JP2018140416A - Composite member, joining member used for producing the same, and cutting tool formed from composite member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite member excellent in high-temperature joining strength, formed by joining, via a joining member, two types of WC-based hard metal alloys different from each other in at least one of Co content, amount of added component, and average particle diameter of WC particles, and to provide a joining member therefor and to provide a cutting tool formed from this composite member.SOLUTION: In a composite member, a Ti surface of a joining member formed from a Ti-Sn laminate is diffused and joined to a WC-based hard metal alloy member A in solid phase, thereby forming a reaction layer and a Ti-Co alloy layer at a junction and, meanwhile a Sn surface of the joining member is PTLP-joined to a WC-based hard metal alloy member B, thereby forming a reaction layer, a Ti-Sn alloy phase, and a Ti-Co alloy layer at the junction, the reaction layer is mainly formed from a metal W phase and a TiC phase. The Ti-Co alloy layer formed further on the center side of the junction than the reaction layer is formed from a composition of 45 to 75 atom % of Ti and 25 to 55 atom % of Co. A Ti-Sn alloy phase intermittently formed between the reaction layer and the Ti-Co alloy layer is formed from a composition of 65 to 85 atom % of Ti and 15 to 35 atom % of Sn. A cutting tool is formed from this composite member.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a composite member excellent in high-temperature bonding strength of a joint, and in particular, a composite member obtained by bonding a WC-based cemented carbide and a WC-based cemented carbide, a bonding member used for producing the same, The present invention relates to a cutting tool made of this composite member.

  Conventionally, WC-based cemented carbide, TiCN-based cermet, cBN sintered body, and the like are well known as tool materials. However, in recent years, tool materials are not formed from a single material but as a composite member. Has been proposed to form.

  For example, Patent Document 1 discloses a bonded body in which a cermet sintered body is a first material to be bonded 1 and a cBN sintered body or a diamond sintered body is a second material to be bonded 3. The joining material and the second joining material are joined via a joining material 2 (for example, Ti, Co, Ni) that does not generate a liquid phase at a temperature lower than 1000 ° C., and the joining is performed at a pressure of 0.1 MPa to 200 MPa. It has been proposed to perform heating by energization while pressurizing at a pressure, and the bonded body obtained by this can be used for the bonding layer even when the temperature of the brazing material becomes higher than the temperature at which the brazing material generates a liquid phase during cutting. Since the bonding strength does not decrease, it is considered suitable as a high-speed cutting tool or a CVD-coated cutting tool.

  Patent Document 2 discloses a bonded body in which a cemented carbide sintered body is a first material to be bonded 1 and a cBN sintered body is a second material to be bonded 2. The two materials to be joined are joined to each other by at least two surfaces consisting of a back surface and a bottom surface of the second material to be joined, with a joining material 3 containing titanium (Ti), A titanium nitride (TiN) compound layer having a thickness of 10 to 300 nm is formed at the interface with the bonding material, and the bonding strength is reduced by making the thickness of the bonding layer on the back surface smaller than the thickness of the bonding layer on the bottom surface. It has been proposed to obtain a joined body such as a high cutting tool.

  Further, Patent Document 3 discloses a cBN sintered body containing 20 to 100% by mass of cBN, and carbides, carbonitrides, and mutual solid solutions of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. Hard phase consisting of at least one selected from the group consisting of: 50 to 97% by mass, and the balance of the binder phase consisting mainly of at least one selected from the group consisting of Co, Ni and Fe: 3 to In a composite of 50% by mass of a hard alloy, a bonding layer is provided between the cBN sintered body and the hard alloy, and the bonding layer is composed of a ceramic phase and a metal phase. It has been proposed to increase the bonding strength of the composite by setting the thickness to 2 to 30 μm.

JP 2009-241236 A JP 2012-111187 A JP 2014-131819 A

The composite material proposed in Patent Documents 1 to 3 or a cutting tool made of the same exhibits a certain level of performance under normal conditions of cutting. For example, a high load acts on the cutting edge, and high heat generation occurs. Under the accompanying high feed and high cutting heavy cutting conditions, the high-temperature bonding strength cannot be said to be sufficient, and there has been a problem that breakage occurs from the bonded portion.
Therefore, a composite member having a joint portion having a higher high-temperature joint strength that causes a high load to act on the cutting edge and that does not cause breakage from the joint portion even under heavy cutting conditions with high heat generation, and A cutting tool is desired.

  In order to solve the problems of the conventional composite member and the cutting tool comprising the same, the present inventors have prepared a composite member comprising a WC-base cemented carbide and a WC-base cemented carbide and a cutting tool comprising the composite material, for example, Joins cutting edge part and composite WC base cemented carbide substrate (base metal) made of composite sintered body joined with WC base cemented carbide (backing material) simultaneously with sintering of cBN sintered body during ultra high pressure and high temperature sintering As a result of diligent research on measures to improve the joint strength of the joint in a cutting tool joined via a member, the following findings were obtained.

When the WC-based cemented carbide member to be joined is the same material, the WC-based cemented carbide member is adjacent to the WC-based cemented carbide member when the WC-based cemented carbide members are joined to each other by solid phase diffusion bonding via a joining member made of Ti foil. In the joining portion, a reaction layer composed of a metal W phase and a TiC phase is formed, and a Ti—Co alloy layer is formed on the center side of the joining portion from the reaction layer, thereby providing excellent joining strength. Is formed.
However, as the WC-based cemented carbide member, two types of WC-based cemented carbide members differing in at least one of the Co content of the WC-based cemented carbide member, the average particle size of the WC particles, and the content of the additive component were used. In the case (hereinafter, for the sake of simplicity, a WC-based cemented carbide member having a relatively large Co content, a WC-based cemented carbide member having a large average particle size of WC particles, or a content of an additive component is relatively small. Many WC-based cemented carbide members are referred to as “WC-based cemented carbide members A” and are relatively WC-based cemented carbide members having a low Co content or WC-based cemented carbides having a small average WC particle size. The alloy member or the WC-based cemented carbide member having a small content of additive components is referred to as “WC-based cemented carbide member B”), the bonding strength between the WC-based cemented carbide member A and the joint portion, Difference in bonding strength between WC-base cemented carbide member B and joint Since the bonding strength of the joint of the composite member is uneven, it was found that disadvantage that it is possible to increase the high temperature bond strength of the entire composite member occurs.
In other words, when the composite member is used as a cutting tool material, there is a risk of fracture at a joint having a low joint strength when a high load is applied. Can't extend life.

