JP2017096887A - Hydrogen brittleness evaluation device and hydrogen brittleness evaluation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen brittleness evaluation device and a hydrogen brittleness evaluation method capable of evaluating hydrogen influence on peeling strength of a microstructure interface.SOLUTION: A device 100 is configured to evaluate a hydrogen brittleness characteristic of a test piece 1 formed with a minute cantilever 10 extending in a Y direction. The test piece 1 has only one microstructure interface 1b passing between a stationary end 10a and a free end 10b of the minute cantilever 10. The microstructure interface 1b is substantially perpendicular to the Y direction. The minute cantilever 10 has a first surface 10c formed on a surface 1a of the test piece 1, and a second surface 10d substantially perpendicular to the first surface 10c and substantially parallel with the Y direction. The minute cantilever includes: an electrolyte tank 2; a counter electrode 3; an external power supply 4; an indenter 5 provided on a free end 10b side with respect to the microstructure interface 1b on the second surface 10d, and configured to apply a load to a direction substantially perpendicular to the second surface 10d; and a measurement unit 6 configured to measure the displacement and the load of the indenter 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydrogen embrittlement evaluation apparatus and a hydrogen embrittlement evaluation method.

  It is known that metal materials such as high-strength steel, nickel alloy, and titanium alloy are broken by hydrogen that has entered from the environment (hydrogen embrittlement). In many cases, the fracture mode at this time is fracture at the crystal grain boundary. In addition, it has been reported that the boundary (heterophase interface) between the second phase and the parent phase such as inclusions becomes a fracture starting point. Therefore, in order to improve the hydrogen embrittlement resistance, a technique for evaluating the influence of hydrogen on the peel strength at the crystal grain boundary or the heterogeneous interface is required. In the following description, boundary surfaces appearing in metal structures such as crystal grain boundaries (including twin boundaries, random grain boundaries, etc.) and heterophase interfaces may be collectively referred to as “microstructure interfaces”.

  For example, in Patent Document 1, a bending test is performed by applying a load to a measurement specimen having a columnar support beam including a grain boundary, and the fracture characteristics are calculated from the load when the measurement specimen is broken. A method for measuring grain boundary fracture characteristics is disclosed.

JP 2014-174036 A

  However, the method described in Patent Document 1 is mainly intended for ceramic samples, and no investigation has been made on the evaluation of hydrogen embrittlement.

  Further, in clarifying the cause of peeling, it is important to know the plastic deformation state and the strain state of the plane perpendicular to the bending rotation axis (the axis serving as the center of bending). However, when the method described in Patent Document 1 is adopted, the support beam portion is bent toward the inside of the test piece. For this reason, it is impossible to know the plastic deformation state and the strain state of the plane perpendicular to the bending rotation axis by using electron beam backscatter diffraction (EBSD) or atomic force microscope (AFM).

  An object of the present invention is to solve the above problems and provide a hydrogen embrittlement evaluation apparatus and a hydrogen embrittlement evaluation method capable of evaluating the influence of hydrogen on the peel strength at the microstructure interface.

  The present invention has been made in order to solve the above problems, and the gist of the present invention is the following hydrogen embrittlement evaluation apparatus and hydrogen embrittlement evaluation method.

(1) An apparatus for evaluating hydrogen embrittlement characteristics of a test piece in which a microcantilever extending in one direction from a fixed end toward a free end is formed,
The test piece has only one microstructure interface passing between the fixed end and the free end of the microcantilever,
The microstructure interface is substantially perpendicular to the one direction;
The micro cantilever has a first surface formed on the surface of the test piece, and a second surface substantially perpendicular to the first surface and substantially parallel to the one direction,
An electrolytic bath for immersing the microcantilever in an electrolytic solution;
A counter electrode immersed in the electrolyte;
An external power source that generates a potential difference between the test piece and the counter electrode;
An indenter for applying a load in a direction substantially perpendicular to the second surface on the free end side of the microstructure interface of the second surface;
A measuring unit for measuring the displacement and load of the indenter;
A hydrogen embrittlement evaluation apparatus.

  (2) The hydrogen embrittlement evaluation apparatus according to (1), wherein the test piece has the microstructure interface on the fixed end side from the longitudinal center point of the microcantilever.

  (3) The notch is formed so as to extend from one end of the intersecting line to the other end along the intersecting line between the second surface and the microstructure interface. Hydrogen embrittlement evaluation equipment.

