Linear friction build-up method

Abstract

A linear friction build-up method includes: a first step of bringing a metal material plate into contact with a build-up material; and a second step of forming a build-up layer in such a manner of pressing the metal material plate against the build-up material with the metal material undergone a linear sliding engagement therewith, and building up a tip part of the metal material plate softened by frictional heat resulted from the linear sliding engagement on the build-up material.

Description

Linear friction overlay method

[0001] The present disclosure relates to a linear friction surfacing method.

[0002] Metal additive manufacturing (AM) is sometimes used as one method for manufacturing metal parts. Because AM generally involves a melting process, the structure of the manufactured metal part includes a solidification structure that differs from that of the base material. Therefore, the metal part is prone to embrittlement due to the solidification structure. For this reason, in recent years, attention has been focused on AM methods that do not involve the melting process, i.e., methods that perform metal deposition without melting the metal. For example, Patent Document 1 below discloses a build-up method that utilizes friction stirring. Specifically, the friction build-up method discloses a friction build-up method in which a substantially cylindrical build-up member is pressed against the surface of a base material while rotating, and the build-up member is softened by frictional heat to perform build-up processing on the base material.

[0003] JP 2010-227967 A

[0004] In the build-up method using friction stirring as disclosed in Patent Document 1, the frictional heat input between the build-up member and the base material surface is unstable, so the shape of the build-up layer tends to be non-uniform. Therefore, there is a need for a metal additive manufacturing method that does not include a melting process and can form a build-up layer with a uniform shape. There is also a need for a method that can form a large metal object in a short time.

[0005] An object of one aspect of the present disclosure is to provide a linear friction surfacing method that does not include a melting step and that can efficiently form a uniform shape of the buildup layer.

[0006] A linear friction build-up method according to one aspect of the present disclosure includes a first step of bringing a metal material plate into contact with a material to be built up, and a second step of pressing the metal material plate against the material to be built up while linearly sliding it, and building a build-up layer on the material to be built up by laying a tip portion of the metal material plate, which is softened by frictional heat generated by the linear sliding, on the material to be built up.

[0007] According to one aspect of the present disclosure, a linear friction buildup method can be provided that can efficiently form a buildup layer with a uniform shape.

[0008] FIG. 1 is a schematic diagram illustrating a linear friction build-up method according to an embodiment. FIG. 2 is a schematic diagram illustrating a linear friction build-up method according to a modified example. FIG. 3 shows a photograph of the appearance of the build-up layer formed in Test Example 1. FIG. 4(a) shows a photograph of the appearance of the build-up layer formed in Test Example 2, and FIG. 4(b) shows a photograph of the appearance of the build-up layer formed in Test Example 3. FIG. 5(a) shows a photograph of the appearance of the build-up layer formed in Test Example 4, and FIG. 5(b) shows a photograph of the appearance of the build-up layer formed in Test Example 5. FIG. 6 shows a photograph of the appearance of the build-up layer formed in Test Example 6. FIG. 7 shows a photograph of the appearance of the build-up layer formed in Test Example 7. FIG. 8(a) is a photograph showing the cross section of a sample formed in Test Example 8. FIG. 8(b) is an enlarged photograph of the area surrounded by a square shown in FIG. 8(a). FIG. 9(a) is a photograph showing the cross section of a sample formed in Test Example 9. FIG. 9(b) is an enlarged photograph of the squared area shown in FIG. 9(a). FIG. 10(a) is a photograph showing a cross section of a sample formed in Test Example 10. FIG. 10(b) is an enlarged photograph of the squared area shown in FIG. 10(a). FIG. 11(a) is a photograph showing a cross section of a sample formed in Test Example 11. FIG. 11(b) is an enlarged photograph of the squared area shown in FIG. 11(a). FIG. 12(a) is a photograph showing a cross section of a sample formed in Test Example 12. FIG. 12(b) is an enlarged photograph of the squared area shown in FIG. 12(a). FIG. 13(a) is a photograph showing a cross section of a sample formed in Test Example 13. FIG. 13(b) is an enlarged photograph of the squared area shown in FIG. 13(a). FIG. 14 is a diagram showing the location where the mechanical properties of the sample of Test Example 8 are evaluated. Fig. 15 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 8. Fig. 16 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 9. Fig. 17 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 10. Fig. 18 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 11. Fig. 19 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 12. Fig. 20 is a graph showing the measurement results of the Vickers hardness distribution of Test Example 13.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, identical elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted. In this specification, the term "same" and similar words are not limited to "completely identical." Furthermore, since the drawings are intended to conceptually explain the embodiments, the dimensions and ratios of the depicted components may differ from the actual dimensions.

[0010] (1) Overview of the Linear Friction Building Method In the linear friction building method (metal additive manufacturing) according to this embodiment, a building method utilizing friction is carried out, similar to the friction building method described in Patent Document 1. However, unlike the friction building method described in Patent Document 1, linear friction is utilized. Furthermore, the building layer formed by this linear friction building method and the material on which the building layer is formed do not need to be joined to each other. In other words, linear friction welding does not need to be performed in this linear friction building method.

