WO2016050003A1 - Structure-controllable tizr-based amorphous material and preparation method - Google Patents

Abstract

A method for preparing a TiZr-based amorphous composite material, comprising: determining chemical components of an amorphous matrix phase and chemical components of a second precipitate phase in a two-phase equilibrium alloy of a TiZr-based amorphous composite material; refining alloys separately according to the obtained chemical components; preparing a preform having a desired structure from the alloy refined according to the chemical components of the second precipitate phase, and placing the preform into a mold together with the alloy refined according to the chemical components of the amorphous matrix phase; and preparing an amorphous composite material via a pressure infiltration method.

Description

Structure controllable TiZr-based amorphous composite material and preparation thereof Technical field

The invention relates to the field of amorphous alloy composite materials, and particularly provides a design and preparation method of an amorphous composite material based on two-phase equilibrium characteristics.

Background technique

Amorphous composites have special properties due to their unique structural characteristics, such as high specific strength, high wear resistance, high corrosion resistance, and unique deformation characteristics. It has broad application prospects in aerospace materials, space exploration, defense industry and biomedicine. Amorphous alloy composites can be divided into two types according to the preparation process: external crystalline phase amorphous alloy composites and in-situ endogenous toughness crystalline phase amorphous alloy matrix composites (hereinafter referred to as "additional phase amorphous composite materials" respectively) And "endogenous phase amorphous composites"). For example: external phase amorphous composite W fiber/Zr-based amorphous composite material, SiC/Zr-based amorphous composite material, endogenous phase amorphous composite material β-Ti/TiZr-based amorphous composite material, in-situ precipitation B2CuZr phase/ZrCu-based amorphous composite material.

The added phase amorphous composite material has the advantages of controllable volume fraction of the second phase and structural morphology, but the second phase and the alloy melt are prone to strong interaction at the interface, leading to diffusion of alloy elements and interfacial reaction, resulting in matrix non- The formation ability of the crystal is lowered, and the performance of the reinforcing phase is deteriorated. The performance of the amorphous composite material cannot be fully exerted; the endogenous composite material has the advantages of good two-phase interface bonding and excellent mechanical properties, but the crystalline phase is affected by the alloy composition and solidification. The process constraints are mostly dendritic or granular, and the volume fraction and morphology of the crystalline phase are difficult to control. Therefore, looking for a new design idea of amorphous composite materials, can take into account the advantages of the above two types of materials and avoid the disadvantages, in the basic Both the theory and the practical application have important significance. In view of this, the present invention combines the preparation concepts of the above two types of amorphous composite materials, and fully utilizes the advantages of both to construct a novel amorphous composite material.

Summary of the invention

The object of the present invention is to provide a novel TiZr-based amorphous composite material designed and prepared based on the two-phase equilibrium characteristic between an amorphous alloy melt and an in-situ precipitation phase, and a preparation method thereof, the amorphous alloy composite material having both The advantages of strengthening phase amorphous alloy composites and endogenous crystalline strengthened amorphous alloy composites are good, the interface is well combined, and the structural form can be constructed according to requirements.

The invention particularly provides a preparation method of a structure controllable TiZr-based amorphous composite material, which is characterized in that: firstly, the chemical composition of the matrix amorphous phase (ie TiZr-based amorphous phase) in the TiZr-based amorphous composite two-phase equilibrium alloy is determined. And precipitating the second phase chemical component, separately preparing the alloy according to the obtained component, and then, according to the need, preparing the alloy prepared according to the precipitation of the second phase chemical component into a preform of a desired structure, and chemically reacting with the amorphous phase according to the matrix The alloys were placed together in a mold, and an amorphous composite was prepared by a pressure infiltration method. The construction method of such amorphous composite materials is also suitable for other alloy systems.

