JPH0260747B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a Ni-based alloy having excellent strength and high ductility. (Prior Art) Ni-based alloys, particularly Ni-based alloys having L1 ₂ type intermetallic compounds, are well known. For example, according to the equilibrium phase diagram of the conventional Ni-Al binary alloy,
At room temperature, Al in the range of about 23 to 28 at%
When Ni ₃ Al and Ni coexist, at less than about 8 atomic %, it is a Ni solid solution containing Al as a solid solution. Among the Ni-based alloys having this L1 type ₂ intermetallic compound, Ni ₃ Ge, Ni ₃ Si,
Those containing compounds such as Ni ₃ Al are Trans, JIM,
20 (1979) 634, Trans, JIM, 21 (1980) 273, it has the characteristic that its strength at high temperatures is higher than that at room temperature, and its usefulness at high temperatures has attracted attention. ing. (Problem to be solved by the invention) However, conventional L1 type ₂ intermetallic compound Ni-based alloys
Since the crystal structure is ordered close to the melting point, it is brittle at room temperature and cannot be processed using general metal processing methods such as rolling or wire drawing. For this reason, Ni-based materials cannot be formed using methods other than casting.
Although much research is being conducted on imparting ductility at room temperature to Ni-based alloys containing L1 ₂ type intermetallic compounds, as described in Journal of the Japan Institute of Metals 43 (1979) 358, 1190, L1 ₂ type intermetallic compounds There is only a report on improving the ductility at room temperature by adding B to the intermetallic compound Ni ₃ Al. According to this method, the brittle L1 ₂ type Ni ₃ Al intermetallic compound has high ductility due to the addition of B, and its breaking strength and elongation are also improved. However, this mechanical property was not very good, and it was not practical. On the other hand, basic research using single crystals is also being conducted on B-2 type intermetallic compounds, but like the L1 ₂ type intermetallic compounds, they are brittle and cannot be plastically worked, so they are currently used in alnico magnets, etc. It is simply used in its fragile state. Also, recently, Fe
- There is a report that a B-2 type intermetallic compound with stickiness and high electrical resistance was obtained by rapidly solidifying Cr-Al-Nb alloys using the liquid quenching method (Japan Institute of Metals Spring Academic Society, 1982 Summary Collection P249). (Means for Solving the Problems) The present inventors first discovered that an L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound having high strength and high ductility could be obtained by using a liquid quenching method, and the patent Although the application was filed (Japanese Patent Application No. 57-36226), we continued to develop Ni-based alloys with even higher strength, good ductility, and excellent economic efficiency, oxidation resistance, corrosion resistance, and electromagnetic properties. As a result of extensive research, we found that when a molten Ni-based alloy with a specific composition is rapidly solidified, B
- It has a mixed structure of type 2 non-equilibrium intermetallic compound and L1 ₂ type Ni ₃ Al nonequilibrium intermetallic compound, and L1 ₂ type
The present invention was completed based on the discovery that a Ni-based alloy having even higher strength and ductility than the Ni ₃ Al non-equilibrium intermetallic compound single-phase alloy can be obtained. That is, in the present invention, Al is 8 atomic % or more, 30
less than atomic %, and at least one of Fe and Co is more than 25 atomic % and 70 atomic % or less (Fe is 30 atomic % or more and 70 atomic % or less, Co is more than 25 atomic % and 70 atomic % or less) ), and the remainder is essentially
High strength and high ductility Ni-based alloy consisting of Ni and having a mixed structure of B-2 type non-equilibrium intermetallic compound and L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound, and Al content of 8 at% or more , less than 30 atom%,
At least one of Fe and Co is more than 25 atomic %,
70 atomic% or less (Fe is 30 atomic% or more and 70 atomic% or less, Co is more than 25 atomic% and 70 atomic% or less), Nb, Ta, Mo, V, Ti, Mn,
A total of 2.0 at% of one or more elements selected from the group consisting of Cr, Zr, W, Si, Y, and Cu
In the following, a high-strength and high-ductility Ni base with the remainder essentially consisting of Ni and a structure consisting of a mixed structure of a B-2 type non-equilibrium intermetallic compound and a L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound will be described. The main focus is on alloys. Since the alloy of the present invention is in the low Al, high Fe, and high Co content regions,