[0011] As a specific example, the linear friction buildup method according to this embodiment comprises a first step of bringing a metal material plate into contact with the material to be builtup, and a second step of pressing the metal material plate against the material to be builtup and linearly sliding it, and building the tip portion of the metal material plate, which has been softened by frictional heat generated by the linear sliding, onto the material to be builtup, thereby forming a buildup layer.

[0012] (2) Details of the Linear Friction Building Method Next, with reference to FIG. 1 , the linear friction building method according to this embodiment will be described in detail. First, with reference to FIG. 1 , each component used in the linear friction building method will be described. FIG. 1 is a schematic diagram for explaining the linear friction building method according to this embodiment. FIG. 1 shows a workpiece P, a metal material plate M that presses the workpiece P, a gripping mechanism G that grips the metal material plate M, and a buildup layer BL provided on the workpiece P. Hereinafter, the direction in which the metal material plate M presses the workpiece P will be referred to as a first direction X, the direction in which the workpiece P moves relative to the metal material plate M will be referred to as a second direction Y, and the direction perpendicular to the first direction X and the second direction Y will be referred to as a third direction Z. In FIG. 1 , arrow A1 indicates the direction in which the metal material plate M slides, arrow A2 indicates the direction in which the workpiece P moves relative to the metal material plate M, and arrow A3 indicates the direction in which the workpiece P presses the metal material plate M.

[0013] The metal material plate M is the raw material for the buildup layer BL formed by the linear friction buildup method according to this embodiment. In this embodiment, the metal material plate M has a flat plate shape, but is not limited to this. The shape of the metal material plate M may be any shape that allows the linear friction buildup method to be implemented. The metal material plate M is gripped by the gripping mechanism G so that it extends along the first direction X, for example. The metal material plate M extending along the first direction X corresponds to the longest side of the metal material plate M (the length of the metal material plate M) extending along the first direction X. From the perspective of preventing breakage of the metal material plate M during linear friction, the protrusion length of the metal material plate M is 1 to 5 times the width of the metal material plate M, for example, 2 mm to 50 mm. The thickness of the metal material plate M is, for example, 2 mm or more. The size of the buildup layer BL to be formed can be adjusted depending on the width of the metal material plate M.

[0014] The tip portion M1 of the metal material plate M is a portion that can come into contact with the cladding material P. The base portion M2 of the metal material plate M is a portion that is gripped by the gripping mechanism G. The metal material plate M may be a plate-shaped member containing a single type of metal, or a plate-shaped member containing multiple types of metals. In the latter case, the metal material plate M is, for example, an alloy plate-shaped member. The metal material plate M may contain, for example, metals such as iron, titanium, aluminum, copper, magnesium, chromium, zinc, nickel, molybdenum, and cobalt. Specific examples of the metal material plate M include aluminum plate-shaped members, aluminum alloy plate-shaped members, copper plate-shaped members, copper alloy plate-shaped members, titanium plate-shaped members, titanium alloy plate-shaped members, magnesium alloy plate-shaped members, Invar plate-shaped members (iron-nickel alloy plate-shaped members), and steel plate-shaped members. In this embodiment, the metal material plate M is an aluminum alloy plate-shaped member. The aluminum alloy may contain, for example, iron, copper, manganese, magnesium, zinc, titanium, and silicon in addition to aluminum.

[0015] The build-up material P is a member on which a build-up layer BL formed from a softened metal material plate M is provided. The build-up material P is arranged so as to extend, for example, along the second direction Y. In this embodiment, the build-up material P and the metal material plate M are arranged so as to be perpendicular to each other. The build-up material P may be a plate-shaped member made of the same material as the metal material plate M, or may be a plate-shaped member made of a material different from the metal material plate M. The build-up material P may contain the metal contained in the metal material plate M. The build-up material P is fixed, for example, on a stage (not shown). The stage is movable along the second direction Y. Therefore, the build-up material P is movable relative to the metal material plate M. The speed at which the build-up material P moves relative to the metal material plate M is, for example, 120 mm / min, but is not limited to this. In addition, the fact that the build-up material P extends along the second direction Y corresponds to the fact that the build-up material P extends along the shortest side of the metal material plate M (the thickness of the metal material plate M).

[0016] The gripping mechanism G is a mechanism included in a device (not shown) for fixing and moving the metal material plate M, and is movable in the first direction X and the second direction Y. Movement of the gripping mechanism G in the first direction X allows the metal material plate M to continuously press the buildup material P. Movement of the gripping mechanism G in the second direction Y allows the metal material plate M to frictionally contact the buildup material P. In this embodiment, the gripping mechanism G repeatedly reciprocates along the width or thickness of the metal material plate M, while moving along the first direction X to approach the buildup material P. This allows for continuous linear friction between the metal material plate M and the buildup material P. The gripping mechanism G or the device may have, for example, a hydraulically controlled slide mechanism or an actuator. Although not shown, the device including the gripping mechanism G may further include a mechanism capable of accommodating multiple metal material plates M and supplying the multiple metal material plates M to the gripping mechanism G. In this case, the replacement work of the metal material plate M, which is a consumable item, is simplified.

