JP6308424B2 - Fe-based damping alloy, method for producing the same, and Fe-based damping alloy material - Google Patents

Description

  The present invention relates to an Fe-based damping alloy having damping characteristics, a manufacturing method thereof, and an Fe-based damping alloy material.

  One of the measures to reduce machine vibration and noise is the application of damping alloys. A damping alloy is an alloy that absorbs vibration by converting vibration energy from outside into heat by internal friction, and has four types of composite type, ferromagnetic type, dislocation type, and twin crystal type depending on the mechanism of its damping property. It is roughly classified into types (see, for example, Non-Patent Document 1).

  A composite damping alloy is an alloy in which a parent phase and a second phase exist, and uses energy dissipation due to interactions such as plastic deformation, sliding, and viscous flow that occur at the interface between the parent phase and the second phase. . Examples include cast iron and Al—Zn alloy, but both of these vibration damping characteristics and strength are low.

  The dislocation type damping alloy obtains damping characteristics due to the static hysteresis type energy loss accompanying the dislocation from the fixing point. An example of the Mg alloy is superior to other alloys in terms of damping characteristics and weight, but on the other hand, the strength is low and the workability is also poor.

  A ferromagnetic vibration-damping alloy utilizes magnetic / mechanical static hysteresis energy loss accompanying irreversible movement of a domain wall (see, for example, Patent Document 1). Many of these alloys are Fe-based alloys such as Fe-Cr-Al-based alloys and 12Cr steel. These damping characteristics improve as the distortion amplitude increases. However, at a distortion amplitude larger than the saturation magnetostriction amount, the vibration energy absorbed by the movement of the domain wall is saturated, so that the damping characteristic is rather lowered (for example, non-patent) Reference 2). In addition, there is a problem that a change in the external magnetic field affects the damping characteristics.

  The twin-type damping alloy uses energy dissipation due to the movement of the transformation twin interface or the interface between the parent phase and the martensite phase. The main alloy systems include Mn-Cu system, Ti-Ni system, There is a Cu-Al-Ni system (see, for example, Patent Document 2). Twin-type damping alloys have high damping characteristics, and in addition, they are characterized by having excellent strength characteristics as damping alloys. Typical examples of these twin-type damping alloys include sonostone alloy (Mn-37Cu-4Al-3Fe-2Ni) and inclamute alloy (Cu-45Mn-2Al). An excellent Mn-20Cu-5Ni-2Fe alloy is disclosed.

  In recent years, the Fe-Mn-Al-Ni-based shape memory alloy disclosed in Patent Document 3 forms a thermoelastic martensitic structure including a large number of transformation twins. Application as an alloy is expected. However, when such a superelastic alloy is used for vibration control, vibration is suppressed by static hysteresis type energy loss accompanying the generation and disappearance of stress-induced martensite. The effect is not obtained. Further, it cannot be said that the effect of sufficient coarsening is obtained only by the simple solution treatment shown in Patent Document 3, and the damping characteristics are realized by realizing more remarkable crystal grain growth. It is necessary to improve.

JP 2001-134271 A JP 2009-174013 A International Publication WO2011 / 044605

: Koichi Sugimoto, Iron and Steel, 60 (1974), No. 14, p127. : Fukuboshi, Science and Education, 55 (2007), No. 9, p442.

  As described above, in the twin type damping alloy, Mn—Cu based alloy, Ti—Ni based alloy, and Cu—Al—Ni based alloy are listed as main alloy systems. If a damping alloy with a low raw material cost with Fe as the main element is developed, it can be expected to be applied to various fields as a more practical damping alloy. There are no examples of twin-type vibration-damping alloys. Although Fe-Mn-Al-Ni alloy is promising as a candidate material for Fe-based damping alloys, it is necessary to obtain a damping effect in a stress range lower than the transformation-induced critical stress in order to realize application as a damping alloy Therefore, it is necessary to absorb the vibration energy by the twin interface movement in the martensite. In addition, it cannot be said that a sufficient effect of coarsening is obtained only by a simple solution treatment, and the damping characteristics are improved by performing a heat treatment that enables more remarkable grain growth. There is a need.