When the present inventors examined the cause of such a phenomenon, the thickness of the reaction layer formed at the joint interface between the WC-based cemented carbide member A and the joint, and the joint between the WC-based cemented carbide member B and the joint. The thickness of the reaction layer formed at the joint interface of the joint is different, in other words, the thickness of the reaction layer formed at the joint interface of the WC-base cemented carbide member B and the joint is WC-base cemented carbide member. Compared to the thickness of the reaction layer formed at the joint interface between A and the joint, it becomes excessively thick and brittle, or the reaction formed at the joint interface between the WC-based cemented carbide member A and the joint. The main reason is that the thickness of the layer is excessively thin compared to the thickness of the reaction layer formed at the joint interface between the WC-based cemented carbide member B and the joint, and the joint strength cannot be exhibited. I found out.
Therefore, the present inventors have further researched on measures for increasing the strength of the entire composite member in which the WC-based cemented carbide member A and the WC-based cemented carbide member B are joined via the joint. As a joining member, a laminated body in which Sn foil is laminated on any one of the front and back surfaces of Ti foil, or a laminated body in which a Sn vapor deposition film is formed on any one of the front and back surfaces of Ti foil is used as a joining member. The Ti surface of the laminate is disposed opposite to the WC-based cemented carbide member A, and the Sn surface of the laminate is disposed opposite to the WC-based cemented carbide member B. In this case, the thickness of the reaction layer formed at the bonding interface between the WC-based cemented carbide member B and the bonding portion becomes excessively thick, or the bonding interface between the WC-based cemented carbide member A and the bonding portion. The thickness of the reaction layer formed on the Therefore, the bonding strength at the bonding interface between the WC-based cemented carbide member A and the bonding portion, and the bonding interface between the WC-based cemented carbide member B and the bonding portion are substantially equal, so that the composite It has been found that the high-temperature bonding strength of the entire member can be improved.

When the composite member is used as a material for a cutting tool, even if it is a case where a heavy load acts on the cutting blade and is subjected to heavy cutting of steel or cast iron accompanied by high heat generation, WC Excellent cutting over a long period of use without breakage from the joining interface between the base cemented carbide member and the joint, in particular, the joining interface between the WC base cemented carbide member B and the joint. It was found that it performs well.

The present invention has been made based on the above findings,
“(1) A WC-based cemented carbide member A and a WC-based cemented carbide member B that are different in at least one of the Co content, the average particle size of the WC particles, and the content of the additive component are joined via the joint. A composite member comprising:
(A) The joint has an average layer thickness of 1 to 50 μm, and contains Ti in an average composition of 60 to 99 atomic%,
(B) When the longitudinal cross section of the bonding interface between the WC-based cemented carbide member A and the joint is observed, the WC-based cemented carbide member A is adjacent to the WC-based cemented carbide member A and has an average layer thickness of 0.5 to 5 μm. In addition, a reaction layer containing a total of 90 atomic% or more of the metal W phase and the TiC phase is formed, and further, Ti is 45 to 75 atomic% from the reaction layer to the center side in the thickness direction of the joint. A Ti—Co alloy layer containing Co in an amount of 25 to 55 atomic% is formed;
(C) When a longitudinal section of the bonding interface between the WC-based cemented carbide member B and the joint is observed, the reaction layer and the Ti—Co alloy layer of (b) are formed, and the reaction layer and the A composite member characterized in that a Ti-Sn alloy phase containing 65 to 85 atomic% Ti and 15 to 35 atomic% of Sn is formed between the Ti-Co alloy layer.
(2) The WC-based cemented carbide member A is a WC-based cemented carbide member having a relatively higher Co content than the WC-based cemented carbide member B, or the average particle size of WC particles. The composite member according to (1), wherein the composite member is a WC-based cemented carbide member having a large content or a WC-based cemented carbide member having a large content of additive components.
(3) The WC-based cemented carbide member A has a Co content of 10 to 30% by mass, a total content of VC, TaC, ZrC, NbC, and Cr ₃ C ₂ as additive components: 0 to 20% by mass, The balance is composed of WC and inevitable impurities, and the average particle size of the WC particles is 0.8 to 10 μm.
(4) The WC-based cemented carbide member B has a Co content of 4 to 12% by mass, a total content of VC, TaC, ZrC, NbC, and Cr ₃ C ₂ as additive components: 0 to 20% by mass, The balance is composed of WC and inevitable impurities, and the average particle size of the WC particles is 0.3 to 2 μm.
(5) When observing a longitudinal section parallel to the thickness direction of the joint portion in contact with the WC-base cemented carbide member A and the WC-base cemented carbide member B, the area ratio occupied by the Ti—Co alloy layer is It is 1-10 area% of a partial area, The composite member in any one of said (1) thru | or (4) characterized by the above-mentioned.
(6) A longitudinal section parallel to the thickness direction of the joint portion in contact with the WC-based cemented carbide member B is observed, and the interface length of the reaction layer and the interface length of the Ti—Sn alloy phase in contact with the reaction layer Any one of (1) to (5) above, wherein the ratio of the interface length of the Ti—Sn alloy phase to the interface length of the reaction layer is 10 to 50% when the thickness is measured. A composite member according to 1.
(7) The Ti—Sn alloy phase is intermittently formed between the reaction layer and the Ti—Co alloy layer, according to any one of (1) to (6), Composite member.
(8) The Ti—Sn alloy phase is intermittently present between the reaction layer and the Ti—Co alloy layer so as to fill the concave portion on the surface of the WC-based cemented carbide member B. The composite member according to any one of the above (1) to (7).
(9) A joining member used for manufacturing the composite member according to any one of (1) to (8), wherein the joining member is any one of a front surface and a back surface of a Ti foil having a thickness of 1 to 50 μm. Or a laminated body in which a Sn foil having a thickness of 0.1 to 5 μm is laminated on one surface, or a Ti foil having a thickness of 1 to 50 μm and a thickness of 0.1 to 5 μm on either one of the front and back surfaces of the Ti foil. A joining member comprising a laminate in which an Sn vapor deposition film is formed, and the thickness of the Sn foil or the Sn vapor deposition film in the laminate is 10% or less of the thickness of the Ti foil. .
(10) A cutting tool comprising the composite member according to any one of (1) to (8).
(11) The cutting tool according to (10), wherein a cutting blade for a cutting tool is formed on the WC-based cemented carbide member B side. "
It is characterized by.

  The present invention is described in detail below.

  As shown in FIG. 1, the composite member of this invention arrange | positions a joining member between WC base cemented carbide member A and WC base cemented carbide member B (refer FIG. 1 (a)), and joins a joining member. The WC-based cemented carbide member A and the WC-based cemented carbide member B are brought into contact with each other through a predetermined temperature and time with a predetermined pressure applied, and the WC-based cemented carbide member A and the joining member. And WC-based cemented carbide member B and the joining member are joined by PTLP (Partial Transient Liquid Phase) (see FIG. 1 (b)). This is a composite member in which the WC-base cemented carbide member B is joined through a joint (see FIG. 1C).