The method for preparing a structure controllable TiZr-based amorphous composite material according to the present invention is characterized in that the specific preparation process is as follows:

(1) Determination of the composition of the two-phase equilibrium alloy of TiZr-based amorphous composite material:

Taking a two-phase equilibrium alloy of TiZr-based amorphous composite material, respectively determining the chemical composition of the amorphous phase of the matrix and the precipitation of the second phase; or obtaining an amorphous composite material having a two-phase equilibrium property by adjusting the alloy composition and preparing the solidification process, When the volume fraction and composition of the two phases in the composite remain unchanged with the change of cooling rate, the two phases have reached equilibrium, and the matrix TiZr-based amorphous phase is determined separately. And the chemical composition of the second phase is precipitated (that is, for the alloy which does not satisfy the characteristics of the two-phase equilibrium alloy of the TiZr-based amorphous composite material, it is heated to the solid-liquid two-phase region of the alloy for semi-solid treatment, and TiZr-based amorphous is obtained after the heat preservation. Composite two-phase equilibrium alloy);

(2) refining the alloy according to the components of the two equilibrium phases;

(3) preparing a preform of the desired structure according to the actual application, and preparing the preform according to the chemical composition of the second phase; placing the preform together with the alloy refined according to the chemical composition of the matrix amorphous phase; Vacuum 1×10 ^-1 to 1×10 ^-4 Pa, heated to the melting point of the alloy refined according to the chemical composition of the matrix amorphous phase, filled with an inert gas, impregnated under inert gas pressure to precipitate the second phase alloy prefabricated In the body, heat preservation and water quenching, a TiZr-based amorphous composite two-phase equilibrium alloy with different structures is obtained.

The method for preparing a structure controllable TiZr-based amorphous composite material according to the present invention is characterized in that: the chemical composition of the amorphous phase of the matrix is Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 , and the chemical composition of the second phase is Ti _61.5 Zr _36.4 Cu _2.1 . By alloy composition adjustment, such as Ti-Zr-Cu-Ni (Fe or Co)-Be, or Ti-6Al-4V alloy, etc., added to the TiZr-based amorphous alloy, and then combined with the preparation process to obtain two phases Balanced in-situ endogenous TiZr-based amorphous composites.

The method for preparing the structure controllable TiZr-based amorphous composite material is characterized in that: after vacuuming, heating to 50-300 ° C, charging argon gas 1 to 5 atmospheres, and holding time is 0-30 min.

The method for preparing a structure-controllable TiZr-based amorphous composite material according to the present invention is characterized in that: when a second phase alloy preform is deposited in a mold together with a matrix amorphous alloy, the matrix amorphous alloy is placed in a precipitation stage. Above the two-phase alloy preform.

The method for preparing a structure-controllable TiZr-based amorphous composite material according to the present invention is characterized in that the preform may be in the form of a sheet, a fiber, a mesh or a porous.

组元在非晶合金熔体和析出第二相之间的扩散达到动态平衡。由于析出第二相是在合金熔体凝固过程中析出的，其与基体非晶相具有较好的润湿性；两平衡相之间界面结合好，且界面处无其它析出相形成。The TiZr-based amorphous composite material prepared by the method of the invention is characterized in that the material is a two-phase equilibrium alloy of TiZr-based amorphous composite material, and the chemical potential of any i component in the amorphous alloy melt is equal to its precipitation. The chemical potential in the second phase, ie

The diffusion of the component between the amorphous alloy melt and the precipitated second phase reaches a dynamic equilibrium. Since the precipitated second phase precipitates during the solidification of the alloy melt, it has good wettability with the matrix amorphous phase; the interface between the two equilibrium phases is well combined, and no other precipitated phase is formed at the interface.

The TiZr-based amorphous composite material of the present invention is characterized in that the TiZr-based amorphous composite material changes with a cooling rate during the preparation process (such as a decrease in cooling rate or an increase in casting size), and a matrix in the composite material is not The chemical composition and volume fraction of the crystalline phase and the precipitated second phase remain unchanged.

