JPS6128736B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to amorphous metal alloy compositions, and in particular to amorphous metal alloys containing iron, nickel and/or cobalt and having improved resistance to embrittlement during heat treatment. Previous studies have shown that solid amorphous metals can be obtained for certain alloy compositions. Amorphous materials are generally characterized as having non-crystalline or glassy characteristics, ie, without substantially any long-range order. X-ray diffraction tests are generally suitable for distinguishing amorphous materials from crystalline materials. Additionally, transmission electron microscopy and electron diffraction can also be used to distinguish between amorphous and crystalline states. The strength of amorphous metals changes slowly with the diffraction angle.
Produces a line diffraction image. Such images are qualitatively similar to diffraction images of liquids or ordinary window glass. Crystalline metals, on the other hand, give diffraction patterns whose intensity changes rapidly with the diffraction angle. These amorphous metals exist in a metastable state.
When heated to a sufficiently high temperature they generate a heat of crystallization and crystallize, and the X-ray diffraction pattern changes from having a glassy or amorphous character to having a crystalline character. It is possible to produce metals that are entirely amorphous or consist of a two-phase mixture of amorphous and crystalline states. The term “amorphous metal” used here
refers to a metal that is at least 50% amorphous, preferably 80% amorphous, and may have some minor fraction of material present as intervening crystallites. By appropriate processing, metal alloys can be obtained in an amorphous state. One typical method is to bring the molten alloy into contact with a solid metal substrate such as copper or aluminum and spread it thinly, allowing the heat of the molten alloy to escape to the substrate. Thick molten metal
10 ⁶ when expanded to 0.005 cm (0.002 inch)
Cooling rates on the order of °C/sec are achieved. For example, R.
C. Rule “Material Science and
Engineering, Volume 1, pp. 313-319 (1967) discusses the relationship between cooling rate and processing conditions for molten metal. Any method that provides a suitably high cooling rate, such as on the order of 10 ^<5> to ^10<6> C/sec, can be used. Illustrative examples that can be used to create amorphous alloys are HS Chain and CE Miller in the Review of Scientific Instruments. 41, pages 1237-1238 (1970), and the R.
Pound Giunia and R. Madein, Transactions of the Metaradical Society, AIMM, vol. 245, pages 2475-2476 (1969).
This is the rotating cylinder method described in 2010). A novel amorphous metal alloy is disclosed and claimed in U.S. Pat. No. 3,856,513 (December 24, 1974) to Chen and DE Polk. These amorphous metal alloys have the formula MaYbZc, where M is at least one metal selected from the group consisting of iron, nickel, cobalt, chromium and vanadium, and Y consists of phosphorus, boron and carbon. At least one element selected from the group, Z is aluminum, antimony, beryllium, germanium, indium,
at least one element selected from the group consisting of tin and silicon, a in the range of about 60 to 90 atomic percent, b in the range of about 10 to 30 atom percent, and c in the range of about 0.1 to 90 atom percent; It is in the range of 15 atom%. These alloys have been found suitable for a wide variety of applications including ribbons, sheets, wires, powders, and the like. formula
Also disclosed and claimed are amorphous alloys having TiXj, where T is at least one transition metal and X is aluminum, antimony, beryllium, boron, germanium, carbon, indium, phosphorous, silicon and at least one element selected from the group consisting of tin, where i is approximately 70 to 87 atomic%
and j is in the range of about 13 to 30 atomic percent. These alloys have been found suitable for wire applications. Ductility is generally used to enable mechanical applications.
Alternatively, it may be desirable to facilitate product handling and processing. It is known that amorphous metal alloys tend to lose ductility in bending when heated to temperatures close to the temperature at which crystallization occurs (crystallization temperature). Prolonged heating at low temperatures, as is often the case, is also sufficient to cause embrittlement. Iron known in the art,
Many amorphous alloys containing nickel, cobalt and/or chromium contain phosphorus as a glass-forming aid, but are susceptible to embrittlement when heated at temperatures in the range of about 200° to 350°. Although many applications involving these amorphous alloys will not require such heat treatment, there are certain instances where such heating is necessary and where it is desirable to utilize such alloys.
In the latter case, many of these alloys are relatively inexpensive components. According to the present invention, an amorphous metal alloy consisting essentially of at least one element selected from the group consisting of iron, nickel and cobalt is resistant to embrittlement when heat treated in a temperature range of about 200° to 350°C. improvement of the alloy composition by adding the entire amount of boron and at least one element selected from the group consisting of carbon and aluminum.
This is achieved by containing 17 to 22 atomic percent.
