JP4436018B2 - How to use metal materials that can generate heat - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is heatable metallic materials, in particular, relates to the use how the metallic material capable of expressing actuator function due to heat generation.
[0002]
[Prior art]
Conventionally, it is a common sense of design that the structural material is not greatly deformed, and the movable part is divided, mechanically coupled, and mechanically operated by an actuator or the like. On the other hand, the present inventors proceeded with research and development of a material having an actuator function by actively causing deformation of a structural material, that is, an active material, and developed a laminated composite material having an actuator function ( For example, JP-A-10-138380.
[0003]
[Problems to be solved by the invention]
Conventional energization heating such as nichrome wire, tungsten wire, and molybdenum wire is used for energization to heat the CFRP / aluminum plate laminate and continuous SiC fiber / aluminum composite material, which are active materials developed by the present inventors. Carbon fiber, SiC fiber, etc. that are lighter than the wire rod are used.
[0004]
The present invention does not use expensive carbon fiber or SiC fiber, and has excellent bondability with matrix metal using metal fiber, and can produce heat-resistant metal material that can be manufactured at a light weight and low cost, and also exhibits excellent actuator function. An object is to provide a method for using and manufacturing a metal material that can be produced.
[0005]
[Means for Solving the Problems]
The present invention uses Ti having a specific resistance as large as 55 μΩ · cm (20 ° C.) as compared with iron group metals such as Fe, Co, Ni, and Al, and a small thermal expansion coefficient, as a line for heating and heating. The oxide film (TiO) formed by oxidizing the surface of the Ti wire is embedded in a metal matrix as an electrically insulating coating to form a Ti fiber composite metal material, which can generate heat only from a metal material using Ti as a heating wire. We found that a new metal material can be obtained.
[0006]
Also, by embedding continuous or discontinuous fibers with a smaller coefficient of thermal expansion than that of the metal matrix in this heat-generating metal material, it is possible to regulate the thermal expansion of the metal matrix due to heat generation, thereby providing an actuator function for the metal material. I found that I could grant it.
[0007]
Incidentally, the present inventor has previously developed a device to function as a strain sensor and a temperature sensor said insulated metal fibers by embedding the insulating metal fibers to the metal material (JP 2001-188027). This means, a portion of the insulating metal fibers when dielectric breakdown that part and contacts, together with the thermocouple is formed so that it is the temperature measured between the metallic material matrix surrounding the periphery thereof and a metal fiber, insulating By passing an electric current between the metal fiber and the matrix through the fracture, and detecting the expansion and contraction of the insulating metal fiber due to the strain applied to the matrix as an electrical resistance change, the temperature change and strain change of the metal-based material can be detected simultaneously. Measurement is possible.
[0008]
Therefore, if the above-mentioned Ti heating wire is used so as to function also as a strain sensor and a temperature sensor, it has an unprecedented multifunctional function including a heat generation function, an actuator function, a strain sensor function and a temperature sensor function. A metallic material can be provided.
[0009]
That is, first, the TiO ₂ and electrically insulating coating Ti continuous fibers forming the TiO ₂ film on a surface by oxidizing the surface (hereinafter referred to as "TiO ₂ / Ti fibers") without other insulated at least one current and heating TiO ₂ / Ti fibers striatum of, dielectric breakdown of the part of the TiO ₂ or TiO ₂ / Ti fibers TiO for at least one measuring tip and dielectric breakdown of the ₂ / Ti fiber filaments are embedded in a metal matrix made of aluminum or an aluminum alloy plate . At this time, vent conductive heating TiO ₂ / Ti fibers striatum, the both end portions so that the terminal by removing the TiO ₂ out to the outside of the metal matrix, said measuring TiO ₂ / Ti fiber linear The strip is embedded so that the dielectric breakdown portion is in the metal matrix and at least one of both end portions thereof is taken out of the metal matrix and the TiO ₂ is removed to form a terminal.
At the same time, a continuous metal or discontinuous fiber having a smaller coefficient of thermal expansion than that of the metal matrix is embedded and joined in a straight line in one direction to produce a composite metal sheet .
Plate-like metal material, since the curvature by the heating temperature is changed, the plate-like metal material, using a metallic structural materials, or machine element itself, through the terminal to TiO ₂ / Ti textile the electrical heating current Then, the TiO ₂ / Ti fiber is used as an energization heating element to apply a bending driving force due to heat generation to the metal-based structural material or machine element to develop an actuator function, and the measurement TiO ₂ / Ti fiber terminal and the metal matrix the electrically connected to the measuring instrument, monitor the deformation of the metallic structural materials or mechanical elements.
