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WO2019031145A1 - Procédé d'assemblage d'un alliage magnésium-lithium, et corps assemblé - Google Patents

Procédé d'assemblage d'un alliage magnésium-lithium, et corps assemblé Download PDF

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Publication number
WO2019031145A1
WO2019031145A1 PCT/JP2018/026130 JP2018026130W WO2019031145A1 WO 2019031145 A1 WO2019031145 A1 WO 2019031145A1 JP 2018026130 W JP2018026130 W JP 2018026130W WO 2019031145 A1 WO2019031145 A1 WO 2019031145A1
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joined
magnesium
friction stir
tool
stir welding
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Japanese (ja)
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藤井　英俊
好昭 森貞
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University of Osaka NUC
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Osaka University NUC
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Priority to JP2019535043A priority Critical patent/JP7121402B2/ja
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/12—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating the heat being generated by friction; Friction welding

Definitions

  • the present invention relates to a bonding method in which at least one material to be bonded is a magnesium-lithium alloy and a bonded body obtained by the bonding method, and more specifically, an efficient bonding method using friction stir welding. And a joined body obtained by the joining method.
  • Magnesium is high in specific strength and is attracting attention as a substitute material for conventionally used steel materials and aluminum alloys from the viewpoint of weight reduction of automobiles, trains, and aircraft.
  • magnesium alloys generally have poor formability at room temperature because they have an HCP structure.
  • Non-Patent Document 1 Microstructure and mechanical properties of Mg-lithium after TIG welding”, Transactions of Nonferrous Metals Society of China, 21.3 (2011), 477-481.
  • TIG welding Magnesium using TIG welding is used.
  • a lithium-based alloy is joined is disclosed, due to the temperature history at the time of welding, grain coarsening of the weld and softening of the heat-affected zone are inevitable.
  • the upper and lower plates are appropriately agitated and diffused by friction agitation, and bonding is performed in the solid phase state, so that a magnesium-lithium based alloy plate is obtained as in the conventional rolling bonding.
  • the surface in contact with the plate of aluminum and aluminum or its alloy is acid-washed beforehand, and a strong bond is made even without pretreatment such as polishing with a metal wire brush to remove oxide film etc. It says that product cost and manufacturing cost can be kept low compared to rolling bonding.
  • the joint strength of the obtained magnesium-lithium alloy is 84% or less of that of the base material, and the ductility is also lower than that of the base material.
  • a large amount of argon must be used to completely eliminate oxygen in the atmosphere.
  • a tool for friction stir welding is inserted from the side of the aluminum alloy plate disposed on the upper side, and the upper aluminum alloy plate and the lower magnesium A material based on lithium-based alloy is joined, and on the magnesium-lithium alloy side, almost no material flow occurs due to the action of the tool, and from the viewpoint of "frictional stirring technology", it conforms to friction stir welding of aluminum alloy. is there. That is, it can not be said that a method of obtaining a good joint of magnesium-lithium based alloy by friction stir welding has been established.
  • the present invention provides a simple and efficient friction stir welding method in which at least one bonding material is a magnesium-lithium alloy, and the stirring portion A bonding method capable of providing strength and plastic workability higher than that of a base material, and a bonded body obtained by the bonding method.
  • the present invention provides a modification method capable of imparting strength and plastic workability higher than that of a base material to an arbitrary region of a magnesium-lithium alloy, and a metal structure obtained by the modification method. Also aims.
  • the present inventor has conducted intensive studies on the material and the like of the friction stir welding tool, and as a result, the adhesion of the material to be welded (magnesium-lithium alloy) to the tool surface is suppressed.
  • the inventors have found that the present invention is extremely effective.
  • the present invention A method of friction stir welding one to-be-joined material and the other to-be-joined material At least one of the materials to be joined is a magnesium-lithium alloy, Use one of cemented carbide tools, cermet tools, ceramic tools, intermetallic compound tools and ceramic coated tools as friction stir welding tools, Inserting the friction stir welding tool into the one workpiece side;
  • the present invention provides a friction stir welding method of a metal material, characterized in that
  • Aluminum alloys and magnesium alloys can be easily friction stirred with steel tools, and there is no particular problem with tool life, so conventional friction stir welding is also made of steel (eg, from the viewpoint of tool price etc.)
  • Tools of hot tool steel: such as SKD 61) have been used.
