. The purpose of the heat treatment is to eliminate this adverse effect and restore the strength. The heat treatment can dissolve these coarsened strengthening phases (solid solution treatment), and re-precipitate in the form of fine dispersion (aging treatment). The selection of the temperature and time of the solid solution treatment can make the precipitated phase in the aluminum alloy be fully dissolved, and not be locally liquefied (burnt).

[0065] Here, the above method is described as follows:

[0066] 1) In the above step of the present application, the strain energy is introduced into the additive structure by plastic processing treatment of the additive part, which promotes the recrystallization nucleation and growth in the additive structure, and inhibits the abnormal grain growth during the heat treatment.

[0067] 2) In the above steps, the applied friction extrusion deposition process and other solid phase additive manufacturing technologies are used. In the additive process, the raw material does not undergo melting and solidification process, and the temperature is relatively low, which avoids the defects that may occur in the melting additive manufacturing, and is suitable for the additive manufacturing of aluminum alloy materials.

[0068] In another aspect, the application provides an aluminum alloy part obtained by any of the above preparation methods; the grain size of the aluminum alloy part is ≤200 μm; the nanoscale precipitates are dispersedly distributed in the grains of the aluminum alloy part; wherein the width of the nanoscale precipitates is ≤20 nm; the average yield strength of the solid-phase additive aluminum alloy part is ≥300 MPa, and the elongation after fracture is ≥8%.

[0069] The application will be further described below in conjunction with specific examples and comparative examples.

[0070] Example 1

[0071] The application provides a hybrid manufacturing method of an aluminum alloy part, comprising the following steps:

[0072] The step of preparing the additive part: polish and clean an 8 mm thick aluminum alloy substrate, and clamp it on the workbench; then feed the 2219 aluminum alloy rod into the friction extrusion die, rotate the friction extrusion die around its axis and rub with the raw material, so that the raw material locally softens; with the feeding of the raw material, the softened material is extruded out of the orifice of the friction extrusion die, and the extruded material forms an additive layer on the substrate as the die travels; after the friction extrusion deposition is completed, an additive part is obtained;

[0073] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10 mm, the rotation speed of the friction extrusion deposition die is 300 r / min, the feeding rate c of the aluminum alloy rod is 10 mm / min, the thickness t of the single additive layer is 1 mm, the width a of the single additive layer is 26 mm, and the traveling speed v of the friction extrusion deposition die is 100 mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0074] The step of plastic processing treatment: the additive part is subjected to plastic processing treatment to introduce strain energy into the additive part, and an additive part after plastic processing treatment is obtained; wherein the true strain of the plastic processing treatment is 22%; the plastic processing treatment adopts rolling.

[0075] The step of heat treatment: the additive part after plastic processing treatment is quenched after being kept at 500℃ for 1h to obtain a hybrid manufacturing part after solid solution treatment; then, the hybrid manufacturing part after solid solution treatment is artificially aged at 200℃ for 6h; finally, the excess material is cut off to obtain an aluminum alloy part.

[0076] Figure 1 A process schematic diagram of the additive part prepared in step 1 of this example, which includes feeding the raw material 1 into the inner sleeve 2, rubbing with the rotating die 3 and being softened, and after extrusion, forming an additive layer 4. Figure 2 A physical diagram of the additive part prepared in step 1 of this example, Figure 3 A physical diagram of the aluminum alloy part prepared in this example, it can be seen that the additive process is well formed, and no defects such as pores, cracks, etc. are generated. Figure 4 The grain structure of the aluminum alloy part prepared in this example can be seen, and the average grain size is about 180 μm. Figure 5 The precipitates of the aluminum alloy part prepared in this example can be seen, and the nanoscale precipitates are dispersed in the grain, wherein the size of the nanoscale precipitates is not greater than 20 nm. The average yield strength of the solid-phase additive aluminum alloy part prepared in this example reaches 367 MPa, and the elongation after fracture is 10%.

