JP2000160308A - High specific strength titanium base amorphous alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a Ti base amorphous alloy excellent in glass forming performance and specific strength. SOLUTION: This alloy has a compsn. shown by the formula of Ti100-a-b-cM 'cTMaMb [M' denotes one or >= two kinds of elements selected from the groups consisting of Zr, Nb and Ta, TM denotes one or >= two kinds of elements selected from the groups consisting of Fe, Co, Ni and Cu, M denotes one or >=two kinds of elements selected from the groups consisting of B, Ge, and Si, (a), (b) and (c) respectively denote atomic %, and 30<=a<=70, 5<=b<=10, and 0<=c<=20 are satisfied] and contains amorphous phases of >=50% by volume percentage. The amorphous alloy can be produced as an alloy rod or an alloy sheet having >=0.5 mm2 cross-sectional area and exhibiting specific strength of >=3.1×105 N.m/kg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Ti-based amorphous alloy having amorphous forming ability and excellent specific strength.

[0002]

2. Description of the Related Art It is well known that an amorphous metal material having various shapes such as a ribbon shape, a filament shape, and a granular material can be obtained by rapidly cooling a molten alloy.
Amorphous alloy ribbons can be easily manufactured by a method such as a single-roll method, a twin-roll method, or a spinning-in-rotating-liquid method that can provide a large cooling rate.
Numerous amorphous alloys have been obtained for o-based, Pd-based, Cu-based, Zr-based or Ti-based alloys, and properties unique to amorphous alloys such as high corrosion resistance and high strength have been clarified.
Above all, Ti-based amorphous alloys have much better corrosion resistance than other amorphous alloys and are less harmful to the human body, so they are structural materials, medical materials,
It is expected to be applied to fields such as chemical materials.

However, amorphous alloys obtained by the above-described manufacturing method are limited to ribbons and thin wires, and it is difficult to process them into a final product shape using them.
From an industrial point of view, its use has been quite limited. On the other hand, it is known that when an amorphous alloy is heated, a specific alloy system transitions to a supercooled liquid state before crystallization, and shows a sharp decrease in viscosity. For example, Zr-A1-Ni-C
It has been reported that a u-amorphous alloy can exist as a supercooled liquid region at a heating rate of 40 ° C. per minute and about 120 ° C. before crystallization (“Mater. Trans., JIM, Vol. 3”).
2 (1991), paragraph 1005).

In such a supercooled liquid state, since the viscosity of the alloy is reduced, it is possible to produce an amorphous alloy compact having an arbitrary shape by a method such as closed forging. (See "Nikkan Kogyo Shimbun", November 12, 1992). Therefore,
It can be said that an amorphous alloy having a wide supercooled liquid region has excellent workability.

[0005] Among such amorphous alloys having a supercooled liquid region, a Ti-Ni-Cu alloy has a temperature range of a supercooled liquid region of 50 ° C or more and has high practicality such as excellent corrosion resistance. It was considered to be an amorphous alloy (see the 110th Abstract of the Japan Institute of Metals (1992), section 273). In addition, the workability and mechanical properties of these amorphous alloys were improved,
Ti-Ni-Cu- (Fe, Co, Zr, H) having the above supercooled liquid region and the strength exceeding 1000 MPa
f) Amorphous amorphous alloys have been developed and are known (JP-A-6-264199 and JP-A-6-26420).
No. 0). However, transition metals such as Ni and Cu, which are basic additive elements in the above-mentioned Ti-based amorphous alloy, have a large specific gravity, so that the specific gravity of the alloy itself becomes large, and an amorphous alloy having high mechanical properties can be easily obtained. However, the high specific strength characteristic peculiar to the Ti alloy is impaired.