  • any of cemented carbide tools, cermet tools, ceramic tools, intermetallic compound tools and ceramic coated tools as tools for friction stir welding can be effectively reduced by using
  • the affinity with the magnesium-lithium alloy can be reduced (a cemented carbide or cermet has a metal bonding phase, but the inorganic nonmetal phase is mainly used. Component).
  • the temperature of friction stir welding can be reduced, and it is possible to form a stirring unit having a finer and more homogeneous structure and having excellent strength and plastic workability.
  • (1) end portions of the metal plates are butted to form a bonding portion, and the rotary tool is moved while rotating along the longitudinal direction of the processed portion to move the metal plates together.
  • Bonding bonding (2) end portions of metal plates are butted to form a bonding portion, and spot bonding in which a rotary tool is rotated without moving at the bonding portion and bonded, and (3) metal plates are overlapped in the bonding portion Align, insert the rotary tool into the joint, and rotate the rotary tool without moving it at that point to join the metal plates by spot welding, (4) Overlay the metal plates at the joint, and rotate the joint to the joint Inserts the tool and moves it while rotating the rotating tool along the longitudinal direction of the joint to move it to join the metal plates together, including four aspects (1) to (4) of bonding and their combinations Friction stir Welding tool magnesium - inserted into lithium-based alloy.
  • the tool life can be shortened by inserting the tool into the magnesium-lithium alloy having a small plastic deformation resistance. It can also be improved.
  • the method of bonding a metal material according to the present invention is characterized in that a friction stir welding tool is inserted into one of the materials to be bonded (magnesium-lithium alloy side). More specifically, when one of the materials to be joined is a magnesium-lithium alloy and the other material to be joined is other than a magnesium-lithium alloy, the center of the friction stir welding tool in the butt welding (probe The center of the portion is on one side of the material to be joined with respect to the butt surface, and in overlap bonding, one material to be joined is placed on the upper side, and the friction stir welding tool is inserted from the one material side .
  • general friction stir welding conditions such as the rotational speed, moving speed, insertion amount and applied load of the tool may be appropriately set from the viewpoint of defect formation in the stirring portion and bonding efficiency.
  • the shape of the tool is not particularly limited as long as the effects of the present invention are not impaired, and various shapes of conventionally known friction stir welding tools can be used.
  • the other material to be bonded is a magnesium-lithium alloy.
  • the materials to be joined together be magnesium-lithium alloys, the importance of the friction stir action on magnesium-lithium alloys is increased, so that the effects of the method of joining metal materials of the present invention can be obtained more remarkably. Can.
  • the surface of the friction stir welding tool is not grooved. Since tool wear and tool breakage are unlikely to occur in friction stir welding of aluminum alloys and magnesium alloys, it is common to grooving such as screwing on the bottom of the shoulder and the side of the probe to increase the stirring effect of the tool. It is On the other hand, the adhesion of the magnesium-lithium alloy to the surface of the tool can be suppressed by not subjecting the groove processing to the tool. On the other hand, since the magnesium-lithium based alloy has excellent plastic workability, material flow can be sufficiently generated even with a tool without groove processing, and the stirring portion can be formed.
  • the tool for friction stir welding which is not grooved means a tool having a shoulder bottom surface and a probe side surface in a flat state.
  • the peripheral speed of the outermost periphery of the shoulder portion of the friction stir welding tool is 23.6 mm / s to 78.5 mm / s.
  • the peripheral speed range is a low speed area which is not common in friction stir welding of magnesium alloys, but when a magnesium-lithium alloy having room temperature workability is used as a material to be joined, sufficient friction stir action should be obtained. it can.
  • the peripheral speed at the outermost periphery of the probe portion of the friction stir welding tool is set to 9.5 mm / s to 31.4 mm / s.
  • the peripheral speed range is a low speed area which is not common in friction stir welding of magnesium alloys, but when a magnesium-lithium alloy having room temperature workability is used as a material to be joined, sufficient friction stir action should be obtained. it can.
  • butt joining is preferable.
  • the formation of the agitating part is more important than the superposition joining, but in the joining method of the metal material of the present invention, a favorable agitating part is obtained even when the magnesium-lithium alloy is used as a material to be joined. Since it can be formed, even if it is butt joint, jointing can be achieved efficiently.