  When using the damping alloy, the damping characteristic, which is an important characteristic at the time of use, is also important, but at the same time, it is necessary to consider the balance with the formability, which is an important characteristic at the time of manufacture. However, there are many alloy systems that have a problem in molding processability, such as the above-mentioned sonostone and inclamute alloy, and improvement of the characteristics regarding the molding processability has been demanded.

  The present invention has been made to solve the above problems, and has a Fe-based alloy composition, a twin-type vibration-damping alloy excellent in vibration-damping characteristics and workability, a method for producing the same, and a Fe-based vibration-damping alloy. The purpose is to provide materials.

That is, among the Fe-based damping alloys of the present invention, the first present invention contains 25 to 42 atomic% of Mn, 12 to 18 atomic% of Al, and 5 to 12 atomic% of Ni, and the balance. there have a composition consisting of Fe and unavoidable impurities, a thermoelastic martensitic structure containing metal structure transformation twinned, its grain size number is equal to or is -5.5 or less.

The Fe-based damping alloy of the second invention contains 25 to 42 atomic% of Mn, 12 to 18 atomic% of Al, and 5 to 12 atomic% of Ni, and further 0.1 to 5 atoms. % Si, 0.1-5 atomic% Ti, 0.1-5 atomic% V, 0.1-5 atomic% Cr, 0.1-5 atomic% Co, 0.1-5 atomic % Cu, 0.1-5 atomic% Mo, 0.1-5 atomic% W, 0.001-1 atomic% B, and 0.001-1 atomic% C. containing 15 atomic% or less of at least one total, it possesses the balance consisting of Fe and unavoidable impurities, a thermoelastic martensitic structure containing metal structure transformation twins, its grain size number -5.5 or less .

  The Fe-based vibration damping alloy of the third aspect of the present invention is characterized in that, in the first or second aspect of the present invention, the operating temperature range is from room temperature to a temperature range exhibiting a thermally induced martensite structure. And

  The Fe-based damping alloy of the fourth aspect of the present invention is characterized in that in the first to third aspects of the present invention, the Fe-based vibration-damping alloy has an FCC structure phase formed by precipitation.

A method for producing an Fe-based vibration damping alloy according to a fifth aspect of the present invention is the method for producing an Fe-based vibration damping alloy according to any one of claims 1 to 3, wherein the first or second aspect of the present invention is applied. It has the process of solution-treating at 1100-1300 degreeC with respect to the alloy which has this composition, It is characterized by the above-mentioned.

  According to a sixth aspect of the present invention, there is provided a method for producing an Fe-based vibration damping alloy, comprising the step of adjusting the composition in the fifth aspect of the present invention.

  According to a seventh aspect of the present invention, there is provided a method for producing an Fe-based vibration damping alloy according to the fifth or sixth aspect of the present invention, wherein the alloy having the composition of the first or second aspect of the present invention is 10 to 1100-1300 ° C. An initial heating step of heating and holding for at least minutes, an annealing step of gradually cooling the alloy heated in the initial heating step to a temperature range of 300 to 1000 ° C. at a cooling rate of 500 ° C./hour or less, and the annealing step And a reheating step in which the gradually cooled alloy is heated at a heating rate of 500 ° C./hour or less and heated and held at 1100 to 1300 ° C. for 10 minutes or more.

  According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the slow cooling step and the reheating step are alternately repeated a plurality of times after the initial heating step. It is characterized by.

  The manufacturing method of the Fe-based vibration damping alloy of the ninth aspect of the present invention includes the step of aging treatment at 100 to 350 ° C. after the solution treatment in any of the fifth to eighth aspects of the present invention. Features.

  The method for producing an Fe-based vibration damping alloy according to the tenth aspect of the present invention includes the step of aging treatment at 100 to 350 ° C. after the reheating step in any of the seventh to ninth aspects of the present invention. Features.

The Fe-based vibration damping alloy material of the eleventh aspect of the present invention is characterized by having a rod-like shape or a plate shape made of the Fe-based vibration damping alloy according to any one of the first to fourth aspects of the present invention.

  Next, the reason for limiting the component range in the present invention will be described below.

