JPS6132386B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to copper-based alloys with a predominant spinodal structure. Alloys containing copper, nickel, and tin have been proposed as economical alternatives to copper-beryllium and phosphor-bronze alloys in the manufacture of molded articles such as wires, wire connectors, springs, and relay elements. Such uses are based on the alloy's properties of high strength, moldability, corrosion resistance, solderability and electrical conductivity. Cu-Ni-Sn alloys with desirable properties are disclosed in U.S. Pat.
No. 4052204, No. 4090890 (inventor JTPlewes)
is shown. U.S. Pat. No. 3,937,638 describes the treatment of Cu-Ni-Sn ingots, which includes homogenization, cold working, and aging, and results in a predominant spinodal structure in the treated alloy. It is something. For example, in the case of an alloy containing 7% Ni, 8% Sn and the remainder copper, one method is to homogenize the ingot, cold work it to achieve a 99% area reduction, and Requires aging at 425°C for 8 seconds. The resulting product has a 0.01% yield strength of 1193 MPa (173000 PSI) and a ductility of 47% fracture area reduction. U.S. Patent No. 4,052,204 discloses not only Cu, Ni, and Sn, but also at least one of the following elements: Fe, Zn,
A quaternary alloy containing an additional element selected from Mn, Zr, Nb, Cr, Al and Mg is shown. A predominant spinodal structure similar to that of US Pat. No. 3,937,638 is created in these alloys by homogenization, cold working, and aging. U.S. Pat. No. 4,090,890 shows a cold-rolled and aged strip material having the same composition as the alloy shown in U.S. Pat. No. 3,937,638 and application no. Furthermore, it is made from an alloy that has substantially isotropic formability. As a result, such strip material is particularly suitable for manufacturing products that require rolling to bend the strip in a direction that has a substantial component of force in the perpendicular direction. Cu-Ni-Sn alloys and their properties are also the subject of the following publications: LH Schwartz,
S. Mahajan and JT Plewes, “Spinodal decomposition of a tin alloy containing 9% Cu and 6% nickel,” Acta Metallurgica,
Vol. 22, May 1974, pp. 601-609; LH Schwartz and JT Plewes, "Spinodal decomposition of Cu 9 wt% Nickel 6 wt% Tin. Critical test of mechanical strength of spinodal alloys" Acta Metallurgica, Vol.22, July 1974,
pp. 911-921; John T. Plewes, “Spinodal Cu-Ni-Sn alloys are strong and ultra-ductile,” Metal Progress, 1974.
July, pp. 46-50; JT Plewes, “High strength Cu-Ni-Sn alloys by thermomechanical treatment”
Metallurgical Transactions A, Vol.6A, 1975
March, pp. 537-544. Achieving good strength and bending properties in alloys based on copper and containing Ni and Sn was also shown in U.S. Pat. This is the purpose of the method. Prior shows a method of treating the ingot with homogenization, cold rolling, aging, and re-cold rolling. The inventor found that when Ni is 3-20% by weight, 3.5% when Ni is 3%
-10 wt% Sn to 20% Ni 3.5-12 wt%
Annealing, quenching and aging to eliminate the predominant spinodal structure in copper-based alloys, consisting of elements selected from the group consisting of Sn, Mo, Nb, Ta, V and Fe, and the balance copper. We discovered that it can be formed by processing. Since this process does not require cold deformation, these alloys are equally suitable for producing products by hot working, cold working, casting, forging, extrusion, hot pressing or cold working. . The resulting product has high strength, ductility and isotropic formability. FIG. 1 is a diagram showing a combination of yield strength on the vertical axis and elongation at break on the horizontal axis, showing two types of prior art alloys (designated 1 and 2) and alloy 4 of the present invention.
Species (designated 3, 4, 5 and 6) are indicated. Figure 2 shows yield strength on the vertical axis and Cu-15 Ni-8 Sn annealed and aged to various degrees.
It is a diagram showing the elongation of −0.2Nb alloy on the horizontal axis. Figure 1 shows curves 1 and 2 corresponding to the prior art alloys Cu-15%Ni-8%Tin and Cu-2%Be, and Cu-15%Ni-8%Sn-0.07%.
