CN1294285C - Scandium-base large amorphous alloy and method for preparing same - Google Patents

Abstract

The invention discloses a scandium-based bulk amorphous alloy, which uses scandium as the main component and rare earth as one of the basic alloy elements, and its atomic ratio composition is expressed by the following formula: Sc _60-x Co ₂₀ (Y, Gd) ₂₀ Al _x or Sc _45-z Co _10+z (Y, Gd) ₂₀ Al ₂₅ or Sc ₄₆ Co ₂₀ Y ₁₀ Al ₂₄ or Sc ₄₁ Co ₂₀ Y ₁₅ Al ₂₄ ; where x=14~25, z=5~10 . The advantages of the present invention are: 1. The critical cooling rate of the scandium-based bulk amorphous alloy is low. 2. Has a high specific modulus. 3. High thermal stability. 4. The scandium-based bulk amorphous alloy is suitable for industrial use, and can be processed by heating sufficiently above the glass transition temperature without crystallization. 5. The scandium-based bulk amorphous alloy has high manufacturing performance. The purity requirement of the rare earth alloy elements is not high, and the preparation process is simple and easy to operate.

Description

Scandium-based bulk amorphous alloy and preparation method thereof

technical field

The invention relates to the field of amorphous alloys or metallic glasses, in particular to a high specific modulus scandium with scandium as the main component, added with an appropriate amount of transition elements and yttrium rare earth elements, and containing more than 50% volume percentage of amorphous phase Based bulk amorphous alloy.

Background technique

Since H.S.Chen, A.Inoue, W.L.Johnson et al prepared a variety of bulk amorphous alloy systems such as Pd-Cu-Si, La-Al-(Ni, Cu)-Co, Mg-(Cu, Ni)-( Since Y, Nd), Zr-Al-Ni-Cu, Zr-Ti-Cu-Ni-Be, bulk amorphous materials have attracted the attention of physicists and material scientists due to their unique physical and mechanical properties. great concern. At present, the glass transition, glass forming ability or mechanism, crystallization mechanism, and deformation mechanism of bulk amorphous materials have become research hotspots in the fields of materials science and engineering. Zr-based alloy system is one of the alloy systems with the strongest glass-forming ability, and its strength can reach more than 2000 MPa, which exceeds the current highest strength steel, and its specific strength and specific stiffness far exceed steel. The specific stiffness of zirconium-based bulk amorphous material reaches 15N.m, which is one of the materials with the highest specific stiffness at present.

Contents of the invention

The invention provides a novel scandium-based (ScAlCo) bulk amorphous alloy with higher specific stiffness and a preparation method thereof. The specific stiffness of the amorphous alloy material is as high as 20N. Improve by about 33%.

The purpose of the present invention is achieved through the following technical solutions:

The scandium-based bulk amorphous alloy provided by the present invention takes scandium as the main component and rare earth as the alloying element, and its atomic ratio composition is expressed by the following formula:

Sc _60-x Co ₂₀ (Y, Gd) ₂₀ Al _x

or Sc _45-z Co _10+z (Y, Gd) ₂₀ Al ₂₅

or Sc ₄₆ Co ₂₀ Y ₁₀ Al ₂₄ or Sc ₄₁ Co ₂₀ Y ₁₅ Al ₂₄ ;

Where x=14-25, z=5-10, the purity of each constituent element is not lower than 90 at%, and the scandium-based bulk amorphous alloy contains at least 50 volume percent amorphous phase.

The present invention provides a method for preparing the above-mentioned scandium-based bulk amorphous alloy, comprising the following steps:

1) In an electric arc furnace with an argon atmosphere adsorbed by titanium, the above components are mixed according to the required atomic ratio and smelted evenly;

2) Using a conventional metal mold casting method, casting in a metal mold to obtain a scandium-based bulk amorphous alloy Sc _60-x Co _20-y (Y, Gd) _20-z Al _x (x=14～24, y =5～15, z=5～15).