Taking Ti _45.7 Zr _33.0 Ni _3.0 Cu _5.8 Be _12.5 alloy as an example, the preparation method of the present invention is mainly divided into two steps:

The first step: determining the composition of the two-phase equilibrium alloy of TiZr-based amorphous composite

By adjusting the alloy composition of Ti-Zr-Ni-Cu-Be amorphous composites and combining the preparation of solidification process, an amorphous alloy endogenous composite Ti _45.7 Zr _33.0 Ni _3.0 Cu _5.8 Be with two-phase equilibrium characteristics was obtained. _12.5 (referred to as ZT-M alloy), as shown in Figure 1, the matrix amorphous component is Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 (referred to as ZT-A alloy), and the second phase is Ti _61.5 Zr _36.4 Cu _2.1 Solid solution (abbreviated as β-Ti alloy), the melting point of the β-Ti phase is higher than that of the TiZr-based amorphous phase.

Fig. 2 is the XRD diffraction spectrum of the cross section of the core and different mass button ingots of different diameter bars (different cooling rate) cast by ZT-M alloy copper mold, which shows that the ZT-M alloy structure prepared under different cooling conditions is β-Ti /TiZr-based amorphous composite material with the same structure.

Figure 3. Schematic diagram of ZT-M alloy prepared for different cooling rates (from left to right in the figure) From top to bottom, Φ2mm, Φ5mm, Φ8mm, Φ15mm, 15g and 120g), the volume fraction of precipitated phase of β-Ti alloy is basically unchanged with the change of cooling rate, about 50%, and the two phases have reached equilibrium. Please see Table 1).

Table 1. Precipitated phase volume fraction in ZT-M alloy at different cooling rates

The above results show that the ZT-M amorphous composite has the characteristics of two-phase equilibrium solidification. In view of the special solidification structure of ZT-M alloy, we propose a two-phase equilibrium amorphous alloy endogenous composite material concept, and establish a corresponding two-phase equilibrium amorphous alloy endogenous composite solidification process.

β-Ti相的化学成分和体积分数不再发生变化。继续降温时，由于Gibbs-Thomson效应，3-Ti相会在其与过冷液相之间界面能的驱动下进行熟化过程，导致小颗粒消失，大颗粒继续长大，这个过程中β-Ti相的体积分数和化学成分几乎保持不变。④当合金温度降至T_g时，剩余过冷液相经过玻璃化转变成为非晶合金固体，合金组织被冻结至室温。The solidification of the ZT-M alloy melt at a certain cooling rate will experience four characteristic temperatures of T _l , T _n , T _e and T _g , as shown in Fig. 4 . The four characteristic temperatures correspond to the theoretical precipitation temperature of the β-Ti phase nucleus, the actual precipitation temperature of the β-Ti phase nucleus, the two-phase equilibrium temperature of the β-Ti phase and the remaining liquid phase, and the glass transition temperature of the remaining liquid. Two-phase equilibrium amorphous alloy endogenous composite material in the solidification process of its alloy melt: 1 When the temperature is lower than the theoretical precipitation temperature T _l of β-Ti crystal nucleus, the alloy melt enters the inoculation stage of precipitation β-Ti phase At this time, the precipitation of the β-Ti phase can lower the Gibbs free energy of the melt. However, due to the supercooling effect caused by the faster cooling rate, the size of the small crystal nucleus of the β-Ti phase in the melt is mostly smaller than the critical size in which the crystal nucleus is stable, and the β-Ti phase has not yet precipitated. 2 As the alloy melt continues to cool to the temperature of T _n , the size of the β-Ti nucleus is larger than the critical size of the stable existence. At this time, the large degree of subcooling causes a large amount of nucleation of the β-Ti phase. As the degree of subcooling increases, the melt tends to grow larger in the β-Ti nucleus. On the other hand, due to the high temperature of the alloy melt, the diffusion and transport of atoms in the melt is very easy, which makes the 3-Ti phase growth process driven by the difference in chemical potential of each component very rapid. 3 With the growth of β-Ti phase, the volume fraction will gradually increase, and the chemical composition of the remaining melt and β-Ti phase will also change significantly, which leads to the difference of chemical potentials of various components in the two phases. Nearly zero. When the melt is cooled to a temperature T _e, the chemical potential of the various components of the β-Ti phase and the remaining liquid phase are equal, i.e.,