[0077] Example 2

[0078] The present example provides a hybrid manufacturing method of an aluminum alloy part, comprising the following steps:

[0079] The additive part preparation step: polish and clean the 5mm thick aluminum alloy substrate, clamp it on the workbench; then feed the 2195 aluminum alloy rod into the friction extrusion die, rotate the friction extrusion die around its axis and rub with the raw material, so that the raw material is locally softened, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, with the travel of the die, the extruded material forms an additive layer on the substrate, after the friction extrusion deposition is finished, the additive part is obtained;

[0080] In the process of friction extrusion deposition, the radius r of the alloy rod is 20 mm, the rotation speed of the friction extrusion deposition die is 600 r / min, the feeding rate c of the aluminum alloy rod is 10 mm / min, the thickness t of the single additive layer is 0.5 mm, the width a of the single additive layer is 60 mm, and the travel rate v of the friction extrusion deposition die is 330 mm / min; the above parameters satisfy: c·(2~5)·r=v·t·a and a>2.5r. 2

[0081] Plastic processing step: plastic processing treatment is performed on the above additive part to introduce strain energy into the additive part, and the additive part after plastic processing treatment is obtained; wherein the true strain of plastic processing treatment is 51%; the plastic processing treatment adopts the rolling mode.

[0082] The heat treatment step: the additive part after plastic processing is quenched after being kept at 500℃ for 0.5h, to obtain the mixed manufacturing part after solid solution treatment; then, the mixed manufacturing part after solid solution treatment is artificially aged at 170℃ for 10h; finally, the excess material is cut off, to obtain the aluminum alloy part.

[0083] Figure 6 The physical map of the aluminum alloy part prepared in this embodiment is shown in the figure, and the additive process is well formed without defects such as holes and cracks. Figure 7 The grain structure of the aluminum alloy part prepared in this embodiment can be seen, and the average grain size is about 28μm. Figure 7 The grain structure of the aluminum alloy part prepared in this embodiment can be seen, and the nanoscale precipitates are dispersedly distributed in the grain, wherein the size of the nanoscale precipitates is not greater than 20nm. The average yield strength of the solid-phase additive aluminum alloy part prepared in this embodiment reaches 351MPa, and the elongation after fracture is 11%.

[0084] Example 3

[0085] The embodiment provides a mixed manufacturing method of an aluminum alloy part, comprising the following steps:

[0086] The additive part preparation step: a 5mm-thick aluminum alloy substrate is polished and cleaned, and clamped on a workbench; then a 7075 aluminum alloy rod is fed into a friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, and with the travel of the die, the extruded material forms an additive layer on the substrate, and after the friction extrusion deposition is completed, an additive part is obtained;

[0087] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 5mm, the rotation speed of the friction extrusion deposition die is 300r / min, the feeding rate c of the aluminum alloy rod is 500mm / min, the thickness t of the single additive layer is 2mm, the width a of the single additive layer is 30mm, and the travel rate v of the friction extrusion deposition die is 500mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0088] The plastic processing treatment step: the additive part is subjected to plastic processing treatment to introduce strain energy into the additive part, and an additive part after plastic processing treatment is obtained; wherein the true strain of the plastic processing treatment is 161%; the plastic processing treatment adopts the rolling mode.

[0089] The heat treatment step: the additive part after plastic processing is quenched after holding at 440℃ for 4h to obtain the mixed manufacturing part after solid solution treatment; then, the mixed manufacturing part after solid solution treatment is artificially aged at 100℃ for 48h; finally, the excess material is cut off to obtain the aluminum alloy part.

[0090] Figure 9 The physical map of the aluminum alloy part prepared in this embodiment can be seen that the additive process is well formed without defects such as holes and cracks. Figure 10 The grain structure of the aluminum alloy part prepared in this embodiment can be seen that the average grain size is about 5μm. Figure 11 The precipitated phase of the aluminum alloy part prepared in this embodiment can be seen that there are nanoscale precipitated phases dispersedly distributed in the grain, wherein the size of the nanoscale precipitated phase is not greater than 20nm. The average yield strength of the solid-phase additive aluminum alloy part prepared in this embodiment reaches 503MPa, and the elongation after fracture is 9%.

[0091] Embodiment 4

[0092] The embodiment provides a mixed manufacturing method of an aluminum alloy part, comprising the following steps:

[0093] The additive part preparation step: a 5mm thick aluminum alloy substrate is polished and cleaned, and clamped on the workbench; then a 2024 aluminum alloy rod is fed into the friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, and with the travel of the die, the extruded material forms an additive layer on the substrate, and after the friction extrusion deposition is completed, an additive part is obtained;

[0094] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 5mm, the rotation speed of the friction extrusion deposition die is 300r / min, the feeding rate c of the aluminum alloy rod is 500mm / min, the thickness t of the single additive layer is 2mm, the width a of the single additive layer is 30mm, and the travel rate v of the friction extrusion deposition die is 500mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0095] The plastic processing treatment step: the additive part is subjected to plastic processing treatment to introduce strain energy into the additive part, and the additive part after plastic processing treatment is obtained; wherein the true strain of the plastic processing treatment is 161%; the plastic processing treatment adopts the rolling mode.