[0017] The buildup layer BL is a solidified portion of the metal material plate M (e.g., the tip portion M1). The shape of the buildup layer BL as viewed from the first direction X is determined by the shapes of the metal material plate M and the workpiece P (particularly the width dimension of the metal material plate M), the trajectory of the relative movement of the metal material plate M with respect to the workpiece P, and other factors. For example, the buildup layer BL can be easily enlarged by increasing the sizes of both the metal material plate M and the workpiece P. The thickness of the buildup layer BL is adjusted by, for example, the allowance of the metal material plate M. In FIG. 1 , the thickness of the buildup layer BL is constant, but this is not limited thereto. The allowance of the metal material plate M corresponds to the length of contraction of the metal material plate M during linear friction in the first direction X.

[0018] Next, an example of the linear friction surfacing method according to this embodiment will be described in detail.

[0019] First, the metal material plate M is brought into contact with the workpiece P (first step). In the first step, the metal material plate M, which is arranged to extend along the first direction X, is brought into contact with the workpiece P, which is arranged to extend along the second direction Y. Therefore, in the first step, the extending direction of the metal material plate M and the extending direction of the workpiece P are perpendicular to each other. At least at the start of the first step, the tip portion M1 of the metal material plate M is in contact with the workpiece P.

[0020] Next, the metallic material plate M is pressed against the workpiece P while linearly sliding, and the tip portion M1 of the metallic material plate M, which is softened by frictional heat generated by the linear sliding, is laid on the workpiece P, thereby forming the buildup layer BL (second step). In the second step, a load is first applied to the metallic material plate M in the first direction X toward the workpiece P, thereby pressing the metallic material plate M against the workpiece P. The pressure applied by the metallic material plate M to the workpiece P in the first direction X is adjusted, for example, based on the softening temperature of the metallic material plate M. In this embodiment, the applied pressure is 10 MPa or more and 100 MPa or less, but is not limited thereto. Next, while pressing the metallic material plate M against the workpiece P, the metallic material plate M is repeatedly moved back and forth along the third direction Z. At this time, the metallic material plate M is repeatedly moved back and forth along the arrow A1 shown in FIG. 1 while being pressed against the workpiece P. This causes the metallic material plate M to linearly slide against the workpiece P. The frequency of the reciprocating movement is, for example, 10 Hz or more and 100 Hz or less, but is not limited to this. When the frequency of the reciprocating movement is 50 Hz, the metal material plate M reciprocates relative to the buildup material P at a rate of 50 times per second. The amplitude of the reciprocating movement is, for example, ±1.0 mm to ±4.0 mm, but is not limited to this. In the second step, the metal material plate M reciprocates along the third direction Z while the buildup material P is fixed, but is not limited to this. Both the metal material plate M and the buildup material P may reciprocate along the third direction Z, or the metal material plate M may be fixed and the buildup material P may reciprocate along the third direction Z.

[0021] The frictional heat generated by the linear sliding softens the tip portion M1 of the metal material plate M. The softened tip portion M1 is pushed out from between the metal material plate M and the build-up material P and built up on the build-up material P, thereby forming the build-up layer BL. In the second step, the position at which the metal material plate M is linearly slid relative to the build-up material P changes over time. In this embodiment, the build-up material P moves along the second direction Y, causing the metal material plate M to move relative to the build-up material P. This gradually displaces the interface between the metal material plate M and the build-up material P, resulting in the build-up layer BL being formed over a wide area on the build-up material P.

[0022] Assuming that the build-up efficiency is 100% (i.e., that the entire consumption of the metal material plate M is assumed to become the build-up layer BL) and that the shape of the build-up layer BL is assumed to be a rectangular parallelepiped, the volume of the build-up layer BL corresponds to the consumption of the metal material plate M. In this case, the thickness h of the build-up layer BL can be calculated by the following formulas 1 and 2 (where w is the width of the metal material plate M, v Ｐ : moving speed of the cladding material P, d: thickness of the metal material plate M, v Ｍ : pressing speed of the metal material plate M, t: movement time of the cladding material P).

[0023] The pressing speed of the metal material plate M can be determined, for example, by the pressure applied to the cladding material P of the metal material plate M. The pressing speed of the metal material plate M is, for example, 0.3 mm / s or more and 3 mm / s or less, 0.3 mm / s or more and 2 mm / s or less, 0.3 mm / s or more and 1.5 mm / s or less, 0.5 mm / s or more and 3 mm / s or less, 0.5 mm / s or more and 2 mm / s or less, 0.5 mm / s or more and 1.5 mm / s or less, 0.75 mm / s or more and 3 mm / s or less, 0.75 mm / s or more and 2 mm / s or less, 0.75 mm / s or more and 1.5 mm / s or less, 1 mm / s or more and 3 mm / s or less, 1 mm / s or more and 2 mm / s or less, 1 mm / s or more and 1.5 mm / s or less, 1.5 mm / s or more and 3 mm / s or less, 1.5 mm / s or more and 2 mm / s or less, etc. From the viewpoint of the joining strength between the buildup material P and the buildup layer BL, the pressing speed of the metal material plate M may be greater than 1 mm / s and less than 3 mm / s, or may be 1.5 mm / s or more and 2 mm / s or less. In this case, the occurrence of unjoined portions between the buildup material P and the buildup layer BL can be effectively suppressed while reducing the discharge of burrs. In addition, the buildup material P, which is the base material, is less likely to soften, and a decrease in hardness of the buildup material P in the vicinity of the buildup layer BL is less likely to occur. From the viewpoint of the forming efficiency of the buildup layer BL, the pressing speed of the metal material plate M may be 1 mm / s or more and 3 mm / s or less, 1.5 mm / s or more and 3 mm / s or less, 2 mm / s or more and 3 mm / s or less, 1 mm / s or more and 2 mm / s or less, or 1.5 mm / s or more and 2 mm / s or less. The building efficiency of the build-up layer BL is the volume (cm ３ / h). In this embodiment, the molding efficiency of the build-up layer BL is, for example, 200 cm ３ / h or more 2000cm ３ The efficiency of building up a cladding layer using a conventional laser is 100 cm / h or less. ３ / h.

