JPS6144143B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is designed to prevent pollution caused by vibrations and noises of various transportation systems and large machines, performance deterioration caused by vibrations of various precision machines and electronic devices, and vibrations that are optimal for preventing various vibrations and noise pollution that exist in the living environment. This relates to a vibration-absorbing alloy with large damping ability. The damping capacity Q ^-1 , which is generally used to compare damping capacities, has a relationship with the vibrational energy ΔE lost during one cycle of vibration and the total vibrational energy E as shown in the following equation. Q ^-1 = 1/2π·ΔE/E In other words, the larger the value of Q ^-1 , the smaller the amplitude of vibration becomes in a shorter time and the greater the damping effect. Conventionally known vibration absorbing alloys include Fe-based alloys such as dientalloy, Mn-Cu alloys, and Al-Cu alloys.
-Ni-based alloys and Ni-Ti-based alloys. Fe-based vibration-absorbing alloys such as Dientalloy and Mn-Cu-based alloys have high damping ability, but their specific gravity is around 8 g/ ^cm3 , making them unsuitable when reducing the weight of equipment.Al-Cu-Ni Ni-Ti alloys and Ni-Ti alloys have the disadvantage that cold working is not possible at all. In order to obtain a vibration-absorbing alloy that is lighter than conventional vibration-absorbing alloys, we developed a binary alloy based on Al, which has a very small specific gravity of 2.7 g/cm ³ , and added zinc in a weight ratio of 2 to 82%. Cold working is applied at a cold working rate of 5% or more to refine the crystal grains and increase dislocations, resulting in large damping capacity and high strength due to the grain boundary effect of the crystal grains and the hysteresis phenomenon of dislocations. The purpose of the present invention is to provide a vibration-absorbing alloy that has a vibration-absorbing effect. Next, a method for manufacturing the alloy of the present invention will be explained. First, an alloy with the above composition range is melted in an ordinary melting furnace in air, an inert gas, or a vacuum, and then thoroughly stirred to make a uniform molten metal.Then, the alloy is poured into a sand mold or metal mold, and an ingot is poured into an ingot. Build. In addition, during this dissolution, it is used as a blocking agent.
Total amount of MgCl ₂ , borax, CaF ₂ , KCl, ZnCl ₂ etc. 5
% or less of flux and a deoxidizing agent such as magnesium or beryum may be added in an amount of 0.5% or less as a deoxidizing agent. Next, this ingot is subjected to the following steps. (A) 250 below the melting point of the alloy due to homogenization
At a temperature of ℃ or higher for 5 minutes or more (preferably 30 minutes or more)
After heating (about 100 hours), cool rapidly or slowly at a rate of 1°C per second or less. Subsequently, cold working such as forging, rolling, extrusion, swaging, or drawing is performed at room temperature at a cold working rate of at least 5%. (B) Next, heat at a temperature of 250°C or lower for 5 minutes or more and 100 hours or less, and then quench or slowly cool to room temperature. The reason why homogenization treatment is performed in step (A) is that non-uniformity of components may occur in the ingot due to temperature differences between different parts of the ingot and differences in specific gravity between the solid and liquid phases during molten metal solidification.
This is to make the ingredients homogeneous. If the heating temperature is high, the heating time can be shortened, and if the weight of the molded product is large, it is necessary to increase the heating temperature and lengthen the heating time. This is because unless the solution treatment is sufficiently performed, it may not be possible to make the performance of the product, such as the damping capacity, uniform. Next, in (A), cold working refines crystal grains and increases dislocation density due to processing strain. As a result, this is an essential step in order to obtain the large damping ability that is the object of the present invention due to the movement of grain boundaries and the hysteresis phenomenon of dislocations, and also to increase the tensile strength of the molded body. In addition, in order to increase the damping capacity, cold working of 5% or more is sufficient to achieve the objective, but depending on the composition of the alloy, forming by bending, deep drawing, punching, etc. may be difficult. There is. For this purpose, in step (B), the reason why the material is heated to a temperature of 250° C. or less after cold working is to facilitate forming such as bending, deep drawing, and punching. The reason why the temperature is set at 250°C or lower is that the attenuation ability decreases if the temperature is reheated to 250°C or higher. A total of 100 g of metal with the composition shown in Table 1 was melted in an alumina crucible in a high-frequency induction electric furnace while passing Ar gas to the surface, and cast into an iron mold with a diameter of 10 mm.
An ingot was obtained. Next, this was heated at 350°C for 5 hours, slowly cooled, and then subjected to intermediate heat treatment at 350°C for 1 hour, cold swaging and drawing to 1.1
mm wire, and cut a 150 mm long wire from it to use as a sample. The damping capacity Q ^-1 was measured using the inverted torsion pendulum method at a frequency of approximately 1 Hz and a maximum strain amplitude γm = 10.
It was carried out at ×10 ^-6 . The damping capacity Q ^-1 and strength of Al-based alloys depend on the cold working rate. Examples of samples No. 1, No. 2, No. 4, No. 6, No. 8, and No. 8 are shown in FIG. 1 and FIG. 2.
Similarly, Figure 2 shows the relationship between damping capacity Q ^-1 and cold working rate when 9 alloys were heated at 350°C for 5 hours, slowly cooled, and processed by cold swaging and drawing. The relationship between the tensile strength σ _t and cold working rate of No. 6 alloy is shown. Both the damping capacity Q ^-1 and the tensile strength σ _t increase as the cold working rate increases, indicating that the grains become finer and the dislocation density increases as the working strain increases. . In order to obtain the damping capacity Q ^-1 = 6 x 10 ^-3 or more (γm = 10 x 10 ^-6 ) which is the objective of the present invention, it is necessary to perform cold working of at least 5% or more. It is better to make it as large as possible, even 99.99%. Since the cold working rate is (πD ² −πd ² )/πD ² ×100 (%), when a 10 mm diameter piece is reduced in area to a 0.1 mm diameter, the working rate is 99.99%. Next, Table 1 shows the damping capacity Q ^-1 and specific gravity ρ when processing the Al-Zn binary alloy at a cold working rate of 95% after slow cooling from 350°C.