Here, the solid phase diffusion bonding means that the WC-base cemented carbide member A and the bonding member are abutted and a predetermined temperature (for example, 0.5 to 10.0 MPa) is applied and a predetermined temperature (for example, 0.5 to 10.0 MPa) is applied. , 600 to 900 ° C.) and holding for a predetermined time (for example, 5 to 600 minutes), the components constituting the WC-base cemented carbide member A react with the joining member to form an alloy. However, the melting point of the bonding member itself is relatively high (1200 ° C. or higher), reacts with the WC-based cemented carbide at 1000 ° C. or lower, and the brittle phase generated by the reaction does not reduce the strength of the bonding interface. Conditions that the reaction can be controlled and that the Kirkendall void, which occurs due to the diffusion rate being unbalanced in the interdiffusion between the WC-base cemented carbide and the bonding member, are difficult to generate. It is.
PTLP bonding refers to a predetermined temperature (for example, 400 to 400 mm) in a state in which the WC-base cemented carbide member B and the bonding member are butted and a predetermined pressure (for example, 0.5 to 10.0 MPa) is applied. 900 ° C.) for a predetermined time (for example, 5 to 600 minutes), only a part of the joining member is melted during joining, and the melted member is the other part of the joining member or a WC-based cemented carbide member. The member diffused in B and melted is changed into a high melting point phase, and after joining is completed, a low melting point phase does not exist and is a joining means for forming a joint having high heat resistance that does not melt at the joining temperature.
In the present invention, as a bonding member meeting the requirements of the solid phase diffusion bonding and the PTLP bonding, a laminated body in which Sn foil is laminated on any one of the front and back surfaces of the Ti foil, or the front and back surfaces of the Ti foil The laminated body in which Sn vapor deposition film was formed in any one surface is used.
Then, the joining member is arranged so that Ti of the laminate is opposed to the WC-based cemented carbide member A side on which solid phase diffusion bonding is performed, and is laminated on the WC-based cemented carbide member B side on which PTLP bonding is performed. Joining is performed by arranging the joining members so that Sn of the body faces each other.

The WC-based cemented carbide member A and the WC-based cemented carbide member B in which at least one of the Co content, the average particle size of the WC particles, and the content of the additive component in the present invention is different include, for example, the Co content, When there is a difference of 5% by mass or more, or a difference of 5% by mass or more in the total content of additive components (for example, VC, TaC, ZrC, NbC, Cr ₃ C ₂ etc.) of the WC-based cemented carbide member Or there is a difference of 2 μm or more in the average particle diameter of WC particles.
More specifically, examples of the WC-based cemented carbide suitable for the WC-based cemented carbide member A include the following.
Co content: 10-30% by mass, preferably 15-25% by mass,
Total content of additive components: 0 to 20% by mass,
Average particle diameter of WC particles: 0.8 to 10 μm, preferably 2 to 6 μm.
Examples of the WC-based cemented carbide suitable for the WC-based cemented carbide member B include the following.
Co content: 4 to 12% by mass, preferably 4 to 10% by mass,
Total content of additive components: 0 to 20% by mass,
Average particle diameter of WC particles: 0.3-2 μm, preferably 0.3-1.5 μm.
The difference in the Co content, the average particle size of the WC particles, and the content of the additive component is a relative value when comparing the WC-based cemented carbide members located on both sides of the joint. It is not limited only to the WC-based cemented carbide suitable for the WC-based cemented carbide member A or WC-based cemented carbide member B.

FIG. 2 shows an enlarged schematic diagram of FIG.
In FIG. 2, when the vicinity of the joining interface between the WC-based cemented carbide member A and the joint is viewed, an average layer thickness of 0.5 to 5 μm is formed at the joining interface between the WC-based cemented carbide member A and the joint. And a reaction layer containing a total of 90 atomic% or more of the metal W phase and the TiC phase is formed adjacent to the WC-based cemented carbide member A.
In the reaction layer, the additive component of WC-based cemented carbide member A such as VC, TaC, ZrC, NbC, Cr ₃ C ₂ , Co which is a binder phase component of WC-based cemented carbide member A, or bonding Ti which is a component of the member is allowed to be contained in a total content of less than 10 atomic% (note that the content is atomic% in terms of metal component).
And from the reaction layer to the thickness direction center side of a junction part, it consists of a composition of 45-75 atomic% Ti, 25-55 atomic% Co (henceforth "atomic%" is simply shown with "%"). A Ti—Co alloy layer is formed.

Further, in FIG. 2, when the vicinity of the bonding interface between the WC-based cemented carbide member B and the bonded portion is seen, an average layer of 0.5 to 5 μm is formed at the bonded interface between the WC-based cemented carbide member B and the bonded portion. A reaction layer having a thickness and containing a total of 90 atomic% or more of the metal W phase and the TiC phase is formed adjacent to the WC-based cemented carbide member B, and the thickness direction center side of the joint portion from the reaction layer A Ti—Co alloy layer having a composition of 45 to 75 atomic% Ti and 25 to 55 atomic% Co is formed.
In the reaction layer, the additive component of the WC-based cemented carbide member B such as VC, TaC, ZrC, NbC, Cr ₃ C ₂ , Co that is the binder phase component of the WC-based cemented carbide member B, or WC It is permissible for Sn and Ti, which are components of the joining member on the base cemented carbide member B side, to be contained in a total content of less than 10 atomic% (the content is atomic% in terms of metal component). Is done.
Furthermore, between the reaction layer and the Ti—Co alloy layer, it is in contact with the interface between the reaction layer and the Ti—Co alloy layer and has a composition of 65 to 85 atomic% Ti and 15 to 35 atomic% Sn. Ti-Sn alloy phases are formed intermittently.
The Ti—Sn alloy phase does not have to be formed in contact with the entire interface between the reaction layer and the Ti—Co alloy layer, and is continuous or intermittent in contact with the interface between the reaction layer and the Ti—Co alloy layer. What is necessary is just to be formed.

The reaction layers adjacent to the WC-based cemented carbide member A and the WC-based cemented carbide member B are diffused during solid phase diffusion bonding between the WC-based cemented carbide member A and the joining member (Ti in the laminate). In addition, the metal W phase, which is a component constituting the reaction layer, is formed by diffusion during PTLP joining of the WC-based cemented carbide member B and the joining member (Sn in the laminate). Since the TiC phase has a smaller thermal expansion coefficient than the base cemented carbide, and the TiC phase has a thermal expansion coefficient larger than that of the WC based cemented carbide but smaller than that of the metal Ti, the apparent thermal expansion coefficient of the reaction layer is WC It becomes an intermediate value between the base cemented carbide and the metal Ti.
Therefore, a reaction layer composed of a TiC phase and a metal W phase is formed in contact with the WC-based cemented carbide member A and the WC-based cemented carbide member B, so that the WC-based cemented carbide alloy is bonded to the WC-based cemented carbide due to the difference in thermal expansion coefficient. The thermal stress at the time of joining generated with the part is relaxed, and the formation of residual stress is also suppressed.
In the reaction layer, the total of the metal W phase and the TiC phase is determined to be 90 atomic% or more, but this is a component other than the metal W and the TiC phase when the total amount of the metal W phase and the TiC phase is less than 90 atomic%. This is because the thickness of the reaction layer is likely to be non-uniform at the location where segregation occurs, making it difficult to ensure the bonding strength.
In the reaction layer, VC, TaC, ZrC, NbC, Cr ₃ C _{2 and the} like, which are additive components of the WC-based cemented carbide, Co, which is a binder phase component of the WC-based cemented carbide, and constituent components of the joining member Ti and Sn (where Sn is a joint portion on the WC-base cemented carbide member B side) are allowed to be contained within a range not exceeding 10 atomic%.