[0096] ​The heat treatment step: the additive part after plastic processing is quenched after holding at 500℃ for 4h, to obtain the mixed manufacturing part after solid solution treatment; then, the mixed manufacturing part after solid solution treatment is naturally aged for 96h; finally, the excess material is cut off, to obtain the aluminum alloy part.

[0097] The average yield strength of the solid-phase additive aluminum alloy part prepared in this example is 323MPa, and the elongation after fracture is 19%.

[0098] Comparative Example 1

[0099] This comparative example provides a mixed manufacturing method of an aluminum alloy part, comprising the following steps:

[0100] The additive part preparation step: the 8mm thick aluminum alloy substrate is polished and cleaned, and clamped on the workbench; then the 2024 aluminum alloy rod is fed into the friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, and with the travel of the die, the extruded material forms an additive layer on the substrate, and after the friction extrusion deposition is completed, an additive part is obtained;

[0101] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10mm, the rotation speed of the friction extrusion deposition die is 300r / min, the feeding rate c of the aluminum alloy rod is 10mm / min, the single-layer additive layer thickness t is 1mm, the single-layer additive layer width a is 26mm, and the travel speed v of the friction extrusion deposition die is 100mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0102] The heat treatment step: the additive part after plastic processing is quenched after holding at 500℃ for 1h, to obtain the mixed manufacturing part after solid solution treatment; then, the mixed manufacturing part after solid solution treatment is naturally aged for 96h; finally, the excess material is cut off, to obtain the aluminum alloy part.

[0103] Figure 12 The grain structure of the aluminum alloy part prepared in this comparative example can be seen that the average grain size is about 1300μm. The average yield strength of the solid-phase additive aluminum alloy part prepared in this comparative example is 287MPa, and the elongation after fracture is 18%. Because the grain size of the additive part is small, a large amount of grain boundary energy is stored in the structure, so during the solid solution heat treatment, the abnormal grain growth occurs in the structure under the driving force of the reduction of grain boundary energy, resulting in millimeter-level grain size.

[0104] Comparative Example 2

[0105] The comparative example provides a hybrid manufacturing method of an aluminum alloy piece, comprising the following steps:

[0106] An additive manufacturing step: an 8mm thick aluminum alloy substrate is polished and cleaned, and clamped on a workbench; then a 2024 aluminum alloy rod is fed into a friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, with the travel of the die, the extruded material forms an additive layer on the substrate, after the friction extrusion deposition is completed, an additive piece is obtained;

[0107] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10mm, the rotation speed of the friction extrusion deposition die is 300r / min, the feeding rate c of the aluminum alloy rod is 10mm / min, the thickness t of the single additive layer is 1mm, the width a of the single additive layer is 26mm, and the travel speed v of the friction extrusion deposition die is 100mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0108] A plastic processing step: the additive piece is subjected to plastic processing to introduce strain energy into the additive piece, and a plastic processing additive piece is obtained; wherein the true strain of the plastic processing is 11%; the plastic processing adopts rolling.

[0109] A heat treatment step: the plastic processing additive piece is quenched after being kept at 500℃ for 1h to obtain a solid solution treated hybrid manufacturing piece; then, the solid solution treated hybrid manufacturing piece is naturally aged for 96h; finally, the excess material is cut off to obtain an aluminum alloy piece.

[0110] Figure 13 The grain structure of the aluminum alloy piece prepared in the comparative example can be seen, and the average grain size is about 580μm. The average yield strength of the solid-phase additive aluminum alloy piece prepared in the comparative example is 294MPa, and the elongation after fracture is 19%. Due to the small true strain of the plastic processing in the comparative example 2, the strain energy introduced in the structure is insufficient, and it is difficult to inhibit the abnormal grain growth during heat treatment.

