A method of friction stir welding to produce a foam metal

Abstract

The application discloses a method for preparing foamed metal by friction stir welding, and belongs to the technical field of foamed metal material preparation, and comprises the following steps: taking an alloy plate as a raw material, and first performing mechanical processing on the plate to form a groove for filling foaming agent powder and foaming auxiliary powder; preparing the foaming agent powder and the foaming auxiliary powder according to a certain proportion, mixing the powders to form a powder mixture; filling the powder mixture into the groove of the alloy plate, and preparing the alloy plate filled with the mixed powder into a welded plate by adopting a friction stir welding technology; performing multi-pass rolling on the welded plate to form a rolled plate; preheating the rolled plate in a heating furnace; and finally foaming in the heating furnace to prepare foamed metal. Compared with the prior art, the application is favorable for controlling porosity and adjusting pore diameter in the foaming process, can significantly improve the distribution and microstructure of the foaming agent mixed powder, and is helpful for the formation of a pore structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of foam metal material preparation, and particularly relates to a method for preparing foam metal by friction stir welding. BACKGROUND

[0002] Foam metal is a structural and functional integrated material composed of metal phase and a large number of pores. The pores can be three-dimensionally connected or closed and isolated, and have different shapes and sizes. In addition to magnesium and aluminum as main elements, foam magnesium and foam aluminum also contain other element components such as rare earth elements and zinc. Due to the porous structure, foam magnesium and foam aluminum have the characteristics of light weight and high strength, and also have multiple functional properties such as vibration reduction, damping, sound absorption, heat dissipation, impact energy absorption, electromagnetic shielding, etc. Therefore, foam magnesium and foam aluminum have wide application prospects in the fields of rail transportation, automobile manufacturing, aerospace, etc.

[0003] There are many methods for preparing magnesium and aluminum foams. Chinese invention patent application number CN 104818401 A discloses a method for preparing metal foams using friction stir welding. This method uses metal sheets as the raw material, replacing alloy powder or granules used in traditional foaming processes. Chinese invention patent application number CN 105478994 A uses friction stir welding to first prepare a sandwich of aluminum foam preforms with high density and uniformity, and a strong metallurgical bond strength at the core-plate interface. This sandwich is then joined over a large area to the sandwich of aluminum foam preforms or aluminum alloy sheets to form a tailor-welded component of a predetermined size, achieving tailor-welded formation of metal foam and solid sheet materials. Chinese invention patent application number CN 108396163 A provides a method for preparing carbon nanotube-reinforced aluminum foam composites. This method applies friction stir welding to the preparation of reinforced aluminum foam composites, using carbon nanotubes as the reinforcement phase. The aluminum foam composite is prepared by friction stir welding. The carbon nanotube mixture is filled into metal sheets, and a solid-phase bonded structure is achieved using friction stir welding. Chinese invention patent application number CN109048211 A utilizes two solid metal sheets combined with a trace amount of foaming powder to form a foamed aluminum preform via friction stir welding. The foamed aluminum preform is then heated, formed, and foamed, then heated and stamped, followed by in-mold foaming and quenching. Chinese invention patent application number CN112959012 A provides a method for preparing a foamed aluminum sandwich panel using friction stir welding. Leveraging the solid-phase and semi-solid-phase welding properties of friction stir welding, the surface aluminum sheets of the foamed aluminum sandwich panel preform are welded. The welded sheet is then foamed in a heating furnace to achieve continuous core cell formation. The process described in the aforementioned patent differs from the present invention primarily in two aspects: First, in terms of process, the aforementioned patent uses friction stir welding to prepare the welded sheet, which is then directly foamed to produce the foamed metal. The present invention uses friction stir welding to prepare the welded sheet, which is then rolled, and finally foamed. Second, in terms of materials, the foaming agent used in the above patents is generally a single type of granular powder, and the auxiliary powder for foaming is aluminum powder, carbon nanotubes, etc. The foaming agent used in the present invention is a mixture of two granular powders, and the auxiliary powder for foaming is spinel powder.