The measurement of the content of the metal W phase and the TiC phase in the reaction layer can be obtained, for example, by the following method.
Using a scanning electron microscope and an Auger electron spectrometer, observe the longitudinal section of the vicinity of the boundary between the WC-based cemented carbide member A and the joint, and the vicinity of the boundary between the WC-based cemented carbide member B and the joint, The place where the metal W phase and the TiC phase exist is identified as the reaction layer, the composition analysis of 10 points is performed in the reaction layer, the contents of W, Ti and C are obtained from the average value, and the metal W phase and the TiC phase are obtained. Content.

The average layer thickness of the reaction layer is set to 0.5 to 5 μm, but if the average layer thickness is less than 0.5 μm, sufficient stress relaxation cannot be achieved, while the average layer thickness is 5 μm. If exceeded, the brittleness of the reaction layer becomes obvious, and when a high load is applied to the joint location of the composite member (particularly, the joint interface between the WC-based cemented carbide member B and the joint), the generation of cracks and the crack propagation path Since it becomes difficult to maintain a strong bonding state with the WC-based cemented carbide, the average thickness of the reaction layer is set to 0.5 to 5 μm.
In the present invention, by facing the WC-based cemented carbide member B where the layer thickness of the reaction layer is likely to be thick, the Sn surface of the joining member made of a laminate of Ti and Sn is placed facing and subjected to PTLP bonding, Between the reaction layer and the Ti—Co alloy layer, the Ti—Sn alloy phase having a composition of 65 to 85 atomic% Ti and 15 to 35 atomic% Sn is intermittently in contact with the interface between the reaction layer and the Ti—Co alloy layer. Thus, the presence of this Ti—Sn alloy phase suppresses the reaction layer adjacent to the WC-based cemented carbide member B from becoming too thick.

The average layer thickness of the reaction layer can be determined, for example, by the following method.
Using a scanning electron microscope and an Auger electron spectrometer, observe the longitudinal section of the vicinity of the boundary between the WC-based cemented carbide member A and the joint, and the vicinity of the boundary between the WC-based cemented carbide member B and the joint, When viewed from the WC-based cemented carbide member side, the critical position where the WC crystal grains are observed is defined as the interface between the WC-based cemented carbide member and the joint, and a line segment is drawn from the interface in a direction perpendicular to the interface. A line analysis is performed on 20 lines with an interval of 5 μm, and the thickness of the reaction layer is measured. The average value of these measured values is defined as the average layer thickness of the reaction layer.

45-75 atomic% Ti, 25-55 atomic% of the joint where the WC-based cemented carbide member A or WC-based cemented carbide member B is joined to the center in the thickness direction of the joint from the reaction layer. A Ti—Co alloy layer made of Co is formed.
In the Ti-Co alloy layer, when Ti is less than 45% and Co is more than 55%, the amount of Co diffusion from the WC-based cemented carbide is too large, and the strength of the WC-based cemented carbide itself tends to decrease. On the other hand, when Ti exceeds 75% and Co becomes less than 25%, atomic diffusion between the WC-based cemented carbide member and the joint is not sufficient, and WC-based cemented carbide A or WC through the joint is not sufficient. It becomes impossible to maintain a strong bonded state at the bonded portion of the base cemented carbide member B.
Therefore, the Ti content in the Ti—Co alloy layer formed at the center of the joint in the thickness direction from the reaction layer is 45 to 75%, and the Co content is 25 to 55%.

Moreover, when the area ratio of the said Ti-Co alloy layer which occupies for the whole junction part is measured, it is preferable that the area ratio of a Ti-Co alloy layer shall be 1-10 area%.
This is because if the area ratio of the Ti—Co alloy layer is less than 1%, the diffusion of Co from the WC-based cemented carbide member is not sufficient, and it is difficult to exhibit satisfactory bonding strength, and the area ratio is 10%. This is because the amount of Co diffusion from the WC-based cemented carbide member is too large, and the strength of the WC-based cemented carbide member A itself or the WC-based cemented carbide member B itself tends to decrease.
Moreover, the area ratio of a Ti-Co alloy layer can be calculated | required as follows.
Centering on the interface between the WC-base cemented carbide member A and the joint, element mapping is performed in a cross section parallel to the thickness direction of the joint within a range of ± 50 μm in the direction perpendicular to the interface, and the WC phase, Co phase, While specifying the TiC phase, the metal W phase, and the Ti—Co alloy phase, the WC base cemented carbide member A, the reaction layer, and the Ti—Co alloy layer are specified. The area ratio of the vertical cross-sectional area of the Ti—Co alloy layer specified on the side to the vertical cross-sectional area of the entire joint can be determined.
Further, element mapping is performed in a cross section parallel to the thickness direction of the joint within a range of ± 50 μm in the direction perpendicular to the interface centering on the interface between the WC-based cemented carbide member B and the joint, and the WC phase, Co Phase, TiC phase, metal W phase, Ti—Sn alloy phase and Ti—Co alloy phase (described later), WC-based cemented carbide member, reaction layer, Ti—Sn alloy phase and Ti (described later) -Co alloy layer is specified, and the area ratio of the vertical cross-sectional area of the Ti-Co alloy layer specified on the WC-based cemented carbide member B side to the vertical cross-sectional area of the entire joint is obtained from the element mapping result. Can do.

FIG. 3 shows an enlarged schematic view of the vicinity of the joint interface between the WC-based cemented carbide member B and the joint. The reaction layer and the Ti—Co alloy at the joint on the WC-based cemented carbide member B side are shown. A Ti—Sn alloy phase having a composition of 65 to 85% Ti and 15 to 35% Sn is formed between the layers.
In the Ti—Sn alloy phase, when Ti is less than 65% and Sn exceeds 35%, Ti ₆ Sn ₅ and metal Sn having a lower melting point than Ti ₃ Sn appear, and the high-temperature bonding strength is reduced. When it exceeds 85% and Sn becomes less than 15%, Sn becomes deficient due to solid solution of Sn in Ti, and as a result, it becomes difficult to form a Ti—Sn alloy phase sufficient to fill the substrate recess. Since the effect of suppressing the increase in the thickness of the layer is reduced, the bonding strength between the WC-based cemented carbide member B and the bonding portion is reduced.
Therefore, the Ti content in the Ti—Sn alloy phase formed between the reaction layer and the Ti—Co alloy layer in the joint is 65 to 85%, and the Sn content is 15 to 35%.