The amorphous metal alloy of the present invention consists essentially of the composition MaXb, where M is at least one of iron, nickel and cobalt, and X is boron and at least one of carbon and aluminum. , a is 78~
83 atom % and b is 17 to 22 atom %.
Preferably, 60-80% of X is boron. These alloy compositions can contain up to 30 atomic percent cobalt, such as on the order of 15 to 25 atomic percent. According to the invention, an improved resistance to embrittlement during heat treatment is also obtained in alloys consisting essentially of the composition M'aBb, where M' is selected from the group consisting of iron, nickel, cobalt and chromium. The amount of each of iron, nickel and cobalt is in the range of 20 to 35 at.%, preferably 20 to 30 at.%, and the amount of chromium is in the range of 5 to 20 at.%, preferably 5 to 30 at.%. in the range of 15 atom%, and a is 75
~85 atom %, and b is in the range 15 to 25 atom %. Preferably b is in the range of 17 to 22 atom %. The alloys of the present invention do not become brittle in bending when heated to temperatures typically used in subsequent processing. These alloys are also characterized by increased mechanical strength. The amorphous metal alloys of the present invention are prepared by forming a melt of the desired composition and then casting the molten alloy onto a quench wheel or injecting it into a quench liquid at a rate of about 10 ⁵ -10 ⁶ °C/sec. Made by a method that involves rapid cooling. Improved physical and mechanical properties and a higher degree of amorphism are achieved by casting the molten alloy onto a quench wheel in a partial vacuum at less than about 5.5 cm Hg absolute pressure. Thermal stability of amorphous metal alloys is an important property in certain applications. Thermal stability is characterized by the time-temperature transformation behavior of the alloy and is determined in part by DTA (Differential Thermal Analysis). As considered herein, relative thermal stability is also indicated by the retention of ductility in bending after heat treatment.
Amorphous metal alloys with similar crystallization behavior as observed by DTA can exhibit different brittle behavior when exposed to the same heat treatment cycle.
In DTA measurements, the crystallization temperature Tc gradually heats the amorphous metal alloy (at a rate of about 20° to 50°C/min) and over a limited temperature range (crystallization temperature) excess heat is generated. It can be accurately determined by noting whether or not excess heat is absorbed over a specific temperature range (glass transition temperature).
Generally, the glass transition temperature Tg is close to the minimum or first crystallization temperature Tcl and, as is usually the case, the temperature at which the viscosity is in the range of about 10 ¹³ to 10 ¹⁴ poise. Amorphous metal alloy compositions containing iron, nickel, cobalt and/or chromium and containing phosphorus among other metalloids generally have a weight of about 18650-24610 Kg/cm ²
Ultimate tensile strength of 265000~350000psi) and 400°~
Shows a crystallization temperature of 460°C. For example composition
Fe ₇₆ P ₁₆ C ₄ Si ₂ Al ₂ (Subscript numbers indicate atomic percent)
The amorphous metal alloy is approximately 21800Kg/cm ² (310000psi)
An amorphous metal alloy with an ultimate tensile strength of about Kg/cm ² (265000 psi) and a crystallization temperature of about 460°C and a composition Fe ₃₀ Ni ₃₀ Co ₂₀ P ₁₃ B ₅ Si ₂
and has a crystallization temperature of 415℃, and a composition of
Fe _74.3 Cr _4.5 P _{15.9 C 5} B _{0.3 has an} ultimate tensile strength of about 24610Kg _/
cm ² (350,000 psi) and crystallization temperature of 446°C. These compositions have poor thermal stability in the temperature range of about 200-350°C. For example, heat treatment required for curing the edge of a razor blade with polytetrafluoroethylene may require heat treatment at 330°C for 5 minutes. It shows a tendency of embrittlement after aging. According to the invention, by replacing phosphorus with boron, or with boron and at least one metalloid element of carbon and aluminum, about 200
The resistance to brittleness when heat treated in the temperature range of ~350°C can be improved. Specifically, the amorphous metal alloy of the present invention consists essentially of the composition MaXb, where M is at least one element selected from the group consisting of iron, nickel and cobalt, and X is boron. and at least one element selected from the group consisting of carbon and aluminum, where a is in the range of 78 to 83 atom % and b is in the range of 17 to 22 atom %. Regarding these amorphous metal alloys, ease of glass formation occurs with b ranging from 17 to 22 atomic percent. Optimum thermal stability is achieved in compositions where 60-80% of X is boron. Therefore, such a composition is preferred. Glass formation is aided in these amorphous metal alloys by the inclusion of up to 30 atomic percent cobalt. Glass forming is easier and preferred when cobalt is present in an amount of 15 to 25 atomic percent of the total alloy composition. The amorphous metal alloys of the present invention also have a composition essentially