[0024]

[0025]

[0026] In this embodiment, the second step may be performed on the formed buildup layer BL. This allows the buildup layer BL to be thickened and three-dimensionally shaped. Furthermore, by supplying a new metal material plate M to the gripping mechanism G during the second step, the buildup layer BL can be efficiently formed.

[0027] According to the linear friction deposition method of this embodiment described above, the buildup layer BL can be formed without performing a melting process. Furthermore, because the metallic material plate M and the workpiece P undergo linear sliding, the interface between the metallic material plate M and the workpiece P is uniformly heated. Therefore, the shape (thickness, etc.) of the buildup layer BL tends to be uniform. Additionally, by performing the linear friction deposition method using the metallic material plate M, a large-area buildup layer BL can be efficiently formed compared to a friction stir deposition method using a rod-shaped metallic material. Therefore, according to the linear friction deposition method of this embodiment, the buildup layer BL can be efficiently formed with a uniform shape without including a melting process.

[0028] In addition, since the metal material plate M is pressed against the workpiece P, strain is introduced at the interface between the metal material plate M and the workpiece P. Therefore, it is possible to control the microstructure of the buildup layer BL to be formed.

[0029] In one example, in the second step, the position at which the metal material plate M is linearly slid relative to the workpiece P may change over time. In this case, the buildup layer BL can be formed over a wide range on the workpiece P.

[0030] A linear friction build-up method according to a modified example of the above embodiment will be described below. In the description of the modified example, descriptions that overlap with the above embodiment will be omitted, and only differences will be described. In other words, to the extent technically possible, the descriptions of the above embodiment may be used appropriately in the modified example.

[0031] FIG. 2 is a schematic diagram illustrating a linear friction build-up method according to a modified example. As shown in FIG. 2, this modified example differs from the above-described embodiment in that the metallic material plate MA is a plate-shaped member inclined relative to the surface P1 of the workpiece P. In this modified example, the length of the metallic material plate MA is inclined relative to the surface P1. The inclination angle θ of the metallic material plate MA is, for example, 10° or more and 60° or less. The leading end surface M3 included in the leading end portion M1 of the metallic material plate MA extends along the second direction Y. That is, the leading end surface M3 extends parallel to the surface P1. In this case, frictional heat is efficiently generated at the interface between the metallic material plate MA and the workpiece P, and the build-up layer BL tends to be uniformly formed.

[0032] In the first modified example, in the first step, the metal material plate MA is pressed against the build-up material P while being inclined relative to the surface P1 of the build-up material P. In the second step, the metal material plate MA is linearly slid against the build-up material P while being inclined relative to the surface P1 of the build-up material P. In this modified example, in the second step, the position at which the metal material plate MA is linearly slid against the build-up material P does not need to change over time. This is because even without this change over time, the interface between the metal material plate MA and the build-up material P will shift as the metal material plate MA shrinks.

[0033] In the first modified example, when the position where the metallic material plate MA is linearly slid relative to the workpiece P does not change over time, the thickness h of the buildup layer BL can be calculated by the following formulas 3 and 4. On the other hand, in the first modified example, when the position where the metallic material plate MA is linearly slid relative to the workpiece P changes over time, the thickness h of the buildup layer BL can be calculated by the following formulas 5 and 6 (where w is the width of the metallic material plate MA, d is the thickness of the metallic material plate MA, and v Ｍ : Pressing speed of metal material plate MA, v Ｐ : moving speed of the workpiece P, t: moving time of the workpiece P, θ: tilt angle of the metal material plate MA).

[0034]

[0035]

[0036]

[0037]

[0038] The above-described modified example also achieves the same effects as the above-described embodiment. In addition, by performing the second step with the metal material plate MA inclined relative to the surface P1 of the workpiece P, the interface between the metal material plate MA and the workpiece P shifts as the metal material plate MA shrinks. Therefore, even if the position at which the metal material plate MA is linearly slid relative to the workpiece P in the second step does not change over time, the buildup layer BL can be formed over a wide area on the workpiece P.