Moreover, it is preferable that the Ti-Sn alloy phase exists intermittently so as to fill the concave portion on the surface of the WC-based cemented carbide member B through the reaction layer.
As will be described later, this is a case where PTLP bonding is performed using a bonding member made of a laminated body in which an Sn foil is laminated on the surface of the Ti foil or a laminated body in which an Sn vapor deposition film is formed on the surface of the Ti foil. In addition, for example, Ti ₃ Sn is used so that Sn having a low melting point is melted to secure the bondability with the WC-based cemented carbide and to be firmly bonded, and to fill the concave portion on the surface of the WC-based cemented carbide member B. Thus, even when the surface roughness of the WC-based cemented carbide member B is rough, the generation of voids at the joint is reduced, and the surface of the WC-based cemented carbide member B is reduced. This is because a strong bonding strength can be obtained by increasing the interface length.
In addition, since the melting point of the Ti ₃ Sn alloy formed at the time of PTLP bonding is very high at 1670 ° C., even if the formed composite member is used in a temperature environment higher than the melting point of Sn (232 ° C.), the WC-based carbide The joint itself adjacent to the alloy member B is not melted / softened and has high high-temperature joint strength.
The contact interface length between the reaction layer formed adjacent to the WC-based cemented carbide member B and the Ti-Sn alloy phase is measured in the vicinity of the interface between the WC-based cemented carbide member B and the joint. The reaction layer can be obtained by observing a cross section parallel to the thickness direction and measuring the interface length of the reaction layer and the interface length of the Ti—Sn alloy phase in contact with the reaction layer. The ratio of the contact interface length of the Ti—Sn alloy phase to the interface length is preferably 10 to 50%.
This is because when the ratio of the contact interface length is less than 10%, the effect of filling the recesses on the surface of the WC-base cemented carbide member B is not sufficiently exhibited, voids are generated at the bonding interface, and the bonding strength is liable to decrease. This is because when the proportion of the contact interface length exceeds 50%, the brittleness of the Ti—Sn alloy phase becomes obvious, and interface peeling tends to occur.
Further, in the method of measuring the recesses on the surface of the WC-based cemented carbide member B, first, the interface between the WC-based cemented carbide member B and the reaction layer is represented as a curve, and the length ratio of the curve is 50:50. A reference line approximately parallel to the bisecting interface is drawn. If the interface is closer to the WC-based cemented carbide member B than the reference line, the surface of the WC-based cemented carbide member B at that location is a recess. In addition, when a straight line perpendicular to the reference line is drawn and both the recess and the Ti—Sn alloy phase exist on the same line, the Ti—Sn alloy phase is formed on the recess on the surface of the WC-based cemented carbide member B. And At the same time, the ratio of the contact interface length between the reaction layer and the Ti—Sn alloy phase is 10 to 50%, and in the cross-sectional SEM image of 2,000 times, the Ti—Sn alloy phase is present on the recess. When there are three or more places formed, it is assumed that the Ti—Sn alloy phase is formed so as to fill the concave portion on the surface of the WC-based cemented carbide member B.

The composite member of the present invention having the structure as described above includes a reaction layer and a Ti—Co alloy layer in which WC-based cemented carbide member A and Ti of a joining member facing the WC base cemented carbide member A are joined by solid phase diffusion bonding. A junction is formed, and the WC-based cemented carbide member B and the Sn of the joining member opposed to the WC-based cemented carbide member B are joined by PTLP joining, and includes a reaction layer, a Ti—Sn alloy phase, and a Ti—Co alloy layer. A composite member having a high temperature joint strength can be obtained by forming the joint portion having the above structure.
In addition, when a cutting tool is constructed from the above composite member, even if it is subjected to heavy cutting where a high load acts on the cutting blade, it will not break from the joint, and it can be used for a long time. Excellent cutting performance is exhibited throughout.
The cutting blade for a cutting tool is desirably formed on the WC-based cemented carbide member B side having relatively high hardness and excellent wear resistance.

In the present invention, a specific bonding member is used, and the WC-based cemented carbide member A side is bonded to the bonding member by solid phase diffusion bonding, and the WC-based cemented carbide member B side is bonded to the bonding member by PTLP bonding. As a result, the composite member of the present invention having excellent high-temperature bonding strength can be obtained.
As described above, the bonding member used in the present invention is a laminate in which Sn foil is laminated on either the front surface or the back surface of the Ti foil, or Sn vapor deposition on any one surface of the Ti foil. A laminated body on which a film is formed can be used, the average thickness of Ti foil is 1 to 50 μm, the average thickness of Sn foil (deposited film) is 0.1 to 5 μm, and Sn foil The thickness of the (deposited film) is preferably 10% or less of the thickness of the Ti foil.
This is because when the thickness of the Sn foil (deposited film) exceeds 5 μm or exceeds 10% of the thickness of the Ti foil, the ratio of the contact interface length of the Ti—Sn alloy phase is 50%. The Ti-Sn alloy phase is not easily formed due to the brittleness of the Ti-Sn alloy phase, and when the Sn foil (deposited film) thickness is less than 0.1 μm. This is because it becomes sufficient and excessive growth of the thickness of the reaction layer cannot be suppressed, and as a result, the bonding strength tends to decrease.
Moreover, about the average composition as the whole joining member, when Ti content will be less than 60%, it will become impossible to ensure the intensity | strength of joining part itself, on the other hand, when Ti content exceeds 99%, Sn content will become The Ti content is set to 60 to 99% because the effect of Ti-Sn alloy phase formation on the WC-based cemented carbide member B side is reduced too much.
In addition, the said joining member can be produced by laminating | stacking Sn foil of predetermined | prescribed thickness only on the single side | surface of Ti foil, for example, and Sn of predetermined | prescribed thickness is only on the single side | surface of Ti foil. It can produce by forming as a vapor deposition film, The preparation method is not specifically limited.

The composite member of the present invention can be produced, for example, by the following method.
Between the WC-based cemented carbide member A and the WC-based cemented carbide member B, Ti is opposed to the WC-based cemented carbide member A and Sn is opposed to the WC-based cemented carbide member B. For example, in a vacuum of 1 × 10 ⁻¹ Pa or less, hold at a predetermined temperature in the range of 600 to 900 ° C. for 5 to 600 minutes, pressurize under conditions of a load of 0.5 to 10.0 MPa, By performing solid phase diffusion bonding between the cemented carbide member A and the bonding member, and by performing PTLP bonding between the WC group cemented carbide member B and the bonding member, on the WC group cemented carbide member A side, By forming a joint including a reaction layer and a Ti—Co layer, and forming a joint including a reaction layer, a Ti—Sn alloy phase, and a Ti—Co layer on the WC-based cemented carbide member B side, The composite member of the present invention can be produced.
In PTLP bonding, a reaction layer composed of a metal W phase and a TiC phase is formed at the interface between the WC-based cemented carbide member B and the bonding member, and the Sn foil (thin film) is melted in the above temperature range. It is filled with Sn melted so as to fill the recesses present on the surface of the base cemented carbide member B, and enhances the bondability between the surface of the WC base cemented carbide member B and the joining member, thereby providing strong adhesion. By forming a bond and further suppressing an excessive increase in the thickness of the reaction layer, a decrease in high-temperature bonding strength due to embrittlement of the reaction layer is prevented.
Further, the molten Sn diffuses into the Ti foil as a joining member, and forms an alloy phase (for example, Ti ₃ Sn phase) having a melting point higher than the melting point of Sn alone (about 232 ° C.) and solidifies. Even when used in a temperature environment higher than the melting point of a single substance, the joint does not melt or soften, and a composite material having excellent high-temperature joint strength is formed.

The composite member of the present invention produced by the solid phase diffusion bonding and the PLTP bonding constitutes a cutting tool by using, for example, a WC-based cemented carbide member B as a cutting blade and a WC-based cemented carbide member A as a base. can do.
Further, for example, by using the composite WC-based cemented carbide member B as a backing material of a cBN sintered body constituting the cutting blade and the WC-based cemented carbide member A as a base (base metal), cBN cutting is performed. A tool can also be formed.

