Method for preparing foam metal through friction stir welding

Abstract

The invention discloses a method for preparing foam metal through friction stir welding, and belongs to the technical field of foam metal material preparation, and the method comprises the following steps: an alloy plate is used as a raw material, and the plate is firstly machined to form a groove for filling foaming agent powder and foaming auxiliary powder; preparing foaming agent powder and foaming auxiliary powder according to a certain proportion, and mixing the powder to prepare a powder mixture; filling the powder mixture into a groove of an alloy plate, and preparing the alloy plate filled with the mixed powder into a welding plate by adopting a friction stir welding technology; the welded plate is subjected to multi-pass rolling to form a rolled plate; compared with the prior art, the method has the advantages that porosity control and pore diameter adjustment in the foaming process are facilitated, distribution and microstructure of foaming agent mixed powder can be remarkably improved, and formation of a pore structure is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of foam metal material preparation, and in particular relates to a method for preparing foam metal by friction stir welding. Background Art

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

[0003] There are many methods for preparing foamed magnesium and foamed aluminum. The Chinese invention patent with application number CN 104818401 A discloses a method for preparing foamed metal by friction stir welding, which uses metal plates as raw materials, replacing the traditional foaming process using alloy powder or alloy particles as raw materials; the Chinese invention patent with application number CN 105478994 A uses friction stir welding to first prepare a sandwich plate of a foamed aluminum preform with high density and uniformity and high metallurgical bonding strength at the plate-core interface, and then connects it with the sandwich plate of the foamed aluminum preform or the aluminum alloy plate for a large area to form a welded component of a set size, thereby realizing the welding forming of foamed metal and solid plate; the Chinese invention patent with application number CN 108396163 A provides a method for preparing a carbon nanotube reinforced foamed aluminum-based composite material, which applies friction stir welding to the preparation of reinforced foamed aluminum composite materials, uses carbon nanotubes as the reinforcement phase, and prepares the foamed aluminum-based composite material by friction stir welding. The carbon nanotube mixture is filled into the metal plate, and the solid phase connection organization is realized by the friction stir welding process. The Chinese invention patent with application number CN109048211 A uses two solid metal plates combined with a trace amount of foaming powder to prepare a foam aluminum preform through stir friction welding, and then the foam aluminum preform is heated-formed-foamed, heated and stamped, and then foamed and quenched in the mold; the Chinese invention patent with application number CN 112959012 A provides a method for preparing a foam aluminum sandwich panel based on stir friction welding connection. The characteristics of stir friction welding to achieve solid phase and semi-solid phase welding are utilized to weld the surface aluminum plate of the foam aluminum sandwich panel preform, and then the welded plate is foamed in a heating furnace to achieve the continuity of the core layer pores. The difference between the process described in the above patent and the present invention is mainly in two aspects: First, in terms of process, the above patent is to prepare the welding plate by stir friction welding, and then directly foam the welding plate to obtain the foam metal. The present invention is to prepare the welding plate by stir friction welding, then roll the welding plate, and finally foam the rolled piece. 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] The Chinese invention patent with application number CN 109652674 A provides a foaming method for preparing foamed metal by powder metallurgy, wherein metal powder or alloy powder is mixed with a foaming agent to obtain a core layer mixture, the core layer mixture is pressed to form a foaming precursor, the foaming precursor is placed in a foaming mold, the foaming mold is placed in a foaming furnace for foaming, and finally a foamed metal is obtained. The Chinese invention patent with application number CN 104805324 A discloses a method for preparing a foamed zinc-based material by powder metallurgy, wherein zinc powder, magnesium powder and calcium carbonate powder are mixed uniformly, cold pressed into a prefabricated block, heat treated for alloying, and then hot pressed into a foamable prefabricated body, and finally placed in a resistance furnace for foaming to obtain a foamed zinc-based material. The Chinese invention patent with application number CN 114406029 A proposes a method for preparing a continuous density gradient foam aluminum sandwich panel by rolling, wherein the metal is melted to form a melt and kept warm, a tackifier and a stabilizer are added and stirred continuously, and then a foaming agent is added for stirring and dispersion to obtain a foamed metal liquid, which is then cast and rolled into a foamed prefabricated plate, the prefabricated plate is cut into strips of a specific size, and finally the strip is placed in a heat preservation furnace for heat preservation and foaming to form a foamed metal. The difference between the process described in the above patent and the present invention is that: first, the above patent is to press or roll the metal powder (or alloy powder) and the foaming powder to densify it, and then foam the pressed part or rolled part to obtain the foamed metal. The present invention is to uniformly disperse the foaming agent powder and the foaming auxiliary powder in the alloy plate by stir friction welding, and then roll the welded part, and finally foam the rolled part to obtain the foamed metal. Second, the foaming process in the above patent is a process designed in consideration of the metallurgical foaming characteristics of the mixed powder, and the present invention is a process designed in consideration of the foaming characteristics of the rolled part. Summary of the invention

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

[0006] In order to realize the above method, the present invention proposes the following technical route: A method for preparing foamed metal by friction stir welding comprises the following steps: Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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 the average pore size is adjusted between 1 and 10 mm.