[0039] The method and apparatus for joining metallic materials according to the present disclosure are as described in [1] to [8] below, and have been described in detail based on the above-mentioned embodiments and modified examples. [1] A linear friction surfacing method comprising: a first step of bringing a metallic material plate into contact with a workpiece; and a second step of pressing the metallic material plate against the workpiece while linearly sliding it, and forming a buildup layer on the workpiece by depositing a tip portion of the metallic material plate, which has been softened by frictional heat generated by the linear sliding, on the workpiece. [2] The linear friction surfacing method according to [1], wherein in the first step, the metallic material plate is pressed against the workpiece while being inclined with respect to the surface of the workpiece, and in the second step, the metallic material plate is linearly slid against the workpiece while being inclined with respect to the surface of the workpiece. [3] The linear friction surfacing method according to [2], wherein in the second step, the position at which the metallic material plate is linearly slid against the workpiece does not change over time. [4] The linear friction surfacing method according to [1] or [2], wherein in the second step, the position at which the metallic material plate is linearly slid against the workpiece changes over time. [5] The linear friction surfacing method according to any of [1] to [4], wherein the metallic material plate is an aluminum plate-shaped member or an aluminum alloy plate-shaped member. [6] The linear friction surfacing method according to any of [1] to [4], wherein in the second step, the plunge speed of the metallic material plate is greater than 1 mm / s and less than 3 mm / s. [7] The linear friction surfacing method according to [6], wherein in the second step, the plunge speed of the metallic material plate is 1.5 mm / s or more and 2 mm / s or less. [8] The linear friction surfacing method according to [7], wherein in the second step, the friction allowance of the metallic material plate is less than 4 mm.

[0040] However, one aspect of the present disclosure is not limited to the above-described embodiment, the above-described modified example, and the above-described [1] to [8]. One aspect of the present disclosure can be further modified within the scope of the gist thereof.

[0041] For example, the above embodiment and the above modification may be combined with each other. In one example, the linear friction building up method described in the above embodiment may be performed after the linear friction building up method described in the above modification. In this case, the first and second steps described in the above embodiment are performed, and then the first and second steps described in the above modification are performed. Alternatively, the linear friction building up method described in the above modification may be performed after the linear friction building up method described in the above embodiment. Alternatively, the linear friction building up method described in the above embodiment and the linear friction building up method described in the above modification may be performed alternately and repeatedly. As described above, by appropriately combining the linear friction building up method described in the above embodiment and the linear friction building up method described in the above modification, a metal additive manufacturing method can be performed that can control the thickness, shape, and formation rate of the build up layer.

[0042] In the above embodiment and modified example, the buildup efficiency is assumed to be 100%, but this is not limiting. For example, the buildup efficiency may not be 100%, and a frictional margin may occur in the second step. In this case, the metal material plate and the workpiece are preheated before the buildup layer is formed. The frictional margin is the length (consumption amount) of the metal material plate worn out before the buildup layer is formed. In one example, the frictional margin corresponds to the length of the metal material plate worn out before the position of the linear sliding of the metal material plate against the workpiece changes. The frictional margin may be, for example, 1 mm to 8 mm, 1 mm to 6 mm, 1 mm to 5 mm, 2 mm to 8 mm, 2 mm to 6 mm, 2 mm to 5 mm, 3 mm to 8 mm, 3 mm to 6 mm, 3 mm to 5 mm, or 3 mm to 4 mm. From the viewpoint of the hardness distribution between the material to be overlaid and the overlay layer, the frictional margin may be smaller than 5 mm, smaller than 4 mm, 1 mm or more, 2 mm or more, 1 mm or more and smaller than 5 mm, 1 mm or more and smaller than 4 mm, 2 mm or more and smaller than 5 mm, or 2 mm or more and smaller than 4 mm. From the viewpoint of the unjoined portion between the material to be overlaid and the overlay layer, the frictional margin may be larger than 2 mm, 3 mm or more, or 4 mm or more.

[0043] The present disclosure will be explained in more detail by the following examples, but the present disclosure is not limited to these examples.

[0044] (Test Example 1) A flat plate (thickness: 5 mm, width: 20 mm, length: 65 mm) made of an aluminum alloy (A6061-T6) was prepared as a metal material plate (feed material) that is the material for the build-up layer. Also, a flat plate (thickness: 7-8 mm, width: 30 mm, length: 77 mm) made of an aluminum alloy (A6061-T6) was prepared as a build platform on which the build-up layer was to be formed.

[0045] First, the metal plate was brought into contact with the workpiece. The metal plate was butted against the workpiece so that the lengthwise direction of the metal plate and the lengthwise direction of the workpiece were perpendicular to each other. The dimensions of the surface of the metal plate that butted against the workpiece were 5 mm x 20 mm, and the dimensions of the surface of the workpiece that butted against the metal plate were 30 mm x 77 mm. Next, the metal plate was fixed to a hydraulically controlled slide mechanism, and the workpiece was fixed to a movable stage. Next, the metal plate was reciprocated along the width direction of the metal plate while being pressed against the workpiece under the following conditions: applied pressure: 20-100 MPa, frequency: 50 Hz, amplitude: ±2.0 mm, and approach: 10 mm. Additionally, the metal plate was moved relative to the workpiece at 120 mm / min along the lengthwise direction of the workpiece. As described above, linear friction was performed between the metal plate and the workpiece, and a buildup layer was formed on the workpiece from the softened portion of the metal plate. The appearance of the buildup layer was observed visually and with a three-dimensional shape measuring machine (Keyence Corporation, "VR-3200"). In addition, the behavior of the softened portion of the metal plate during linear friction was photographed with a high-speed camera (Nac Image Technology Corporation, "MEMRECAM").