(4) A plurality of the cantilevers are formed on the test piece,
The hydrogen embrittlement evaluation apparatus according to any one of (1) to (3), wherein the microstructure interface passing through each microcantilever is the same.

  (5) The electrolyte bath has a through-hole at the bottom and is placed on the surface of the test piece via a sealing material surrounding the back surface of the through-hole to electrolyze the microcantilever The hydrogen embrittlement evaluation apparatus according to any one of (1) to (4), which is immersed in a liquid.

  (6) The hydrogen embrittlement evaluation apparatus according to any one of (1) to (5), further including a temperature adjustment unit that adjusts the temperature of the test piece.

(7) A method for evaluating hydrogen embrittlement characteristics of a test piece,
(A) a first surface extending in one direction from the fixed end toward the free end, a second surface formed on the surface of the test piece, and a second surface substantially perpendicular to the first surface and substantially parallel to the one direction A micro-cantilever having a plane, the test specimen has only one microstructure interface between the fixed end and the free end, and the microstructure interface is substantially perpendicular to the one direction. A step of forming
(B) immersing the microcantilever in an electrolyte;
(C) causing a potential difference between the test piece and a counter electrode immersed in the electrolytic solution, and electrochemically introducing hydrogen into the microcantilever;
(D) using an indenter, applying a load in a direction substantially perpendicular to the second surface to the free end side from the microstructure interface of the second surface;
(E) measuring the displacement and load of the indenter;
A method for evaluating hydrogen embrittlement.

  (8) In the step (a), a notch is formed so as to extend from one end of the intersecting line to the other end along the intersecting line between the second surface and the microstructure interface, (7) The hydrogen embrittlement evaluation method described in 1.

  (9) In the step (a), a plurality of micro-cantilever beams having only one micro-structure interface between the fixed end and the free end, and the micro-structure interface passing through each micro-cantilever The hydrogen embrittlement evaluation method according to the above (7) or (8), which is formed so as to be the same.

(10) A displacement and a load measured through the steps (a) to (e) for one micro cantilever of the plurality of micro cantilevers,
Comparing the displacement and load measured by the steps (a), (d) and (e) for the other minute cantilever beams among the plurality of minute cantilever beams,
The hydrogen embrittlement evaluation method according to (9), wherein the hydrogen embrittlement characteristics of the test piece are evaluated.

(11) Displacement and load measured by the steps (a) to (e) for one of the plurality of minute cantilevers,
Compare the displacement and load measured by the steps (a), (b), (d) and (e) for the other micro cantilever beams of the plurality of micro cantilever beams,
The hydrogen embrittlement evaluation method according to (9) or (10), wherein the hydrogen embrittlement characteristics of the test piece are evaluated.

  According to the present invention, it is possible to evaluate the influence of hydrogen on the peel strength at a boundary surface such as a grain boundary or a heterogeneous interface, and measure the plastic deformation state and strain state of a surface perpendicular to the bending rotation axis. It becomes possible to do.

It is the figure which showed typically an example of the hydrogen embrittlement evaluation apparatus which concerns on one Embodiment of this invention. It is the figure which showed typically the shape of the micro cantilever which concerns on one Embodiment of this invention, and the load direction of a load. It is the figure which showed typically the shape of the micro cantilever beam in a comparative example, and the load direction of a load. It is a figure for demonstrating typically the formation method of the notch in a comparative example. It is the figure which showed the relationship between the angle which the beam axis direction and the notch extension direction make, and the hardness in a notch bottom. It is a figure for demonstrating typically the formation method of the notch in one Embodiment of this invention. It is the figure which showed typically an example of the shape of a notch. It is the figure which showed typically an example of the shape of an indenter. In an Example, it is the figure which showed the dimension of the micro cantilever processed on the surface of the test piece. It is the figure which showed typically the slip line observed by AFM.

  A hydrogen embrittlement evaluation apparatus and an evaluation method using the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing an example of a hydrogen embrittlement evaluation apparatus 100 according to an embodiment of the present invention. FIG. 2 schematically shows the shape of the minute cantilever 10. A hydrogen embrittlement evaluation apparatus 100 according to an embodiment of the present invention includes a test piece 1 in which a microcantilever 10 extending in one direction (Y direction in FIG. 2) from a fixed end 10a toward a free end 10b is formed. An apparatus for evaluating hydrogen embrittlement characteristics. The minute cantilever 10 has a first surface 10c formed on the surface 1a of the test piece 1, and a second surface 10d substantially perpendicular to the first surface 10c and substantially parallel to the Y direction. The material of the test piece 1 is not particularly limited, and for example, a steel material or an alloy material can be used.