[0006]

SUMMARY OF THE INVENTION The aforementioned Ti-Ni-
Cu-based, Ti-Ni-Cu- (Fe, Co, Zr, H
f) Amorphous alloys have a supercooled liquid region of 30 ° C. or higher, a large amorphous forming ability, and relatively good high-strength characteristics exceeding 1000 MPa, but many transition metal elements are contained in the alloy. , It is unavoidable to increase the specific gravity, and it cannot be said that the Ti alloy originally has a high specific strength.

[0007]

In order to solve the above-mentioned problems, the present inventors have obtained a high specific strength without impairing the temperature range of the supercooled liquid region, and can be applied to industrial materials. Ti that has the ability to form an amorphous material that can achieve dimensions
As a result of intensive studies for the purpose of providing an amorphous amorphous alloy material, a Ti-TM system having a specific composition [TM: F
1 selected from the group consisting of e, Co, Ni and Cu
Species or two or more elements] and an alloy obtained by adding one or more elements selected from the group consisting of B, Ge, and Si, or a more specific amount of Zr, Nb
And alloys to which one or more elements selected from the group consisting of Ta and Ta are melted and rapidly cooled and solidified from a liquid state to provide a Ti-based alloy having both high specific strength characteristics and a large amorphous forming ability. The inventors have found that an amorphous alloy can be obtained, and have completed the present invention.

That is, the present invention provides a compound of the formula: Ti _100-abc
M _'c TM _a M _b [wherein, M' is Zr, Nb and Ta
One or more elements selected from the group consisting of:
TM is one or more elements selected from the group consisting of Fe, Co, Ni and Cu, M is B, Ge,
And at least one element selected from the group consisting of Si and a, b and c each represent atomic%, and 30 ≦ a ≦ 70, 5 ≦ b ≦ 10, and 0 ≦ c ≦ 20. Satisfaction], and a Ti-based amorphous alloy containing an amorphous phase in a volume percentage of 50% or more.

The "supercooled liquid region" in this specification is defined as the difference between the glass transition temperature and the crystallization temperature obtained by performing differential scanning calorimetry at a heating rate of 40 ° C. per minute. The "converted vitrification temperature" is defined by a numerical value obtained by dividing the glass transition temperature obtained by the above calorimetric analysis by the melting point of the alloy. The “supercooled liquid region” is a numerical value indicating workability, and the “converted vitrification temperature” is a numerical value indicating the easiness of amorphization. The alloy of the present invention has a supercooled liquid region of 30 ° C. or higher and a reduced vitrification temperature of 0.55 or higher.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. Formula of the present invention: Formula: Ti _100-abc M ′ _c TM
In Ti-based amorphous alloy represented by _a M _b, TM is
One or more element groups selected from the group consisting of Fe, Co, Ni and Cu, and the content of this element group is 30 atom% or more and 70 atom% or less. When the content of this element group is less than 30 atomic% or more than 70 atomic%, a supercooled liquid region is not exhibited, and therefore an amorphous phase is not formed even by a single roll method having a small amorphous forming ability and a high cooling rate. . M 'is one or more elements selected from the group consisting of Zr, Nb and Ta, and is not necessarily an essential element, but the addition of M' can improve the amorphous forming ability. it can.

M is at least one element group selected from B, Ge, and Si. When the content of this element group is less than 5 atomic%, non-rolling by a single-roll method with a high cooling rate is performed. Despite the formation of a crystalline phase, it does not show the amorphous forming ability enough to obtain an amorphous alloy rod and an amorphous alloy plate, and the specific gravity of the alloy itself is high, so that high specific strength characteristics cannot be obtained. . If the content of this element group exceeds 10 atomic%, the element group represented by M and Ti form a high-melting compound such as TiB ₂ , and this high-melting compound acts as a nucleus for crystal growth. Instead, the ability to form is reduced.

The Ti-based amorphous alloy of the present invention is cooled and solidified from a molten state by various methods such as a single-roll method, a twin-roll method, a spinning method in a rotating liquid, an atomizing method, and the like. A granular amorphous solid can be easily obtained. Further, the alloy of the present invention has a markedly improved amorphous forming ability as compared with the conventional Ti-based amorphous alloy,
Preferably, an amorphous alloy rod and plate of any shape can be obtained by filling and casting the molten alloy in a mold.