  • Friction stir welding for the purpose of joining and friction stir process for the purpose of reforming are basically techniques based on the same principle, and the method of joining metal materials of the present invention described above is the modification of metal materials. It can also be used as a method. Specifically, friction stirring may be performed using a tool having an appropriate shape and size in consideration of the shape, size, position, and the like of a desired reformed part.
  • the present invention is It is a joined body in which one to-be-joined material and the other to-be-joined material are joined via a stirring part, At least one of the materials to be joined is a magnesium-lithium alloy,
  • the stirring portion includes recrystallized grains of the ⁇ phase of the magnesium-lithium alloy;
  • the crystal orientation of the recrystallized grain is random,
  • a zygote characterized by
  • the stirring portion since the stirring portion is formed by friction stir welding at a relatively low temperature, the stirring portion includes recrystallized grains of the ⁇ phase having the HCP structure and the ⁇ phase having the BCC structure.
  • the recrystallized grains of the ⁇ phase are clearly refined compared to the base material.
  • the crystal orientation of the ⁇ phase is randomized. Since the ⁇ phase has an HCP structure, a strong texture is generally formed after a processing process such as extrusion and rolling in which a simple shear stress is applied. On the other hand, by friction stirring under appropriate conditions using the bonding method of the present invention, it is possible to randomize the crystal orientation of the ⁇ phase, and the mechanical properties decrease and anisotropy due to the strong texture. Can be suppressed.
  • being randomized means that a strong bottom surface texture of the ⁇ phase is not formed, for example, in the orientation map of EBSD measurement, recrystallized grains of the ⁇ phase are displayed only in the same systematic color It is good without it. More specifically, in the pole figure, the Texture Intensity is preferably 1 to 10, and more preferably 1 to 5.
  • the hardness is higher than that of the base material.
  • there is no heat-affected zone at the outer edge of the agitating zone due to the temperature rise during joining there is no region where the hardness is lower than that of the base material.
  • the minimum hardness in the region of the magnesium-lithium alloy of the bonded body is 50 HV or more, and that the joint efficiency with respect to the one workpiece is 100%. Is more preferred.
  • the tensile strength of the stirring portion is preferably 1.1 times or more, more preferably 1.3 times or more of the base material tensile strength of the one material to be bonded. Most preferably 1.5 times or more.
  • the tensile strength of the stirring portion may be slightly higher than the tensile strength of the base material under bonding conditions where the heat input is relatively small.
  • the stirring portion is formed under low heat input conditions uncommon to friction stir welding of magnesium alloys, and the stirring portion is nano-organized (average crystal grain size of ⁇ phase is less than 1 ⁇ m) By doing this, the tensile strength of the stirring portion can be made 1.1 times or more the tensile strength of one of the materials to be joined.
  • the stirring portion having the nano structure is preferable also from the viewpoint of processability because it exhibits excellent superplasticity.
  • the other material to be bonded is preferably a magnesium-lithium alloy, and more preferably a butt bonded body.
  • the bonded body of the present invention can be suitably manufactured by the method of bonding the metal material of the present invention described above.
  • the present invention A metal structure including a reformed portion of a magnesium-lithium alloy, The reformed portion includes recrystallized grains of the ⁇ phase of the magnesium-lithium alloy; The crystal orientation of the recrystallized grain is random, Also provided is a metal structure characterized by The metal structure of the present invention has isotropically excellent mechanical properties and plastic workability since it has a reformed portion including recrystallized ⁇ -phase recrystallized grains.
  • the average grain size of the recrystallized grains is preferably less than 1 ⁇ m.
  • the metal structure of this invention can be suitably manufactured by the modification method of the metal material similar to the joining method of the metal material of the above-mentioned this invention.
  • the present invention is a simple and efficient friction stir welding method in which at least one of the materials to be joined is a magnesium-lithium alloy, which imparts strength and plastic workability greater than that of the base material to the stirring portion.
  • the present invention can provide a bonding method that can be used, and a bonded body obtained by the bonding method. Further, according to the present invention, there is provided a reforming method capable of imparting strength and plastic workability higher than that of a base material to an arbitrary region of a magnesium-lithium based alloy, and a metal structure obtained by the reforming method. You can also
  • Friction stir welding is called FSW (Friction Stir Welding), butt ends of two materials to be joined, which are to be joined, butt the protuberance (probe) provided on the tip of the rotating tool.