[0007] Furthermore, the alloy plate is a weldable plate, and the alloy plate is selected from a magnesium alloy plate or an aluminum alloy plate, with grades of AZ31, ZK60, and 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.

[0008] Furthermore, the foaming agent powder is a mixed powder consisting 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.

[0009] Furthermore, the foaming auxiliary powder is spinel powder with a powder particle size of 500nm, and is used as foaming auxiliary powder.

[0010] 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, and the mass of the mixed powder is 8% of the mass of the alloy removed when machining the groove.

[0011] Furthermore, in step three, the alloy plate filled with 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.

[0012] Furthermore, the friction stir welding is a multi-pass processing route, the shoulder pressure reduction is 0.1 mm, and the number of welding passes is 3.

[0013] Furthermore, the welded plate is heated to 250-350°C and kept constant for 10 minutes, and the rolling speed is 15r / min. 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.

[0014] Furthermore, the rolled plate is placed in a heating furnace for preheating, and 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, and a is the rolling pass.

[0015] Furthermore, the preheated sheet is placed in a heating furnace for foaming, and the heating temperature and heating time 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, and a is the rolling pass.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: (1) Unlike the stir friction welding foaming method which uses a single type of foaming agent, the present invention uses a mixture of titanium hydride and calcium carbonate in a mass ratio of 3:1 for foaming. The decomposition temperature of titanium hydride is relatively low, which is conducive to the formation of tiny pores during the preheating process; the decomposition temperature of calcium carbonate is relatively high, which is conducive to controlling the porosity and adjusting the pore size during the foaming process.

[0017] (2) The pore collapse of the foamed metal prepared by the traditional foaming method and ordinary stir friction welding is reduced. By rolling the plate after stir friction welding, the distribution and microstructure of the foaming agent mixed powder can be significantly improved, which is conducive to the formation of the pore structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart for preparing foam metal by friction stir welding.

[0019] Figure 2 This is a picture of magnesium foam. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0022] 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 the 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.

[0023] The foaming agent powder is a mixed powder, which consists 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.

[0024] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0025] 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.

[0026] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0027] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0028] The welded plate was rolled, the welded plate was heated to 250°C, and the temperature was kept constant for 10 minutes, the roll speed was 15r / min, and the rolling was performed once, with a reduction rate of 10%.

[0029] The rolled plate is preheated in a heating furnace at a preheating temperature of 397°C and a preheating time of 494s.

[0030] The preheated sheet was heated for foaming at a temperature of 579°C and a heating time of 606s.

[0031] Embodiment 2: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0032] 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 the 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.

[0033] 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 at a mass ratio of 3:1 and used as a mixed foaming agent.

[0034] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0035] 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.

[0036] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1.5 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0037] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0038] The welded plate was rolled, the welded plate was heated to 260℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling pass was 3, and the reduction rate was 10%, 14%, and 18%.

[0039] The rolled plate is preheated in a heating furnace at a preheating temperature of 357°C for a preheating time of 520s.

[0040] The preheated sheet was heated for foaming at a temperature of 583°C and a heating time of 592s.

[0041] Embodiment 3: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0042] 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 the 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.

[0043] The foaming agent powder is a mixed powder, which consists 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.

[0044] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0045] 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.

[0046] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 2 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0047] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0048] The welded plate was rolled, the welded plate was heated to 270℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling pass number was 5, and the reduction rate was 10%, 14%, 18%, 22%, 16%.

[0049] The rolled plate is preheated in a heating furnace at a preheating temperature of 325°C for a preheating time of 554s.

[0050] The preheated sheet was heated for foaming at a temperature of 595°C and a heating time of 570s.

[0051] Embodiment 4: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0052] 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 the 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.

[0053] The foaming agent powder is a mixed powder, which consists 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.

[0054] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0055] 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.

[0056] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0057] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0058] The welded plates were rolled, heated to 280°C, and the temperature was kept constant for 10 min, the roll speed was 15 r / min, the rolling passes were 7, and the reduction rates were 10%, 14%, 18%, 22%, 16%, 14%, and 12%.

[0059] The rolled plate is preheated in a heating furnace at a preheating temperature of 301°C and a preheating time of 596s.

[0060] The preheated sheet was heated for foaming at a temperature of 615°C and a heating time of 540s.

[0061] Example 5: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0062] 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 the 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.

[0063] The foaming agent powder is a mixed powder, which consists 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.

[0064] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0065] 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.

[0066] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1.5 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0067] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0068] The welded plates were rolled, heated to 290°C, and the temperature was kept constant for 10 min, the roll speed was 15 r / min, the rolling passes were 9, and the reduction rates were 10%, 14%, 18%, 22%, 16%, 14%, 12%, 10%, and 8%.

[0069] The rolled plate is preheated in a heating furnace at a preheating temperature of 285°C for a preheating time of 646s.

[0070] The preheated sheet was heated for foaming at a temperature of 648°C and a heating time of 502s.

[0071] Example 6: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0072] 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 the 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.

[0073] The foaming agent powder is a mixed powder, which consists 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.

[0074] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0075] 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.