Mn: 25 to 42 atomic%
Mn is an element that promotes the formation of the martensite phase. By adjusting the content of Mn, the start temperature (Ms) and end temperature (Mf) of the martensite transformation, the start temperature (As) and end temperature (Af) of the reverse martensite transformation, and the Curie temperature (Tc) Can be changed. When the content of Mn is less than 25 atomic%, the BCC structure of the matrix phase is too stable, so that a martensite structure may not be formed at the use temperature. On the other hand, when it exceeds 42 atomic%, the parent phase does not have a BCC structure. The lower limit of the Mn content is preferably 30 atomic%, the upper limit is preferably 40 atomic%, the lower limit is more preferably 34 atomic%, and the upper limit is 38 atomic%. Is more desirable.

Al: 12-18 atomic%
Al is an element that promotes the generation of a parent phase having a BCC structure. When the Al content is less than 12 atomic%, the parent phase has an FCC structure. On the other hand, if it exceeds 18 atomic%, the BCC structure is too stable and no martensitic transformation occurs. The lower limit of the Al content is preferably 13, the upper limit is preferably 17 atomic%, the lower limit is more preferably 14 atomic%, and the upper limit is further 16 atomic%. desirable.

Ni: 5-12 atomic%
Ni is an element that precipitates a regular phase in the matrix and promotes the formation of thermoelastic martensite. When the Ni content is less than 5 atomic%, thermoelastic martensite cannot be obtained. On the other hand, if it exceeds 12 atomic%, the ductility is lowered. The upper limit of the Ni content is preferably 10 atomic%, more preferably 6 atomic%, and even more preferably 8 atomic%.

  Ductility and corrosion resistance are improved by containing a total of 15 atomic% or less of at least one element selected from the group consisting of Si, Ti, V, Cr, Co, Cu, Mo, W, B and C. At the same time, Ms and Tc can be changed by adjusting their contents. Co has an effect of improving magnetic characteristics. If the total content of these elements exceeds 15 atomic%, the alloy may become brittle. The total content of these elements is desirably 10 atomic percent or less, and more desirably 6 atomic percent or less.

  As described above, in the present invention, a thermoelastic martensitic structure including a large number of transformation twins is generated in an Fe-based alloy, and the crystal grains are coarsened by heat treatment. Offering became possible. Further, in the Fe-based vibration damping alloy of the present invention, the FCC phase generated by precipitation is excellent in workability, and therefore it becomes possible to obtain good forming workability by precipitating the FCC phase during cooling. .

It is a figure which shows the heat pattern at the time of the heat processing (initial heating process, slow cooling process, and reheating process) in one Embodiment of this invention. FIG. 2 is a drawing-substituting photograph showing an optical microscope of invention alloy 2 heat-treated under the conditions of FIG. 1 in an example of the present invention. It is the figure which showed the relationship between the temperature of invention alloy 2, and a loss coefficient. Similarly, it is the figure which showed the relationship between the final temperature of a slow cooling process, and a crystal grain diameter at the time of performing the heat processing of FIG. Similarly, it is the vibration damping characteristic test result of the sample which performed the heat processing of FIG. 1 by making final temperature of a slow cooling process into 900 degreeC with respect to invention alloy 2, and then aging-treated at 200 degreeC for 6 hours.

[Production method]
The Fe-based twin-type vibration damping alloy according to an embodiment of the present invention includes melt casting, forging, hot working (hot rolling, etc.), cold working (cold rolling, wire drawing, etc.), press working, etc. After forming into a desired shape by the above, it can be produced by applying a solution treatment. With respect to melting and processing of the alloy, the present invention is not particularly limited, and conventional methods can be employed.

The manufacturing process essentially includes a solution treatment process. The solution treatment is carried out by heating the Fe-based vibration-damping alloy that has been melt-cast and formed by hot and cold working or the like to the solution temperature to make the structure a matrix phase (BCC phase) and then rapidly cooling it. The solution treatment is desirably performed at 1100 to 1300 ° C., more preferably the lower limit is 1200 ° C. and the upper limit is 1250 ° C. If the solution treatment temperature is less than 1100 ° C., the crystal growth does not proceed due to the pinning effect of the FCC phase, which is the second phase. If the solution treatment temperature exceeds 1300 ° C., a liquid phase is generated. I can't get it.
In addition, it is desirable that the solution treatment is held by heating for 10 minutes or more. If the heating is maintained for less than 10 minutes, the solution cannot be sufficiently formed, and the crystal grain growth does not proceed.
The cooling rate in cooling after the solution treatment is preferably 200 ° C./second or more, and more preferably 500 ° C./second or more. Cooling can be performed by putting it in a refrigerant such as water or by air cooling.