The chemical composition and volume fraction of the β-Ti phase no longer change. When the temperature continues to decrease, due to the Gibbs-Thomson effect, the 3-Ti phase undergoes a ripening process driven by the interfacial energy between it and the supercooled liquid phase, causing the small particles to disappear and the large particles to continue to grow. In this process, β-Ti The volume fraction and chemical composition of the phase remain almost unchanged. 4 When the alloy temperature drops to T _g , the remaining supercooled liquid phase undergoes vitrification to become an amorphous alloy solid, and the alloy structure is frozen to room temperature.

The criterion for the amorphous alloy endogenous composite material is a two-phase equilibrium composite material, T _e >T _g , that is, the two phases can reach equilibrium before the residual liquid phase glass transition is frozen. The construction method of such amorphous composite materials is also suitable for other alloy systems.

Step 2: Construction of Structure-Controllable TiZr-Based Amorphous Composites

The TiZr-based amorphous alloy and the β-Ti alloy obtained from the two-phase equilibrium endogenous composite have a very special coexistence property, which lays a foundation for the design and preparation of amorphous composite materials. An amorphous composite material is prepared based on this design. Specific steps are as follows:

(1) The chemical composition of the two equilibrium phase β-Ti and the matrix TiZr-based amorphous phase in the ZT-M amorphous composite material was determined, and the alloy was separately refined according to the two equilibrium phase β-Ti and TiZr amorphous phase components. Matrix amorphous component Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 (ZT-A alloy, melting point 688 ° C) and precipitated second phase component Ti _61.5 Zr _36.4 Cu _2.1 solid solution (β-Ti alloy, melting point 1430 ° C), The purity of the alloying element is selected to be ≥99% wt.

(2) According to the application requirements, β-Ti is prepared into the desired structure, such as: lamellar, fibrous, net A preform having a different structural form such as a porous shape or a porous shape is shown in FIG.

(3) The β-Ti preform and TiZr-based amorphous alloy with different structural forms are placed in a mold, and the amorphous composite material is prepared by pressure infiltration method, that is, vacuuming to 1×10 ^-1 to 1×10 ^{- 4} Pa, heated to above the melting point of TiZr-based amorphous alloy (50-300 ° C is preferable, also higher than 300 ° C), and impregnated into β-Ti alloy under high purity argon pressure (1 to 5 atm) In the preform, the water is quenched after being kept for a certain period of time (1 to 30 minutes), and the desired amorphous composite material of different structure is obtained.

The invention has the following advantages:

The novel amorphous alloy composite material of the invention has the advantages of externally strengthened phase amorphous alloy composite material and endogenous crystalline strengthened phase amorphous composite material: volume fraction and structure morphology of the second phase in the external phase amorphous composite material The controllable advantages also maintain the advantages of the two-phase interface combination in the endogenous phase amorphous composite. And according to the actual application requirements, the second phase structure shape and volume fraction can be designed, and can also be designed into complex structural components; the interface structure is the same as the endogenous composite material, the interface combination is good, and the performance is excellent.

DRAWINGS

Figure 1. ZT-M alloy as-cast microstructure: (a) TEM bright field phase of as-cast microstructure; (b) HRTEM interface of precipitated phase and matrix amorphous phase, the inset is the SEAD map of the corresponding region.

Figure 2. XRD diffraction spectrum of ZT-M alloy under different solidification conditions.

Figure 3. Schematic structure of ZT-M alloy under different cooling rate conditions (Table 1).

Figure 4. Schematic diagram of the solidification process of a two-phase equilibrium amorphous endogenous composite.

Figure 5. Schematic diagram of the structural design of an amorphous composite.

Figure 6. The appearance of the amorphous composite material at 0860 ° C for 0 minutes (in the illustration is the shape of the preform).

Figure 7. The morphology of the amorphous composite was held at 7.860 ° C for 5 minutes.