[0076] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 2 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0077] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0078] The welded plates were rolled, heated to 300°C, and kept at a constant temperature for 10 minutes, with a roll speed of 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%.

[0079] The rolled plate is preheated in a heating furnace at a preheating temperature of 280°C for a preheating time of 674s.

[0080] The preheated sheet was heated for foaming at a temperature of 660°C and a heating time of 480 seconds.

[0081] Embodiment 7: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0082] A 6061 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 the 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.

[0083] The foaming agent powder is a mixed powder, which consists 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.

[0084] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0085] 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.

[0086] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0087] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0088] The welded plate was rolled, the welded plate was heated to 310℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling passes were 8, and the reduction rates were 10%, 14%, 18%, 22%, 16%, 14%, 12%, 10%.

[0089] The rolled plate is preheated in a heating furnace at a preheating temperature of 292°C for a preheating time of 620s.

[0090] The preheated sheet was heated for foaming at a temperature of 628°C and a heating time of 522s.

[0091] Embodiment 8: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0092] A 6061 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 the 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.

[0093] The foaming agent powder is a mixed powder, which consists 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.

[0094] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0095] 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.

[0096] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1.5 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0097] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0098] The welded plate was rolled, the welded plate was heated to 330℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling passes were 6, and the reduction rates were 10%, 14%, 18%, 22%, 16%, and 14%.

[0099] The rolled plate is preheated in a heating furnace at a preheating temperature of 312°C and a preheating time of 574s.

[0100] The preheated sheet was heated for foaming at a temperature of 604°C and a heating time of 490s.

[0101] Embodiment 9: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0102] A 6061 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 the 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.

[0103] The foaming agent powder is a mixed powder, which consists 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.

[0104] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0105] 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.

[0106] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 2 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0107] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0108] The welded plate was rolled, the welded plate was heated to 340℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling pass was 4, and the reduction rate was 10%, 14%, 18%, 22%.

[0109] The rolled plate is preheated in a heating furnace at a preheating temperature of 340°C and a preheating time of 536s.

[0110] The preheated sheet was heated for foaming at a temperature of 588°C and a heating time of 582s.

[0111] Embodiment 10: A method for preparing foamed metal by friction stir welding, comprising the following steps Step 1: Using the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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.

[0112] A 6061 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 the 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.

[0113] The foaming agent powder is a mixed powder, which consists 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.

[0114] The foaming auxiliary powder is composed of spinel powder, the powder particle size is 500nm, and is used as foaming auxiliary powder.

[0115] 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.

[0116] Porous foam metal is prepared by friction stir welding. The alloy plate filled with mixed powder is covered with a homogeneous alloy plate. The thickness of the alloy plate is 1 mm, and the length and width are the same as those of the groove plate. The two plates are friction stir welded. The rotation speed of the friction stir welding is 1000 r / min and the forward speed is 30 mm / min.

[0117] Friction stir welding is a multi-pass processing route, with a shoulder reduction of 0.1 mm and 3 welding passes.

[0118] The welded plate was rolled, the welded plate was heated to 350℃, and the temperature was kept constant for 10min, the roll speed was 15r / min, the rolling pass was 2, and the reduction rate was 10% and 14%.

[0119] The rolled plate is preheated in a heating furnace at a preheating temperature of 376°C and a preheating time of 506s.

[0120] The preheated sheet 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 the alloy plate as the 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 proportion, 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 by using a stir friction welding technique; Step 4, rolling the welded plate in step 3 for multiple passes to form a rolled plate; 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 the average pore size is adjusted between 1 and 10 mm.

2. The method for preparing foamed metal by friction stir welding according to claim 1, characterized in that: The alloy plate is a weldable plate, and the alloy plate is a magnesium alloy plate or an aluminum alloy plate, with grades of AZ31, ZK60, and 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.

3. The method for preparing foamed metal by friction stir welding according to claim 2, characterized in that: The foaming agent powder is a mixed powder consisting 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.

4. The method for preparing foamed metal by friction stir welding according to claim 3, characterized in that: The foaming auxiliary powder is spinel powder with a powder particle size of 500nm, and is used as foaming auxiliary powder.

5. The method for preparing foamed metal by friction stir welding according to claim 4, characterized in that: The foaming agent powder and the foaming auxiliary powder are mixed in a mass ratio of 1:1, and 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. The mixed powder of the mixed 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.

6. The method for preparing foamed metal by friction stir welding according to claim 5, characterized in that: In the step three, the alloy plate filled with 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.

7. The method for preparing foamed metal by friction stir welding according to claim 6, characterized in that: The friction stir welding is a multi-pass processing route, the shoulder pressure reduction is 0.1 mm, and the number of welding passes is 3.

8. The method for preparing foamed metal by friction stir welding according to claim 7, characterized in that: Heat the welded plate to 250-350℃ and keep the temperature constant for 10min. 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.

9. The method for preparing foamed metal by friction stir welding according to claim 8, characterized in that: The rolled plate is placed in a heating furnace for preheating. The preheating temperature and preheating time are related to the rolling pass as follows: 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.

10. The method for preparing foamed metal by friction stir welding according to claim 9, characterized in that: 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, and a is the rolling pass.

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