Further, when the crystal grains are coarsened, an initial heating step of heating at the solution treatment temperature for 10 minutes or more, and a slow cooling step of gradually cooling the heated Fe-based alloy to a temperature range of 300 to 1000 ° C. It can also be produced by a solution treatment comprising a reheating step of reheating and holding the slowly cooled Fe-based alloy. The heat pattern during the heat treatment is shown in FIG.
The initial heating step and the reheating step are preferably performed at 1100 to 1300 ° C, more preferably the lower limit is 1200 ° C and the upper limit is 1250 ° C.
In the gradual cooling after the initial heating step, the cooling rate is desirably 500 ° C./hour or less, and more desirably 10 to 50 ° C./hour.
The FCC phase that precipitates with slow cooling exhibits a pinning effect, but in the reheating step, the pinning effect is reduced, resulting in rapid crystal grain growth. When the cooling rate exceeds 500 ° C./hour, the effect of coarsening cannot be obtained due to a decrease in the FCC phase precipitation amount.
In slow cooling, it may be slow cooled to any temperature of 300 to 1000 ° C., and the cooling rate thereafter is not particularly limited. Moreover, after slow cooling, you may transfer to a reheating process immediately.

  The cooling rate after reheating is desirably 200 ° C./second or more, and more desirably 500 ° C./second or more. Moreover, the cooling method can also be performed by water cooling or air cooling similarly to the above.

Repetition of heat treatment For the purpose of promoting crystal grain growth, the slow cooling step and the reheating step can be repeated. It is desirable to do.

  From the viewpoint of obtaining a precipitation strengthening effect by precipitation of B2 phase due to precipitation of NiAl or the like, it is desirable to further perform aging treatment at 100 to 350 ° C. after the solution treatment, and the lower limit of the aging treatment temperature is 150 ° C. and the upper limit is 250 ° C. It is more desirable to do so. The aging treatment time varies depending on the composition and temperature, but is preferably 5 minutes or more. If the aging treatment time is less than 5 minutes, the effect is insufficient. On the other hand, if it is too long (for example, several hundred hours), the ductility is lowered. For the same reason, it is more desirable that the lower limit of the aging treatment time is 30 minutes and the upper limit is 24 hours.

[Organization]
The Fe-based vibration damping alloy of the present invention undergoes martensitic transformation from the parent phase (α phase) of the BCC structure. In the temperature range higher than Ms, it has a matrix structure of the BCC structure, and in the temperature range lower than Mf, it has a martensite structure. In this alloy, since vibration is suppressed by movement of twin boundaries in the martensite structure, the alloy is preferably used in a temperature range where many martensite structures can be obtained. In the present alloy, a small amount of FCC structure γ phase generated by precipitation during cooling may be present. The γ phase precipitates mainly at the grain boundaries during cooling after the solution treatment or after the reheating step, or contributes to the improvement of ductility by precipitation at the solution treatment temperature or the reheating temperature. The characteristics are damaged. When the γ phase is precipitated to improve ductility, the volume fraction is preferably 10% or less, and more preferably 5% or less. The crystal structure of the martensite phase is a long-period structure such as 2M, 8M, 10M, or 14M.

Relationship with service temperature The Fe-based vibration damping alloy of the present invention exhibits a martensitic structure at room temperature. As a use temperature range of this invention, it can be used as a damping alloy in the temperature range which shows a martensitic structure from room temperature.

Description of B2 Phase In the Fe-based vibration damping alloy of the present invention, the B2 phase, which is one of the ordered phases, precipitates during the aging treatment after the solution treatment. Since the B2 phase exhibits a high precipitation strengthening action, it is desirable to exhibit a structure in which fine B2 phases are dispersed in the martensite phase or the BCC phase.

[Member made of Fe-based damping alloy]
Since the Fe-based damping alloy is rich in hot workability and cold workability, it can be easily formed into shapes such as bars and plates.