Mo, Cu−15%Ni−8%Sn−0.02%Ta, Cu−15
%Ni-8%Sn-0.18%Nb, and Cu-15%Ni-8
Curves 3, 4, corresponding to each alloy of %Sn-0.38%V
5 and 6 are shown. Cu-Be alloy can be obtained through retail channels. The Cu-Ni-Sn alloy was annealed at 825°C for 1 hour, water-cooled and graded at 400°C with a long aging time corresponding to a high yield strength and a short aging time corresponding to a high elongation at break. It was aged. FIG. 1 illustrates the high strength and ductility of this new alloy compared to prior art alloys. Figure 2 shows 0.03″ (0.076cm) of Cu-15%Ni-8%
The properties of Sn-0.2%Nb alloy wire are shown. The solid line is
This corresponds to the properties of wires heated at 825°C for 7-20 minutes, 1 hour, 4 hours and 17 hours, then rapidly cooled and aged at 400°C for 1 hour. The broken line is
The properties correspond to wires annealed at 900° C. for 1, 4, and 17 hours, then quenched and aged at 400° C. for 1 hour. FIG. 2 shows the effect of annealing temperature on the final properties of the alloy and the effect of annealing time on such properties at a fixed annealing temperature. It is clear from FIG. 2 that short annealing times and low annealing temperatures are desirable. The alloy of this invention contains 3-20 wt.% Ni, 3.5-10 wt.% Sn at 3% Ni and 3.5-12 wt.% at 20% Ni.
% by weight. The Sn content range for intermediate Ni content can be obtained by linear interpolation between the upper and lower limits of 3% and 20% Ni. Although the formation of the Cu-Ni-Sn-Fe alloy melt of the present invention can be carried out by conventional metallurgical methods, melts containing the refractory elements Mo, Nb, Ta or V may be used. Formation requires special care. Formation of such a latter melt can proceed, for example, as follows. Alloy of Cu and Ni or Cu
When -Ni alloy is melted in air at around 1300°C, a melt containing a large amount of oxygen and a small amount of hydrogen is obtained. A cover of dry graphite chips is placed over the melt to reduce the oxygen content. At the same time, an inert gas such as argon is bubbled through the melt for about 30 minutes and prevents the hydrogen content of the melt from increasing.
Add Sn while the inert gas continues to bubble.
Then, the temperature of this Cu-Ni-Sn melt is lowered to around 1250℃. It has been found that adding a small amount of Mn to the melt at this temperature is beneficial to inactivate residual sulfur. It is also beneficial to introduce a small amount of Mg into the melt as a pre-deoxidizer at this temperature. 0.1−0.3% Mn and 0.05−
0.1% Mg is generally suitable for such purposes and the Mg is preferably added in the form of a CuMg alloy. Mo, Nb, Ta or V is now introduced into the melt, preferably as a eutectic mixture with Ni to facilitate mixing. The low melting point eutectic composition is as follows. Ni-50%Nb, Ni-35%Ta, Ni-47%
V, Ni-46%Mo. The above method uses heat-resistant metals such as Mo, Nb, Ta or V.
was found to be added to Cu, Ni and Sn melts with yields of 60-80%. In order to ensure the presence of the desired proportion of refractory metal in the final alloy, a correspondingly large amount of starting material must be added initially. Adding Mg to the melt as required above provides a residual amount of Mg to be present in the alloy. Such presence does not substantially reduce the optimum alloy properties and up to 0.1% Mg can be tolerated. Higher amounts of Mn can be tolerated and up to 5% can be intentionally added as an inexpensive copper replacement. Similarly, up to 5% Zn can be replaced with Cu without significantly reducing alloy properties. Other impurities such as those present in commercially available alloy components are Co0.2%, Al 0.1%, P0.01%, Si0.05%,
Can withstand up to 0.005% Pb. Oxygen content should be kept below 100 ppm to prevent the formation of refractory metal oxides. The total amount of impurities in the alloy should preferably not exceed 5% by weight. The product of this invention can be formed into a slab, or the ingot can be forged at or above the recrystallization temperature.
