JPS601378B2 - Amorphous alloy with excellent fiber formability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous alloy having high strength, high corrosion resistance, high stability, and excellent fiber formability.

In this case, an amorphous alloy refers to an alloy in which no diffraction lines characteristic of crystals appear in X-ray diffraction or electron beam diffraction, and only a wide halo is observed. Amorphous alloys have attracted considerable academic and practical interest since it was discovered that certain alloys can be made amorphous by rapidly cooling them from their molten state.

One reason for this is the high strength found especially in iron-based amorphous alloys and the combined rutting properties. This gave rise to expectations for its practicality as a high-strength material. Since then, much research has been conducted to improve the properties of amorphous alloys. It is not always easy to make an alloy amorphous by rapid cooling. Furthermore, amorphous alloys have instability in that they easily lose their ductility and become brittle at high temperatures, and then change to a crystalline state. For this purpose, Tokuseki Sho 49
It has been reported that the addition of SL mountains in addition to metalloid elements such as P, C, and B facilitates amorphization, as seen in No. 191,014. In addition, corrosion resistance is an important property for practical materials, and by adding Cr as an essential component, for example, Fe7oP
,3C7Cr,. The alloy has been shown to have corrosion resistance that far exceeds that of conventional stainless steel. It has since been discovered that the coexistence of P is essential for corrosion resistance. Furthermore, regarding stability at high temperatures,
It has been reported that the addition of Si and AI increases the crystallization temperature. As seen in the above examples, the compositional system of amorphous alloys is characterized by ease of amorphization, stability, strength,
It has been studied from the perspective of improving properties such as corrosion resistance.

However, the biggest problem when viewed as a practical material is the fiber formability associated with rapidly solidifying molten metal into a fibrous shape. In other words, it is necessary to be able to easily form fibers with sufficient uniformity in size, shape, and properties to withstand practical use. There are no examples of research on component systems. For example, the addition of Si and AI is said to facilitate amorphization and increase the crystallization temperature, but on the other hand, in some alloys containing P, Si
The present inventors have found that as the amount of AI added increases, it becomes difficult to produce a fibrous sample with an excellent shape. As seen in this example, the components of the amorphous alloy should be selected depending on the required properties, and a highly practical component system has an optimal range of components depending on the properties that the material should have.

The inventor has developed an amorphous alloy that has high strength, high stability, and high corrosion resistance, and is easy to form into fibrous materials from an industrial perspective. This is something that I succeeded in discovering. The amorphous alloy with high strength, high stability, high corrosion resistance, and excellent formability obtained by the present inventors contains 5 to 20% Cr and 0 P in atomic percent.
．． Contains 5% or more, further contains 15 to 35% of one or more of C, B, Sj, AI, and the balance is Fe, Nj, C
o and unavoidable impurities, in which Sj or AI of the above elements is contained singly or in a total amount of 1% or more, and P 16 (AI 16)
．． It is characterized by satisfying a relationship of 5%.

The reason why the composition of the alloy of the present invention was determined as described above will be described below.

FIG. 1 shows, as a measure of high temperature stability, the temperature at which FeP, 3C7 amorphous alloy crystallizes when heated, and Si and AI significantly raise the crystallization temperature.

Figure 2 also shows FeP, 3C7 alloy at 325qC.
The stability when treated for a long period of time is shown by the representative crystallization temperature, and SLAI is particularly effective in improving the stability of ductile high-temperature aging. However, in an amorphous alloy containing a large amount of P, fiber formability deteriorates when the amount of Si and AI added increases. On the other hand, FeNiS
In amorphous alloys that do not contain any P, such as old Cr alloys, S
It can be contained in an amount of up to 20 at % or more, and has excellent stability over time and high temperature stability.

However, if P is not included at all, the corrosion resistance will not be sufficient even if about 10 at % of Cr, which is extremely effective for corrosion resistance, is added. Table 1 shows the results of measuring the corrosion loss of amorphous alloy fibers when immersed in 80o05% day 2S04 for 6 hours, and it can be seen that the corrosion resistance of the P-free material is inferior. . Also, as is already well known, Cr
Without the addition of , its corrosion resistance is extremely insufficient.
In other words, in order to ensure excellent corrosion resistance, P and Cr
The combined addition of The above results can be summarized as follows. '1} S to improve high temperature stability over time
i. Addition of AI is effective.

■ To ensure high corrosion resistance, combined addition of P and Cr is essential.

{3' Adding a large amount of Si or AI to the P-containing amorphous alloy leads to deterioration of fiber formability.