In the present invention, a WC-based cemented carbide member A and a WC-based cemented carbide member B that are different in at least one of the Co content, the average particle size of WC particles, and the content of additive components are joined via a joint. In the composite member having a relatively large Co content, a large average particle diameter of WC particles, or a large content of additive components, a reaction layer and a joint layer on the WC-based cemented carbide member A side Since the Ti—Co alloy layer is formed and the reaction layer, the Ti—Sn alloy phase, and the Ti—Co alloy layer are formed at the joint on the WC base cemented carbide member B side, the WC base cemented carbide member B An excessive increase in the layer thickness of the reaction layer formed on the side bonded portion can be suppressed, and a composite member excellent in high-temperature bonding strength of the bonded portion can be obtained.
And the cutting tool comprised from the said composite member does not produce the fracture | rupture from a junction part even if it is a case where it uses for the heavy cutting which a high load acts on a cutting blade, Over a long-term use It demonstrates excellent cutting performance.

It is the schematic diagram which showed the preparation process of the composite member of this invention, Comprising: (a) before joining, (b) at the time of solid phase diffusion joining and PTLP joining, (c) by solid phase diffusion joining and PTLP joining. The composite member after joining obtained is shown. It is an expansion schematic diagram of Drawing 1 (c), and shows the joint vicinity neighborhood expansion schematic diagram of the present composite member. FIG. 3 is an enlarged schematic diagram of FIG. 2, showing an enlarged schematic view of the vicinity of the joint portion on the WC-based cemented carbide member B side of the composite member of the present invention. An example of the cross-sectional SEM image of the junction part vicinity of the WC base cemented carbide member A side of the composite member of this invention is shown. An example of the cross-sectional SEM image of the junction part vicinity of the WC base cemented carbide member B side of the composite member of this invention is shown.

Next, the present invention will be specifically described based on examples.
In addition, the Example demonstrated below is one embodiment of this invention, Comprising: Specific embodiment of this invention is not restrict | limited to this.

WC powder, VC powder, TaC powder, ZrC powder, NbC powder, Cr ₃ C ₂ powder and Co powder are prepared as raw material powders. These raw material powders are blended into a predetermined blending composition and wet mixed in a ball mill for 24 hours. After being dried, it was press-molded into a green compact at a pressure of 100 MPa, and this green compact was sintered in a 6 Pa vacuum at a temperature of 1400 ° C. and a holding time of 1 hour. WC-based cemented carbide members a to h (hereinafter simply referred to as “carbide members a to h”) made of a sintered WC-based cemented carbide alloy were produced.

Next, cBN powder, TiN powder, TiCN powder, TiB ₂ powder, TiC powder, AlN powder, Al ₂ O each having an average particle size in the range of 0.5 to 4 μm as the raw material powder of the cBN sintered body ₃ powders were prepared, these raw material powders were blended in a prescribed composition, wet mixed with acetone for 24 hours in a ball mill, dried, and then pressure having a size of 15 mm diameter × 1 mm thickness at 100 MPa pressure. Press-molded into powder.
Next, the cemented carbide member for the backing material prepared above (hereinafter, the cemented carbide member for the backing material is referred to as “carbide member B”) is formed into a sintered body having a diameter of 15 mm × thickness of 2 mm. The cBN compact is laminated in the combination shown in Table 2 on the backing material, and the laminated material is then laminated at a temperature of 1300 using an ultra-high pressure generator. The composite sintered bodies C1 to C5 were manufactured by sintering under the conditions of ° C., pressure: 5.5 GPa, and time: 30 minutes.
Regarding the composition of the cBN sintered bodies of the composite sintered bodies C1 to C5, the area% of cBN was determined as the volume% by image analysis of the SEM observation result of the cross-section polished surface of the cBN sintered body.
About components other than cBN, it stopped only to confirm the component which comprises the main binder phase and other binder phases. The results are shown in Table 2.

Next, in order to produce this invention joining members 1-10, joining member D1-D3 which consists of a laminated body which laminated | stacked Sn foil on the single side | surface of Ti foil shown in Table 3, and Sn vapor deposition film on the single side | surface of Ti foil Bonding members D4 to D6 made of a laminated body in which were formed were prepared.
Moreover, for the comparative example described later, as a comparative example joining member, the joining member D7 consisting of only the Ti foil shown in Table 3 and the laminate obtained by laminating the Sn foil on both the front and back surfaces of the Ti foil, Ti foil A joining member D9 made of a laminate in which Sn vapor deposition films were formed on both front and back surfaces was also prepared.

Next, between the cemented carbide member (hereinafter referred to as “carbide member A”) serving as a base (base metal) and the composite sintered bodies C1 to C5 (the backing material is the cemented carbide member B), The present invention joining members D1 to D6 shown in Fig. 3 are inserted, and the conditions shown in Table 4 (that is, kept at a predetermined temperature in the range of 400 to 900 ° C for 5 to 600 minutes in a vacuum of 1 x 10 ^-1 Pa or less. Then, the composite sintered bodies C1 to C5 and the cemented carbide member A are joined under a condition in which a pressing force of 0.5 to 5 MPa is applied), so that the composite sintered bodies C1 to C5 side (i.e., super In the hard member B side), the reaction layer shown in Table 6, the Ti—Sn alloy phase, and the joint portion where the Ti—Co alloy layer is formed, and in the super hard member A side, which is the base (base metal), are shown in Table 7. The composite members 1 to 10 of the present invention having the joint portion in which the reaction layer shown and the Ti—Co alloy layer were formed were produced.
In the bonding, the composite sintered bodies C1 to C5 were arranged such that the cBN sintered body was the outer surface and the backing material was the inner surface. That is, the cemented carbide member B that is the backing material and the cemented carbide member A that is the base (base metal) are arranged so as to be joined via the joining member, and the joining member D1 is disposed on the cemented carbide member A side. On the other hand, the joining members were arranged on the cemented carbide member B side which is the backing material of the composite sintered bodies C1 to C5 so that the Sns of the joining members D1 to D6 face each other so that Ti of .about.D6 faces.
FIG. 4 shows an example of a cross-sectional SEM image (magnification: 10,000 times) in the vicinity of the bonded portion on the cemented carbide member A side that is the base (base metal) of the composite member of the present invention.
FIG. 5 shows an example of a cross-sectional SEM image (magnification: 10,000 times) in the vicinity of the joint on the cemented carbide member B side which is the backing material of the composite member of the present invention.

For comparison, the joining members D7 to D9 shown in Table 3 are used, and this is inserted between the cemented carbide member A and the composite sintered bodies C1 to C5 (the backing material is the cemented carbide member B). And the composite sintered compact and the cemented carbide member were joined on the conditions shown in Table 5, and the comparative example composite members 1-10 which have a junction part shown in Table 8 and Table 9 were produced.
The joint arrangement of the composite sintered body was the same as that of the composite member of the present invention.
Table 8 shows a reaction layer, a Ti—Sn alloy phase, and a Ti—Co alloy layer formed at the joint portion of the cemented carbide member B which is the backing material on the side of the composite sintered bodies C1 to C5. 2 shows a reaction layer, a Ti—Sn alloy phase, and a Ti—Co alloy layer formed at a bonding portion on the cemented carbide member A side that is a base (base metal).