[0004] Chinese invention patent application number CN 109652674 A provides a powder metallurgy method for preparing metal foams. The method involves mixing metal powder or alloy powder with a foaming agent to produce a core layer mixture. The core layer mixture is then pressed to form a foaming precursor. The foaming precursor is then placed in a foaming mold, which is then placed in a foaming furnace for foaming to produce the metal foam. Chinese invention patent application number CN 104805324 A discloses a powder metallurgy method for preparing zinc-based foam materials. Zinc powder, magnesium powder, and calcium carbonate powder are uniformly mixed, cold-pressed into a prefabricated block, heat-treated for alloying, and then hot-pressed into a foamable preform. The preform is then placed in a resistance furnace for foaming to produce the zinc-based foam material. Chinese invention patent application number CN 114406029 A proposes a method for producing continuous density gradient aluminum foam sandwich panels by rolling. The method involves melting metal to form a melt and holding it warm. A viscosity enhancer and stabilizer are added and continuously stirred. A foaming agent is then added and stirred to disperse the melt to produce a foamed metal solution. This is then cast and rolled to form a foamed preform. The preform is then cut into strips of a specific size, and the strips are placed in a holding furnace for holding and foaming to form the foamed metal. The process described in the aforementioned patent differs from the present invention in the following ways: First, the aforementioned patent involves compacting or rolling metal powder (or alloy powder) and foaming powder to densify them, and then foaming the compacted or rolled part to produce the foamed metal. The present invention utilizes friction stir welding to uniformly disperse foaming agent powder and auxiliary foaming powder in an alloy sheet, welding the welded part. The welded part is then rolled, and finally, the rolled part is foamed to produce the foamed metal. Second, the foaming process in the aforementioned patent is designed based on the metallurgical foaming properties of the mixed powder, while the present invention is designed based on the foaming properties of the rolled part. Summary of the Invention

[0005] The present invention provides a method for preparing foam metal material by friction stir welding, which is used to overcome common problems of traditional foam metal preparation methods and obtain high-quality foam metal material.

[0006] In order to implement the above method, the present invention proposes the following technical route:

[0007] A method for preparing foamed metal by friction stir welding comprises the following steps:

[0008] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0009] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0010] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique;

[0011] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0012] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare a foamed metal. The foamed metal has a closed-cell structure and an average pore size adjusted between 1 and 10 mm.

[0013] Furthermore, the alloy plate is a weldable plate, and the alloy plate is selected from magnesium alloy plate or aluminum alloy plate, with grades AZ31, ZK60, 6061. A groove is cut in the middle of the surface of the alloy plate. The width of the groove is 4 mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate. The groove is used to fill the foaming agent powder and the foaming auxiliary powder.

[0014] Furthermore, the foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0015] Furthermore, the foaming auxiliary powder is spinel powder with a powder particle size of 500 nm, and is used as the foaming auxiliary powder.

[0016] Furthermore, the mixed foaming agent and the foaming auxiliary powder are mixed in a mass ratio of 1:1, mixed for 2 hours using a planetary ball mill, with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min, and the mixed powder of the mixed foaming agent and the foaming auxiliary powder is filled into the groove of the alloy plate in step one. The mass of the mixed powder is 8% of the mass of the alloy removed when processing the groove.

[0017] Furthermore, in step three, the alloy plate filled with the mixed powder is covered with a homogeneous alloy plate, the thickness of the alloy plate is 1-2 mm, and the length and width are the same as the groove plate. The two plates are stir-friction welded, and the rotation speed of the stir-friction welding is 1000 r / min and the forward speed is 30 mm / min.

[0018] Furthermore, the friction stir welding is a multi-pass processing route, the shoulder reduction is 0.1 mm, and the number of welding passes is 3.

[0019] Furthermore, the welded plate is heated to 250-350°C and kept constant for 10 minutes, with the roller speed at 15 r / min. The rolling reduction ratio is implemented according to the following relationship:

[0020] ;

[0021] Wherein a is the rolling pass, h is the reduction ratio of a pass.

