Formation of Zr-Ti-Cu-Ni-Be-Fe bulk amorphous alloys and amorphous nanocomposites

The crystal formation ability of the magnetic susceptibility and its thermal stability. As a result, an amorphous matrix composite containing nanocrystalline grains can be obtained at a suitable cooling rate when the content exceeds 10 atomic fraction.

In recent years, zirconium-based multicomponent alloy systems with good amorphous formation ability have attracted great interest from researchers. The zirconium-based bulk amorphous alloy has high tensile strength, good ductility, high elasticity, and strong corrosion resistance. 41. The iron-based bulk amorphous alloy shows excellent soft magnetic properties. 5. The alloy, which has a good ability to form a bulk amorphous alloy, is mainly a small atom 86. Previous work on the increase of oxygen content in the zirconium-based alloy with higher 681 content can lead to the precipitation of the crystalline phase NiZr2. It was also found that the addition of rhenium and on the microstructure of the bulk amorphous alloy and the national natural science fund project 59871059 received The first draft date was 19990930, and the date of receipt of the revised draft 199922 could have a great influence. The above work shows that the addition of certain special elements can improve the performance of amorphous alloys and the ability to form amorphous alloys. The bulk amorphous alloy contained is an ideal soft magnetic material, but the iron-based bulk amorphous alloy has a poor ability to form an amorphous alloy. The maximum size of these alloys is only about 2m1Ql. Therefore, for a bulk amorphous material containing Fe The study of alloys is also an effective method to explore the effect of similar elements on the properties of bulk amorphous alloys and the ability to form amorphous alloys. In this paper, ferromagnetic Fe is selected as an additive element, which replaces Ni, Z and Be, respectively, and its effect on the performance of 7414, 12.5-order amorphous alloy 8622.5 and the amorphous formation ability are studied.

1 Experimental method According to the required atomic ratio by repeated arc smelting method to obtain the composition of the ingot. The ingot is crushed into a quartz glass tube, evacuated and then vacuum-packed. The ingot is remelted in the furnace and then quenched with water. A homogeneous ZTiCuNiBee columnar bulk alloy with a diameter of 816 mm 1 and a length of 1020 was obtained. The alloy containing 8 atomic fraction was prepared by using ice water plus 101 solution as quenching solution 1 during water quenching.

To determine the quality of the sample, the loss of the sample is less than 0. Therefore, it is ignored. Sectional sections of the sample were used for X-ray diffraction XRD differential thermal analysis, 5 hardness tests and magnetic tests. Using 3160,5, ray diffractometer 1 粑, radiant measurement of each sample of children, 1 spectrum, using, pillow, hour 0 Ding 7 differential thermal analyzer measurement Oh, 弋 heating of all samples, 0 21 metallurgical microscope With accessories, the hardness of the tester is measured in Vickers hardness. The relationship between the rate and degree of classification was measured with a 182 magnetic balance. The electron microscope photographs were taken in 2000.

2 Experimental results and discussion I=2, 5, 8 and 10 alloys and XRD curves of alloys 0, 5 and 3 after replacing Z and Be with Fe respectively and 0 and X respectively after changing Z and Be There is a large scale near 2=40. No crystalline peaks appear, which means that they are amorphous phases. Transmission electron microscopy now confirms this result. When the content reaches 10, when the alloy is completely substituted, the sharp crystal peak of 1 min 0 of the alloy is superposed on the amorphous package. This partially crystallization of the alum alloy is identified by the superposition of crystalline peaks. On the amorphous package. However, the half widths of these shape peaks are wider, and the average size of the crystal grains is estimated to be approximately 10 using the 3 and 63 formulas. 2 is the transmission of the Zr3d 4.1218,0 alloy sample obtained after quenching with a cooling rate of 103. Electron microscope photo. It is clear that the alloy is a composite containing nanocrystallites on an amorphous substrate. The nanoparticle formation is mainly due to the rearrangement of the neighboring atoms at the solid-liquid interface during the growth of the grains in the liquid alloy, and this diffusion is used to maintain this rearrangement. Since there is a large negative heat of mixing with 21 relative to other constituents, this means that there is a tendency for them to form compounds more strongly. When the increase of the content reaches a certain limit, FeZ2 phase will be preferentially nucleated. However, the alloy has a very viscous viscosity in the molten state, the long-range diffusion of atoms is difficult, and the cooling rate is fast, inhibiting the growth of the nucleus to obtain nano-sized grains.