Subsequently, with respect to the composite members 1 to 10 of the present invention, the components of the reaction layer adjacent to the composite sintered bodies C1 to C5 (that is, the reaction layer adjacent to the cemented carbide member B), the Ti—Sn alloy phase, and the Ti—Co alloy layer. The composition, the average layer thickness, and the component composition of the reaction layer and Ti—Co alloy layer adjacent to the cemented carbide member A, the average layer thickness, etc. are as follows using a scanning electron microscope and an Auger electron spectrometer. Measured and calculated.
Similarly, with respect to the composite members 1 to 10 of the comparative examples, the bonded portion adjacent to the cemented carbide member B of the composite sintered bodies C1 to C5, the reaction layer of the bonded portion adjacent to the cemented carbide member A, the Ti—Sn alloy phase, and Ti The component composition, average layer thickness, and the like of the -Co alloy layer were measured and calculated as follows using a scanning electron microscope and an Auger electron spectrometer.

First, for the vicinity of the boundary between the composite sintered bodies C1 to C5 and the joint, in other words, the vicinity of the boundary between the cemented carbide member B and the joint, a longitudinal section parallel to the thickness direction of the joint is observed. When viewed from the side of the hard member B, the critical position where WC crystal grains are observed was determined as the interface between the cemented carbide member B and the joint.
Next, a planar elemental analysis is performed from the interface to the direction perpendicular to the interface ± 50 μm. First, in the cemented carbide member B and the joint, a phase containing a metal W phase and a TiC phase is used as a reaction layer, and Ti A phase containing 65 to 85% of Sn and 15 to 35% of Sn was used as a Ti-Sn alloy phase, and a phase containing 45 to 75% of Ti and 25 to 55% of Co was used as a Ti-Co alloy layer. The identified Ti—Sn alloy phase and Ti—Co alloy layer are subjected to 10 point composition analysis, and the results of 10 points are averaged to obtain Ti, Sn content and Ti—Co alloy of the Ti—Sn alloy phase. The Ti and Co contents of the layer were calculated.
Next, for the reaction layer specified above, the layer thickness of the reaction layer was measured by the following method, the average layer thickness was obtained, and the interface length of the reaction layer was further obtained.
Using a scanning electron microscope and an Auger electron spectrometer, observe the longitudinal section of the vicinity of the boundary between the cemented carbide member B and the joint, and view the critical position where WC crystal grains are observed from the cemented carbide member B side. The interface between the member B and the joint is defined, a line segment is drawn from the interface in a direction perpendicular to the interface, and the thickness of the reaction layer is measured by performing a line analysis on 20 lines with an interval of 5 μm between the line segments. The average value of these measured values was determined as the average layer thickness of the reaction layer.
In addition, the triple point where the reaction layer composed of the metal W and the TiC layer, the Ti-Co alloy layer, and the three regions of the Ti-Sn alloy phase are adjacent at one point is specified, and the linear distance between the adjacent triple points is determined. Asked. When the Ti—Sn alloy phase exists on the same line, the straight line is the contact interface length of the Ti—Sn alloy phase. When the Ti—Sn alloy phase does not exist, the contact interface between the reaction layer and the Ti—Co alloy phase. It was a length. These two contact interface lengths were summed to determine the ratio from the relationship with the interface length of the reaction layer and the contact interface length of the Ti—Sn alloy phase. A schematic diagram of the measurement / calculation method is shown in FIG. In addition, when the Ti-Sn alloy phase was formed in layers and no triple point was present, the contact interface length ratio was set to 100% for convenience.
Also, the interface between the cemented carbide member B and the reaction layer is expressed as a curve, and a reference line approximately parallel to the interface that bisects the length ratio of the curve to 50:50 is drawn, and the interface is cemented with carbide from the reference line. If it is the member B side, the surface of the carbide member B at that location is a recess, and then a straight line perpendicular to the reference line is drawn, and when both the recess and the Ti-Sn alloy phase exist on the same line, It is assumed that a Ti—Sn alloy phase is formed on the concave portion of the surface of the cemented carbide member B. In a 2,000-fold cross-sectional SEM image, the number of locations where a Ti—Sn alloy phase was formed on the concave portion was determined.
Subsequently, the ratio of the longitudinal cross-sectional area of the Ti-Co layer located in the central part in the thickness direction of the joint in the longitudinal section of the entire joint was determined from the planar elemental analysis results.
Similarly, the average composition of Ti was determined from the elemental analysis results on the above-mentioned surface for the entire joint.
The above is the measurement and calculation method for the vicinity of the boundary between the composite sintered bodies C1 to C5 and the joint, that is, the joint on the cemented carbide member B side. The same measurement and calculation as described above were performed, and the component composition, average layer thickness, and the like of the reaction layer and the Ti—Co alloy layer were measured and calculated.
In addition, about the comparative example composite members 1-10, the junction part by the side of the carbide member A was measured by the method similar to the measurement and calculation about the junction part by the side of the carbide member B.
Tables 6 to 9 show the results.

Next, a cutting tool was produced from the composite members 1 to 10 of the present invention and the composite members 1 to 10 of the comparative example, and the presence or absence of occurrence of breakage in the cutting process was investigated, thereby evaluating the characteristics of the composite members 1 to 10 of the present invention. .
First, the cutting tool which consists of a composite member was produced as follows.
The composite sintered bodies C1 to C5 (carved with the carbide member B as the backing material) prepared above are cut into a plane shape: an isosceles triangle having an opening angle of 80 ° on one side and a thickness of 2 mm. did. Subsequently, the cemented carbide member A is a sintered body having a planar shape: 12.7 mm inscribed circle and an opening angle of 80 ° rhombus × thickness: 4.76 mm. A notch having a size corresponding to the shape of the composite sintered body was formed in one corner of any of the surfaces using a grinding machine. The area of the bottom surface of this notch is 2.96 mm ² and the area of the side surface is 4.89 mm ² . Next, the joining members D1 to D6 shown in Table 3 are inserted between the cemented carbide member A and the composite sintered bodies C1 to C5, and the composite sintered bodies C1 to C5 and the cemented carbide member are inserted under the conditions shown in Table 4. The present invention cutting tools 1 to 10 having an ISO standard / CNGA120408 insert shape are formed by press-bonding A, grinding the outer periphery of this composite member, and then performing a honing process of R: 0.07 mm on the cutting edge portion. Produced.
In the composite sintered bodies C1 to C5, the cBN sintered body is the outer surface, and the backing material (carbide member B) is the inner surface, that is, the backing material and the base (base metal) are joined via the joining member. Arranged.
Moreover, it confirmed that the junction part of these invention cutting tools 1-10 was substantially the same as this invention composite member 1-10 shown in Table 6, Table 7. FIG.
Similarly, the joining members D7 to D9 shown in Table 3 are inserted between the composite sintered bodies C1 to C5 produced above and the cemented carbide A produced above, and pressurization is performed under the conditions shown in Table 5. It joined and produced the comparative example cutting tools 1-10.
Moreover, it confirmed that the junction part of these comparative example cutting tools 1-10 was substantially the same as the comparative example composite members 1-10 shown in Table 8, Table 9.

