JPWO2002027055A1 - Amorphous alloy and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to produce a ZrC particle-dispersed amorphous alloy composite having excellent mechanical properties at low cost. According to the method for producing a ZrC particle-dispersed amorphous alloy composite material of the present invention, carbon particles and a Zr pure metal or a Zr alloy are added to an alloy of a matrix and melted at a temperature equal to or higher than the melting point of the Zr pure metal or the Zr alloy + 100K. During the dissolution, Zr and C are reacted to generate ZrC particles. Thus, a ZrC particle-dispersed amorphous alloy can be produced by preparing a mother alloy having glass-forming ability in which ZrC particles are uniformly dispersed and adjusting this.

Description

TECHNICAL FIELD The present invention relates to an amorphous alloy, and more particularly, to a ZrC particle dispersed amorphous alloy.
Background Art There has been a remarkable research on metallic glass in recent years. Metallic glasses having high glass-forming ability and high thermal stability against crystallization have been found and are widely used from basic to applied. Among them, Zr-Al-TM (TM is a transition metal) is one of the alloy compositions having the best glass forming ability. As for the Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ glass alloy, a columnar bulk glass alloy having a diameter of 30 mm has been successfully produced by differential pressure casting.
This metallic glass, like other amorphous alloys, is elastic in uniaxial compression and tensile tests at room temperature, exhibits almost no plastic elongation, and has local unstable fracture at the maximum shear plane. Is generated. For the purpose of improving such mechanical properties, amorphous alloy composite materials containing a second phase such as ceramics and metals have been developed to date. In 1980, it was reported for the first time that the yield strength was increased and the delocalization of fracture was caused by the composite of an amorphous alloy. In other words, this means that the Ni ₇₈ Si ₁₀ B ₁₂ quenched ribbon in which micron-sized tungsten carbide particles are dispersed has high strength.
In recent years, we have shown that zirconium carbide (ZrC) particle dispersed Zr-Al-Ni-Cu bulk glass composites have higher strength and higher ductility than Zr-Al-Ni-Cu single phase bulk glass. Later, the California Institute of Technology group succeeded in increasing the strength and ductility of metallic glass by combining tungsten and steel material fibers with the same idea, and demonstrated the same effect using these particles and ceramic particles. ing.
Important factors in designing a composite material using such a metallic glass as a matrix are as follows. The absence of reactivity between the mother phase and the dispersed phase, good wettability, and a small difference in coefficient of thermal expansion and specific gravity. Many studies have been conducted on the basis of these. Utilizing the so-called in-situ reaction of Zr and C, in which the reaction generation of ZrC particles by Zr metal and graphite particles is performed during the production of the composite material, is effective for the wetting of the mother phase and the dispersed phase and the uniform dispersion of the particles. is there. This is because the in-situ reaction between the Zr metal and the graphite particles has the effect of preventing aggregation of the particles.
When a ZrC particle-dispersed Zr-based amorphous alloy is produced by using a ZrC particle-dispersed mother alloy produced by melting ZrC particles and a Zr alloy,
1) ZrC particles are expensive,
2) the dispersion of the ZrC particles is non-uniform;
3) There was a problem that the bonding property between the ZrC particles and the amorphous matrix was insufficient.
Therefore, an object of the present invention is to produce a ZrC particle-dispersed amorphous alloy composite having excellent mechanical properties at low cost.
DISCLOSURE OF THE INVENTION In order to achieve the above object, the present invention provides a method of melting a matrix alloy, adding carbon particles and a Zr alloy to the alloy, and melting the alloy at a temperature equal to or higher than the melting point of the Zr alloy + 100K. This is a method for producing a ZrC particle-dispersed amorphous alloy, which comprises reacting Zr and C during melting to produce ZrC particles and producing an alloy in which the ZrC particles are uniformly dispersed.
Further, by adding carbon particles and Zr pure metal to the alloy and melting the alloy at a temperature equal to or higher than the melting point of the Zr metal + 100 K, Zr and C are reacted during melting to generate ZrC particles, and the ZrC particles are uniformly formed. This is a method for producing a ZrC particle-dispersed amorphous alloy, characterized by producing a dispersed alloy.
Further, a ZrC particle-dispersed amorphous alloy having a desired shape can be formed from an alloy having glass forming ability obtained by adjusting an alloy in which the ZrC particles are uniformly dispersed.
The present invention also includes a ZrC particle-dispersed amorphous alloy produced by the method for producing a ZrC particle-dispersed amorphous alloy.
BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a ZrC-particle-dispersed Zr-based amorphous alloy composite material using the present invention is characterized in that carbon particles and a Zr pure metal or a Zr alloy are added to an alloy of a parent phase to obtain a Zr pure alloy. Melting is performed at a temperature equal to or higher than the melting point of the metal or the Zr alloy + 100 K, and Zr and C are reacted during melting to generate ZrC particles. Thus, a ZrC particle-dispersed amorphous alloy can be produced by preparing a mother alloy having glass-forming ability in which ZrC particles are uniformly dispersed and adjusting this. It is desirable that the size of the carbon particles used for the fabrication be 100 micrometers or less, and the size of the ZrC particles be 100 micrometers or less. Further, it is desirable that the dispersion ratio of the produced ZrC particles is 20% or less by volume.
(Example)