For example, in a typical mold casting method,
After melting the alloy in a quartz tube in an Ar atmosphere, the molten alloy is filled and solidified in a copper mold at an ejection pressure of 0.5 to 2.0 kg / cm ² to obtain an amorphous alloy mass. it can. Further, the Ti-based amorphous alloy of the present invention
Lighter weight than the i-type amorphous alloy is achieved, and high specific strength characteristics can be obtained.

[0014]

Embodiments of the present invention will be described below. With respect to the materials having the alloy compositions shown in Table 1 (Examples 1 to 9 and Comparative Examples 1 to 4), round bar-shaped samples having a diameter of 2 mm and a length of 50 mm were produced by die casting. Glass transition temperature (Tg), crystallization onset temperature (Tx), melting point (T
m) was measured by differential scanning calorimetry. The degree of vitrification of the volume fraction (Vf) of the amorphous phase contained in this round bar-shaped sample was determined by using a differential scanning calorimetry to determine the calorific value at the time of crystallization and the single roll foil in which the amount of heat was completely amorphized The evaluation was made by comparison with the belt.

From these values, the supercooled liquid region (Tx-T
g) and reduced vitrification temperature (Tg / Tm) were calculated. Further, a tensile test was performed on the round bar-shaped sample, and the tensile strength at break (σ _f ) was evaluated. Further, the specific strength (σ _f / ρ) was calculated using the specific gravity of the sample by the Archimedes method as ρ.

[0016]

[Table 1]

[0017]

[Table 2]

As is clear from Tables 1 and 2, Example 1
The amorphous alloys of Examples 9 to 14 and Examples 10 to 14 exhibit a supercooled liquid region of 30 ° C. or more, a reduced vitrification temperature of 0.55 or more, and a specific strength of 3.1 × 10 ⁵ N · m / m. kg
The above shows the high specific strength. However, the alloys of Comparative Examples 1 and 5 contain only 20% or less of the elements of the TM group, and the alloys of Comparative Example 2 contain 80% of the elements of the TM group.
, The degree of vitrification was 0% in both cases, and the tensile test was not performed because of brittleness. Further, in the alloys of Comparative Example 3, Comparative Example 4, and Comparative Example 6, the content of the elements of Group M is out of the range described in claim 1 of the present invention. Since it does not contain, it does not have mechanical properties that can withstand practical use.

[0019]

As described above, the Ti-based amorphous alloy of the present invention exhibits a supercooled liquid region of 30 ° C. or more, a reduced vitrification temperature of 0.55 or more, and 3.1 × 10 ⁵ N.
-High specific strength characteristics of m / kg or more. From these, a practically useful Ti-based amorphous alloy having excellent glass-forming ability and specific strength can be provided.

Claims (3)

[Claims] 1. The formula: Ti _100-abc M ′ _c TM _a M _b [wherein M ′ is one or more elements selected from the group consisting of Zr, Nb and Ta, and TM is Fe , Co,
One or two selected from the group consisting of Ni and Cu
At least one kind of element, M is one or more kinds of elements selected from the group consisting of B, Ge, and Si;
b and c each represent atomic%, and 30 ≦ a ≦ 70;
5 ≦ b ≦ 10, 0 ≦ c ≦ 20], and contains at least 50% by volume of an amorphous phase by volume.
Amorphous alloy. 2. A supercooled liquid region of 30 ° C. or more and 0.55
2. The Ti-based amorphous alloy according to claim 1, which has an amorphous forming ability exhibiting the above-mentioned reduced vitrification temperature. 3. It has a cross-sectional area of 0.5 mm ² or more.
3. The Ti-based amorphous alloy according to claim 1, which exhibits a specific strength of 1 × 10 ⁵ N · m / kg or more.