The structure is a mixture of L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound crystal grains, and the crystal grain size is even finer, less than 1 μm, compared to the L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound single phase alloy. Has high strength. To explain the structure of the alloy of the present invention, it is necessary that the Al content is 8 atomic % or more and less than 30 atomic %. If the Al content is less than 8 atomic %, it becomes a Ni solid solution containing Al as a solid solution, and B- A type 2 non-equilibrium intermetallic compound cannot be obtained, and if Al is more than 30 at%, a single phase B-2 type intermetallic compound or a B-2 type intermetallic compound is obtained.
-The structure becomes brittle and impractical because the L1 ₂ type Ni ₃ Al intermetallic compound is precipitated at the grain boundaries of the type 2 intermetallic compound. Next, regarding Fe and Co, at least one of Fe and Co is more than 25 at% and 70 at% or less (Fe
is more than 30 atom% and less than 70 atom%, and Co is 25
If Fe is 30 atomic % or less and Co is 25 atomic % or less, L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound single phase structure will be formed. , strength is not improved. Also,
When Fe is more than 70 atomic%, FeAl and Fe ₃ Al are precipitated, and when Co is more than 70 atomic%, L1 ₂ type Ni ₃ Al intermetallic compound is precipitated at the grain boundaries. They form a compound between the two, and both become brittle. In particular, in the alloy of the present invention, for example, in the Ni-Al-Fe ternary alloy, Al16-29 at%, Fe30-40 at%,
In the Ni-Al-Co ternary alloy, Al16-29 atomic%,
An alloy consisting of 30 to 60 atomic % of Co and the balance substantially of Ni is preferable because it has significantly higher strength than the L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound single phase alloy. The alloy of the present invention includes Nb, Ta, Mo, V, Ti, Mn,
A total of 2.0 at% of one or more elements selected from the group consisting of Cr, Zr, W, Si, Y, and Cu
If added below, strength can be further improved without reducing ductility. In addition, impurities present in ordinary industrial materials, such as B, P,
Even if As, S, etc. are contained in small amounts, this does not pose any problem in achieving the present invention. Next, in order to obtain the alloy of the present invention, it is desirable to melt the alloy having the composition adjusted as described above by heating in an atmosphere or in a vacuum, and rapidly solidify the melted liquid state. For example, a liquid quenching method with a cooling rate of about 10 ⁴ -10 ⁶ °C/sec is useful. Moreover, when the shape of the obtained alloy requires a flat ribbon shape, it is desirable to use one of the single roll method, twin roll method, or centrifugal quenching method using rotating rolls made of metal.
Further, in order to obtain a thin wire-shaped alloy having a circular cross section, it is desirable to directly jet the molten metal into a rotating cooling liquid and rapidly solidify it. In order to manufacture alloys with particularly high-quality circular cross sections, molten metal is jetted from a spinning nozzle into a rotating cooling liquid formed in a rotating cylinder and rapidly solidified, which is the so-called rotating liquid spinning method (Japanese Patent Application Laid-open No. 55-69948) is industrially more preferred. As mentioned above, the alloy of the present invention has excellent workability at room temperature and can be cold rolled and cold drawn.
In particular, thin wire-shaped alloys can be continuously cold-drawn using a regular die to achieve a reduction in area (reduction ratio) of 80% or more, and the tensile strength can also be dramatically improved. (Example) Next, the present invention will be specifically explained using examples. Examples 1 to 10, Comparative Examples 1 to 6 Ni-Al-Fe and Ni-Al- consisting of various compositions
After melting the Co-based alloy in an argon atmosphere, the pore size
Using a ruby nozzle with a diameter of 0.3 mm, argon was jetted onto the surface of a 200 mm diameter steel roll (3500 rpm) rotating at an argon jet pressure of 2.0 Kg/cm ² to create a ribbon approximately 50 μm thick and approximately 2 mm wide. This sample was tested using an Instron tensile tester at a strain rate of 4.17 at room temperature.
×10 ^-4 /sec, 180° close bendability was measured as an evaluation of breaking strength and ductility, and at the same time, the crystal structure was identified by X-ray diffraction and transmission electron microscopy, and the results are shown in Table- They are summarized in 1.

