JP3903168B2 - Method for producing two-phase alloy foil comprising Ni3Al phase and Ni solid solution phase - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of this application relates to a method for manufacturing a two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase. More specifically, the invention of this application is excellent in high-temperature creep characteristics, and Ni ₃ Al phase and the Ni ₃ Al phase capable of producing foil of the two-phase alloy composed of two phases and Ni solid solution phase and Ni solid solution phase a method for producing a two-phase alloy foil made.
[0002]
[Prior art and its problems]
Ni ₃ Al is an intermetallic compound having an L1 ₂ type ordered structure, is what is known as a gamma 'phase of Ni-base superalloys. Unlike general metal materials, this Ni ₃ Al is an intermetallic compound with high high-temperature strength that increases in yield strength at higher temperatures and reaches 5 times the room-temperature strength at 800 ° C. Ni ₃ Al also has good oxidation resistance and corrosion resistance.
[0003]
On the other hand, Ni ₃ Al has the disadvantage that it is brittle at room temperature and cannot be plastically processed.
Therefore, the inventor of the invention of this application provides a method for producing Ni ₃ Al with improved room temperature ductility by unidirectional solidification such as a floating zone method, a Bridgman method, and a pulling method (Japanese Patent No. 1917916). . In this Ni ₃ Al manufacturing method, a Ni ₃ Al single phase is obtained by solidifying a Ni ₃ Al raw material at a crystal growth rate of 13 mm / hr or more at 1350-1500 ° C. and then strongly orienting it in the [111] direction. Growing columnar crystals. In order to obtain the Ni ₃ Al single phase, in the Ni ₃ Al manufacturing method, the Al content in the chemical composition of the raw material is in the range of about 12.1 to 14.9% by weight. The resulting Ni ₃ Al exhibits, for example, a large elongation of about 17% or more and has room temperature ductility.
[0004]
Further, the inventor of the invention of this application is based on the above Ni ₃ Al production method, has a chemical composition containing Ni as a main component and containing 12.8 wt% or more and 13.6 wt% or less of Al, and a thickness of 200 μm or less Ni ₃ Al foil and its manufacturing method are also proposed (Japanese Patent Laid-Open No. 2001-121202). Ni ₃ Al foil goes through the steps of making a raw material rod by arc melting, growing columnar crystal structure by unidirectional solidification at a speed of 25 mm by the floating method, etc., cutting out a plate sample, and cold working Manufactured.
[0005]
This Ni ₃ Al foil can be assembled into a honeycomb structure by laser welding (for example, JP-A-2001-138418), and the obtained Ni ₃ Al honeycomb structure is excellent in lightweight heat resistance together with a laminate structure, It is considered promising as a member for jet engines and automobile engines, as a carrier for automobile exhaust gas purification catalysts, and as a heat shielding material for space vehicles.
[0006]
However, in order to be able to put these honeycomb structures and laminate structures into practical use, it is necessary to realize ones with better high-temperature creep characteristics. At the same time, aspects such as production cost and production efficiency are issues to be considered.
[0007]
The invention of this application was made in view of the circumstances as described above, and is for producing a two-phase alloy foil having two phases of a Ni ₃ Al phase and a Ni solid solution phase, which is excellent in high-temperature creep characteristics. and an object to be achieved by providing a method for producing a two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase as possible.
[0008]
[Means for Solving the Problems]
The Ni ₃ Al phase is an intermetallic compound having a stoichiometric composition of Ni-13.3 wt% Al. The Ni solid solution phase is a phase in which Al is solid-solved up to 9.2 wt% (concentration at 1385 ° C.) in Ni, and has a face-centered cubic structure similar to Ni. It is already known that a two-phase alloy composed of two phases of Ni ₃ Al phase and Ni solid solution phase is superior in high-temperature creep characteristics to Ni ₃ Al single-phase alloy.
[0009]
However, the two-phase alloy, like the Ni ₃ Al single-phase alloy, was brittle at room temperature and could not be plastically processed. The cause of the brittleness is that it easily breaks grain boundaries.
[0010]
Therefore, the inventors of the invention of this application further studied a two-phase alloy composed of two phases of a Ni ₃ Al phase and a Ni solid solution phase in order to solve the above-mentioned problems. It has been found that it is possible to produce a two-phase alloy foil consisting of a Ni ₃ Al phase and a Ni solid solution phase, which is free from brittleness and has better high-temperature creep characteristics than a single-phase Ni ₃ Al foil. The invention of the application was completed.