  • FSW Full Stir Welding
  • butt ends of two materials to be joined which are to be joined
  • protuberance probe
  • two metal members are joined by inserting them between the two ends and rotating and moving a rotary tool along the longitudinal direction of the ends.
  • FIG. 1 is a schematic view showing one embodiment of the method of bonding metal materials of the present invention. Inserting the to-be-joined material 2 (one to-be-joined material) and the to-be-joined material 2 ′ (the other to-be-joined material), inserting the rotated tool 4 into the desired joining area and moving along the to-be-joined line
  • the joint 6 can be obtained by
  • the bonding material 2 and the bonding material 2 ′ are both made of a magnesium-lithium alloy, basically, the butt wire is inserted so that the centers of the protruding portions (probe portions) 8 of the tool 4 coincide with each other. .
  • the protrusion (probe portion) 8 constituting the tool 4 is used in the method of bonding a metal material of the present invention. And most of the main body portion (shoulder portion) 10 abuts on the side of the workpiece 2.
  • any one of a cemented carbide tool, a cermet tool, a ceramic tool, an intermetallic compound tool, and a ceramic-coated tool can be used to make a magnesium-lithium alloy to be joined.
  • the adhesion of the alloy can be effectively reduced.
  • the surface of the tool 4 made of an inorganic nonmetal the affinity with the magnesium-lithium alloy can be reduced.
  • the temperature of friction stir welding can be reduced, and it is possible to form the stirring portion 12 having a finer and more homogeneous structure and having excellent strength and plastic workability.
  • the composition and structure of cemented carbide, cermet, ceramics and intermetallic compounds used as a tool material are not particularly limited as long as the effects of the present invention are not impaired, and various compositions and structures conventionally known may be used. Although it is possible, for cemented carbides and cermets, it is preferable to reduce the metallic bonding phase. Further, as the ceramics, for example, silicon carbide, silicon nitride, sialon, boron nitride, zirconia, alumina, titanium diboride and the like can be used, and as the intermetallic compound, for example, Ti—Al based or Ni—Al Intermetallic compounds can be used.
  • the main body of the tool 4 may be made of metal, for example, it can be made of hot tool steel (SKD 61).
  • the composition, structure, thickness and the like of the ceramic film are not particularly limited as long as the effects of the present invention are not impaired, and various compositions, structures and thicknesses conventionally known can be used. For example, they are used for cutting tools Various hard coatings can be used.
  • the above-mentioned tool material and ceramic film from the viewpoint of wettability with a magnesium-lithium based alloy, and it is preferable to make the contact angle of magnesium droplet and these materials 90 ° or more .
  • the torque applied to the tool 4 can be reduced by selecting the tool material and the ceramic coating whose contact angle is 90 ° or more.
  • FIG. 1 shows the case where a tool 4 having a cylindrical protrusion (probe portion) 8 on the bottom of a cylindrical main body (shoulder portion) 10 is used, but the shape of the tool 4 is as follows: There is no particular limitation as long as the effects of the present invention are not impaired, and various shapes of conventionally known friction stir welding tools can be used. Moreover, it is preferable not to have groove processing, such as screw processing, in the bottom face of the main-body part (shoulder part) 10 and the side surface of the projection part (probe part) 8 which contact
  • groove processing such as screw processing
  • the magnesium-lithium-based alloy used as the at least one material to be joined by the method of joining metal materials according to the present invention is mainly composed of magnesium, and an alloy to which lithium is added in order to impart plastic workability at room temperature is widely used. It is included.
  • the alloy includes an alloy to which aluminum, zinc, manganese, yttrium, lanthanoid, zirconium, silver, silicon, calcium or the like is added in order to improve strength and heat resistance.
  • lithium is preferably contained in the range of 5 to 15% by weight.
  • the content of lithium is less than 5% by weight, the plastic formability at room temperature is not improved significantly, and conversely, when the content of lithium exceeds 15% by weight, intergranular cracking (surface crack) may be caused. Also, the cost is high because lithium is expensive.
  • the other material to be joined 2 ' is also a magnesium-lithium alloy.
  • the importance of the friction stir action on magnesium-lithium alloys increases, so the effect of the joining method of the metal material of the present invention becomes more remarkable. Can be obtained.
  • General friction stir welding conditions such as rotational speed, moving speed, insertion amount and applied load of the tool 4 may be appropriately set from the viewpoint of defect formation in the stirring portion 12 and bonding efficiency.