A detailed description will be given in the case of dispersing ZrC particles generated by using a reaction between Zr atoms and C atoms in a parent phase having a composition of Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscript is atomic%) as an amorphous alloy. I do.
(1) In a pure argon atmosphere, pure Zr, Al, Ni, and Cu metals measured so as to have an atomic ratio of Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ are alloyed by an arc melting method.
(2) Graphite particles (particle size of less than 10 microns, purity 99.99%) and excess pure Zr which reacts with the particles to generate ZrC are added to the alloy and mixed again by the arc melting method. It is considered that Zr reacts with C at a ratio of 1: 1 and that Zr in the mother phase reacts with C.
Zr metal has the highest reactivity with graphite as compared to the other three metal elements, and since the generated zirconium carbide (ZrC) is the most stable, only ZrC particles are dispersed by this dissolution. It is created as a phase. (3) The mother alloy containing the ZrC particles is pulverized, charged into a quartz nozzle, and subjected to high frequency melting in a vacuum atmosphere of 10 ⁻⁴ Torr or less, and then a copper mold (diameter 2 mm, high (50 mm shape).
FIG. 1 is an optical micrograph of a cross section of the cast composite material produced as described above. From this photograph, it can be seen that particles of 10 μm or less are uniformly dispersed in the parent phase.
FIG. 2 shows an X-ray diffraction pattern of a cross section of a cast composite material containing 15 vol% (volume fraction) dispersed particles. Since this is composed of five peaks indicating ZrC and a halo pattern indicating an amorphous structure, the obtained composite material has a matrix of Zr-Al-Ni-Cu amorphous alloy and a dispersion of ZrC particles. Yes, it can be seen that the graphite has disappeared.
FIG. 3 shows a differential scanning calorimetry (DSC) curve (heating rate of 0.67 Ks ⁻¹ ) of a ZrC particle-dispersed Zr-based amorphous alloy composite material containing 15 vol% of dispersed particles, and Zr ₅₅ Al ₁₀ Ni ₅ Cu _30. These are shown together with those of a single-phase amorphous alloy. The glass transition temperature Tg and the crystallization onset temperature Tx in these two curves coincide at about 680K and 760K, respectively. From this, all of the added graphite reacts with Zr atoms in the molten metal during arc melting to form ZrC particles. As a result, the amorphous alloy of the parent phase, despite the addition of extra pure Zr, It can be seen that the composition of Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscript is atomic%) is maintained.
Among the ZrC particle-dispersed Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscript is atomic%) amorphous alloy composite material produced by the method described above, 7.5 vol% and 15 vol% (both volume fraction) of ZrC particles of the amorphous alloy composite material The results of a compression test (strain rate of 5.0 × 10 ⁻⁴ s ⁻¹ ) of a sample in which Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscripts are atomic%) of a single-phase amorphous alloy obtained by uniformly dispersing Also shown in FIG.
From FIG. 4, it can be seen that the compression rupture strength of the Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscript is atomic%) single-phase amorphous alloy is 1836 MPa and the plastic strain is almost 0%, whereas 7.5 vol% And ZrC particles in which ZrC particles of 15 vol% (both volume fractions) are uniformly dispersed Zr ₅₅ Al ₁₀ Ni ₅ Cu ₃₀ (subscript is atomic%) The amorphous alloy composite material has a compressive rupture strength and a plastic strain. Have reached 1996 MPa, 1.4% and 2060 MPa, 5%, respectively.
FIGS. 5 to 7 show how the maximum stress (FIG. 5), the plastic strain (FIG. 6), and the Young's modulus (FIG. 7) change according to the change in the volume fraction of the ZrC particles.
From these figures, it can be seen that when the volume fraction is 20% or less, the ZrC particle ratio increases and the performance increases with respect to the maximum stress and Young's modulus, but the plastic strain peaks at a volume fraction of 10%. There is.
[Brief description of the drawings]
FIG. 1 is an optical micrograph of a cross section of a cast composite made of an alloy according to the present invention.
FIG. 2 is a graph of X-ray diffraction of a cross section of a cast composite material made of the alloy according to the present invention.
FIG. 3 is a graph showing a differential scanning calorimetry curve of a cast composite material made of the alloy according to the present invention.
FIG. 4 is a graph showing a stress-strain curve under a compression test of an alloy in which ZrC particles are uniformly dispersed.
FIG. 5 is a graph showing the maximum stress in a compression test with respect to the volume fraction of ZrC particles.
FIG. 6 is a graph showing plastic strain in a compression test with respect to the volume fraction of ZrC particles.
FIG. 7 is a graph showing a Young's modulus by a compression test with respect to a volume fraction of ZrC particles.

Claims (4)

Dissolve the alloy that will be the parent phase,
By adding carbon particles and a Zr alloy to the alloy and melting at a temperature equal to or higher than the melting point of the Zr alloy + 100 K, Zr and C are reacted during melting to generate ZrC particles,
A method for producing a ZrC particle-dispersed amorphous alloy, which comprises producing an alloy in which ZrC particles are uniformly dispersed. Dissolve the alloy that will be the parent phase,
By adding carbon particles and Zr pure metal to the alloy and melting at a temperature equal to or higher than the melting point of Zr metal + 100 K, Zr and C are reacted during melting to form ZrC particles,
A method for producing a ZrC particle-dispersed amorphous alloy, which comprises producing an alloy in which ZrC particles are uniformly dispersed. The ZrC particle-dispersed amorphous alloy according to claim 1 or 2,
Further, a ZrC particle-dispersed amorphous alloy, wherein a ZrC particle-dispersed amorphous alloy having a desired shape is formed from an alloy having a glass forming ability obtained by adjusting an alloy in which the ZrC particles are uniformly dispersed. A ZrC particle-dispersed amorphous alloy produced by the method for producing a ZrC particle-dispersed amorphous alloy according to claim 1.

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