Figure 8. As-cast microstructure of ZT-A and Ti ₆ Al ₄ V mixed components.

The morphology of the amorphous composite was maintained at 9.830 ° C for 5 minutes.

detailed description

Example 1

1. Determination of the composition of two-phase equilibrium alloy of TiZr-based amorphous composite material:

The amorphous alloy endogenous composite material having two-phase equilibrium characteristics is Ti _45.7 Zr _33.0 Ni _3.0 Cu _5.8 Be _12.5 (referred to as ZT-M alloy). As shown in Fig. 1, the matrix amorphous component is Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 (abbreviated as ZT-A alloy, melting point 688 ° C), and the second phase is precipitated as Ti _61.5 Zr _36.4 Cu _2.1 solid solution (abbreviated as β). -Ti alloy, melting point of 1430 ° C). The volume fraction of precipitated phase of β-Ti alloy in ZT-M alloy prepared under different cooling rate conditions remained unchanged with the cooling rate, about 50%. The results show that ZT-M amorphous composite has The characteristic of two-phase equilibrium solidification. The chemical compositions of the two equilibrium phases β-Ti and TiZr phases are determined separately;

Second, the structure of the structure controllable TiZr-based amorphous composite material:

(1) According to the ZT-M alloy, the matrix amorphous component Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 (ZT-A alloy) and the precipitated second phase component Ti _61.5 Zr _36.4 Cu _2.1 (β-Ti alloy) solid solution respectively Melting alloy. The purity of the alloying element is selected to be ≥99% wt.

(2) The β-Ti alloy was processed into a sheet having a thickness of 500 μm, and then the sheets were combined into a preform in the inset of Fig. 6, and the sheets were equidistant between each other at about 700 μm.

(3) The preform is placed in a stainless steel mold, and a component of ZT-A alloy is placed over the preform. The vacuum was evacuated to 5 × 10 ^-3 Pa, and the temperature was raised to 860 ° C. At this time, the ZT-A alloy was melted, passed through a high-purity argon atmosphere at atmospheric pressure, and then water quenched to obtain a layered structural amorphous composite material. The alloy structure of the amorphous composite material is shown in Fig. 6. It can be seen that the composite material has uniform structure, no other compounds are formed at the interface, and the interface is excellent.

Example 2

The difference from Example 1 is that the nominal composition of the β-Ti alloy is processed into a "comb-like" preform having a "comb" thickness and a "backlash" width of about 300 μm. The preform was placed in a stainless steel mold and a ZT-A alloy was placed over the preform. Vacuuming to 5×10 ^-3 Pa, heating to 860 ° C, at this time ZT-A alloy has been melted, passed into high purity argon 2 atmospheres, held for 5 minutes, and then water quenched to obtain a layered amorphous composite . The alloy structure of the amorphous composite material is as shown in Fig. 7. It can be seen that the composite material has a uniform structure, no other compounds are formed at the interface, and the interface is excellent.

Example 3

The principle and method for preparing the amorphous composite material can be applied to other alloy systems, such as mixing and melting ZT-A alloy and Ti ₆ Al ₄ V, and obtaining a two-phase equilibrium alloy composition by solidification control. The amorphous composite structure is shown in Fig. 8. The matrix amorphous phase composition Ti _61.7 Zr _13.9 Cu _4.1 Al _5.5 Ni _2.4 V ₂ Be _10.4 (abbreviated as ZD alloy), and the second phase composition is Ti _78.9 Zr _8.6 Al _7.5 V _2.8 Cu _1.6 Ni _0.6 (referred to as β-Ti alloy in this embodiment).

The ZD alloy and the β-Ti alloy are respectively smelted, and the purity of the alloying element is selected to be ≥99%wt.