  • the peripheral speed of the outermost periphery of the main body (shoulder portion) 10 of the tool 4 be 23.6 mm / s to 78.5 mm / s.
  • the peripheral speed range is a low speed area that is not common sense in friction stir welding of magnesium alloys, but when using a magnesium-lithium alloy having room temperature workability as the workpieces 2 and 2 ', sufficient friction stir action is required. You can get it.
  • the peripheral speed of the outermost periphery of the main body portion (shoulder portion) 10 is 23.6 mm / s or more, formation of a defect due to insufficient agitation can be suppressed, and 78.5 mm / s or less
  • the peripheral speed of the outermost periphery is approximately 23.6 mm / s by setting the rotational speed to 30 rpm, and approximately 78.5 mm by setting 100 rpm. / S.
  • the circumferential speed of the outermost periphery of the protruding portion (probe portion) 8 of the tool 4 be 9.5 mm / s to 31.4 mm / s.
  • the peripheral speed range is a low speed area that is not common sense in friction stir welding of magnesium alloys, but when using a magnesium-lithium alloy having room temperature workability as the workpieces 2 and 2 ', sufficient friction stir action is required. You can get it.
  • the circumferential speed of the outermost periphery of the protrusion (probe portion) 8 is set to 9.5 mm / s or more, formation of a defect due to insufficient stirring can be suppressed, and 31.4 mm / s or less Thus, the formation of defects due to the adhesion of the magnesium-lithium alloy to the surface of the tool 4 can be suppressed.
  • the peripheral speed of the outermost periphery is approximately 9.5 mm / s by setting the rotational speed to 30 rpm, and approximately 31.4 mm by setting 100 rpm. / S.
  • the formation of the stirring portion 12 is more important than the superposition joining, but in the joining method of the metal material of the present invention, the magnesium-lithium alloy is used as the joining members 2 and 2 '. However, since a good stirring portion 12 can be formed, bonding can be efficiently achieved by using the bonding method of the present invention.
  • FIG. 2 shows a schematic cross-sectional view in the vicinity of a bonded portion in the bonded body of the present invention.
  • a butt junction part is shown in FIG.
  • the bonded body 20 of the present invention is a bonded body in which one of the materials to be bonded 2 and the other material to be bonded 2 ′ are bonded via the stirring portion 12, and at least one material to be bonded 2 is magnesium-lithium. It is a system alloy, and is characterized in that recrystallization of the ⁇ phase is included in the region of the magnesium-lithium alloy in the stirring section 12.
  • the shape and size of the bonding members 2 and 2 ' are not particularly limited as long as the effects of the present invention are not impaired, and bonding may be performed by the bonding method of the present invention.
  • the magnesium-lithium alloy has an ⁇ phase of HCP structure and a ⁇ phase of BCC structure, but in the extruded material and the rolled material, the ⁇ phase is elongated and distributed in a streak shape.
  • the ⁇ phase is macroscopically distributed in the stirring section 12 as well, the ⁇ phase is recrystallized, and the equiaxed ⁇ phase is in a state of being gathered.
  • the magnesium-lithium-based alloy as at least one of the materials to be joined 2 contains magnesium as a main component, and widely includes an alloy to which lithium is added in order to impart plastic workability at room temperature thereto.
  • the alloy includes an alloy to which aluminum, zinc, manganese, yttrium, lanthanoid, zirconium, silver, silicon, calcium or the like is added in order to improve strength and heat resistance.
  • lithium is preferably contained in the range of 5 to 15% by weight.
  • the content of lithium is less than 5% by weight, the plastic formability at room temperature is not improved significantly, and conversely, when the content of lithium exceeds 15% by weight, intergranular cracking (surface crack) may be caused. Also, the cost is high because lithium is expensive.
  • the hardness is higher than that of the base material. Further, since there is no heat-affected zone at the outer edge of the agitating unit 12 due to the temperature rise during joining, there is no region where the hardness is lower than that of the base material.
  • the average grain size of recrystallized grains of the ⁇ phase is preferably less than 5 ⁇ m, more preferably less than 3 ⁇ m, and most preferably less than 1 ⁇ m.
  • the minimum hardness in the region of one of the bonding members 2 (magnesium-lithium-based alloy) of the bonded body 20 is preferably 50 HV or more, and one bonding member 2 of the bonded body 20 (magnesium-lithium-based alloy)
  • the joint efficiency for 100% is more preferably 100%.