  As shown in FIG. 1, the hydrogen embrittlement evaluation apparatus 100 includes an electrolytic solution tank 2, a counter electrode 3, an external power supply 4, an indenter 5, and a measurement unit 6. That is, in the evaluation method according to an embodiment of the present invention, after forming the fine cantilever 10 having the first surface 10c and the second surface 10d described above (step a), the fine cantilever 10 is replaced with an electrolytic bath. 2 is immersed in the electrolytic solution 20 (step b), a potential difference is generated between the test piece 1 and the counter electrode 3 using the external power source 4, and hydrogen is electrochemically introduced into the microcantilever 10. In the state (step c), a load is applied to the second surface 10d by the indenter 5 in a direction substantially perpendicular to the second surface 10d (step d), and the displacement and the load of the indenter 5 are measured by the measuring unit 6. By (step e), it is possible to evaluate the hydrogen embrittlement characteristics of the test piece. Each component will be described in detail below.

  As shown in FIG. 2, in the microcantilever 10, the microstructure interface 1b of the test piece 1 passes through only one between the fixed end 10a and the free end 10b, and the microstructure interface 1b is in the Y direction. It is formed so as to be substantially perpendicular to. The microstructure interface 1b of the test piece 1 is preferably present on the fixed end 10a side with respect to the longitudinal center point of the microcantilever 10 and more preferably on the fixed end.

  Here, the “microstructure interface” in the present invention means a discontinuous surface appearing in a metal structure such as a steel material or an alloy material, for example, a crystal grain boundary (including a twin crystal interface, a random interface, etc.), Includes heterogeneous interfaces.

  Although there is no restriction | limiting in particular about the method of forming the micro cantilever 10, For example, laser processing and focused ion beam (FIB) processing can be used. Further, the cross-sectional shape of the minute cantilever 10 is not particularly limited as long as the first surface 10c and the second surface 10d are formed. In the case of forming by using the above method, a right triangle as shown in FIG. 2 is preferable because the processing time can be shortened.

  Furthermore, there is no restriction on the dimensions of the minute cantilever 10. As described above, since it is necessary to have only one microstructure interface 1b passing between the fixed end 10a and the free end 10b of the microcantilever 10, the crystal grain size of the test piece 1 or inclusions, etc. It is preferable to set the dimensions according to the size of the second phase.

  A notch 10e extending from one end of the intersecting line to the other end along the intersection line of the second surface 10d and the microstructure interface 1b so that peeling at the microstructure interface 1b is likely to occur during the bending test. May be formed. In the configuration according to the present invention, since the notch 10e is formed in the second surface 10d substantially perpendicular to the surface 1a of the test piece 1, not only can the damage to the notch bottom be prevented, but also the shape of the notch can be accurately determined. It becomes possible to apply with various dimensions. These effects will be described in detail below.

  As shown in FIG. 3, unlike the configuration according to the present invention, a load is applied to the first surface 10 c formed on the surface 1 a of the test piece 1 in a direction substantially perpendicular to the first surface 10 c by the indenter 5. Consider the case. In this configuration, as shown in the schematic diagram of FIG. 4, for example, FIB processing is performed along the intersection line of the first surface 10c and the microstructure interface 1b so that peeling at the microstructure interface 1b is likely to occur. Using this, the notch 10e is formed.

  Therefore, the direction of the FIB beam axis (Z direction in FIG. 4) and the direction in which the notch 10e extends (X direction in FIG. 4) are substantially perpendicular. As a result, since the ion beam is irradiated to the notch bottom, lattice defects such as dislocations are introduced, resulting in a problem that test accuracy is lowered. The relationship between the angle between the beam axis direction and the extending direction of the notch 10e and the influence of dislocations applied to the notch bottom will be described in more detail.

  FIG. 5 is a diagram showing a result of a microhardness test performed on the notch bottom when the notch is formed with the angle between the beam axis direction and the extending direction of the notch being 0 °, 45 °, and 90 °. It is. The notch was formed using FIB processing, and beam irradiation was performed so as to dig about 100 nm in a 20 μm square region at any of the above angles. The micro hardness test was performed using a nanoindentation device, and the hardness when the indenter indentation depth was 30 nm was measured.