Tian 22, 14 of them, 12.5150, 20,512 alloys from the photo and electronic alloys 8, 10 alloys and carefully replaced and as follows, 3, curves. The heating rate is 10% of their crystallization, 2% of the total crystallization temperature, glass transition temperature, supercooled liquid zone melting temperature, and melting enthalpy change, and about 7 glass transition temperatures are listed in 1. From 1 and 3 it can be seen that all alloys have a wide range of supercooled liquids, and the addition of these alloys does not change the alloy significantly. However, 7 and 7 vary with the content. In addition. 030 curve, shape and location are different. Crystallization disappeared with the increase of cerium content, indicating that the crystallization behavior of amorphous alloys is related to the content thereof. The crystallization enthalpy increased after partial substitution of Ni with 2Fe. However, as the Fe content increases, the crystallization enthalpy decreases from 25 to 68.39 as compared with the alloy not containing yttrium. The increase in the amount of ceremonial heating from 3 to 68.39 吖M. Special attention should be paid to the addition of 8 to Naa water quenching, the cooling rate is relatively faster than other alloys. The resulting curve is due to a more metastable state of energy. For alloys containing nanocrystalline grains. Because they have been partially crystallized, the crystallization enthalpy is smaller.

The simple glass transition temperature of gold and the width of the supercooled liquid region are related to the content of 6,6. Except for 8 alloys. The basicity and the width of the supercooled liquid region are decreasing with increasing. According to the proposed method of evaluating the amorphous formation ability, if 723, the uniform nucleation rate of the alloy in the supercooled liquid region will become very low, and the critical cooling rate required for the formation of the amorphous phase will become very low. Bulk amorphous alloys are available. The middle curve confirms this point, except for the partially crystallized alloys, 7 and 1 of the other alloys are all large bodies. With the increase in content, little change has occurred. While the change ratio of several is larger, the variation trend is similar to that of the other, except for the curve of the microhardness and composition of the alloys of Tian 52141514, 12.5 and 13622.561+1+2, and 6 is the magnetic susceptibility curve containing 12 and 18 iron. Since the parameters such as the crystallization temperature and the like of the amorphous alloy system are related to the heating rate, the heating rate used in the experiment is due to the heating rate used in the 080 experiment. It can be seen from 6 that each curve can be divided into parts, and the magnetic susceptibility characteristics of the alloys at different temperatures are substituted. The first part is from 300K to TA. In this temperature range, the alloy is still in the amorphous state.

The first part from Qiao to 800, the alloy has been crystallized. In these two parts, the relationship between magnetic susceptibility and temperature accords well with the definition rate, and paramagnetism appears. The first part is from 7 to Hua, which is a transition area. In 4 to 4, the magnetic susceptibility changes slowly with temperature, and in the past, the magnetic susceptibility rapidly increases with increasing temperature. Since 6 is located near the crystallization temperature, the region from 718 to 718 is in the supercooled liquid region. In the middle, structural relaxation occurs, but only from a metastable state with higher energy to a lower metastable state of energy, the disordered phase structure of the alloy does not change significantly, so the magnetic susceptibility changes slowly. However, in the supercooled liquid region, the magnetic susceptibility of the added alloy has an abnormally steep rise, and this is more thermally stable than the amorphous alloy containing 8 and 10.