  • the tensile strength of the stirring portion 12 is preferably 1.1 times or more, more preferably 1.3 times or more, and more preferably 1.5 times or more of the tensile strength of one of the materials to be joined 2. Is most preferred.
  • the tensile strength of the stirring portion may be slightly higher than the tensile strength of the base material under bonding conditions where the heat input is relatively small.
  • the stirring portion 12 is formed under low heat input conditions that are not common sense as friction stir welding of a magnesium alloy, and the stirring portion 12 is nano-organized (average crystal grain size of ⁇ phase is less than 1 ⁇ m)
  • the tensile strength of the stirring portion 12 can be made 1.1 times or more of the tensile strength of one of the bonding members 2.
  • the stirring part 12 which has the said nano structure expresses the outstanding superplasticity ability, it is preferable also from a viewpoint of processability.
  • the crystal orientation of the ⁇ phase is randomized in the recrystallization region of the stirring unit 12.
  • the crystal orientation of the ⁇ phase can be randomized, and the decrease in mechanical properties and anisotropy caused by the strong texture can be suppressed. can do.
  • the other material to be bonded 2 is also preferably a magnesium-lithium alloy, and more preferably a butt bonded body.
  • the reformed portion in the metal structure of the present invention has the same characteristics as the stirring portion in the joined body of the present invention.
  • LZ 91 magnesium alloy (9 wt% Li-1 wt% Zn-Mg Bal.) Plates having a length of 200 mm, a width of 65 mm and a thickness of 3 mm were butted together to obtain a joined body by friction stir welding.
  • the friction stir welding was performed under tool position control under the following conditions. Note that no shielding gas is used during friction stir welding, and groove processing is not performed on the bottom of the shoulder of the tool and the side of the probe.
  • Friction stir welding was performed in the same manner as in Example 1 except that the material of the tool was made of hot tool steel (SKD 61).
  • Suitable bonding conditions In order to confirm the suitable joining conditions for obtaining a good joined body, the surface and the cross section of the joint (stirred part) were observed by an optical microscope. If defects are formed in the stirring part, x, if no defects are formed, but if a large amount of burrs or surface roughness is observed, ⁇ , if defects are not formed and the surface state of the stirring part is smooth The results of the examples are shown in Table 1 with ⁇ . In addition, in the comparative example, since a defect was formed on all the conditions (evaluation of x on all the conditions), it has not shown.
  • the joint method of the present invention can provide a good joint under a wide range of joint conditions.
  • the rotational speed is higher than 150 rpm, the metallic luster on the surface of the agitating portion is lost, and the cause may be formation of oxidation or liquid phase accompanying the increase in bonding temperature.
  • the favorable stirring part surface which maintained metallic luster was able to be obtained by using argon gas as shield gas.
  • the material to be bonded adheres to the surface of the tool under all the bonding conditions, and a groove-like defect is formed in the stirring portion.
  • the material to be joined adheres to the side surface of the probe portion and the bottom surface of the shoulder portion, making it difficult to grasp the tool prototype.
  • the other tools there was a portion where coloring due to the material to be joined was present on the side surface of the probe portion and the bottom surface of the shoulder portion, but significant adhesion was not confirmed.
  • FIG. 4 shows the hardness distribution (horizontal direction of the joint at the center of the plate thickness) of the cross section of the joint obtained at a tool moving speed of 100 mm / min and a tool rotational speed of 100 to 300 rpm.
  • the hardness of all the stirring parts is higher than that of the base material, and the increase in hardness of the stirring parts is remarkable particularly at a lower tool rotation speed.
  • no softened region is observed at the outer edge of the stirring portion.
  • FIG. 5 shows the tensile properties of the joint obtained at a tool movement speed of 100 mm / min and a tool rotation speed of 30 to 100 rpm.
  • the tension test result of a base material is shown as a comparison.
  • a small tension having a parallel part of 4 mm long x 2 mm wide x 2 mm thick Also shown are the results of preparing test pieces and evaluating the bonding direction as a tensile axis at a tensile speed of 0.08 mm / min.
  • the joints obtained in the examples have the same tensile properties as the base material, and the joint efficiency is 100%. Further, the tensile properties of the stirring portion are significantly higher than that of the base material, and the tensile strength is about twice that of the base material.