[0046] (Test Example 2) A buildup layer was formed in the same manner as in Test Example 1, except that the metal material plate was inclined at 45° with respect to the surface of the workpiece, the lean-to was 1 mm, and the metal material plate was not moved relative to the workpiece. The appearance of the buildup layer was also observed in the same manner as in Test Example 1. Note that the metal material plate in Test Example 2 was pre-processed so that the surface that abuts against the surface of the workpiece extended parallel to that surface.

[0047] Test Example 3 Except for the fact that the approach allowance was set to 3 mm, a buildup layer was formed in the same manner as in Test Example 2. Furthermore, as in Test Example 2, the appearance of the buildup layer was observed.

[0048] Test Example 4 Except for setting the approach allowance to 5 mm, a buildup layer was formed in the same manner as in Test Example 2. Further, as in Test Example 2, the appearance of the buildup layer was observed.

[0049] Test Example 5 Except for setting the approach allowance to 10 mm, a buildup layer was formed in the same manner as in Test Example 2. Further, as in Test Example 2, the appearance of the buildup layer was observed.

[0050] Test Example 6: A metal plate and a workpiece were prepared similar to those in Test Example 1. Next, the metal plate was fixed to a hydraulically controlled slide mechanism, and the workpiece was fixed to a movable stage. Next, the metal plate was reciprocated along its width while being pressed against the workpiece under the following conditions: applied pressure: 10-100 MPa, frequency: 50 Hz, amplitude: ±2.0 mm, pressing speed of the metal plate: 1 mm / s, and distance: 10 mm. After the metal plate had consumed 5 mm of friction (friction distance), the metal plate was moved relative to the workpiece at 120 mm / min along its length. This resulted in linear friction between the metal plate and the workpiece, forming a buildup layer on the workpiece from the softened portion of the metal plate. The appearance of the formed buildup layer was observed visually and with a three-dimensional shape measuring machine ("VR-3200" manufactured by Keyence Corporation).

[0051] (Test Example 7) A buildup layer was formed in the same manner as in Test Example 6, except that the metal material plate was inclined at an angle of 30° relative to the surface of the workpiece. The appearance of the buildup layer was also observed in the same manner as in Test Example 6. Note that the metal material plate in Test Example 7 was pre-processed so that the surface that would come into contact with the surface of the workpiece extended parallel to that surface.

[0052] (Test Example 8) A flat plate (plate thickness: 10 mm, width: 20 mm, length: 69 mm) made of an aluminum alloy (A6061-T6) was prepared as the metal material plate (feed material) that was the material for the buildup layer. Furthermore, a flat plate (plate thickness: 5 mm, width: 35 mm, length: 62 mm) made of an aluminum alloy (A6061-T6) was prepared as the build platform on which the buildup layer was to be formed. Next, the metal material plate was fixed to a hydraulically controlled slide mechanism, and the buildup material was fixed to a movable stage. At this time, the metal material plate was inclined at 30° relative to the surface of the buildup material. The metal material plate of Test Example 8 was pre-processed so that the surface that abutted against the surface of the buildup material extended parallel to that surface.

[0053] Next, the metal material plate was pressed against the workpiece under the following conditions: applied pressure: 10-100 MPa, frequency: 50 Hz, amplitude: ±2.0 mm, metal material plate pressing speed: 1 mm / s, and distance: 10 mm. The metal material plate was then moved back and forth along its width direction. After the metal material plate had consumed 4 mm, the metal material plate was moved relative to the workpiece at 36 mm / min along its length. This caused linear friction between the metal material plate and the workpiece, and a buildup layer was formed on the workpiece from the softened portion of the metal material plate.

[0054] To confirm the cross-section of the formed buildup layer, a portion of the metal plate was first removed using a fine cutter (Sakamoto Machine Works, high-speed wet cutting machine UC62 type). Next, the center of the buildup layer was cut out along the width direction of the metal plate using an NC wire-cut electric discharge machine (Sodick Corporation, "AG360L"). This exposed the cross-section of the center. The surface of the cross-section was then wet-polished using waterproof abrasive paper (No. 240 to No. 3000). The surface was then mirror-polished using an alumina abrasive suspension (Baikowski Japan, particle size: 1.0 μm) and a polishing cloth (Struers S.A.S, MD-Nap). This process created a sample for cross-sectional observation of the buildup layer.

[0055] (Test Example 9) A buildup layer was formed in the same manner as in Test Example 8, except that the pressing speed of the metal material plate was set to 1.5 mm / s, and that after the consumption of the metal material plate reached 4 mm, the metal material plate was moved relative to the buildup material at 54 mm / min along the length of the buildup material. Then, a sample for observing the cross section of the buildup layer was prepared in the same manner as in Test Example 8.