  As can be seen from FIG. 5, the hardness tends to increase as the angle between the beam axis direction and the direction in which the notch extends increases as compared with the hardness of the sample surface subjected to electropolishing. This indicates that lattice defects such as dislocations are introduced by irradiating the notch bottom with an ion beam. On the other hand, in the configuration according to the present invention, as shown in the schematic diagram of FIG. 6, the direction of the FIB beam axis and the extending direction of the notch 10e are parallel (Z direction in FIG. 6). Damage to the bottom of the bottom can be minimized.

  In addition, the depth of the notch will be adjusted by changing the ion beam irradiation time, acceleration voltage, current, etc., but the strength of the specimen is often not uniform, and both sides of the microstructure interface are sandwiched. Since the strength may vary, it is difficult to form a notch with the intended dimensions. Further, the notch shape is also limited to a rectangle as shown in FIG.

  As shown in FIG. 7, there is a problem that stress is concentrated on the corner during the bending test because the corner has a corner. By adopting the configuration according to the present invention, not only can a U-shaped or V-shaped shape having a stress concentration portion at one point in the microstructure interface 1b, but also the dimensional accuracy can be greatly improved. To do.

  The electrolytic solution tank 2 is for immersing the fine cantilever 10 in the electrolytic solution 20 and electrochemically introducing hydrogen into the fine cantilever 10. Although there is no restriction | limiting in particular about the structure of the electrolyte solution tank 2, as shown in FIG. 1, the surface 1a of the test piece 1 is provided through the sealing material 2b which has the through-hole 2a in the bottom part and surrounds the back surface of the through-hole 2a. The cantilever 10 can be soaked in the electrolytic solution 20.

  The counter electrode 3 is immersed in the electrolytic solution 20. Then, a potential difference is generated between the test piece 1 and the counter electrode 3 by using the external power source 4, and the test piece 1 is set to a negative potential with respect to the counter electrode 3, thereby electrochemically hydrogenating the microcantilever 10. Is introduced. Although there is no restriction | limiting in particular about the material of the counter electrode 3, For example, platinum can be used.

  As shown in FIG. 1, the reference electrode 7 may be immersed in the electrolytic solution 20 together with the counter electrode 3 as necessary. Although only the counter electrode 3 can introduce hydrogen into the microcantilever 10 only by current control, the use of the reference electrode 7 makes it possible to introduce hydrogen even by potential control.

  The test piece 1, the counter electrode 3, and the reference electrode 7 are each connected to an external power source 4 via a conductive wire 40. When introducing hydrogen by controlling the potential, a potentiostat is used for the external power source 4. On the other hand, when hydrogen is introduced by current control, a galvanostat is used for the external power source 4 and the reference electrode 7 is omitted.

  Then, a bending test is performed by applying a load to the minute cantilever 10 using the indenter 5. Since the purpose is to evaluate the peel strength at the microstructure interface 1b, it is necessary to apply a load to the free end 10b side of the microstructure interface 1b of the microcantilever 10. In the configuration according to the present invention, a load is applied to the second surface 10d in a direction substantially perpendicular to the second surface 10d (X direction in FIG. 2). Therefore, the first surface 10c formed on the surface 1a of the test piece 1 is a surface substantially perpendicular to the direction of the bending rotation axis (Z direction in FIG. 2). This makes it possible to easily investigate the plastic deformation state and the strain state of the surface perpendicular to the bending rotation axis. There is no restriction | limiting in particular about the investigation method of a plastic deformation state and a distortion state, For example, the measurement using EBSD or AFM can be performed.

  Although there is no restriction | limiting in particular about the front-end | tip shape of the indenter 5, For example, as shown in FIG. 8, the tip is a cylindrical indenter (a), the conical indenter (b) whose opening angle is 60 ° or less, or one of the ridge lines A triangular pyramid shaped indenter (c) substantially parallel to the Z direction can be used. The material of the indenter 5 is not particularly limited, and for example, a diamond or ceramic indenter can be used.

  The displacement and load of the indenter 5 during the bending test are measured by the measuring unit 6. When the microstructure interface 1b peels, a discontinuous change occurs in the recorded load-displacement relationship. From the load at which this discontinuous change occurs, the peel strength at the microstructure interface 1b in the hydrogen environment is evaluated.