The β-Ti alloy was processed into a sheet having a thickness of 500 μm and a sheet having an equidistance between the sheets of about 500 μm. The preform was placed in a stainless steel mold, and a ZD alloy was placed over the preform. Vacuuming to 5×10 ^-3 Pa, heating to 830 °C, at this time ZD alloy has been melted, passed into high-purity argon at 2 atm, and kept for 5 minutes, then water quenched to obtain a layered amorphous composite. 9 is shown. The amorphous composite material has a uniform structure, no other compounds are formed at the interface, and the interface is excellent. This interface is very similar to the two-phase interface in endogenous amorphous alloy composites.

The above embodiments are merely illustrative of the technical concept and the features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the present invention and to implement the present invention, and the scope of the present invention is not limited thereto. Equivalent variations or modifications made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims (8)

A preparation method of structure-controllable TiZr-based amorphous composite material is characterized in that: firstly, the chemical composition of the amorphous phase of the matrix and the chemical composition of the second phase of the TiZr-based amorphous composite two-phase equilibrium alloy are determined, respectively, according to the obtained components Refining the alloy, and then, according to the need, the alloy refined according to the precipitated second phase chemical composition is made into a preform of the desired structure, and placed in a mold together with an alloy refined according to the chemical composition of the matrix amorphous phase, using pressure dipping The infiltration method is used to prepare an amorphous composite material. The method for preparing a structure controllable TiZr-based amorphous composite material according to claim 1, wherein the specific preparation process is as follows: (1) Determination of the composition of the two-phase equilibrium alloy of TiZr-based amorphous composite material: Taking a two-phase equilibrium alloy of TiZr-based amorphous composite material, respectively determining the chemical composition of the amorphous phase of the matrix and the precipitation of the second phase; or obtaining an amorphous composite material having a two-phase equilibrium property by adjusting the alloy composition and preparing the solidification process, When the volume fraction and composition of the two phases in the composite material remain unchanged with the change of the cooling rate, the two phases have reached equilibrium, and the chemical composition of the matrix TiZr-based amorphous phase and the precipitated second phase are respectively determined; (2) refining the alloy according to the components of the two equilibrium phases; (3) preparing a preform of the desired structure according to the actual application, and preparing the preform according to the chemical composition of the second phase; placing the preform together with the alloy refined according to the chemical composition of the matrix amorphous phase; Vacuum 1×10 ^-1 to 1×10 ^-4 pa, heated to the melting point of the alloy refined according to the chemical composition of the matrix amorphous phase, filled with inert gas, kept warm, and water quenched to obtain two-phase equilibrium of TiZr-based amorphous composite alloy. The method for preparing a structure-controllable TiZr-based amorphous composite material according to claim 1 or 2, wherein the chemical composition of the amorphous phase of the matrix is Ti _32.8 Zr _30.2 Ni _5.3 Cu ₉ Be _22.7 , and the second phase is precipitated. The chemical composition is Ti _61.5 Zr _36.4 Cu _2.1 . The method for preparing a structure controllable TiZr-based amorphous composite material according to claim 3, characterized in that after vacuuming, heating to 50-300 ° C, charging argon gas at 1 to 5 atmospheres, and holding time is 0-30 min. The method for preparing a structure controllable TiZr-based amorphous composite material according to claim 3, wherein when the second phase alloy preform is deposited in the mold together with the matrix amorphous alloy, the matrix amorphous alloy is deposited. Above the second phase alloy preform. The method for preparing a structure-controllable TiZr-based amorphous composite material according to claim 3, wherein the preform is in the form of a sheet, a fiber, a mesh or a porous. A TiZr-based amorphous composite material prepared by the method of claim 1, wherein the material is a TiZr-based amorphous composite two-phase equilibrium alloy, and the chemical potential of any i component in the amorphous alloy melt is equal to It is in the chemical potential of the second phase, ie

The diffusion of the component between the amorphous alloy melt and the precipitated second phase reaches a dynamic equilibrium. The TiZr-based amorphous composite material according to claim 7, wherein the TiZr-based amorphous composite material undergoes a change in cooling rate during the preparation process, and a matrix amorphous phase and a chemical composition of the second phase precipitated in the composite material. And the volume fraction remains the same.

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