[0111] Comparative example 3

[0112] The comparative example provides a hybrid manufacturing method of an aluminum alloy piece, comprising the following steps:

[0113] An 8mm thick aluminum alloy substrate is polished, cleaned and clamped on the workbench; then the 2219 aluminum alloy rod is fed into the friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, with the travel of the die, the extruded material forms an additive layer on the substrate, after the friction extrusion deposition is completed, an additive part is obtained;

[0114] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10mm, the rotation speed of the friction extrusion deposition die is 275r / min, the feeding rate c of the aluminum alloy rod is 10mm / min, the single layer additive layer thickness t is 1mm, the single layer additive layer width a is 26mm, and the travel speed v of the friction extrusion deposition die is 100mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0115] Figure 14 The physical map of the aluminum alloy part prepared for the present comparative example can be seen that the rotation speed is too low, which leads to the decrease of heat input, the insufficient plasticity of the material and the decrease of formability, and the additive layer appears hole defects. In addition, the grain size of the additive structure will be reduced due to the decrease of heat input, and the reduction of grain size makes it difficult to effectively accumulate strain energy in the grain, so it is difficult to effectively inhibit abnormal grain growth; and the smaller grain size stores higher grain boundary energy, so the driving force for abnormal grain growth is large, which will promote abnormal grain growth.

[0116] Comparative example 4

[0117] The present comparative example provides a hybrid manufacturing method of an aluminum alloy part, comprising the following steps:

[0118] An 8mm thick aluminum alloy substrate is polished, cleaned and clamped on the workbench; then the 2219 aluminum alloy rod is fed into the friction extrusion die, the friction extrusion die rotates around its axis and rubs with the raw material, so that the raw material locally softens, with the feeding of the raw material, the softened material is extruded from the orifice of the friction extrusion die, with the travel of the die, the extruded material forms an additive layer on the substrate, after the friction extrusion deposition is completed, an additive part is obtained;

[0119] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10mm, the rotation speed of the friction extrusion deposition die is 700r / min, the feeding rate c of the aluminum alloy rod is 10mm / min, the single layer additive layer thickness t is 1mm, the single layer additive layer width a is 26mm, and the travel speed v of the friction extrusion deposition die is 100mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0120] Figure 15 The actual image of the aluminum alloy part produced in this comparative example shows that due to the excessively high rotation speed of the friction extrusion deposition die, the die and the additive layer rubbed too vigorously, resulting in surface defects in the additive layer. Furthermore, excessive heat generation in the material resulted in an overly large grain structure.

[0121] Comparative Example 5

[0122] This comparative example provides a hybrid manufacturing method for an aluminum alloy part, comprising the following steps:

[0123] An 8mm thick aluminum alloy substrate is polished, cleaned, and clamped on a workbench. A 2219 aluminum alloy rod is then fed into a friction extrusion die. The die rotates around its axis and rubs against the raw material, causing it to soften locally. As the raw material is fed, the softened material is extruded from the orifice of the die. As the die advances, the extruded material forms an additive layer on the substrate. After the friction extrusion deposition is completed, an additive part is obtained.

[0124] In the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10 mm, the rotation speed of the friction extrusion deposition mold is 300 r / min, the feed rate c of the aluminum alloy rod is 10 mm / min, the thickness t of the single-layer additive layer is 1 mm, the width a of the single-layer additive layer is 26 mm, and the travel speed v of the friction extrusion deposition mold is 200 mm / min; the above parameters do not meet the following conditions: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0125] Figure 16 The actual picture of the aluminum alloy prepared in this comparative example shows that the friction extrusion deposition parameters do not meet the c·(2~5)·r 2 =v·t·a, resulting in insufficient material in the additive layer and the appearance of holes. The presence of holes can easily cause abnormal grain growth due to surface energy.

[0126] Comparative Example 6

[0127] This comparative example provides a hybrid manufacturing method for an aluminum alloy part, comprising the following steps:

[0128] Preparation steps for additive parts: An 8mm-thick aluminum alloy substrate is polished, cleaned, and clamped on a workbench. A 2219 aluminum alloy rod is then fed into a friction extrusion die. The die rotates around its axis and rubs against the raw material, causing it to partially soften. As the raw material is fed, the softened material is extruded from the orifice of the die. As the die advances, the extruded material forms an additive layer on the substrate. After the friction extrusion deposition is completed, the additive part is obtained.

[0129] Wherein, in the process of friction extrusion deposition, the radius r of the aluminum alloy rod is 10 mm, the rotating speed of the friction extrusion deposition die is 300 r / min, the feeding rate c of the aluminum alloy rod is 10 mm / min, the single layer additive layer thickness t is 1 mm, the single layer additive layer width a is 26 mm, and the traveling speed v of the friction extrusion deposition die is 100 mm / min; the above parameters satisfy: c·(2~5)·r 2 =v·t·a and a>2.5r.