High temperature shear strength measurement test:
About this invention composite member 1-10 produced above and comparative example composite member 1-10, in order to measure the intensity | strength of a junction part, the shear strength measurement test was done.
The test pieces used for the test were composite sintered bodies C1 to C5: 1.5 mm (W) × 1.5 mm (L) from the composite members 1 to 10 of the present invention and the comparative composite members 1 to 10 manufactured above. × 0.75 mm (H), Substrate (base metal) cemented carbide member A: 1.5 mm (W) × 4.5 mm (L) × 1.5 mm (H) cut out to measure shear strength A test piece was obtained.
The upper and lower surfaces of the test piece are clamped and fixed, and a prismatic pressing piece made of cemented carbide with a side of 1.5 mm is used. The ambient temperature is set to 600 ° C., and a load is applied near the center of the upper surface of the test piece. The load at which the test piece breaks was measured.
Table 10 shows the measured shear strength values.

Next, the cutting tools 1 to 10 and the comparative cutting tools 1 to 10 according to the present invention are shown below in the state in which the various cutting tools are all screwed to the tip of the tool steel tool with a fixing jig. A dry high-speed heavy cutting test of carburized and quenched steel was performed, and the presence or absence of the cutting edge and the location of the fracture portion were observed.
Work material: JIS / SCM415 (hardness: 58HRc) round bar,
Cutting speed: 260 m / min. ,
Cutting depth: 0.3 mm,
Feed: 0.4 mm / rev. ,
Cutting time: 16 minutes,
(Normal cutting speed and feed are 150 m / min and 0.2 mm / rev., Respectively)
Table 10 shows the cutting test results.

As shown in Table 10, the composite members 1 to 10 of the present invention have excellent shear strength, and the cutting tools 1 to 10 of the present invention composed of the composite members of the present invention 1 to 10 In addition, since it exhibits excellent cutting performance over a long period of use, it can be said that the joint portion of the composite member of the present invention has excellent high-temperature joint strength.
On the other hand, the comparative example composite members 1-10 are inferior in shear strength compared with this invention composite member 1-10, and the comparative example cutting tool 1 comprised from the comparative example composite members 1-10. In No. 10, the cutting edge comes off from the joint during cutting and the tool life is reached early, so it is clear that the high-temperature joint strength of the joint is inferior to the composite member of the present invention.

  In this embodiment, the insert has been described as an example of the cutting tool. However, the present invention is not limited to the insert, and all cutting tools having a joint between the cutting edge portion and the tool body, such as a drill and an end mill. Needless to say, the present invention is applicable to drilling tools such as bits.

The composite member of the present invention has high joint strength at high temperatures, and cutting tools made from this composite member should be used for high-load cutting such as high-speed heavy cutting of various steels and cast iron. In addition, since it exhibits stable cutting performance over a long period of time, it can sufficiently satisfy the high performance of cutting equipment, labor saving and energy saving of cutting, and further cost reduction. It is.

Claims (11)

A composite member in which a WC-based cemented carbide member A and a WC-based cemented carbide member B having different Co content, average particle size of WC particles, and content of additive components are joined via a joint. There,
(A) The joint has an average layer thickness of 1 to 50 μm, and contains Ti in an average composition of 60 to 99 atomic%,
(B) When the longitudinal cross section of the bonding interface between the WC-based cemented carbide member A and the joint is observed, the WC-based cemented carbide member A is adjacent to the WC-based cemented carbide member A and has an average layer thickness of 0.5 to 5 μm. In addition, a reaction layer containing a total of 90 atomic% or more of the metal W phase and the TiC phase is formed, and further, Ti is 45 to 75 atomic% from the reaction layer to the center side in the thickness direction of the joint. A Ti—Co alloy layer containing Co in an amount of 25 to 55 atomic% is formed;
(C) When a longitudinal section of the bonding interface between the WC-based cemented carbide member B and the joint is observed, the reaction layer and the Ti—Co alloy layer of (b) are formed, and the reaction layer and the A composite member characterized in that a Ti-Sn alloy phase containing 65 to 85 atomic% Ti and 15 to 35 atomic% of Sn is formed between the Ti-Co alloy layer. The WC-based cemented carbide member A is a WC-based cemented carbide member having a relatively large Co content or a WC particle having a larger average particle size than the WC-based cemented carbide member B. 2. The composite member according to claim 1, wherein the composite member is a base cemented carbide member or a WC-based cemented carbide member having a high content of additive components. The WC-based cemented carbide member A has a Co content of 10 to 30% by mass, a total content of VC, TaC, ZrC, NbC, and Cr ₃ C ₂ as additive components: 0 to 20% by mass, and the balance is WC. 3. The composite member according to claim 2, wherein the composite member is made of unavoidable impurities and has an average particle diameter of WC particles of 0.8 to 10 μm. The WC-based cemented carbide member B has a Co content of 4 to 12% by mass, a total content of VC, TaC, ZrC, NbC, and Cr ₃ C ₂ as additive components: 0 to 20% by mass, and the balance is WC. The composite member according to claim 2, wherein the composite member is made of unavoidable impurities, and an average particle diameter of the WC particles is 0.3 to 2 μm. When observing a longitudinal section parallel to the thickness direction of the joint contacting the WC-based cemented carbide member A and the WC-based cemented carbide member B, the area ratio occupied by the Ti-Co alloy layer is the joint area It is 1-10 area%, The composite member as described in any one of Claims 1 thru | or 4 characterized by the above-mentioned. Observe a longitudinal section parallel to the thickness direction of the joint portion in contact with the WC-based cemented carbide member B, and measure the interface length of the reaction layer and the interface length of the Ti—Sn alloy phase in contact with the reaction layer. 6. The composite according to claim 1, wherein a ratio of an interface length of the Ti—Sn alloy phase to an interface length of the reaction layer is 10 to 50%. Element. The composite member according to any one of claims 1 to 6, wherein the Ti-Sn alloy phase is intermittently formed between the reaction layer and the Ti-Co alloy layer. The Ti—Sn alloy phase is intermittently present between the reaction layer and the Ti—Co alloy layer so as to fill a concave portion on the surface of the WC-based cemented carbide member B. The composite member according to any one of claims 1 to 7. It is a joining member used for preparation of the composite member as described in any one of Claims 1 thru | or 8, Comprising: This joining member is 0 in any one of the surface of a Ti foil of 1-50 micrometers thickness, and a back surface. A laminated body in which Sn foils having a thickness of 1 to 5 μm are laminated, or a Sn vapor deposition film having a thickness of 0.1 to 5 μm on one of the front and back surfaces of a Ti foil having a thickness of 1 to 50 μm. A joining member comprising the formed laminate, and the thickness of the Sn foil or the Sn vapor deposition film in the laminate is 10% or less of the thickness of the Ti foil. A cutting tool comprising the composite member according to any one of claims 1 to 8. 11. The cutting tool according to claim 10, wherein a cutting tool cutting blade is formed on the WC-based cemented carbide member B side.