[0011]
In addition, the inventors of the invention of this application may find that the precision casting method is effective as a method for manufacturing the Ni ₃ Al alloy foil as a large area foil that can be wide or long, or both. I found it. The precision casting method can cast a large size unidirectionally solidified ingot in a much shorter time than the floating zone method, and the resulting ingot is plate-like and is required for the floating zone method. There is an advantage that cold rolling can be performed as it is without the need for cutting such as electric discharge machining. By cold rolling, the production of two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase having a large area can be expected.
[0012]
That is, the invention of this application is composed of two phases consisting of a Ni ₃ Al phase and a Ni solid solution phase having a chemical composition comprising Ni as a main component, Al being 5.0 wt% or more and less than 12.2 wt% , and the balance being Ni. Ni ₃ Al phase and Ni solid solution phase, characterized by cold rolling a plate-shaped unidirectionally solidified ingot produced by precision casting of a phase alloy into a foil with a rolling rate of 90% or more and a thickness of 200 μm or less to provide 2 of congruent with gold leaf production how consisting of a.
[0013]
Hereinafter, a manufacturing method of the two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase of the invention of this application while showing Examples will be described in more detail.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Method for producing a 2 congruent gilt consisting of Ni ₃ Al phase and Ni solid solution phase of the invention of this application, as described above, as a main component Ni, an Al containing less than 5.0 wt% or more 12.2% by weight, the balance being Ni become chemical composition, the plate-like unidirectional solidification ingot produced by precision casting of two-phase alloys consisting of two phases of the Ni ₃ Al phase and Ni solid solution phase, as it is rolling rate of 90% or more, a thickness of 200μm or less Cold rolled into a foil.
[0015]
As described above, in order to obtain a high temperature creep characteristics, rather than Ni ₃ Al single phase, two-phase alloy foil with Ni ₃ Al phase consisting of two phases of Ni solid solution phase is effective. Therefore, in the manufacturing method of the two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase of the invention of this application, to unidirectional solidification, the content of Al in the chemical composition of an alloy mainly containing Ni 5.0 Weight% or more and less than 12.2% by weight.
[0016]
When the content of Al is less than 5.0 wt%, even if a two-phase alloy foil consisting of two phases of the Ni ₃ Al phase and Ni solid solution phase, high-temperature creep characteristics thereof, and Ni ₃ Al foil of the single-phase In comparison, it is not so good. When the Al content is 12.2% by weight or more, as described above, a single-phase Ni ₃ Al foil is obtained.
[0017]
The Ni ₃ Al phase and Ni solid solution phase and two-phase alloy foil production method consisting of the invention of this application, as described above, the unidirectional solidification ingot is by Ri work steel precision casting. The unidirectionally solidified ingot obtained by the precision casting method is much larger in size than the floating zone method and can be produced in a short time, as shown in the examples described later. The precision casting method, for example, there are various methods such as investment casting, and there is no particular limitation on the method in the manufacturing method of the two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase of the invention of this application .
[0018]
Further, the ingot obtained by the precision casting method has a plate shape, and there is no need for cutting such as electric discharge machining required for the floating zone method, and cold rolling can be performed as it is after unidirectional solidification. . The cold rolling, rolling rate of 90% or more, a two-phase alloy foil made of a thickness 200μm following Ni ₃ Al phase and Ni solid solution phase. As mentioned in the aforementioned Japanese Patent Laid-Open No. 2001-121202, the addition of boron is effective in improving the brittleness of Ni ₃ Al, but it is cold to foil with a rolling rate of 90% or more and a thickness of 200 μm or less. Rolling is impossible. This also applies to the Ni ₃ Al phase and a manufacturing method of the two-phase alloy foil consisting of Ni solid solution phase of the invention of this application.
[0019]
The lower limit that can be rolled Ni ₃ Al phase and Ni solid solution phase and the thickness of the lower limit of the two-phase alloy foil made of, namely the foil without such breakage is considered to be about 30μm in the present state of the art.
In the manufacturing method of the two-phase alloy foil consisting of Ni ₃ Al phase and Ni solid solution phase of the invention of this application,
Intermediate annealing can be performed during cold rolling. This intermediate annealing can be performed, for example, under conditions of 800 ° C. or more and 20 minutes or more, as described in the above-mentioned JP-A-2001-121202, and this intermediate annealing is performed during cold rolling. It is also possible to do this several times.