[0010]
As a result, a detection circuit for detecting the temperature of the breakdown portion is configured by a thermocouple formed between the TiO ₂ / Ti fiber and the metal matrix with the breakdown portion as a contact point. It can be used as a sensor to measure the temperature rise due to the heat generation and monitor the deformation of the metal-based structural material or machine element from the relationship between the measured temperature and the curvature.
In addition, since the current flowing through the dielectric breakdown portion is measured between the measurement TiO ₂ / Ti fiber filament and the metal matrix, a detection circuit is configured to detect the strain applied to the metal matrix as a change in electrical resistance. Using this detection circuit as a strain sensor, the change in electrical resistance due to the heat generation can be measured, and the deformation of the metal-based structural material or machine element can be monitored from the relationship between the measured resistance and curvature.
[0011]
In the present invention , the metal material capable of generating heat is provided with a U groove in a matrix made of aluminum or an aluminum alloy plate, and the TiO ₂ / Ti fiber is embedded in the U groove by hot pressing or casting, linearly provided U groove, can be prepared by conjugating the metal matrix by embedding into the U grooves small continuous fibers or discontinuous fibers having a thermal expansion coefficient than the metal matrix by hot pressing or casting-.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the method of using the metal material of the present invention, the oxide film formed on the surface of the Ti fiber used as the current heating wire and the temperature and strain measurement wire is thin but has an excellent electrical insulating property, and is a metal matrix. It has excellent bondability. Therefore, Ti continuous fiber (hereinafter referred to as “TiO ₂ / Ti fiber”) whose surface has been oxidized to form an insulating oxide film is firmly bonded to the matrix simply by being embedded in the metal matrix without any other insulation treatment. Thus, the oxide film (TiO ₂ ) functions as an electrical insulating layer.
[0013]
TiO ₂ / Ti fiber can be easily obtained by oxidizing a titanium wire in the atmosphere. For example, a pure titanium wire can be oxidized by an electric furnace in the atmosphere at a temperature of 873 to 1173 K and a holding time of 0.9 to 7.2 ks. In addition, film forming means such as electrolytic oxidation may be used. The titanium wire is not limited to a single titanium metal, but may be a Ti-6Al-4V alloy or other titanium alloy wires.
[0014]
Metal matrix materials include simple metals such as aluminum, magnesium, titanium, nickel, copper, and iron, and alloy materials thereof, or fibers of such simple metals and alloys such as silicon carbide, carbon, alumina, boron, and stainless steel. The target is fiber reinforced composite metal materials reinforced with materials.
[0015]
The platform that uses lightweight, high-strength (high specific strength) materials such as single metals such as aluminum, titanium and magnesium and their alloys as the metal matrix includes aerospace and high-speed vehicle structures and mechanical elements. When using a copper or copper alloy material that is suitable for use and excellent in electrical conductivity, uses such as electrical contacts are further expanded.
[0016]
Continuous fibers or discontinuous fibers for by regulating the thermal expansion of the metal matrix due to heating to impart actuator function metallic materials (hereinafter referred to as "activation") is as long as a small metal matrix by Rinetsu expansion coefficient However, it is appropriately selected depending on the application. For example, in the case of low cost, iron / iron alloy fiber, in the case of light weight, titanium / titanium alloy fiber, and in the case of high specific strength, ceramic fiber such as carbon fiber or SiC fiber may be selected. .
[0017]
To produce the metal material used in the method of use of the present invention, provided such as by cutting a U-shaped groove in the plate-shaped metal or alloy Matrix surface, insert the TiO ₂ / Ti fibers to the U groove, on its A plate-like metal or alloy matrix may be laminated and hot pressed. At this time, the TiO ₂ / Ti fiber filament for electric heating is inserted so that both end portions thereof are exposed to the outside of the matrix and become terminals, and the dielectric breakdown portion of the measurement TiO ₂ / Ti fiber filament is arranged in the matrix. And insert at least one of both end portions out of the matrix so as to be a terminal. It can be embedded in a metal matrix without damage by hot pressing under appropriate conditions. Instead of hot pressing, a casting method such as casting can be used.