Therefore, based on the above research results, the present inventors have determined that Cr, P, C, B, Si,
We talked about the optimal combination of metalloid elements for AI.

As a result, in order to make one or more of Fe, Ni, and Co amorphous, one or more of P, C, B, Si, and AI must be added in a range of 15 to 35 at%. In other words, it was found that an amorphous state could not be obtained even if i was less than 5 atom % or more than 35 atom %. It was also found that in order to improve corrosion resistance, it is necessary to add 5 at % or more of Cr and 0.5 at % or more of P. Furthermore, it has been found that, in order to improve stability, adding Sj or AI in an amount of 1 atomic % or more brings about the effect. In addition to component design that improves the properties of these mainly manufactured amorphous alloys, the fiber formability, which is the most important point for commercialization, requires the amount of P and Si or AI added alone or both. The present inventors found that a suitable combination of the following is necessary and devised this, and this is the most distinctive feature of the present invention. Figure 3 shows FexNi
In the oZCr, o amorphous alloy, the range where fibers with good shape are formed is shown in terms of the relationship between P and Si + mountain amount, and the shaded area in the figure is where fibers with good shape are formed. range.

This range is expressed as P+S(si+AI)Mi16·Genshi% (including the case where AI=0 or Sj20).

It was also found that fiber formability was impaired when Cr was added in an amount of 20 atomic percent or more. The above composition range was determined based on the above results. The fiber formability described here is a property completely different from the amorphous forming ability, which indicates whether or not an amorphous alloy is easily formed, and is thought to be determined by the viscosity and surface tension of the alloy in its molten state. In other words, if the viscosity is too high, the molten alloy will not spread smoothly on a cylindrical steel plate rotating at high speed or in the gap between the rolls, and will break, become uneven, or become bright fibers, or conversely, the viscosity will be too low. If the surface tension is too high, it will be difficult to form fibers. The above combination range of P and Si+AI corresponds to the optimum combination range of viscosity and surface tension. To reiterate the most important feature of the present invention, P, which is essential for ensuring corrosion resistance, and Si or AI, which is essential for improving stability, are optimally combined from the viewpoint of fiber formability, which is most important in practical terms. It is at the point. Examples will be given below to clarify the usefulness of the present invention.

Table 1 shows examples. Examples 1 to 9 are amorphous alloys according to the present invention.

Examples 10 to 12 are excellent in corrosion-resistant fiber formability, but have a structure in which no Si or AI is added, and the long-term high-temperature stability of malleability is extremely insufficient. Example 1
3 to 19 have excellent corrosion resistance, but P and S are AI
Because the combination is inappropriate, it may not become a fiber, or even if it does, it will have an extremely poor shape and cannot be used as a practical material. Example 2u21 had sufficient stability and fiber formability, but was insufficient in terms of corrosion resistance because P was not added.

Further, in Example 22, since only 3 atomic % of Cr was added, the corrosion resistance was insufficient despite the addition of P.

In Examples 23 and 24, the amounts of P, B, Si, and AI were insufficient or too large, so that an amorphous alloy could not be formed.

In addition, in Example 25, there were too many O's, so some fibers had extremely poor shapes. On the other hand, the amorphous alloys according to the present invention shown in Examples 1 to 9 have extremely excellent corrosion resistance, stability, and fiber formability. Table 1 Example *1: 5% day 2S
04, 80℃, 6 hours *2: 300℃ Crystallization start time (min) *3: 300
℃180 unbending start time (min)

[Brief explanation of the drawing]

Figure 1 shows the effect of addition of AI or Si on the crystallization temperature of FeP, 3C7 amorphous alloy, and Figure 2 shows the effect of addition of AI or Si on the crystallization temperature of FeP, 3C7 amorphous alloy.
eP, Influence of addition of AI or Si to 3C7 amorphous alloy on stability against high temperature aging, Figure 3 shows FexN
In iyCozCr, an E crystalline alloy, the range in which fibers with good shape are formed is shown in terms of the relationship between P and the amount of Sj+AI. Multi-figure hair 2 figure 3

Claims (1)

[Claims] Contains 5 to 20% of Cr, 0.5% or more of P, and further contains 15 to 35% of one or more of C, B, Si, and Al, with the balance being Fe, Ni, and Co. Consisting of one or more types and unavoidable impurities, furthermore, among the above elements, Si or Al is contained alone or in a total amount of 1% or more, and the relationship of P + 3/2 (Al + Si) ≦ 16.5% is satisfied. An amorphous alloy with excellent fiber formability.