Processing and shaping can be carried out by methods such as extrusion, hot working or hot pressing. The molded article is heated to a temperature range that depends on the Ni and Sn content of the alloy as shown in Table 1 for four exemplary alloys. Generally, when the amount of Ni is fixed, the upper limit of annealing temperature decreases as the amount of Sn increases, and the lower limit of annealing temperature increases as the amount of Sn increases. Conversely, when the amount of Sn is fixed, both the upper and lower limits of the annealing temperature increase as the amount of Ni increases. To avoid coarsening the distribution, the annealing temperature is preferably chosen near the lower end of the acceptable range for the exemplary formulations of Cu, Ni and Sn as shown in Table 1. Furthermore, as shown in FIG. 2, the annealing time should preferably not exceed 4 hours. For small items, a short annealing time of 7-20 minutes may be sufficient. Such annealing makes this alloy
Formation of a solid solution of Cu--Ni--Sn components and simultaneous solidification of the additive elements at the grain boundaries and within the matrix. After annealing, the workpiece is water or brine quenched (so that the substantially isotropic crystal structure formed by the annealing is essentially retained). Then, it is aged at a temperature of 300℃-475℃. Although aging temperatures of 375-425° C. can be considered typical, the aging temperature can be adjusted to compensate for actual longer or shorter aging times depending on the size and shape of the workpiece. In particular, in order to achieve a uniform internal temperature distribution, bulky articles are preferably aged for a long time, while wires and strips can be aged for a short time, for example in a continuous process. An increase in aging time by a factor of 10 typically corresponds inversely to a decrease in aging temperature by about 50°C. However, the aging temperature should not exceed about 475°C; high temperatures lead to undesirable brittle nucleation and growth transformations. A feature of the method disclosed herein is that no cold working is necessary to form the spinodal structure and thus the products of the invention can be formed by casting, forging, hot working, hot pressing or extrusion. , i.e., can be formed at temperatures at or above the recrystallization temperature of the alloy, resulting in a substantially isotropic crystalline structure that is essentially retained upon quenching and aging. Although processing operations that do not involve cold working are the preferred form of article manufacture of the present invention, it is not precluded that further cold working steps to form the article prior to aging may be carried out to the desired extent. Mo, Nb, in the alloy
The presence of additive elements selected from the group consisting of Ta, V and Fe has a beneficial additional effect, i.e. in applications where the strength of the molded part is a primary requirement, high strength can be achieved with a given amount of cold working. , compared to the strength achieved with the corresponding Cu-Ni-Sn alloy without such additive elements. Area reduction of 25% or less or 20
% or even cold working with an area reduction of less than 15% is beneficial in this situation. Cold working is useful in this case and the usual overlap of cold working and aging is not disturbed. especially,
Instead of going through a series of annealing, quenching, cold working, and aging treatments, such treatments may include, for example, a series of annealing, quenching, cold working, aging, quenching,
It can also undergo cold working and aging treatment. A more detailed method is also within the scope of this invention, provided that it sequentially includes the steps of annealing, quenching and aging. Mo, Nb, desirable for the purpose of this invention
It has been found that the amount of Ta, V or Fe lies within a relatively narrow and strictly limited range, outside of which clearly inferior properties are observed. The specific limit for alloys containing 3% Ni is 0.02−
0.07 wt% Mo, 0.05−0.3 wt% Nb, 0.02−
0.1 wt% Ta, 0.10-0.5 wt% V, or 1-
5% by weight of Fe. The corresponding limits for alloys containing 20% Ni are 0.05-0.1 wt% Mo, 0.08-0.35 wt% Nb, 0.05-0.3 wt% Ta, 0.2-0.5 wt% V, or 2-7 wt% Fe. It is. The limits of Mo, Nb, Ta and V for intermediate amounts of nickel are
It can be obtained by linear interpolation between the Ni3% and 20% limits. Amounts below the given lower limit are undesirable as they result in insufficient solidification of the added element upon heating, while amounts above the given upper limit promote the presence of Ni-refractory metal intermetallic compounds, which reduce ductility. . Additives to achieve the purpose of this invention
Mo, Nb, Ta, V, and Fe may also be used in combination, in which case at least one of these
The species should preferably be present in amounts within the aforementioned limits. Examples 1-18 are shown in Table 2. heat resistant element
Melts containing Mo, Nb, Ta, or V were prepared by the method described above. The ingot was cold rolled with an area reduction of 50%, then annealed, rapidly cooled and aged.