[0018]
In addition, for activation, in addition to the U groove for embedding TiO ₂ / Ti fibers, a plurality of U grooves for embedding continuous fibers or discontinuous fibers having a smaller coefficient of thermal expansion than the metal matrix are provided in parallel in one direction. The continuous fiber or discontinuous fiber is inserted into the U groove. As a result, each continuous fiber or discontinuous fiber and the metal matrix are integrated into a plate shape.
[0019]
Although the metal matrix thermally expands due to self-heating or environmental temperature change caused by energizing the plate-like TiO ₂ / Ti fiber through a terminal, continuous fibers having a small coefficient of thermal expansion arranged linearly in one direction or The thermal expansion of the metal matrix is restricted in the length direction of the discontinuous fibers, and is not restricted in the direction perpendicular to the length direction. As a result, a plate-like actuator material is obtained in which a bending driving force is applied to the metal matrix and the curvature changes depending on the heating temperature of the metal material.
[0020]
Therefore, this metal material can be used as a metal-based structural material and the machine element itself, and can be changed into a desired shape by self-heating by energizing the TiO ₂ / Ti fiber or thermal deformation due to environmental temperature change. Therefore, it is possible to solve the problem of friction and wear due to the reduction of the weight of the metal-based structural material and mechanical elements by removing parts such as actuators and the removal of the joint.
[0021]
Ti fiber itself used as a filament for electric heating can also be used as a continuous fiber having a small coefficient of thermal expansion arranged linearly in one direction. In this case, a single fiber performs both functions of current heating and regulation of the thermal expansion of the metal matrix.
[0022]
Further, the metal material was heated at TiO ₂ / Ti fibers energization heating by using a measuring TiO ₂ / Ti fibers at least one of TiO ₂ / Ti fibers other than for electrical heating complexed joined to the metal matrix A strain and temperature sensing circuit can be constructed between the metal matrix . To configure the detection circuit, or a portion of the insulating oxide film of TiO ₂ / Ti fibers breakdown, or TiO ₂ / Ti a tip of the fiber insulation breakdown, insulating destruction unit in the metal matrix The TiO ₂ / Ti fiber is embedded in a metal matrix so as to be in a predetermined position and at least one of both end portions of the fiber is located outside the matrix, and bonded to the metal matrix to be combined.
[0023]
In order to break down, for example, a part of the insulating oxide film is cut with a cutter in the circumferential direction, or the tip of the TiO ₂ / Ti fiber is cut or slightly peeled off from the tip. What is necessary is just to expose the metal which is not covered with an oxide film. Further, masking may be performed before forming the oxide film, and the masking may be peeled off after forming the oxide film.
[0024]
To connect the metal matrix to the measuring instrument in order to form a strain and temperature detection circuit between the terminal and the metal matrix, with the portion located outside the metal matrix of the measurement TiO ₂ / Ti fiber as a terminal . It is preferable that the conductive metal tape is combined with the metal matrix so that a part of the conductive metal tape is located outside the metal matrix. Alternatively, the metal body may be directly sandwiched between clips.
[0025]
As a result, it is possible to carry out energization heating with the TiO ₂ / Ti fiber, and at the same time, it is possible to monitor the deformation of the structural material and the machine element by temperature measurement and resistance measurement. Therefore, TiO ₂ / Ti fiber not only functions independently as a heating element, but also is an excellent multifunctional fiber that can simultaneously realize a temperature sensor and a strain sensor. As extremely useful.
[0026]
As described above, the metal material having an actuator function used in the method of the present invention can impart a temperature sensor function and a strain sensor function to the TiO ₂ / Ti fiber in addition to the heat generation function, while being a metal material. Has a function similar to a living thing. That is, a metal having a high coefficient of thermal expansion corresponds to a muscle, a metal fiber or ceramic fiber having a smaller coefficient of thermal expansion corresponds to a skeleton, and the stimulus / energy for expanding and contracting the muscle is TiO ₂ for heating. Given by heating with Ti / Ti fiber and heat dissipation of muscle itself and cooling by use environment, the role of nerve to monitor the deformation of metal material is also the measurement of thermoelectromotive force with the same TiO ₂ / Ti fiber for measurement, resistance Can be accomplished by change measurement.
[0027]
Functional evaluation test (1) Production of TiO ₂ / Ti fiber: A pure titanium wire (purity: 99.5%) with a diameter of 0.15 mm was oxidized in an electric furnace in the atmosphere at a temperature of 1073 K and a holding time of 1.8 ks. A good TiO ₂ insulating oxide film with no damage was formed on the surface of the Ti fiber. The thickness of the TiO ₂ oxide film was 2.5 μm.