The hardness of the alloy is 5.4 GPa. In the completely amorphous state, the Fe content of 28,6 changes the hardness of the alloy from 5.40 to 8.99, 6.82 and 4.68 GPa. With the increase of Fe content, the hardness of the alloy decreases continuously. . The hardness of the amorphous and crystalline mixed alloy obtained after incorporation into 103 is reduced to 4.380; 1. Similarly, 6 to 12 of 6 are added, and the obtained alloy becomes an amorphous composite material containing nano-grains, and the hardness value is obvious. decline. The experimental results show that the appropriate amount of incorporation can greatly increase the hardness of this bulk amorphous alloy.

Changes in the curve are related to the heart content. A similar phenomenon was also observed during the crystalline melting process. 121. The susceptibility of the undoped 6 amorphous alloy also changed significantly near the crystallization temperature point, but no steep change in the magnetic susceptibility was observed. 6 is a graph of magnetic susceptibility as a function of temperature for 12 and 18 inclusive. The alloys of these two components are structurally nano-grains deposited on an amorphous substrate. Their magnetic susceptibility did not show abnormal changes in the supercooled liquid region and in the vicinity. In fact, from room temperature to 800 feet they all fit well with the 683 law of the coffee community and paramagnetism still appears.

According to the quantum theory, the relationship between the magnetic susceptibility and the temperature is 2 or less, and the effective magnetic moment at the low frequency can be used as the following formula 12. The 13 is 8 and the magnetite and the stone are high-frequency terms, regardless of the temperature. All curves in 6 are below 7 and higher than Qiao. The slope of the first part of the curve of the crystalline state is significantly higher than the slope of the first part, namely the amorphous curve, ie, the number of samples of the crystalline sample is higher than that of the amorphous state. However, the liquid pure or crystalline Hg amorphous state is similar in structure to the liquid state than in the solid state. This contradictory result of magnetic susceptibility may be due to the presence of atoms in the high-frequency state in the liquid state and the fact that the solid state was originally in the low-frequency state. This needs further research to explain.

B-type alloys have excellent ability to form amorphous alloys because 1 has a large structural size difference between the six kinds of components in the structure, and the multi-component amorphous alloy has a tighter close-packed structure than the amorphous alloy.

The direct effect is to suppress the long-range diffusion in the alloy, so that the alloy has a large viscosity in the supercooled liquid, which hinders the nucleation and growth of the crystalline phase. FeNi is a transitional group element, and they have little difference in atomic structure such as atomic radius and electronegativity. Therefore, the substitution of 6 only has little effect on the amorphous formation ability of the original alloy system. 2 Thermodynamically, there is negative heat of mixing between the components. Among the major components, there is a large negative heat of mixing, especially; and 21 has the greatest negative heat of mixing relative to other components, and now the alloy has a lower melting point. (3) Metal elements with equal or similar electronegativity are formed by alloying metal bonds, but in actual substances, simple metal bonds have few covalent bonds or ionic bonds, most of which exist in the form of mixed chemical bonds. The mixed form is crucial for the formation of D and amorphous states. In the ZrTiCuNiBeFe amorphous alloy, the electronegativity between the components is different, for example, the electronegativities of Ni and 1 are 1.91 and 1.90, respectively, and the difference is close to 0.1 and two, and the difference in electronegativity is also small. However, the difference in the negative charge between two, two, and two is greater. The increase of the electronegativity difference between the components determines the transitional bond type variation and forms a covalent metal mixed bond, leading to the easy change of the mutual positions of the existing atoms in the system, resulting in disordered stacking of atoms; there are also covalent bonds. It is difficult to change the tendency of the bond length and the bond angle to make the disordered structure stable, and it is difficult to move long-distance and easily form an amorphous phase.

3 Conclusions The water-quenching method was used to obtain B, 866 bulk amorphous alloys, and amorphous composites containing nanoparticles were obtained by controlling the content and cooling rate. The amorphous alloy forming ability and performance of this system alloy change significantly with the change of the content, and doping with a suitable child can improve its thermal stability and hardness. Anomalous changes in susceptibility are observed in the supercooled liquid region. This change is related to the added content, and their effective magnetic moment in the amorphous state is lower than in the crystalline state.

Dai Daosheng, Qian Kunming, Ferromagnetics. Booklet, Beijing Science Press, 1998270