  Note that the apparatus according to an embodiment of the present invention may further include a temperature adjusting unit (not shown) that adjusts the temperature of the test piece 1. By providing the temperature adjustment unit, the temperature is the same in all experiments, the experiment conditions are aligned, or the various effects are repeated by changing the temperature, thereby affecting the influence of the temperature on the peel strength of the microstructure interface 1b. It becomes possible to evaluate.

  A plurality of micro cantilevers 10 may be formed on the surface 1 a of the test piece 1. By performing the above bending test on a plurality of microcantilevers 10, for example, investigating variation in results when the same experiment is performed a plurality of times, or verifying analysis accuracy, or under different environments It becomes possible to evaluate the influence of hydrogen in more detail by comparing the test results in. However, when forming a plurality of microcantilever beams 10, it is necessary to make the microstructure interface 1b passing through each microcantilever beam 10 have the same boundary surface in order to unify the experimental conditions.

  For example, in the case where a plurality of microcantilever beams are formed as described above, one of the microcantilever beams is in a state in which hydrogen is introduced by immersion in an electrolytic solution (the state after the above steps a to e). The other microcantilever beam is subjected to a bending test in the atmosphere (the state after the above steps a, d, and e) or in a state in which hydrogen is not introduced only by being immersed in the electrolytic solution (the above step a). , B, d and e), the hydrogen embrittlement characteristics of the test piece can be evaluated in more detail by comparing the displacement and load measured in each test. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples.

  The influence of hydrogen on peel strength was evaluated for the prior austenite (γ) grain boundaries of JIS SCM435 steel having the chemical composition shown in Table 1 and the twin interface of Ni—Cr alloy. The SCM435 steel had an old γ grain size of 40 μm and a tensile strength of 1488 MPa, and the Ni—Cr alloy had a grain size of 50 μm and a tensile strength of 600 MPa.

  Using an electron beam backscatter diffraction and FIB apparatus, the old γ grain boundary / twin interface that intersected the surface of the specimen perpendicularly was searched. For each test piece, a plurality of micro-cantilevers were processed using the FIB apparatus so that only the same old γ grain boundary / twin crystal interface was included. The dimension of the processed minute cantilever is shown in FIG. The length from the free end to the fixed end of the microcantilever was 20 μm, and the cross-sectional shape of the microcantilever was a right isosceles triangle with the width of the first and second surfaces being 4 μm. The distance between the old γ grain boundary / twin interface and the fixed end of the microcantilever is 2 μm, and a V-shaped notch (open) on the intersection line between the second surface and the old γ grain boundary / twin interface (Angle 60 °, notch depth 1.5 μm, notch bottom radius 0.5 μm).

Hydrogen was introduced into the test piece by immersing a counter electrode of platinum in the electrolytic solution. A borate buffer solution (pH: 8.6) was used as the electrolyte, the current density was 5.1 A / m ^2, and hydrogen was introduced under current control. A cylindrical diamond indenter with a diameter of 5 μm was used as the indenter. The indenter was displaced to a maximum displacement of 2 μm by displacement control at a position of 3 μm from the tip of the microcantilever, and the relationship between the load and the indenter displacement was measured. The bending test was performed on each test piece in an air atmosphere and a hydrogen atmosphere.

  Table 2 shows the presence or absence of cracking in the bending test. In SCM435 steel, when bending was applied in an air atmosphere, cracks were not observed until the maximum displacement, and when bending was applied in a hydrogen atmosphere, cracks occurred at the old γ grain boundary in the elastic region. did. On the other hand, in the Ni—Cr alloy, no crack was observed up to the maximum displacement in both the air atmosphere and the hydrogen atmosphere. Thus, it has been found that the peel strength of the old γ grain boundary of SCM435 steel is reduced by hydrogen. Further, it has been found that the twin interface of the Ni—Cr alloy has a sufficiently high peel strength even in a hydrogen atmosphere.

  Furthermore, the surface perpendicular to the bending axis of the microcantilever after the bending test was measured by AFM and EBSD. As a result, since the measurement surface was parallel to the test piece surface, both an AFM image and an EBSD image were easily obtained. As a result, for example, in a Ni—Cr alloy microcantilever bent in a hydrogen environment, as shown in the schematic diagram of FIG. It was found that a slip line was formed. Moreover, it was found from the acquired EBSD image that the plastic deformation was particularly large in the crystal grains near the twin interface.