The rod material made of the Fe-based damping alloy preferably has an average crystal grain size dav equal to or larger than the radius R of the plate material, and more preferably dav ≧ 2R. A bar material satisfying the condition of dav ≧ 2R has a structure in which the grain boundary is located like a bamboo node, and the restraining force between crystal grains is reduced, so that excellent damping characteristics are exhibited.
Even if the condition of dav ≧ R or dav ≧ 2R is satisfied, since the crystal grains have a particle size distribution, there are crystal grains having a particle size d less than the radius R. In order to obtain an Fe-based damping alloy having better damping characteristics, the region where the crystal grain size d is the radius R or more is preferably 30% or more of the total length of the bar, and 60% or more. More preferred.

The plate material made of the Fe-based damping alloy preferably has an average crystal grain size dav equal to or greater than the thickness T of the plate material, and more preferably dav ≧ 2T. The plate material having such crystal grains is in a state where individual crystal grains are released from the grain boundaries on the surface of the plate material. A plate material satisfying dv ≧ T exhibits excellent vibration damping characteristics because the restraining force between crystal grains is reduced.
Even if the condition of dav ≧ T or dav ≧ 2T is satisfied, since the crystal grains have a particle size distribution, there are also crystal grains having a particle size d less than the thickness T. In order to obtain an Fe-based damping alloy having better damping characteristics, the region where the crystal grain size d is equal to or greater than the thickness T is preferably 30% or more of the total area of the plate material, and more than 60%. Is more preferable.
Bars and plates made of Fe-based damping alloys can be applied to machine tools such as lathes and milling machines, and industrial equipment such as various pumps, motors, and compressors by utilizing the damping characteristics.

Example 1
Table 1 shows the chemical compositions (remainder Fe and other inevitable impurities) of the inventive steel prepared as the test material and within the component range of the present invention, and the comparative steel outside the component range of the present invention.
The specimen was melted by VIM (vacuum induction melting) and subjected to heat treatment.
The heat treatment was performed in the pattern shown in FIG. 1, and the initial heating and the reheating conditions were maintained at 1200 ° C. for 1 hour. The cooling rate at the time of slow cooling and the subsequent heating rate were 25 ° C./hour and 50 ° C./hour, respectively, and the temperature at which the cooling was changed to heating was 900 ° C. After reheating, cooling by water cooling was performed. Further, after these heat treatments, an aging treatment was performed at 200 ° C. for 6 hours.
In each of the alloys according to the invention, the FCC phase was precipitated in the BCC phase as the parent phase during slow cooling, and these were re-dissolved in the subsequent heating process. For this reason, in these alloys, remarkable crystal grain growth has occurred. S. No. Coarse crystal grains of -7.5 to -7.0 were observed.

The loss factor of each test material was measured at room temperature by the one-end fixed impact test method of JIS G 0602 “Testing method of vibration damping characteristics of damping steel plate”. The results are shown in Table 1.
The inventive alloys generally showed higher loss factors than the comparative alloys.

Structure Evaluation FIG. 2 shows an optical microscope image of Invention Alloy 2 heat-treated under the conditions of FIG. A martensitic structure was observed on the entire surface of the sample, and it was confirmed that a thermoelastic martensitic structure was exhibited at room temperature, which is the main operating temperature range. Further, FCC phases precipitated at the grain boundaries were observed, and the area fraction was about 3%. Tan δ corresponding to the loss factor of the alloy was evaluated by viscoelasticity measurement using a viscoelasticity measuring device (DMS). Performed in tension mode under conditions of strain amplitude 1.0 × 10 ⁻⁴ , 2.0 × 10 ⁻⁴ and 4.0 × 10 ⁻⁴ , frequency 1 Hz, cooled from room temperature to −150 ° C. and then heated to 200 ° C. And measured. The measurement results are shown in FIG. Since tan δ shows a high value in the range of −150 to 200 ° C., the alloy of the present invention can be used as a damping alloy in this temperature range.

(Example 2)
Each Fe group was prepared in the same manner as in Example 1 except that the composition of Invention Alloy 2 produced in Example 1 was changed to a composition in which a part of Fe was replaced with the elements shown in Table 2 (fifth component). An alloy was made. The grain size numbers and loss factors of these alloys were measured in the same manner as in Example 1 and are shown in Table 2. Fe-based alloys whose elements such as Si, Ti, V, Cr, Co, Cu, Mo, W, B, and C have been added to improve corrosion resistance, strength, ductility, and the like are all the same as in invention alloys 1 to 4. Remarkable grain growth and high loss factor.