[0022] Further, the rolled plate is put into a heating furnace for preheating, the preheating temperature, the preheating time and the rolling pass are in the following relationship:

[0023] S1=a 2 -24a+420, t1=a 2 +9a+484, 10>=a>=1, S1 is the preheating temperature, t1 is the preheating time, and a is the rolling pass.

[0024] Further, the preheated plate is put into a heating furnace for foaming, and the heating temperature and the heating time are in the following relationship:

[0025] S=a 2 -2a+580, t=-a 2 -3a+610, 10>=a>=1, S is the heating temperature, t is the heating time, and a is the rolling pass.

[0026] Compared with the prior art, the present application has the following beneficial technical effects:

[0027] (1) Unlike the single type of foaming agent used in the foaming method of friction stir welding, the present application prepares two foaming agents, titanium hydride and calcium carbonate, according to a mass ratio of 3:1, and uses mixed foaming agents for foaming. Titanium hydride has a lower decomposition temperature, which helps to form small pores in the preheating process; calcium carbonate has a higher decomposition temperature, which is conducive to controlling the porosity and adjusting the pore size in the foaming process.

[0028] (2) The pore collapse of the foamed metal prepared by the traditional foaming method and ordinary friction stir welding is reduced. By rolling the plate after friction stir welding, the distribution of foaming agent mixed powder and the microstructure can be significantly improved, which helps to form the pore structure. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a process flow chart of foamed metal prepared by friction stir welding.

[0030] Figure 2 is a picture of foamed magnesium. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] Example 1: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0033] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0034] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0035] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique;

[0036] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0037] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0038] AZ31 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0039] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0040] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0041] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0042] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0043] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0044] The welded plate was rolled by heating the welded plate to 250°C and keeping the temperature constant for 10 minutes. The rolling speed was 15 r / min. One pass was performed with a reduction rate of 10%.

[0045] The rolled plate is preheated in a heating furnace at a temperature of 397°C for 494 seconds.

[0046] The preheated plate was heated for foaming at a temperature of 579° C. and a heating time of 606 s.

[0047] Example 2: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0048] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0049] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0050] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique;

[0051] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0052] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0053] AZ31 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0054] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The titanium hydride particle size is 45 μm, and the calcium carbonate particle size is 100 μm. The titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0055] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0056] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0057] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1.5 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0058] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0059] The welded plates were rolled by heating them to 260°C and keeping the temperature constant for 10 minutes at a rolling speed of 15 r / min. The number of rolling passes was 3, with reduction ratios of 10%, 14%, and 18%.

[0060] The rolled plate is preheated in a heating furnace at a temperature of 357°C for 520 seconds.

[0061] The preheated plate was heated for foaming at a temperature of 583° C. and a heating time of 592 s.

[0062] Example 3: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0063] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0064] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0065] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and use the friction stir welding technology to prepare the alloy plate filled with the mixed powder into a welded plate;

[0066] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0067] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0068] AZ31 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0069] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0070] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0071] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0072] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 2 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0073] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0074] The welded plates were rolled by heating them to 270°C and keeping the temperature constant for 10 minutes at a rolling speed of 15 r / min. The number of rolling passes was 5, with reduction ratios of 10%, 14%, 18%, 22%, and 16%.

[0075] The rolled plate is preheated in a heating furnace at a temperature of 325°C for 554 seconds.

[0076] The preheated plate was heated for foaming at a temperature of 595° C. and a heating time of 570 s.

[0077] Example 4: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0078] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0079] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0080] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique;

[0081] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0082] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0083] ZK60 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0084] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0085] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0086] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0087] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0088] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0089] The welded plates were rolled, heated to 280°C, and kept at a constant temperature for 10 min, with a roll speed of 15 r / min, 7 rolling passes, and reduction rates of 10%, 14%, 18%, 22%, 16%, 14%, and 12%.

[0090] The rolled plate is preheated in a heating furnace at a temperature of 301°C for 596 seconds.

[0091] The preheated plate was heated and foamed at a temperature of 615° C. for 540 seconds.