[0028]
(2) Production of metal material: As shown in FIG. 1, two U-grooves 2 having a depth of about 0.18 mm provided on an aluminum plate 1 having a thickness t = 0.4 mm, a width 30 mm, and a length 30 mm. each conduction heating TiO ₂ / Ti fibers 3, insert arranged measuring TiO ₂ / Ti fibers 3 ', overlay the aluminum plate having a thickness of t = 0.2 mm thereon, in air, the temperature 798K, pressure 16 Hot pressing was performed at 4 MPa for a time of 1.8 ks to form a TiO ₂ / Ti fiber composite metal material. Incidentally, it provided one central portion (Distance 15mm from both ends) notch in which dielectric breakdown and removal of the oxide film on the portion of A of the measuring TiO ₂ / Ti fibers 3 '. Further, two aluminum tapes 5 were interposed for thermoelectromotive force measurement up to a distance of 10 mm from the left end on the U groove 2.
[0029]
(3) Evaluation of heat generation function: As a result of investigating the relationship between the surface temperature and the time when the TiO ₂ / Ti fiber for energization heating is energized, the surface temperature rapidly increases immediately after the energization is started, and then becomes almost constant. I understood. After 2.4ks the current value is 0.9A or less surface temperature substantially constant, the current heating TiO ₂ / Ti fibers functioned stable as electrical heating element for heating the metallic material complexed.
[0030]
(4) Temperature measurement: A test piece 6 having a thickness t = 0.6 mm, a width 10 mm, and a length 30 mm shown in FIG. 2 is cut out from a metal material, and one end is heated and the other end is cooled to give a temperature gradient. It was. The aluminum tape 5 and the measurement TiO ₂ / Ti fiber 3 ′ extending out of the matrix of the metal material are connected to the measuring device 7, and the embedded measurement TiO ₂ / Ti fiber notch A (the center of the test piece) ) And the metal matrix were measured, and the temperature was calculated from the previously determined thermoelectromotive force characteristics. Further, the surface temperature of the specimen 6 was measured by a K thermocouple 8, it obtains a temperature just above the notch A of the measuring TiO ₂ / Ti fibers were compared with each other.
[0031]
(5) Strain measurement: As shown in FIG. 3, the width 10 mm of the center part of the tensile test piece 6 having a thickness t = 0.6 mm, a width 10 mm, and a length 30 mm cut out from the metal material is removed, and aluminum is provided at both ends thereof. A tab 9 was attached, and a tensile test was performed in the direction of arrow ← → using a strain gauge 10 at a tensile speed of 1 × 10 ⁻⁴ mm / s while monitoring the electrical resistance of the measurement TiO ₂ / Ti fiber 3 ′ .
[0032]
(6) Evaluation of heat generation function: TiO ₂ / Ti fiber for electric heating was cut into a length of 110 mm, and an oxide film at both ends 10 mm was removed to obtain a terminal. An electric current of 0.6 to 1.2 A was applied to this for 2.4 ks, and the surface temperature of the central portion of the TiO ₂ / Ti fiber for current heating at this time was measured with a K thermocouple 8.
[0033]
(7) Evaluation of temperature measurement function: As a result of measuring the thermoelectromotive force for aluminum of the measurement TiO ₂ / Ti fiber, the thermoelectromotive force monotonously increases as the temperature rises and functions as a temperature sensor, and the temperature measurement limit is It turned out to be around 700K.
[0034]
Using this characteristic, the temperature obtained from the thermoelectromotive force at the position of the notch A of the measurement TiO ₂ / Ti fiber embedded in the aluminum plate was 373 K, and the surface temperature of the test piece immediately above it was measured. The result was almost in agreement with the result of 370 K, and it was found that the measurement TiO ₂ / Ti fiber correctly measured the temperature of the notch A.
[0035]
(8) Evaluation of strain measuring function: The relationship between the strain of the test piece 7 and the electrical resistance of the measuring TiO ₂ / Ti fiber when the tensile test of aluminum embedded with the measuring TiO ₂ / Ti fiber was performed was examined. As a result, it was found that the electrical resistance increased almost linearly with increasing strain, and the TiO ₂ / Ti fiber functioned as a strain sensor.