(Example 3)
FIG. 4 is a graph showing the relationship between the final temperature of the slow cooling step and the crystal grain size when the heat treatment of FIG. By performing the heat treatment of FIG. 1, remarkable coarsening is possible.

  FIG. 5 shows the vibration damping characteristic test result of a sample obtained by subjecting the invention alloy 2 to the heat treatment of FIG. 1 and setting the final temperature of the slow cooling step to 900 ° C. In the figure, for comparison, the loss coefficient when the solution temperature and the solution time are changed to be adjusted to about crystal grain size number 2 is also shown. It is clear that the coarsening under the conditions shown in FIG. 1 improves the damping characteristics and enables application as a damping alloy. In particular, more excellent results were shown in a frequency range of 100 Hz or less.

Example 4
A tensile test was performed on the inventive alloys 1 to 4 produced in Example 1 at room temperature. The test results are shown in Table 3. All showed tensile strength of about 650-750 MPa, and it was confirmed that it has the outstanding strength characteristic as a damping alloy. In this alloy, the B2 phase was precipitated by aging, and excellent strength was obtained by the precipitation strengthening action.

Claims (11)

25 to 42 and atomic% of Mn, and 12 to 18 atomic% Al, and contains a 5 to 12 atomic% of Ni, possess the balance consisting of Fe and unavoidable impurities, the metal structure transformation twins A Fe-based damping alloy, characterized in that it has a thermoelastic martensitic structure containing a crystal grain size number of −5.5 or less . Containing 25 to 42 atomic% of Mn, 12 to 18 atomic% of Al, and 5 to 12 atomic% of Ni, and further 0.1 to 5 atomic% of Si, 0.1 to 5 atomic% of Ti 0.1-5 atomic% V, 0.1-5 atomic% Cr, 0.1-5 atomic% Co, 0.1-5 atomic% Cu, 0.1-5 atomic% Mo 0.1 to 5 atomic% of W, 0.001 to 1 atomic% of B, and 0.001 to 1 atomic% of C. possess the balance consisting of Fe and unavoidable impurities, a thermoelastic martensitic structure containing metal structure transformation twinned, its grain size number is equal to or is -5.5 or less Fe Basic damping alloy.   The Fe-based damping alloy according to claim 1 or 2, wherein the temperature range from room temperature to a temperature range exhibiting a thermally induced martensite structure is used.   The Fe-based damping alloy according to any one of claims 1 to 3, wherein the Fe-based damping alloy has an FCC-structured phase formed by precipitation. It is a manufacturing method of the Fe-base damping alloy of any one of Claims 1-3 , Comprising: The process which carries out solution treatment at 1100-1300 degreeC with respect to the alloy which has a composition of Claim 1 or 2 A method for producing an Fe-based vibration damping alloy, comprising:   The method for producing an Fe-based vibration damping alloy according to claim 5, further comprising a step of adjusting the composition.   An initial heating step in which the alloy having the composition according to claim 1 or 2 is heated and held at 1100 to 1300 ° C for 10 minutes or more, and the alloy heated in the initial heating step is heated to a temperature range of 300 to 1000 ° C to 500 ° C. A slow cooling step of slow cooling at a cooling rate of ℃ / hour or less, and the alloy cooled in the slow cooling step is heated at a heating rate of 500 ℃ / hour or less and heated at 1100 to 1300 ° C for 10 minutes or more. A method for producing an Fe-based vibration damping alloy according to claim 5 or 6, further comprising a reheating step for holding.   The method for producing an Fe-based vibration damping alloy according to claim 7, wherein the slow cooling step and the reheating step are alternately repeated a plurality of times after the initial heating step.   The method for producing an Fe-based vibration damping alloy according to any one of claims 5 to 8, further comprising a step of aging treatment at 100 to 350 ° C after the solution treatment.   The method for producing an Fe-based vibration damping alloy according to any one of claims 7 to 9, further comprising a step of aging treatment at 100 to 350 ° C after the reheating step. An Fe-based damping alloy material having a rod-like shape or a plate shape made of the Fe-based damping alloy according to claim 1.