[0130] The plastic processing treatment step: the additive part is subjected to plastic processing treatment to introduce strain energy into the additive part, and the additive part after plastic processing treatment is obtained; wherein the true strain of the plastic processing treatment is 22%; the plastic processing treatment adopts the rolling mode.

[0131] The heat treatment step: the additive part after plastic processing treatment is quenched after being kept at 510℃ for 4h, and the mixed manufacturing part after solid solution treatment is obtained; then, the mixed manufacturing part after solid solution treatment is subjected to artificial aging at 200℃ for 6h; finally, the excess material is cut off, and the aluminum alloy part is obtained.

[0132] Due to the excessively high temperature of the solid solution treatment, abnormal grain growth is easily promoted, and overburning defects appear in the structure, and the average yield strength of the solid-phase additive aluminum alloy part prepared in the embodiment is only 276 MPa, and the elongation after fracture is 6%.

[0133] It is easy for those skilled in the art to understand that the advantageous technical features of the above-mentioned modes can be freely combined and superimposed without conflict.

[0134] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hybrid manufacturing method for aluminum alloy parts, characterized in that: The following steps are involved: The steps of preparing the additive part are as follows: performing solid phase additive manufacturing on the aluminum alloy raw material to obtain the additive part; Plastic processing step: performing plastic processing on the additive component with a deformation amount greater than 20%, thereby obtaining the plastic processed additive component; Heat treatment step: heat treatment is performed on the additive part after the plastic processing to obtain a mixed aluminum alloy part.

2. The hybrid manufacturing method of aluminum alloy parts according to claim 1, characterized in that: In the step of preparing the additive part: The aluminum alloy raw material is a precipitation-strengthened aluminum alloy rod.

3. The hybrid manufacturing method of aluminum alloy parts according to claim 1, characterized in that: In the plastic working step: The true strain of the plastic working treatment is ≥20%; The plastic processing is performed by one of rolling, forging, extrusion and stamping.

4. The hybrid manufacturing method of an aluminum alloy part according to any one of claims 1 to 3, characterized in that: The solid phase additive manufacturing adopts a friction extrusion deposition method.

5. The hybrid manufacturing method of aluminum alloy parts according to claim 4, characterized in that: The friction extrusion deposition step specifically includes: depositing the aluminum alloy rod raw material layer by layer on the surface of the substrate; The substrate is made of aluminum alloy; the thickness of the substrate is ≥5mm.

6. The hybrid manufacturing method of aluminum alloy parts according to claim 4, characterized in that: During the friction extrusion deposition process, ensure that c·(2~5)·r 2 =v·t·a, and a>2.5r; where t is the thickness of a single additive layer, mm; a is the width of a single additive layer, mm; c is the feed rate of the aluminum alloy raw material, mm / min; v is the travel rate of the friction extrusion deposition die, mm / min; r is the radius of the aluminum alloy raw material, mm; The radius of the aluminum alloy raw material is 5-20 mm; the rotation speed of the friction extrusion deposition mold is 300-600 r / min; the feed rate of the aluminum alloy raw material is 10-500 mm / min; the travel rate of the friction extrusion deposition mold is 50-3000 mm / min; the thickness of a single-layer additive layer is 0.5-2 mm; and the width of a single-layer additive layer is 5-60 mm.

7. The hybrid manufacturing method of aluminum alloy parts according to claim 1, characterized in that: The heat treatment step specifically includes: performing solution treatment and aging treatment on the additive component after the plastic processing.

8. The hybrid manufacturing method of aluminum alloy parts according to claim 7, characterized in that: The temperature of the solution treatment is 440-500° C. and the holding time is 0.5-4 hours.

9. The hybrid manufacturing method of aluminum alloy parts according to claim 7, characterized in that: The aging treatment is carried out at a temperature of 100-200° C. and for a time of 6-48 hours.

10. An aluminum alloy part, characterized in that: The aluminum alloy part has a grain size of ≤200 μm; nanoscale precipitates are dispersed within the grains of the aluminum alloy part; wherein the width of the nanoscale precipitates is ≤20 nm; the aluminum alloy part has an average yield strength of ≥300 MPa and an elongation after fracture of ≥8%; Wherein, the aluminum alloy part is obtained by the hybrid manufacturing method described in any one of claims 1-9.

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