[0092] Example 5: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0093] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0094] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0095] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique;

[0096] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0097] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0098] ZK60 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0099] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0100] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0101] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0102] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1.5 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0103] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0104] The welded plates were rolled, heated to 290 °C, and kept at a constant temperature for 10 min, with a roll speed of 15 r / min, 9 rolling passes, and reduction rates of 10%, 14%, 18%, 22%, 16%, 14%, 12%, 10%, and 8%.

[0105] The rolled plate is preheated in a heating furnace at a temperature of 285°C for 646 seconds.

[0106] The preheated plate was heated and foamed at a temperature of 648°C and a heating time of 502s.

[0107] Example 6: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0108] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0109] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0110] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and use the friction stir welding technology to prepare the alloy plate filled with the mixed powder into a welded plate;

[0111] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0112] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0113] ZK60 alloy plate is used as the raw material to cut a groove in the middle of the surface. The groove is used to fill the foaming agent powder and foaming auxiliary powder. The width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0114] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0115] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0116] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0117] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 2 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0118] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0119] The welded plates were rolled by heating the welded plates to 300°C and keeping the temperature constant for 10 minutes. The rolling speed was 15 r / min. The number of rolling passes was 10, and the reduction rates were 10%, 14%, 18%, 22%, 16%, 14%, 12%, 10%, 8%, and 6%.

[0120] The rolled plate is preheated in a heating furnace at a temperature of 280°C for 674 seconds.

[0121] The preheated plate was heated and foamed at a temperature of 660° C. for 480 seconds.

[0122] Example 7: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0123] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0124] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0125] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and use the friction stir welding technology to prepare the alloy plate filled with the mixed powder into a welded plate;

[0126] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0127] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0128] A groove is cut in the middle of the surface of a 6061 alloy plate as the raw material. The groove is used to fill the foaming agent powder and the foaming auxiliary powder. The width of the groove is 4 mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0129] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0130] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0131] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0132] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0133] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0134] The welded plates were rolled by heating them to 310°C and keeping the temperature constant for 10 minutes at a rolling speed of 15 r / min. The number of rolling passes was 8, with reduction ratios of 10%, 14%, 18%, 22%, 16%, 14%, 12%, and 10%.

[0135] The rolled plate is preheated in a heating furnace at a temperature of 292°C for 620 seconds.

[0136] The preheated plate was heated for foaming at a temperature of 628°C and a heating time of 522 seconds.

[0137] Example 8: A method for preparing a foamed metal by friction stir welding, comprising the following steps

[0138] Step one, taking alloy sheet as raw material, the sheet is first machined to make a groove for filling foaming agent powder and foaming auxiliary powder;

[0139] Step two, the foaming agent powder and the foaming auxiliary powder are mixed according to a certain proportion, and the mixed powder is prepared after mixing;

[0140] Step three, the mixed powder in step two is filled into the groove of the alloy sheet, and the alloy sheet filled with the mixed powder is prepared into a welded sheet by friction stir welding technology;

[0141] Step four, the welded sheet in step three is rolled into a rolled sheet by multi-pass rolling;

[0142] Step five, the rolled sheet in step four is preheated in a heating furnace, and finally foamed in the heating furnace to prepare a foamed metal.

[0143] A groove is cut in the middle of the surface of the 6061 alloy sheet as the raw material, the groove is used to fill the foaming agent powder and the foaming auxiliary powder, the width of the groove is 4mm, the depth is 1 / 10 of the thickness of the alloy sheet, and the length is equal to the length of the alloy sheet.

[0144] The foaming agent powder is a mixed powder, which is composed of titanium hydride powder and calcium carbonate powder, the particle size of titanium hydride is 45μm, and the particle size of calcium carbonate is 100μm, titanium hydride and calcium carbonate are weighed and prepared according to the mass ratio of 3:1, and used as mixed foaming agent.

[0145] The foaming auxiliary powder is composed of spinel powder with a particle size of 500nm, which is used as foaming auxiliary powder.