[0056] (Test Example 10) A buildup layer was formed in the same manner as in Test Example 8, except that the pressing speed of the metal material plate was set to 2 mm / s, and that after the consumption of the metal material plate reached 4 mm, the metal material plate was moved relative to the buildup material at 72 mm / min along the length of the buildup material. Then, a sample for observing the cross section of the buildup layer was prepared in the same manner as in Test Example 8.

[0057] Test Example 11 A buildup layer was formed in the same manner as in Test Example 8, except that the pressing speed of the metal material plate was set to 2 mm / s, the draw-up allowance was set to 6 mm, and after the consumption amount of the metal material plate (friction allowance) reached 2 mm, the metal material plate was moved relative to the workpiece at 72 mm / min along the length of the workpiece. Then, a sample for observing the cross section of the buildup layer was prepared in the same manner as in Test Example 8.

[0058] Test Example 12 A buildup layer was formed in the same manner as in Test Example 10, except that the approach allowance was set to 8 mm. Then, a sample for observing the cross section of the buildup layer was prepared in the same manner as in Test Example 8.

[0059] Test Example 13 A buildup layer was formed in the same manner as in Test Example 8, except that the pressing speed of the metal material plate was set to 2 mm / s, the approach distance was set to 10 mm, and after the consumption of the metal material plate reached 6 mm, the metal material plate was moved relative to the workpiece at 72 mm / min along the length of the workpiece. Then, a sample for observing the cross section of the buildup layer was prepared in the same manner as in Test Example 8.

[0060] <Observation Results of the Overlay Layer> Figure 3 shows a photograph of the appearance of the overlay layer formed in Test Example 1. As shown in Figure 3, it was confirmed that by moving the metallic material plate relative to the workpiece, a overlay layer was formed not only between the metallic material plate and the workpiece, but also in areas other than between the metallic material plate and the workpiece. Here, the results of photographing with a high-speed camera confirmed that a overlay layer was formed between the metallic material plate and the workpiece before the metallic material plate was moved relative to the workpiece, and that the overlay layer spread due to this relative movement. It is presumed that the formation of the overlay layer before the relative movement was due to a phenomenon in which the temperature of the metallic material plate became higher than that of the workpiece due to a difference in heat capacity between the metallic material plate and the workpiece.

[0061] Fig. 4(a) shows a photograph of the appearance of the buildup layer formed in Test Example 2. Fig. 4(b) shows a photograph of the appearance of the buildup layer formed in Test Example 3. Fig. 5(a) shows a photograph of the appearance of the buildup layer formed in Test Example 4. Fig. 5(b) shows a photograph of the appearance of the buildup layer formed in Test Example 5. As shown in Figs. 4(a) to 5(b), it was observed that the greater the lean, the wider the area that deformed from the interface between the metal material plate and the buildup material. This observation result shows that by linearly rubbing the metal material plate in an inclined state with respect to the buildup material, it is possible to form and thicken the buildup layer without moving the metal material plate relative to the buildup material.

[0062] Fig. 6 shows a photograph of the appearance of the buildup layer formed in Test Example 6. Fig. 7 shows a photograph of the appearance of the buildup layer formed in Test Example 7. In Figs. 6 and 7, the left-right direction of the paper corresponds to the direction in which the metal material plate moves relative to the material to be built up. The depth direction of the paper corresponds to the direction in which the metal material plate moves back and forth. As shown in Figs. 6 and 7, by tilting the metal material plate, the amount of buildup layer formed is significantly larger. From this, it can be inferred that in the linear friction buildup method, the buildup layer can be formed efficiently by tilting the metal material plate.

[0063] <Results of cross-sectional observation of buildup layer> (a) of Fig. 8 is a photograph showing a cross-section of a sample formed in Test Example 8. (b) of Fig. 8 is an enlarged photograph of the area surrounded by a square shown in (a) of Fig. 8. (a) of Fig. 9 is a photograph showing a cross-section of a sample formed in Test Example 9. (b) of Fig. 9 is an enlarged photograph of the area surrounded by a square shown in (a) of Fig. 9. (a) of Fig. 10 is a photograph showing a cross-section of a sample formed in Test Example 10. (b) of Fig. 10 is an enlarged photograph of the area surrounded by a square shown in (a) of Fig. 10. The photographs shown in (a) and (b) of Fig. 8, (a) and (b) of Fig. 9, and (a) and (b) of Fig. 10 were each obtained using a three-dimensional shape measuring instrument.

[0064] The thickness h1 of the buildup layer shown in FIG. 8(a) was 7.0 mm, and the length l1 of the buildup layer along the width direction of the metal plate was 15.9 mm. The thickness h2 of the buildup layer shown in FIG. 9(a) was 7.4 mm, and the length l2 of the buildup layer along the width direction of the metal plate was 16.6 mm. The thickness h3 of the buildup layer shown in FIG. 10(a) was 8.0 mm, and the length l3 of the buildup layer along the width direction of the metal plate was 16.2 mm. As shown in FIG. 8(b), an unbonded portion was observed between the buildup layer and the workpiece. On the other hand, as shown in FIGS. 9(b) and 10(b), no unbonded portion was observed between the buildup layer and the workpiece.