M′aBb, where M′ is at least three elements selected from the group consisting of iron, nickel, cobalt, and chromium, and the amount of each of iron, nickel, and cobalt is preferably 20 to 35 at%, preferably the amount of chromium is in the range 5 to 20 atom %, preferably 5 to 15 atom %, and a is in the range 20 to 30 atom %;
It is in the range of 75 to 85 atom %, and b is in the range of 15 to 25 atom %. Preferably b is in the range of 17 to 22 atom %. Examples of this alloy include:
Fe ₃₀ Ni ₃₀ Co ₂₀ B ₂₀ , Fe ₃₀ Ni ₃₂ Cr ₂₀ B ₁₈ and
Includes Fe ₂₅ Ni ₂₅ Co ₂₀ Cr ₁₀ B ₂₀ , etc. These amorphous metal alloys containing boron exhibit superior strength over compositions containing phosphorus. For example, an amorphous metal alloy with the composition Fe ₂₅ Ni ₂₅ Co ₂₀ Cr ₁₀ B ₈ P ₁₂ has an ultimate tensile strength of 23200 Kg/cm ² (330000 psi)
shows. However, in this alloy, when the semimetal component is changed to −B ₁₆ P ₄ , the ultimate tensile strength becomes 27,800 Kg/
cm ² (395000psi). The metalloid component is −B ₂₀
For , the ultimate tensile strength is 35150Kg/cm ²
(500000psi). The crystallization temperature is also
In the case of Fe ₂₅ Ni ₂₅ Co ₂₀ Cr ₁₀ B ₈ P ₁₂ , the temperature is 461℃,
For Fe ₂₅ Ni ₂₅ Co ₂₀ Cr ₁₀ B ₂₀ , the temperature rises to 485℃. These amorphous metal alloys in which boron is the only metalloid element are also characterized by high hardness values, typically around 1000 DPH. Amorphous metal alloys are formed by cooling the melt at a rate of about 10 ⁵ -10 ⁶ °C/sec. For this purpose, various methods are currently available which are well known in the art, such as for the production of splatquenched foils, rapid cooling of continuous ribbons, wires, sheets, etc. Typically, a specific composition is selected, the necessary element or powder of a material that can be decomposed into the required element, such as ferroboron, is melted and homogenized in a desired ratio, and then The molten alloy is rapidly cooled on a cold surface, such as a rotating cylinder, or in a suitable fluid medium, such as a cold brine solution. Amorphous metal alloys are formed in air. However, superior physical and mechanical properties may be less than about 5.5 cmHg, preferably about 100 μm, as disclosed in U.S. Patent Application No. 552,673 to R. Ray et al.
This is accomplished by forming these amorphous metal alloys in a partial vacuum at an absolute pressure of m to 1 cm Hg. All materials are of typically commercially available purity. As mentioned above, this amorphous metal alloy is at least 50% amorphous, preferably 80% amorphous;
Virtually 100% amorphous materials can also be obtained by forming these amorphous metal alloys in a partial vacuum. In this case, such alloys which are virtually amorphous are therefore preferred, since the ductility is further improved. The amorphous metal alloys of the present invention exhibit superior manufacturability compared to the prior art. In addition to improved embrittlement resistance during heat treatment, the amorphous metal alloys of the present invention generally have better resistance to oxidation and corrosion than prior art compositions. These alloy compositions remain amorphous even under heat treatment conditions that cause phosphorus-containing amorphous alloys to become brittle. Ribbons of these alloys are used in applications requiring relatively high thermal stability and increased mechanical strength. EXAMPLE The quenching and formation of uniform width thickness and amorphous ribbon pieces from high temperature melting (approximately 1100 DEG -1600 DEG C.) reactive alloys is completed under vacuum. Application of vacuum minimizes oxidation and contamination of the alloy during melting or ejection and also
It also eliminates surface damage (blisters, bubbles, etc.) commonly observed in strips treated in pressurized air or inert gas. A copper cylinder is mounted vertically on the axis of a vacuum rotary supply channel and placed within a stainless steel vacuum chamber. The vacuum chamber is a cylinder joined at both ends with two side holes and is connected to a diffusion pump system. The copper cylinder is rotated by a variable speed electric motor or the like via a supply path. A pot surrounded by a group of induction coils is located above a rotating cylinder in the chamber. An inductive power source was used to melt the alloy in a crucible made from fused silica, boron nitride, alumina, zirconia, or beryllia. An amorphous ribbon melts the alloy in a suitable non-reactive crucible and injects the melt from an outlet at the bottom of the crucible onto the surface of a rotating (approximately 1500-2000 rpm) cylinder under heavy pressure of angone. built. Melting and spouting are carried out using an inert gas such as argon to adjust the degree of vacuum.