[0146] The foaming agent powder and the foaming auxiliary powder are mixed, the mixed foaming agent and the foaming auxiliary powder are mixed according to the mass ratio of 1:1, the planetary ball mill is used for mixing for 2h, the ball powder ratio is 3:1, the grinding speed is 250r / min, the mixed powder is filled into the groove of the alloy sheet, and the mass of the mixed powder is 8% of the mass of the alloy removed during the groove machining.

[0147] A porous foamed metal is prepared by friction stir welding, the alloy sheet filled with mixed powder is covered with a homogenous alloy sheet, the thickness of the alloy sheet is 1.5mm, the length and width are the same as those of the groove sheet, and the two sheets are friction stir welded, the rotation speed of the friction stir welding is 1000r / min, and the forward speed is 30mm / min.

[0148] The friction stir welding is a multi-pass processing route, the shoulder compression amount is 0.1mm, and the welding pass is 3.

[0149] The welded plate was rolled, the welded plate was heated to 330°C, and the temperature was kept constant for 10 min, and the roll speed was 15 r / min. The rolling passes were 6, and the reduction was 10%, 14%, 18%, 22%, 16%, and 14%.

[0150] The rolled plate was preheated in a heating furnace, the preheating temperature was 312°C, and the preheating time was 574 s.

[0151] The preheated plate was heated and foamed, the heating temperature was 604°C, and the heating time was 490 s.

[0152] Example 9: A method for preparing a foamed metal by friction stir welding, comprising the following steps

[0153] Step one, using alloy plate as raw material, the plate is first machined to make a groove for filling foaming agent powder and foaming auxiliary powder;

[0154] Step two, the foaming agent powder and the foaming auxiliary powder are prepared according to a certain proportion, and the mixed powder is prepared into a powder mixture after mixing;

[0155] Step three, the powder mixture in step two is filled into the groove of the alloy plate, and the alloy plate filled with the mixed powder is prepared into a welded plate by using the friction stir welding technology;

[0156] Step four, the welded plate in step three is rolled into a rolled plate by multiple passes;

[0157] Step five, the rolled plate in step four is preheated in a heating furnace, and finally foamed in the heating furnace to prepare a foamed metal.

[0158] The 6061 alloy plate is used as the raw material, and a groove is cut in the middle of the surface for filling foaming agent powder and foaming auxiliary powder. The width of the groove is 4 mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0159] The foaming agent powder is a mixed powder, which is composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared according to a mass ratio of 3:1 for use as a mixed foaming agent.

[0160] The foaming auxiliary powder is composed of spinel powder, and the powder particle size is 500 nm, which is used as a foaming auxiliary powder.

[0161] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0162] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 2 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0163] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0164] The welded plates were rolled by heating them to 340°C and keeping the temperature constant for 10 minutes at a rolling speed of 15 r / min. The number of rolling passes was 4, with reduction ratios of 10%, 14%, 18%, and 22%.

[0165] The rolled plate is preheated in a heating furnace at a temperature of 340°C for 536 seconds.

[0166] The preheated plate was heated for foaming at a temperature of 588°C and a heating time of 582s.

[0167] Example 10: A method for preparing foamed metal by friction stir welding, comprising the following steps:

[0168] Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder;

[0169] Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture;

[0170] Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and use the friction stir welding technology to prepare the alloy plate filled with the mixed powder into a welded plate;

[0171] Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes;

[0172] Step 5: Place the rolled plate in step 4 into a heating furnace for preheating, and finally foam it in the heating furnace to prepare foamed metal.

[0173] A groove is cut in the middle of the surface of a 6061 alloy plate as the raw material. The groove is used to fill the foaming agent powder and the foaming auxiliary powder. The width of the groove is 4 mm, the depth is 1 / 10 of the thickness of the alloy plate, and the length is equal to the length of the alloy plate.

[0174] The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent.

[0175] The foaming auxiliary powder is composed of spinel powder with a powder particle size of 500 nm and is used as the foaming auxiliary powder.

[0176] The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder is filled into the grooves of the alloy plate. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the grooves.