[0020]
【Example】
Ingots for precision casting were prepared by melting 20 kg of several types of alloys containing Ni as the main component and changing the Al content within a range of 5 wt% to less than 12.2 wt% in a high-frequency heating vacuum melting furnace. This ingot is solidified unidirectionally in the same high-frequency heating vacuum melting furnace based on the precision casting method, and has a plate-like single crystal or columnar crystal having a width of 50 mm, a length of 80 mm, and a thickness of 5 mm as shown in FIG. Got the ingot. Such a large-size unidirectionally solidified ingot cannot be produced by the floating zone method.
[0021]
FIGS. 2 (a), (b), (c), and (d) are photographs instead of drawings in which the metal structure of an ingot obtained by unidirectional solidification based on a precision casting method is observed with an electron microscope.
Fig. 2 (a) shows Ni-8.0wt% Al alloy, Fig.2 (b) shows Ni-9.2wt% Al alloy, Fig.2 (c) shows Ni-10.3wt% Al alloy, Fig.2 (d) shows Ni- It is the photograph which copied the metal structure of 11.5 weight% Al alloy.
In these photographs, the Ni ₃ Al phase is shown as a white and angular phase, the Ni solid solution phase is shown as a black matrix, and the resulting ingot is a two-phase alloy consisting of two phases, the Ni ₃ Al phase and the Ni solid solution phase. It is confirmed that there is. The above photographs also confirm that the volume and size of the Ni ₃ Al phase increase as the Al concentration increases. As described above, when the Al concentration exceeds 12.2% by weight, the Ni ₃ Al unit is increased. It is understood that this is a phase.
[0022]
Next, this ingot was rolled as it was to 300 μm using a four-high rolling mill at room temperature, and then rolled to a thickness of 90% or more and a thickness of 200 μm or less using a multi-stage carbide rolling mill.
[0023]
As shown in FIG. 3, the obtained metal foil had a mirror-like smooth surface with a metallic luster. This metal foil also had very small thickness variations in width and length. Note that the metal foil shown in FIG. 3 has a rolling rate of 95% and a thickness of 100 μm.
[0024]
4 (a) and 4 (b) are scanning electron micrographs in place of drawings of the surface structure of the obtained metal foil having a rolling rate of 95% and a thickness of 100 μm, and X-ray (220) pole figures of the metal foil. is there.
FIG. 4 (a) confirms the formation of a deformation band due to the cold rolling on the surface of the metal foil. Further, from FIG. 4 (b), it is confirmed that a texture is formed on the metal foil in which the (110) plane is aligned parallel to the surface of the metal foil. From this, it is considered that the obtained metal foil is not brittle even in the cold rolling state and exhibits sufficient bending ductility.
[0025]
Of course, the invention of this application is not limited by the above embodiments and examples. It goes without saying that various modes are possible for details such as conditions during the production of precision casting ingots, during unidirectional solidification, and further during cold rolling.
[0026]
【The invention's effect】
As described above in detail, the invention of this application can provide a foil of a two-phase alloy composed of two phases of a Ni ₃ Al phase and a Ni solid solution phase, which is excellent in high temperature creep characteristics and can be increased in area. 2-phase alloy foil consisting of the Ni ₃ Al phase and Ni solid solution phase is to enable the manufacture of large honeycomb structures and laminates structure size, therefore, such as improved reduction and production efficiency of the production cost of the Is expected to be achieved.
[Brief description of the drawings]
FIG. 1 is a photograph replacing a drawing showing an example of an ingot obtained by unidirectional solidification based on a precision casting method in Examples.
2 (a), (b), (c), and (d) are photographs in place of drawings in which the metal structure of an ingot obtained by unidirectional solidification based on a precision casting method is observed with an electron microscope.
In Figure 3 embodiment, it is a photograph instead of a drawing showing an example of a two-phase alloy foil comprising the obtained Ni ₃ Al phase and Ni solid solution phase by cold rolling.
FIGS. 4A and 4B are scanning electron micrographs in place of drawings of the surface structure of the obtained metal foil having a rolling rate of 95% and a thickness of 100 μm, and X-ray (220) poles of the metal foil. It is a figure.

Claims (1)

The Ni as a main component, contains less than 5.0 wt% or more 12.2% by weight of Al, the chemical composition and the balance Ni, manufactured by Ni ₃ Al phase and precision casting of two-phase alloys consisting of two phases of Ni solid solution phase Production of a two-phase alloy foil comprising a Ni ₃ Al phase and a Ni solid solution phase, which is obtained by cold-rolling a formed plate-like unidirectionally solidified ingot into a foil having a rolling rate of 90% or more and a thickness of 200 μm or less. Method.

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