Further, the metal mold used may be water-free or water-cooled metal mold.

Compared with existing amorphous alloys, the scandium-based bulk amorphous alloy provided by the present invention has the following advantages:

1. The critical cooling rate of the scandium-based bulk amorphous alloy is low. The cooling rate (Rc) can reach the order of 100K/s, the ability to inhibit crystallization is strong, and it is easy to form large-sized amorphous alloys. The size of each dimension is not less than 1 mm, and the critical diameter is not less than 3 mm.

2. High specific modulus. The density of the glassy alloy is about 4.2g/ ^cm3 , and the specific modulus is 20N.m, which exceeds most crystalline materials and zirconium-based amorphous materials (such as Vit1 is about 15N.m), and the latter is generally considered to be the specific modulus As one of the materials with the highest specific strength, the specific Young's modulus of this series of amorphous materials is much higher than that of zirconium-based amorphous alloys, while maintaining a relatively high ultimate elastic strain, which shows that this series of alloys has excellent elastic properties.

3. High thermal stability. The glass transition temperature is as high as 630-670K, which exceeds other rare earth-based bulk amorphous materials and most Zr-based bulk amorphous materials. It has a wide width of the supercooled liquid phase region, and Tx is 98K.

4. The scandium-based bulk amorphous alloy is suitable for industrial use, and can be processed by heating sufficiently above the glass transition temperature without crystallization.

5. The scandium-based bulk amorphous alloy has high manufacturing performance. The purity requirement of the rare earth alloy elements is not high, and the preparation process is simple and easy to operate.

Description of drawings

The X-ray diffraction analysis spectrum and selected area diffraction pattern of the amorphous alloy (3mm diameter round rod) of Fig. 1 Example 1.

Fig. 2 is the DSC curve diagram of the amorphous alloy provided by the present invention.

Fig. 3 DTA curve of Sc ₃₆ Co ₂₀ Al ₂₄ Y ₂₀ .

Figure 4. The relationship between elastic properties of ScAlCo-based amorphous materials and other rare earth-based bulk amorphous materials and glass transition temperature.

Figure 5 Comparison of the ultimate elastic strain of Sc-based amorphous materials with other amorphous materials.

Detailed ways:

Example 1

Preparation of Sc ₃₆ Co ₂₀ Al ₂₄ Y ₂₀ Columnar Bulk Amorphous Alloy

The scandium-based bulk amorphous alloy is prepared by using Sc, Co, Al and Y with a purity of 90 at.% or more and an atomic ratio of 36:20:24:20. First melt them in an electric arc furnace with an argon atmosphere adsorbed by titanium, mix them evenly, and obtain alloy ingots after cooling; then repeatedly smelt them for 5-10 minutes until the ingots are evenly melted, and finally use metal mold casting method to cast them in water-cooled or In a copper mold without water cooling, a scandium-based columnar bulk amorphous alloy with a uniform composition and a diameter of 3 mm was obtained.

After testing, the alloy has a density of 4.214g/cm ³ , a Young's modulus of elasticity of about 85.2GPa, and a specific modulus of 20N.m, far exceeding that of general Zr-based amorphous materials. The latter is considered to be one of the bulk amorphous materials with the highest specific modulus or specific stiffness.