[0065] FIG. 11(a) is a photograph showing a cross section of a sample formed in Test Example 11. FIG. 11(b) is an enlarged photograph of the area surrounded by a square shown in FIG. 11(a). FIG. 12(a) is a photograph showing a cross section of a sample formed in Test Example 12. FIG. 12(b) is an enlarged photograph of the area surrounded by a square shown in FIG. 12(a). FIG. 13(a) is a photograph showing a cross section of a sample formed in Test Example 13. FIG. 13(b) is an enlarged photograph of the area surrounded by a square shown in FIG. 13(a). The photographs shown in FIGS. 11(a) and 11(b), 12(a) and 12(b), and 13(a) and 13(b) were each obtained using a three-dimensional shape measuring device.

[0066] The thickness h4 of the buildup layer shown in Figure 11(a) was 8.2 mm. The thickness h5 of the buildup layer shown in Figure 12(a) was 8.5 mm. The thickness h6 of the buildup layer shown in Figure 13(a) was 7.8 mm. As shown in Figure 11(b), an unbonded area was observed in part between the buildup layer and the material to be built up. On the other hand, as shown in Figure 12(b) and Figure 13(b), no unbonded area was observed between the buildup layer and the material to be built up, but burrs were observed.

[0067] <Mechanical Property Evaluation> Figure 14 is a diagram showing the locations where the mechanical properties of the sample of Test Example 8 were evaluated. For each of Test Examples 8 to 13, the Vickers hardness distribution was measured at the joint surface between the buildup layer and the welded material and its vicinity. As shown in Figure 14, the location where the buildup layer was first formed or its vicinity was designated as position α, the central part of the buildup layer was designated as position β, and the location where the buildup layer was last formed or its vicinity was designated as position γ. The Vickers hardness distribution was measured at positions α, β, and γ for each of the samples of Test Examples 8 to 13. The Vickers hardness of the samples was measured using a microhardness tester (FM-300, manufactured by Future Tech Co., Ltd.) under conditions of a test load of 100 kgf and a holding time of 15 seconds.

[0068] 15 to 20 are graphs showing the measurement results of the Vickers hardness distributions of Test Examples 8 to 13, respectively. In each of Figures 15 to 20, the horizontal axis represents the distance from the joint surface between the buildup layer and the welded material, the vertical axis represents Vickers hardness, and plot 10 represents the average hardness of the aluminum alloy (A6061-T6). In Figures 15 to 20, plots 11, 21, 31, 41, 51, and 61 represent the Vickers hardness distribution at position α of the corresponding sample, plots 12, 22, 32, 42, 52, and 62 represent the Vickers hardness distribution at position β of the corresponding sample, and plots 13, 23, 33, 43, 53, and 63 represent the Vickers hardness distribution at position γ of the corresponding sample.

[0069] As shown in Figures 15 to 17, it was confirmed that the minimum Vickers hardness value tends to increase as the pressing speed of the metal material plate increases. In particular, it was confirmed that the minimum Vickers hardness value at position γ tends to increase as the pressing speed of the metal material plate increases. Furthermore, as shown in Figures 18 to 20, it was confirmed that the minimum Vickers hardness value tends to increase and become more stable as the friction allowance of the metal material plate decreases.

[0070] BL... Overlay layer, G: Gripping mechanism, M, MA... Metal material plate, M1... Tip portion, M2... Base end portion, M3... Tip surface, P... Material to be built up, P1... Surface.

Claims

1. A linear friction surfacing method comprising: a first step of bringing a metal material plate into contact with a workpiece; and a second step of pressing the metal material plate against the workpiece while linearly sliding it, and laying the tip of the metal material plate, which has been softened by frictional heat generated by the linear sliding, on the workpiece, thereby forming a buildup layer.

2. A linear friction surfacing method as set forth in claim 1, wherein in the first step, the metal material plate is brought into contact with the material to be overlaid while being inclined relative to the surface of the material to be overlaid, and in the second step, the metal material plate is pressed against the material to be overlaid and linearly slid against it while being inclined relative to the surface of the material to be overlaid.

3. A linear friction surfacing method as set forth in claim 2, wherein in the second step, the position at which the metal material plate is linearly slid against the workpiece does not change over time.

4. A linear friction surfacing method as set forth in claim 1 or 2, wherein in the second step, the position at which the metal material plate is linearly slid against the workpiece changes over time.

5. A linear friction surfacing method according to any one of claims 1 to 3, wherein the metal material plate is an aluminum plate member or an aluminum alloy plate member.

6. A linear friction surfacing method according to any one of claims 1 to 3, wherein in the second step, the pressing speed of the metal material plate is greater than 1 mm / s and less than 3 mm / s.

7. A linear friction surfacing method as set forth in claim 6, wherein in the second step, the pressing speed of the metal material plate is 1.5 mm / s or more and 2 mm / s or less.

8. A linear friction surfacing method as set forth in claim 7, wherein in the second step, the friction allowance of the metal material plate is less than 4 mm.

Images