【table】

[Table] From Table-1, Experiment Nos. 2 to 3, 7 to 9, and 12 to 13 are alloys of the present invention, which have a fine grain size of 0.1 to 3 μm, and are B-2 type non-equilibrium intermetallic compounds. and L1 type ₂ Ni ₃ Al
It was a mixed phase structure of non-equilibrium intermetallic compounds. In particular, in Experiment No. 2, the compound particle size was as fine as 0.2 μm or less, and it had high strength and high ductility. experiment
No.10 has a small amount of Al, so it becomes a solid solution of Ni,
The breaking strength was low. Also, experiment No. 1, 4, 6,
11 has a large amount of Al, Fe, and Co, respectively, so the crystal structure is a B-2 type intermetallic compound phase with L1 ₂ type Ni ₃ Al intermetallic compound precipitated at the grain boundaries, and the crystal structure is a B-2 type intermetallic compound phase with a high degree of order. Due to the precipitation of FeAl, the ductility was almost completely lost, making it impractical. Experiment No. 5 is L1 type ₂ due to the small amount of Fe.
A single phase of Ni ₃ Al non-equilibrium intermetallic compound was obtained, and the strength was lower than that of the alloy of the present invention. Example 8 (Experiment No. 14) After melting Ni ₄₅ Al ₂₀ Fe ₃₅ alloy in an argon atmosphere, the pore diameter ^was
A continuous yarn with a uniform diameter of 120 μm is spouted into rotating cooling water with a temperature of 4°C and a depth of 2 cm formed in a cylindrical drum with an inner diameter of 500 mmφ rotating at 300 rpm by a 0.12 mmφ ruby spinning nozzle, and rapidly solidified. Got a thin line. At this time, the distance between the spinning nozzle and the rotating cooling liquid level was maintained at 1 mm, and the angle between the molten metal flow jetted from the spinning nozzle and the rotating cooling liquid level was 70°. The resulting thin metal wire had a breaking strength of 128 Kg/mm ² , an elongation of 10%, and was capable of close bending at 180°. Next, this thin wire was continuously cold drawn using a commercially available diamond die without intermediate annealing, and when the diameter of the thin wire was 100 μm (reduction ratio 31%), the breaking strength was 150 kg/ mm ² , elongation 3
%, and further wire drawing to obtain a fine wire diameter of 38 μm.
When (rolling reduction rate is 90%), the breaking strength is 234Kg/mm ² ,
We were able to dramatically improve the strength with an elongation of 2.5%. In addition, when the structure of this fine line is observed using X-ray diffraction, light microscopy, and transmission electron microscopy, the particle size of the compound is 1 to 1.
2 μm B-2 type nonequilibrium intermetallic compound and L1 ₂ type
It was a mixed phase structure of Ni ₃ Al non-equilibrium intermetallic compound. Examples 9 to 16 Ni-Al-Fe-M and Ni-Al with various compositions
-Co-M (M=Nb, Ta, Mo, V, Ti, Mn,
(Represents additional elements of Cr, Zr, W, Si, Y and Cu)
A ribbon was prepared using the alloy in the same manner as in Example 1. Next, the obtained ribbon was measured for breaking strength and 180° close bendability in the same manner as in Example 1, and at the same time, the crystal structure was also identified. The results are summarized in Table 2. From Table 2, experiments Nos. 15 to 22 are alloys of the present invention, and from X-ray diffraction and transmission electron microscopy observations, B-2 type non-equilibrium intermetallic compounds were detected as L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compounds. It had a mixed phase structure of compounds. In addition, the crystal grain size is
They were fine particles of 0.3 to 2 μm. Furthermore, Table-2
As is clearer, Nb, Ta, Mo, V, Ti,
By adding Mn, Cr, Zr, W, Si, Y, and Cu, a material with higher strength could be obtained.

[Table] (Effects of the invention) The Ni-based alloy of the present invention has a mixed structure of a B-2 type nonequilibrium intermetallic compound and an L1 ₂ type Ni ₃ Al nonequilibrium _{intermetallic} compound. ₃ It has even higher strength and ductility than single-phase aluminum non-equilibrium intermetallic compound alloys. Further, the alloy of the present invention is useful for reinforcing composite materials such as plastics and concrete, and as various industrial materials such as fine mesh filters.

Claims (1)

[Claims] 1 A is 8 atomic % or more and less than 30 atomic %,
At least one of Fe and Co is more than 25 atomic %,
70 atomic % or less (Fe is 30 atomic % or more and 70 atomic % or less, Co is more than 25 atomic % and 70 atomic % or less), the balance is essentially Ni, and the structure is B-2. Type nonequilibrium intermetallic compound and L1 ₂ type Ni ₃ Al
A high strength and high ductility Ni-based alloy consisting of a mixed structure with non-equilibrium intermetallic compounds. 2 Al is 8 at% or more and less than 30 at%,
At least one of Fe and Co is more than 25 atomic %,
70 atomic% or less (Fe is 30 atomic% or more and 70 atomic% or less, Co is more than 25 atomic% and 70 atomic% or less), Nb, Ta, Mo, V, Ti, Mn,
A total of 2.0 at% of one or more elements selected from the group consisting of Cr, Zr, W, Si, Y, and Cu
In the following, a high-strength and high-ductility Ni base with the remainder essentially consisting of Ni and a structure consisting of a mixed structure of a B-2 type non-equilibrium intermetallic compound and a L1 ₂ type Ni ₃ Al non-equilibrium intermetallic compound will be described. alloy.