The X-ray diffraction pattern of the central part of the alloy is shown in Figure 1. No crystallization peak was observed within the effective resolution of the X-ray diffractometer, and there was only one broad diffuse scattering peak, indicating that the alloy was a completely amorphous alloy. Observation under a transmission electron microscope also confirmed that the alloy was completely amorphous. The DSC analysis results listed in Table 1 also confirmed that the assay samples were mostly amorphous. In addition, it can also be found from Table 1 that the reduced glass transition temperature (T _rg ) and glass transition index (γ value) are both high, indicating that the alloy has a good ability to form amorphous, as shown in Figure 3, which is relatively The strong amorphous-forming ability is partly due to its close eutectic composition. The density of the glassy alloy is about 4.2g/ ^cm3 , and the specific modulus is 20N.m, which exceeds most crystalline materials and zirconium-based amorphous materials (such as Vit1 is about 15N.m), and the latter is generally considered to be the specific modulus As one of the materials with the highest specific strength, the comparison between this series of amorphous materials and other amorphous materials is shown in Figure 4. It can be seen that the specific Young's modulus of the new Sc-based amorphous alloy far exceeds that of the famous zirconium-based amorphous alloy. And maintain a very high ultimate elastic strain, showing that the alloy has excellent elastic properties. The glass transition temperature is as high as 630-670K, which is higher than other rare earth-based bulk amorphous materials and most Zr-based bulk amorphous materials. Refer to Figure 5 and Table 1 for details. It has a wide width of the supercooled liquid phase region, and Tx is 98K. High Tg and wide supercooled liquid phase region mean high thermal stability or heat resistance.

Examples 2-11

Various ratios of scandium-based bulk amorphous alloys were prepared according to the method of Example 1, and their compositions and thermophysical parameters are listed in Table 1. DSC heating rate: 20K/min.

Table 1. Composition and thermophysical parameters of scandium-based bulk amorphous alloys ingredients T _g (K) T _x (K) T _m (K) Tl(K) T(K) T _rg (K) gamma Sc ₆₀ Co ₂₀ Al ₂₀ Sc ₃₆ Co ₂₀ Y ₂₀ Al ₂₄ Sc _{40 Co 20 Y 20} Al ₂₀ Sc _{46 Y} 20 Co ₂₀ Al ₁₄ Sc ₅₀ Co ₂₀ Y ₂₀ Al ₁₀ Sc ₄₁ Co ₂₀ Y ₁₅ Al ₂₄ Sc ₄₆ Co ₂₀ Y ₁₀ Al ₂₄ Sc ₃₅ Co ₂₀ Y ₂₀ Al ₂₅ Sc ₄₀ Co ₁₅ Y ₂₀ Al ₂₅ Sc ₄₅ Co ₁₀ Y ₂₀ Al ₂₅ Sc ₃₅ Co ₂₀ Gd ₂₀ Al ₂₅ 670662657633632667664660658645650 730760743684670750730740748690765 1000970990994950956950945980980985 11001048105110531052104511001115104510421052 60988651388366809045115 0.6090.6320.6250.6010.6010.6380.6040.5920.630.6190.618 0.3950.4440.4350.4060.3980.4380.4140.4170.4390.4090.449

Note: 1) where T _rg =T _g /T _m , γ = T _x /(T _g +T _l ).

Table 2 Comparative Examples The thermophysical properties of bulk amorphous materials of other systems ingredients T _g (K) T _x (K) T _m (K) T _l (K) T(K) T _rg (K) gamma Ce ₆₀ Cu ₂₀ Ni ₁₀ Al ₁₀ Gd ₄₀ Y ₁₆ Al ₂₄ Co ₂₀ Dy ₄₀ Y ₁₆ Al ₂₄ Co ₂₀ ^* Pr ₆₀ Cu ₂₀ Ni ₁₀ Al ₁₀ Nd ₆₀ Cu ₂₀ Ni ₁₀ Al ₁₀ Zr ₄₁ Ti ₁₄ Cu _12.5 Ni ₁₀ Be _22.5 Zr ₆₅ A _l7.5 Cu _17.5 Ni ₁₀ Pd ₄₀ Ni ₁₀ Cu ₃₀ P ₂₀ 374598633409438623656575 441653682452478672735670 64597210117057289321108804 67299510318067559961168840 6755494340497995 0.570.600.610.510.580.6250.560.68 0.4220.4100.4090.3720.4010.4150.4030.473

Note: DSC heating rate: 10K/min.