  • the deformation amounts to breakage of the base material and the stirring portion were about 150% and about 1100%, respectively, and it was confirmed that the stirring portion was provided with extremely remarkable superplastic deformability.
  • An overview photograph of the test piece of the stirring unit after the evaluation is shown in FIG.
  • the parallel portion with a length of 4 mm is approximately 44 mm when broken.
  • FIGS. 7 and 8 An SEM photograph of the center of the stirring portion and an orientation map image of the ⁇ phase obtained in the base material and the example (tool movement speed 100 mm / min, tool rotation speed 100 to 300 rpm) are shown in FIGS. 7 and 8, respectively.
  • the base material is composed of an ⁇ phase and a ⁇ phase, and the ⁇ phase is distributed in a streak shape.
  • the ⁇ phase is divided to form equiaxed recrystallized grains.
  • the alpha phase of the matrix has a strong texture, but the alpha phase of the stirring section is randomly oriented.
  • the crystal grain size of the stirring portion is finer than that of the base material, and is more remarkable under the condition that the tool rotation speed is low.
  • the average crystal grain size of the ⁇ phase is less than 5 ⁇ m in the case of 300 rpm, less than 3 ⁇ m in the case of 200 rpm, and less than 1 ⁇ m in the case of 100 rpm.

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  • Pressure Welding/Diffusion-Bonding (AREA)

Abstract

L'invention concerne : un procédé d'assemblage qui permet de conférer à une partie malaxée une résistance et une aptitude au façonnage plastique égales ou supérieures à celles d'un matériau de base et qui constitue un procédé de soudage par friction-malaxage simple et efficace lorsqu'au moins l'un des matériaux à assembler est un alliage de magnésium-lithium ; et un corps assemblé obtenu à l'aide du procédé d'assemblage. L'invention concerne en outre : un procédé de modification qui permet de conférer à une région souhaitée d'un alliage de magnésium-lithium une résistance et une aptitude au façonnage plastique égales ou supérieures à celles d'un matériau de base ; et une structure métallique obtenue à l'aide du procédé de modification. Ainsi, l'invention concerne un procédé de soudage par friction-malaxage d'un matériau à assembler et d'un autre matériau à assembler, le procédé étant un procédé de soudage par friction-malaxage de matériau métallique caractérisé en ce qu'au moins l'un des matériaux à assembler est un alliage de magnésium-lithium, et en ce que tout outil de soudage par friction-malaxage parmi un outil en alliage de métal dur, un outil en cermet, un outil en céramique, un outil composé intermétallique et un outil recouvert de céramique est utilisé, et ledit outil est inséré à partir du côté sur lequel est situé le matériau parmi les matériaux à assembler.
PCT/JP2018/026130 2017-08-08 2018-07-11 Procédé d'assemblage d'un alliage magnésium-lithium, et corps assemblé Ceased WO2019031145A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113502422A (zh) * 2021-06-11 2021-10-15 清华大学 高强韧镁锂合金及其制备方法
CN115461184A (zh) * 2020-06-04 2022-12-09 古河电气工业株式会社 电气·电子设备用部件

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004209522A (ja) * 2003-01-06 2004-07-29 Hyogo Prefecture 金属間の摩擦攪拌接合方法
JP2011079022A (ja) * 2009-10-07 2011-04-21 Kurimoto Ltd ＭｇおよびＭｇ合金の摩擦攪拌接合方法
JP2012143811A (ja) * 2010-12-24 2012-08-02 Sumitomo Electric Ind Ltd マグネシウム合金材

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004209522A (ja) * 2003-01-06 2004-07-29 Hyogo Prefecture 金属間の摩擦攪拌接合方法
JP2011079022A (ja) * 2009-10-07 2011-04-21 Kurimoto Ltd ＭｇおよびＭｇ合金の摩擦攪拌接合方法
JP2012143811A (ja) * 2010-12-24 2012-08-02 Sumitomo Electric Ind Ltd マグネシウム合金材

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115461184A (zh) * 2020-06-04 2022-12-09 古河电气工业株式会社 电气·电子设备用部件
CN113502422A (zh) * 2021-06-11 2021-10-15 清华大学 高强韧镁锂合金及其制备方法

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TW201910035A (zh) 2019-03-16
TWI683715B (zh) 2020-02-01
JP7121402B2 (ja) 2022-08-18
JPWO2019031145A1 (ja) 2020-08-06

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