[0177] Porous foam metal was prepared by friction stir welding. The alloy plate filled with mixed powder was covered with a homogeneous alloy plate. The thickness of the alloy plate was 1 mm, and the length and width were the same as those of the groove plate. The two plates were friction stir welded. The rotation speed of the friction stir welding was 1000 r / min and the forward speed was 30 mm / min.

[0178] Friction stir welding is a multi-pass processing route with a shoulder reduction of 0.1 mm and three welding passes.

[0179] The welded plates were rolled by heating them to 350°C and keeping the temperature constant for 10 minutes. The rolling speed was 15 r / min. The number of rolling passes was 2, and the reduction ratios were 10% and 14%.

[0180] The rolled plate is preheated in a heating furnace at a temperature of 376°C for 506 seconds.

[0181] The preheated plate was heated for foaming at a temperature of 580°C and a heating time of 602s.

Claims

1. A method for preparing foamed metal by friction stir welding, characterized in that: The following steps are involved: Step 1: Using alloy plate as raw material, the plate is first machined to make grooves for filling with foaming agent powder and foaming auxiliary powder; Step 2: preparing the foaming agent powder and the foaming auxiliary powder in a certain ratio, and mixing the powders to form a powder mixture; Step 3: Fill the powder mixture in step 2 into the groove of the alloy plate, and prepare the alloy plate filled with the mixed powder into a welded plate using a stir friction welding technique; Step 4: rolling the welded plate in step 3 into a rolled plate through multiple passes; Step 5: placing the rolled plate in step 4 into a heating furnace for preheating, and finally foaming in the heating furnace to prepare a foamed metal having a closed-cell structure and an average pore diameter adjusted between 1 and 10 mm; The alloy plate is a weldable plate, and the alloy plate is selected from a magnesium alloy plate or an aluminum alloy plate, with a grade of AZ31, ZK60, or 6061. A groove is cut in the middle of the surface of the alloy plate. The groove has a width of 4 mm, a depth of 1 / 10 of the thickness of the alloy plate, and a length equal to the length of the alloy plate. The groove is used to fill the foaming agent powder and the foaming auxiliary powder. The foaming agent powder is a mixed powder composed of titanium hydride powder and calcium carbonate powder. The particle size of titanium hydride is 45 μm, and the particle size of calcium carbonate is 100 μm. Titanium hydride and calcium carbonate are weighed and prepared in a mass ratio of 3:1 and used as a mixed foaming agent. The foaming auxiliary powder is spinel powder with a powder particle size of 500nm, and is used as a foaming auxiliary powder; The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and mixed in a planetary ball mill for 2 hours with a ball-to-powder ratio of 3:1 and a grinding speed of 250 r / min. The mixed powder of the foaming agent and the foaming auxiliary powder is filled into the groove of the alloy plate in step 1. The mass of the mixed powder is 8% of the mass of the alloy removed when machining the groove; In the step 3, the alloy plate filled with the mixed powder is covered with a homogeneous alloy plate, the thickness of the alloy plate is 1-2 mm, and the length and width are the same as those of the groove plate, and the two plates are subjected to friction stir welding. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min; The friction stir welding is a multi-pass processing route, the shoulder pressure is 0.1mm, and the number of welding passes is 3; Heat the welded plate to 250-350℃ and keep the temperature constant for 10 minutes. The roll speed is 15r / min and the rolling reduction rate is implemented according to the following relationship: ； Where a is the rolling pass and h is the reduction rate of one pass.

2. The method for preparing foamed metal by friction stir welding according to claim 1, wherein: The rolled plate is placed in a heating furnace for preheating. The preheating temperature, preheating time and rolling pass are in the following relationship: S1=a 2 -24a+420, t1=a 2 +9a+484, 10≥a≥1, S1 is the preheating temperature, t1 is the preheating time, the unit is s, and a is the rolling pass.

3. The method for preparing foamed metal by friction stir welding according to claim 2, wherein: The preheated sheet is placed in a heating furnace for heating and foaming. The heating temperature and heating time during foaming are in the following relationship: S=a 2 -2a+580, t=-a 2 -3a+610, 10≥a≥1, S is the heating temperature, t is the heating time in seconds, and a is the rolling pass.

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