The annealing temperature was 825°C in Examples 1-10;
In Examples 11-14, the temperature was 850°C, and in Examples 15-18, it was 900°C.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram showing yield strength on the vertical axis and elongation at break on the horizontal axis, showing two alloys of the prior art (1 and 2) and four alloys of the present invention (3, 4, 5, and 6). FIG. 2 is a diagram showing yield strength on the vertical axis and elongation on the horizontal axis for Cu-15Ni-8Sn-0.2Nb alloys subjected to various degrees of annealing temperature and aging.

Claims (1)

[Claims] 1. Consisting of at least 95% by weight of Cu, Ni, Sn and at least one additional element, with Ni in the range of 3-20% and Sn in the range of 3.5-3% by weight.
In a method for producing a spinodal alloy body by treating an initial alloy body in which the amount of Ni is present from 10% to 3.5-12% when Ni is 20%, (1) the additive element is present at 0.02-0.07% when Ni is 3%;
Mo from 0.05−0.1% when Ni is 20%,
From 0.05-0.3% when Ni3% to Ni20%
Nb up to 0.08−0.35%, 0.02− at Ni3%
From 0.01% to 0.05−0.3% when Ni is 20%
Ta, V from 0.1-0.5% for 3% Ni to 0.02-0.5% for 20% Ni, and from 1-5% for 3% Ni to 2-7% for 20% Ni.
and (2) the treatment is carried out in such a way that the treatment is completed in the order of short-time low-temperature annealing, rapid cooling and aging treatment, and the short-time low-temperature annealing is selected from Cu-
The aging treatment is performed at a temperature in the range of 300 to 475°C, and the annealing is performed at a temperature in the range of 300 to 475°C, and the annealing is performed to form a solid solution of Ni-Sn components and precipitate at least one of the above-mentioned additive elements. A method for the production of predominant spinodal alloys, characterized in that it is carried out at temperatures of 625-975° C. over a period of minutes to 4 hours, with lower temperatures corresponding to shorter treatment times and vice versa. 2. The method according to claim 1, wherein the quenching is performed as water quenching or brine quenching. 3 20% carried out during the above treatment and before the aging treatment
3. A method according to claim 1, further comprising at least one cold working step with an area reduction of preferably less than 15%. 4. The method according to any one of claims 1 to 3, characterized in that the treatment is completed with successive steps of annealing, quenching, and aging treatment. 5. Any one of claims 1 to 3, characterized in that the treatment is completed in a continuous process of annealing, quenching, cold working, and aging treatment.
The method described in section. 6. A method according to claim 4 or claim 5, characterized in that the subsequent steps of quenching, cold working and aging are repeated at least once. 7 Selecting the additive elements from Mo, Nb, Ta and/or V and casting the alloy body from the final melt: providing the constituent elements Cu and Ni of the first melt and drying the graphite cover. is placed on this first melt, an inert gas is bubbled into this first melt, and the constituent element Sn is added to this first melt to form Cu,
Obtain a second melt of Ni and Sn, and add 0.1− to this second melt.
1.3 wt% Mn and 0.05-0.1 wt% Mg were added to form a third melt, and in this third melt Mo,
Claims 1 to 6 are characterized in that casting is performed from a final melt produced by adding a fourth constituent element selected from Nb, Ta, and V to obtain a final melt. The method described in any one of the above. 8. A method according to claim 7, characterized in that the fourth constituent element is introduced into the third melt in the form of a low melting point eutectic mixture with Ni.