[0036]
【Example】
Example 1
Production of active composite material: As shown in FIG. 4, an aluminum plate 1 having a thickness of 0.2 mm is provided with U-grooves 2 having a depth of about 0.18 mm at intervals of 1 mm, four TiO ₂ / Ti fibers 3 and aluminum. Three stainless steel wires 11 having a diameter of 140 μm, which has a smaller coefficient of thermal expansion than those, were alternately inserted and arranged. Of the four TiO ₂ / Ti fibers 3, the inner one was a TiO ₂ / Ti fiber having a circumferential notch .
[0037]
The upper superimposing an aluminum plate 4 with a thickness of t = 0.2 mm, the embedded hot pressing to four TiO ₂ / Ti fibers 3 with three stainless steel wire 11 under the same conditions as functional evaluation test Fibers A composite metal material was formed. As it was cooled from the flat state during hot pressing, it bent and deformed, and a metal material having a large curvature at room temperature was obtained. This metallic material, length 30mm shown in FIG. 5, was cut out 6 of width 8 mm, and connect the terminals of TiO ₂ / Ti fibers of the two outer for the energization on both sides of the copper foil 12, the inner A measuring TiO ₂ / Ti fiber terminal having a single circumferential notch and an aluminum tape 5 were connected to a measuring device 13 to measure thermoelectromotive force and electrical resistance.
[0038]
First, the current value of energization was set to 0.2 A, and all measurements (curvature of the test piece , surface temperature at the center of the test piece, TiO ₂ / Ti for measurement ) after 0.3 ks from the start of energization and 0.06 ks. The electrical resistance of the fiber and the thermoelectromotive force with respect to the matrix) were performed, and the current value was increased by 0.2 A after the completion, and the measurement was repeated.
[0039]
FIG. 6 shows the relationship between the surface temperature and the curvature (m ⁻¹ ) of the metal material when the embedded TiO ₂ / Ti fiber for energization heating is energized. As shown in FIG. 6, the curvature is maximum at room temperature, gradually decreases with increasing temperature, and returns to zero, that is, flat at about 520K. Therefore, it can be seen that the TiO ₂ / Ti fiber for electric heating functions as a heater for applying a bending driving force, that is, an actuator function to the metal material.
[0040]
FIG. 7 shows the relationship between the temperature measurement result with the measurement TiO ₂ / Ti fiber and the measurement result of the surface temperature with the K thermocouple when the metal material is energized with the TiO ₂ / Ti fiber for current heating . FIG. 7 shows that although the temperature rises to around 500K and the specimen is deformed until it is almost flat, the two are in good agreement, and the measurement TiO ₂ / Ti fiber is not deformed when the specimen is deformed. It can also be seen that the function as a temperature sensor is maintained.
[0041]
Furthermore, the value of the curvature of the metal material can be monitored by the temperature measured with this measuring TiO ₂ / Ti fiber . FIG. 8 shows the relationship between the surface temperature when a metal material is energized with TiO ₂ / Ti fibers for current heating and the electrical resistance value of the embedded measurement TiO ₂ / Ti fibers. It can be seen from the figure that the electric resistance value increases almost linearly with the measured temperature rise. The increase in the electrical resistance value is due to two factors, namely, the temperature rise of the metal material and the increase in strain due to the curvature change. Therefore, the curvature value can be monitored by the measured temperature, but the electrical resistance value itself. the available on the monitor of the value of the curvature of the metal material is also measured.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an arrangement of an aluminum plate and TiO ₂ / Ti fiber of a metal material for a function evaluation test .
FIG. 2 is a perspective view conceptually showing a temperature measurement method using a test piece cut out from a metal material for a function evaluation test . FIG. 3 is a cut out from a metal material for a function evaluation test . It is a conceptual perspective view which shows the distortion | strain measuring method using a test piece.
4 is a cross-sectional view showing an arrangement of an aluminum plate of metal material, TiO ₂ / Ti fiber, and stainless steel fiber of Example 1. FIG.
5 is a perspective view conceptually showing a thermoelectromotive force and electric resistance measurement method using a test piece cut out from the metal material of Example 1. FIG.
FIG. 6 is a graph showing the relationship between the surface temperature and the curvature of the metal material when the metal material of Example 1 is energized.
FIG. 7 is a graph showing the relationship between the surface temperature when the metal material of Example 1 is energized and the temperature obtained with TiO ₂ / Ti fibers.