[Table] The comparison sample No. 1 shown in Table 1, pure Al containing normal impurities, had a damping capacity Q ^-1 of 4 × 10 ^-3 with a cold working rate of 95% and did not contain Zn. Pure aluminum is not suitable as a vibration absorbing material for the purpose of the present invention, but when 2% or more of Zn is added to Al, the value of damping capacity Q ^-1 = 6 × 10 ^-3 or more, which is the purpose of the present invention, can be achieved. It is possible to obtain a considerably large attenuation capacity. In short, it can be seen that the value of the damping capacity Q ^-1 of the alloy of the present invention is several tens of times larger than the value of Q ^-1 =1×10 ^-3 of general metals. Furthermore, the specific gravity ρ of the alloy of the present invention is considerably smaller than that of general metals, and its tensile strength σ
_t is σ _t = 10 of cold-worked pure Al of comparison sample No. 1
Quite large compared to Kg/mm ² . Further, the specific gravity ρ is considerably smaller than 6.3 g/cm ² of comparative sample No. 3. For example, sample No. 6 of the example has σ _t =24Kg/mm ² and ρ = 4.0
g/cm ³ , sample No. 8 has σ _t = 13Kg/mm ² , ρ = 4.8g/
^cm3 . The relationship between the damping capacity Q ^-1 of the Al-Zn alloy and the amount of Zn is shown in Figure 3. Here, the damping capacity Q
^-1 is the value when slowly or rapidly cooled from 350℃, when cold worked at a cold working rate of 71% and 95% after slow cooling, and when cold worked at a cold working rate of 95% after rapid cooling. is the value of Here, we will discuss the cause of the extremely large attenuation capacity Q ^-1 of the Al-Zn system. Since the solid solubility limit of Zn in Al is very small at room temperature, it has a two-phase structure consisting of an α phase as a solid solution on the Al side and a β phase as a solid solution on the Zn side. heat treated
Al-Zn alloys have a mixture of α-phase and β-phase crystal grains, but when stress (vibration) is applied to this, the crystal grains move viscous at the grain boundaries, causing energy loss. be exposed. As a result, a damping capacity Q ^-1 is generated.
When a heat-treated Al-Zn alloy is subjected to cold working, the crystal grains are crushed, that is, refined, and at the same time many dislocations are introduced into the alloy. As the crystal grains become finer, the number of grain boundaries increases, so the damping capacity Q ^-1 due to viscous movement at the grain boundaries increases. In addition, solute atoms and impurity atoms are affected by Pinning (Granat-
(known as Liicke's theory), a history is generated in the stress-strain curve, and this history is the cause of the damping capacity Q ^-1 . Therefore, when the number of dislocations increases due to cold working, the damping capacity Q ^-1 due to the history increases. Therefore, the damping capacity Q ^-1 of the Al-Zn binary alloy becomes 3rd when gradually cooled from 350℃.
As shown in the figure, it is quite small, but when rapidly cooled, it is quite small as shown in Figure 3, but when rapidly cooled, it becomes slightly larger in alloys containing 70 to 95% Zn, and becomes smaller in alloys containing less than about 65% Zn.
When 95% and 71% cold working is performed after these heat treatments, the damping capacity Q ^-1 becomes very large, and 95% and 71% cold working are performed.
Although there is not much difference from cold working at 71%, the higher the cold working rate, the better the results. The reason for limiting the composition of the alloy of the present invention will be described. First, in binary alloys, zinc not only contributes to improving the damping capacity Q ^-1 but also improves the strength of the alloy. The reason why the weight ratio of zinc is limited to 2 to 82% is because if the lower limit of the composition is not reached, the sufficient damping ability aimed at by the present invention cannot be obtained, and if the above upper limit of the composition is exceeded, the weight ratio of comparative sample No. 3 is So the specific gravity ρ is
This is because ρ becomes too large at 6.3 g/cm ³ . Therefore, the characteristics of the alloy of the present invention are that it has a large damping capacity, is lightweight, has good cold workability, is reinforced, and is non-ferromagnetic. The present invention has these advantages and can be applied to materials for various transportation systems and large machines, moving parts of electronic devices, parts operated by magnetic fields, various household items, and building materials, etc., to prevent vibration and noise, and to be lightweight. It is very suitable for measuring the conversion rate, and is extremely useful when applied to this type of industry.