From the data in Table 1 and Table 2, it can be seen that the thermal stability of different rare earth glasses is different. Referring to the comparative example (Table 2), it can be seen that Sc ₃₆ Co ₂₀ Y ₂₀ Al ₂₄ has relatively high thermal stability. It is also worth pointing out that the glass forming ability (GFA) of different systems is also different. The electronic structure and atomic size of rare earth atoms have significant effects on the GFA of Sc-based bulk amorphous alloys. The atomic size is closely related to its electronic structure, especially the number of electrons in the sub-outer 4f electron shell. Specifically, GFA first increases and then decreases with the increase of atomic size (such as atomic interaction volume). When the atomic interaction volume is 19cm ³ /mol, GFA is the largest. For example, La-Al-Co-Y cannot form bulk amorphous. The critical size of Sm-based bulk amorphous alloys can reach about 3 mm under metal mold casting conditions, and the critical size of Dy-based and Er-based bulk amorphous alloys can reach 5-8 mm.

Table 3 Elastic constants of Sc-BMG and other amorphous materials ingredients T _g (K) E(GPa) G (GPa) B (GPa) Sc ₃₆ Co ₂₀ Y ₂₀ Al ₂₄ Dy ₄₆ Y ₁₀ Al ₂₄ Co ₁₈ Fe ₂ Gd ₃₆ Y ₂₀ Al ₂₄ Co ₂₀ Nd ₆₀ Fe ₂₀ Ni ₁₀ Al ₁₀ Pr ₆₀ Al ₁₀ Ni ₁₀ Cu ₂₀ La ₆₆ Al ₁₄ Cu ₁₀ Ni ₁₀ Ce ₇₀ Al ₁₀ Ni ₁₀ Cu ₁₀ 662627603485417405359 85.264.262.254.137.235.730.3 32.324.423.620.713.613.411.5 77.558.557.454.145.234.927.0

Claims (6)

1, a kind of scandium-base large amorphous alloy is to be main component with the scandium, and rare earth is characterized in that as one of basic alloy element, the following formulate of its atom proportioning composition:

Sc _60-xCo ₂₀(Y，Gd) ₂₀Al _x

Or Sc _45-zCo _10+z(Y, Gd) ₂₀Al ₂₅

Or Sc ₄₆Co ₂₀Y ₁₀Al ₂₄Or Sc ₄₁Co ₂₀Y ₁₅Al ₂₄

X=14～25 wherein, z=5～10.

2, scandium-base large amorphous alloy as claimed in claim 1 is characterized in that, the purity of described rare earth Sc, Y and Gd is not less than 90at%.

3, scandium-base large amorphous alloy as claimed in claim 2 is characterized in that, described scandium-base large amorphous alloy comprises at least 50% volume percent amorphous phase.

4, the preparation method of the described scandium-base large amorphous alloy of a kind of claim 1 comprises the steps:

1) according to

Sc _60-xCo ₂₀(Y，Gd) ₂₀Al _x

Or Sc _45-zCo _10+z(Y, Gd) ₂₀Al ₂₅

Or Sc ₃₆Co ₂₀Y ₂₀Al ₂₄Or Sc ₄₁Co ₂₀Y ₁₅Al ₂₄

Atom proportioning ratio prepare raw material, x=14～25 wherein, z=510;

2) in the electric arc furnace of the argon atmospher of titanium absorption, by needed atom proportioning with above-mentioned component mix, melting is even;

3) use the permanent mold casting method, water and cast from the metal pattern, obtain scandium-base large amorphous alloy.

5, the preparation method of the scandium-base large amorphous alloy of stating as claim 4 is characterized in that the purity of described rare earth Sc, Y and Gd is not less than 90at%.

6, the preparation method of the scandium-base large amorphous alloy of stating as claim 5 is characterized in that described metal pattern is no water-cooled or water-cooled metal mould.

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