  According to the present invention, it is possible to evaluate the influence of hydrogen on the peel strength at a boundary surface such as a grain boundary or a heterogeneous interface, and measure the plastic deformation state and strain state of a surface perpendicular to the bending rotation axis. It becomes possible to do.

Claims (11)

An apparatus for evaluating hydrogen embrittlement characteristics of a test piece formed with a microcantilever extending in one direction from a fixed end toward a free end,
The test piece has only one microstructure interface passing between the fixed end and the free end of the microcantilever,
The microstructure interface is substantially perpendicular to the one direction;
The micro cantilever has a first surface formed on the surface of the test piece, and a second surface substantially perpendicular to the first surface and substantially parallel to the one direction,
An electrolytic bath for immersing the microcantilever in an electrolytic solution;
A counter electrode immersed in the electrolyte;
An external power source that generates a potential difference between the test piece and the counter electrode;
An indenter for applying a load in a direction substantially perpendicular to the second surface on the free end side of the microstructure interface of the second surface;
A measuring unit for measuring the displacement and load of the indenter;
A hydrogen embrittlement evaluation apparatus.   2. The hydrogen embrittlement evaluation apparatus according to claim 1, wherein the test piece has the microstructure interface on a fixed end side with respect to a longitudinal center point of the minute cantilever. 3.   The hydrogen embrittlement evaluation according to claim 1 or 2, wherein a notch is formed so as to extend from one end of the intersection line to the other end along the intersection line between the second surface and the microstructure interface. apparatus. A plurality of the cantilever beams are formed on the test piece,
The hydrogen embrittlement evaluation apparatus according to any one of claims 1 to 3, wherein the microstructure interface passing through each minute cantilever is the same.   The electrolyte bath has a through-hole at the bottom, and is placed on the surface of the test piece via a sealing material surrounding the back surface of the through-hole, and the microcantilever is immersed in the electrolyte The hydrogen embrittlement evaluation apparatus according to any one of claims 1 to 4.   The hydrogen embrittlement evaluation apparatus according to claim 1, further comprising a temperature adjustment unit that adjusts a temperature of the test piece. A method for evaluating the hydrogen embrittlement characteristics of a test piece,
(A) a first surface extending in one direction from the fixed end toward the free end, a second surface formed on the surface of the test piece, and a second surface substantially perpendicular to the first surface and substantially parallel to the one direction A micro-cantilever having a plane, the test specimen has only one microstructure interface between the fixed end and the free end, and the microstructure interface is substantially perpendicular to the one direction. A step of forming
(B) immersing the microcantilever in an electrolyte;
(C) causing a potential difference between the test piece and a counter electrode immersed in the electrolytic solution, and electrochemically introducing hydrogen into the microcantilever;
(D) using an indenter, applying a load in a direction substantially perpendicular to the second surface to the free end side from the microstructure interface of the second surface;
(E) measuring the displacement and load of the indenter;
A method for evaluating hydrogen embrittlement.   8. The hydrogen according to claim 7, wherein, in the step (a), a notch is formed so as to extend from one end of the intersecting line to the other end along the intersecting line between the second surface and the microstructure interface. Brittleness evaluation method.   In the step (a), a plurality of microcantilever beams having only one microstructure interface between the fixed end and the free end, and the microstructure interfaces passing through the microcantilever beams are the same. The hydrogen embrittlement evaluation method according to claim 7 or 8, wherein the hydrogen embrittlement evaluation method is formed as described above. Displacement and load measured through the steps (a) to (e) for one micro cantilever of the plurality of micro cantilevers,
Comparing the displacement and load measured by the steps (a), (d) and (e) for the other minute cantilever beams among the plurality of minute cantilever beams,
The hydrogen embrittlement evaluation method according to claim 9, wherein the hydrogen embrittlement characteristics of the test piece are evaluated. Displacement and load measured by the steps (a) to (e) for one micro cantilever of the plurality of micro cantilevers,
Compare the displacement and load measured by the steps (a), (b), (d) and (e) for the other micro cantilever beams of the plurality of micro cantilever beams,
The hydrogen embrittlement evaluation method according to claim 9 or 10, wherein the hydrogen embrittlement characteristics of the test piece are evaluated.

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