FIG. 8 is a graph showing the relationship between the surface temperature when the metal material of Example 1 is energized and the electrical resistance value of the embedded TiO ₂ / Ti fiber.
[Explanation of symbols]
1 Aluminum plate
2 U groove
3, 3'TiO ₂ / Ti fiber
4 Aluminum plate
5 Aluminum tape
6 Test pieces
7 Measuring instrument
8K thermocouple
9 Aluminum tab
10 Strain gauge
11 Stainless steel wire
12 Copper foil
13 Measuring instrument
A Notch

Claims (3)

At least one in which the TiO ₂ and electrical insulating film without oxidizing the surface Ti continuous fibers forming the TiO ₂ film on the surface (hereinafter referred to as "TiO ₂ / Ti fibers") other insulated TiO ₂ / Ti fiber wire for heating and heating , and at least one TiO ₂ / Ti fiber wire for temperature measurement in which a part of the TiO ₂ is dielectrically broken or the tip of the TiO ₂ / Ti fiber is broken down And
To a metal matrix made of aluminum or aluminum alloy plate ,
The current heating TiO ₂ / Ti fiber filaments have both ends exposed to the outside of the metal matrix to remove the TiO ₂ as terminals, and the temperature measuring TiO ₂ / Ti fiber filaments are the dielectric breakdown. A portion within the metal matrix, and at least one of both end portions thereof is taken out of the metal matrix to remove the TiO ₂ and embedded as a terminal ,
A plate-like metal material whose curvature changes according to a heating temperature in which continuous fibers or discontinuous fibers having a thermal expansion coefficient smaller than that of the metal matrix are embedded and bonded together in a unidirectional linear form,
Used as metal-based structural material or machine element itself,
Energized through the terminal to the TiO ₂ / Ti textile said electric heating metallic structural materials, or by applying a driving force bending due to heating in the machine element to express actuator function TiO ₂ / Ti fibers as the energization heater in With
By a thermocouple formed between the TiO ₂ / Ti fibers and metal matrix the insulating lesion as a contact electrically connects the terminals and the metal matrix of TiO ₂ / Ti textile the temperature measurement instrument Using a detection circuit for detecting the temperature of the dielectric breakdown part as a temperature sensor , and monitoring the deformation of the metal-based structural material or machine element from the relationship between the measured temperature and curvature, a heat-generating metal material How to use. At least one Ti continuous fiber (hereinafter referred to as “TiO ₂ / Ti fiber”) having a TiO ₂ coating formed on the surface by oxidizing the surface and using the TiO ₂ as an electrical insulating coating without any other insulation treatment. TiO ₂ / Ti fiber filaments for current heating and at least one TiO ₂ / Ti fiber for electric resistance measurement in which a part of the TiO ₂ is dielectrically broken or the tip of the TiO ₂ / Ti fiber is broken down The streak
To a metal matrix made of aluminum or aluminum alloy plate,
The electrically heated TiO ₂ / Ti fiber filaments have both end portions taken out of the metal matrix to remove the TiO ₂ as terminals, and the electrical resistance measurement TiO ₂ / Ti fiber filaments are insulated from the insulation. The fracture portion is in the metal matrix, and at least one of both end portions is taken out of the metal matrix and the TiO ₂ is removed and embedded as a terminal ,
A plate-like metal material whose curvature changes according to a heating temperature in which continuous fibers or discontinuous fibers having a thermal expansion coefficient smaller than that of the metal matrix are embedded and bonded together in a unidirectional linear form,
Used as metal-based structural material or machine element itself,
Vent collector to the heating TiO ₂ / Ti fibers energized through a terminal with metallic structural materials, or by applying a driving force bending due to heating in the machine element to express actuator function TiO ₂ / Ti fibers as the energization heater ,
The electrical resistance measurement TiO ₂ / Ti fiber terminal and the metal matrix are electrically connected to a measuring instrument to measure the current flowing through the dielectric breakdown, and the strain applied to the metal matrix is defined as the change in electrical resistance. A method of using a metal material capable of generating heat, characterized by using a detection circuit for detection as a strain sensor and monitoring the deformation of the metal-based structural material or mechanical element from the relationship between measured electrical resistance and curvature. TiO ₂ The continuous fiber or discontinuous fiber having a smaller coefficient of thermal expansion than the Ti / Ti fiber and the metal matrix is embedded in a U-groove provided in the metal matrix by hot pressing or casting. A method of using the heat-generating metal material as described.

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