It is carried out in a partial vacuum of 10 ^-4 μm. The amorphous ribbon is then tested for ultimate tensile strength. The vacuum melt casting apparatus described above was used to cold cast a number of different glass forming metal alloys into continuous ribbons of substantially uniform thickness and width. Typically, its thickness ranges from 0.0025 to 0.0076 cm (0.001 to 0.003 inch), and its width ranges from 0.12 to 0.31 cm (0.05 inch).
~0.12 inch). The mechanical behavior of an amorphous metal alloy with a composition according to the invention as a function of heat treatment conditions was compared with that of a phosphorus-containing amorphous metal alloy. All alloys were manufactured by the method given above. The amorphous ribbons of the alloys of this invention were all ductile in the as-quenched state and remained so when heat treated in the range of about 200 DEG to 350 DEG C. for several minutes. This was in contrast to ribbons of amorphous alloys containing phosphorus as a metalloid element. These alloys exhibited brittleness under the same heat treatment conditions. The ductility of the ribbon in the as-quenched state and in the heat-treated state was measured as follows. I made a loop by overlapping the ends of the ribbon. The diameter of the ring was progressively reduced between the micrometer legs. A ribbon is said to be ductile if it can be bent to a radius of curvature less than about 0.005 inch without breaking. If the ribbon breaks, it is considered brittle. Table 1 shows the results of the test.

[Table] Mechanical and thermal properties (ultimate tensile strength Kg/cm ² ) of some representative amorphous metal alloys according to the present invention
(psi), crystallization temperature °C) are shown in Table 2 below.

【table】

Claims (1)

[Claims] 1. Consisting essentially of the composition MaXb, where M is at least one element selected from the group consisting of iron, nickel and cobalt, and At least one element selected from the group consisting of: a is in the range of 78 to 83 atom%, b is in the range of 17 to 22 atom%, and when heat treated at a temperature range of about 200 to 350 ° C. Amorphous metal alloys that are at least 50% amorphous with improved resistance to embrittlement. 2. The amorphous metal alloy according to claim 1, wherein 60 to 80% of X is boron. 3. The amorphous metal alloy according to claim 1, wherein up to 30 atomic percent of the total alloy composition is cobalt. 4 Consisting essentially of the composition M'aBb, where M' is at least three elements selected from the group consisting of iron, nickel, cobalt and chromium, the amounts of each of iron, nickel and cobalt being between 20 and 35 and the amount of chromium is in the range of 5 to 20 atom%, and a is in the range of 75 to 85 atom%, and b is 15 atom%.
Temperature range approximately 200-350℃, in the range of ~25 atomic%
An amorphous metal alloy that is at least 50% amorphous with improved resistance to embrittlement during heat treatment. 5 The amounts of each of iron, nickel, and cobalt are
The amount of chromium is in the range of 20 to 30 at% and the amount of chromium is 5 to 30%.
6. The amorphous metal alloy according to claim 5, wherein b is in the range of 15 atomic %, and b is in the range of 17 to 22 atomic %. 6. A method for producing an amorphous metal alloy of at least 50% amorphous having improved resistance to embrittlement during heat treatment in the temperature range 200-350°C, comprising: (a) heating the material to have the composition MaXb; forming a molten body, where M is at least one element selected from the group consisting of iron, nickel, and cobalt, and X is at least one element selected from the group consisting of boron, carbon, and aluminum. and the elements,
a is in the range of 78 to 83 atom%, b is in the range of 17 to 22 atom%, and then (b) this is rapidly cooled at a rate of about ¹⁰⁵ to ¹⁰⁶ °C/sec A method for producing an amorphous metal alloy. 7. A method for producing an amorphous metal alloy of at least 50% amorphous having improved resistance to embrittlement during heat treatment in the temperature range 200-350°C, comprising: (a) heating the material to obtain a composition M′aBb; forming a melt with M' being at least three elements selected from the group consisting of iron, nickel, cobalt and chromium, the amounts of each of iron, nickel and cobalt ranging from 20 to 35 at.%; and the amount of chromium is in the range of 5 to 20 at%, and a is
It is in the range of 75 to 85 atom%, and b is 15 to 25 atom%
and (b) rapidly cooling the amorphous metal alloy at a rate of about 10 ⁵ to ^{10 6} °C/sec.