[Brief explanation of the drawing]

Figure 1 shows the damping capacity Q of sample No. 1, No. 2, No. 4, No. 6, No. 8, and No. 9 alloys when they were heated at 350℃ for 5 hours, slowly cooled, and then cold worked. Figure 2 is a curve diagram showing the relationship between ^-1 and cold working rate. Figure 2 is a curve diagram showing the relationship between tensile strength σ _t and cold working rate of sample No. 6 alloy in Figure 1. are the damping capacity Q -1 of the Al-Zn alloy when slowly and rapidly cooled from 350℃, and the damping capacity Q ^-1 after slow cooling and rapid cooling, respectively.
This is a characteristic curve diagram showing the relationship between damping capacity Q ^-1 and Zn content when cold worked at a cold working rate of 71% and 95%, and when cold worked at a cold working rate of 95% after quenching. be.

Claims (1)

[Claims] 1. Consists of 2 to 82% zinc and the balance aluminum by weight, has a structure with fine grains, and has a damping capacity Q ^-1 of 6 × 10 ^-3 or more. An aluminum-based vibration absorbing alloy with high damping ability. 2 For alloys consisting of 2 to 82% zinc and the balance aluminum by weight, (A) Homogenization treatment by heating at a temperature of 250°C or below the melting point of the alloy for 5 minutes or more and 100 hours or less, and after cooling, at least 5% Process at a cold working rate of % or more. (B) Next, heat at a temperature of 250°C or less for 5 minutes or more and 100 hours or less, and then cool. A method for producing an aluminum-based vibration-absorbing alloy with a large damping capacity, characterized by obtaining an alloy having a structure with finer grains and a damping capacity Q ^-1 of 6 × 10 ^-3 or more by sequentially performing the steps. .