JPH01319646A - Aluminum alloy for casting with excellent anti-vibration properties - Google Patents

Abstract

PURPOSE:To obtain the subject Al alloy having high damping capacity and excellent vibration isolation performance by limiting the content of Si, Cu and/or Mg, etc. CONSTITUTION:An Al alloy having the compsn. constituted of, by weight, 8-20% Si and 0.1-5% total of Cu and/or Mg, furthermore of 0.1-3% total of one or more kinds among Fe, Ni, Ti, Mn and Sb, moreover of 0.005-0.5% total of P and/or B and the balance Al with inevitable impurities is prepd. In the above impurities, <=30ppm Na, <=70ppm Ca and <=150ppm Sr are regulated and the total of Na, Ca and Sr is regulated to <=150ppm. By this method, the alloy is provided with excellent damping capacity and is therefore suitable as the material for cast parts such as electronic equipment, automobile parts and precision machine parts in which vibration isolation performance is required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aluminum alloy for casting having excellent vibration-proofing properties. More specifically, the present invention relates to an aluminum alloy for casting having a large damping capacity and excellent vibration-proofing properties, which is suitably used for purposes such as preventing damage caused by vibration noise of various types of equipment.

Here, the damping capacity Q is a measure of converting externally applied vibration energy into thermal energy, and the vibration energy of the vibration system at the beginning of the vibration/cycle is expressed as E,
If the energy converted into thermal energy during one cycle of vibration is ΔE, then the following relationship exists.

[Conventional technology]

The anti-vibration alloy currently used industrially is F
e-based alloy (product name: Xylentalloy and Dientalloy F)
), N】based alloy, Mn-based alloy (product name: Sonostone),
There are Z + Co-based alloys (trade names: Cosmar Z and Hisientalloy A) and Mg-based alloys.

[Problem to be solved by the invention]

Among known anti-vibration alloys, Fe-based alloys, N1-based alloys, and Mn-based alloys have excellent damping ability, but their specific gravity is extremely large, g77- or more, and are unsuitable for reducing the weight of equipment. Zn-based alloys have excellent damping ability, but do they have a high specific gravity? /7 or more, which is large, has low rigidity, and has poor corrosion resistance, causing many practical problems. Mg-based alloys have a large damping capacity and a specific gravity of /, I
? /7, which is lightweight, but the manufacturing cost is high and the versatility is poor. Ushita A] Base alloys have yet to reach a quality level that is practically satisfactory.

[Failure to solve the problem]

In view of the prior art, the object of the present invention is to
The object of the present invention is to provide an aluminum alloy for casting, which is lightweight with a vibration resistance of less than d, has good vibration damping properties, and is practical from the viewpoint of manufacturing technology.

The mechanisms that cause internal friction (damping) in aluminum alloys include viscous flow at the boundaries between second phase particles and the matrix, grain boundaries, and cell grain boundaries, and micro defects in crystals such as dislocations, vacancies, and stacking faults. Absorption of vibrational energy is considered.

The inventor of the present invention has arrived at the present invention as a result of intensive studies to realize the above mechanism while taking the above-mentioned mechanism into consideration.

That is, the gist of the present invention is as follows: (1) Sl is ~2Q% in weight percentage; (2) CLl and/or Mg is in total 0.7~3%; (2)
Fe, N i , T i , Mn and S b
A total of 0.7 to 3% of at least seven elements selected from the group consisting of, and o, oos to 0.3% of B on the gold side.
, with the balance consisting of aluminum and impurities, and the contents of Na, Ca, and Sr in the impurities are respectively 30 ppm or less of NNa, 70 ppm or less of Ca, and 30 ppm or less of S4/301'1lpH'1, and N
a.

The total content of Ca and Sr is 73-01) pm
The present invention relates to an aluminum alloy for casting having excellent vibration damping properties, which is characterized by the following characteristics.

The present invention will be explained in detail below.

When Si is added to AJ, a eutectic and/or primary S1 phase crystallizes depending on the amount added.

The interface between these 81 phases absorbs vibrations and improves the damping ability, but if the Sl content is less than 2%, sufficient damping ability cannot be obtained due to the small amount of Sl phase formed.
When the amount is more than 0.times.10, no improvement in damping ability is observed, and mechanical properties and machinability are deteriorated. The content of Sl in the alloy of the present invention is from g to 10%, preferably from 10 to 10%.

The addition of Cu and Mg strengthens the matrix, increases grain boundaries, and increases the amount of S1 phase crystallization, so that the total content is 0.
．． If it is less than 7%, the effect will be small, and if it exceeds G%, toughness and castability will be impaired. The total content of Cu and/or Mg in the alloy of the present invention is 0.7 to ≠%, preferably 0.3 to ≠5%.

The addition of Fe, Ni, Ti, Mn, and sb forms a compound phase with Sl and other elements, refines the crystal grains, and improves the damping ability. And Fe.

If the total content of at least seven types of Ni, Ti, Ml-1 and sb is less than 0 J%, the effect will be small;
If it exceeds 3%, castability, mechanical properties, machinability, and corrosion resistance will be impaired, so the content is 0.7 to 3%, preferably 0.75 to 2.5%.

The addition of B and P prevents the crystallized S1 phase from becoming fine and granular, forms a large number of flaky Sl phases with complicated shapes, and increases their interfacial area, thereby significantly improving the attenuation ability. Here, the complex-shaped schistose S1 phase, eutectic or primary S] exhibits a complicated shape such as rod-like, needle-like, plate-like, skeleton-like, block-like, or Chinese character-like, and granular It is a general term for those whose surface area is larger than that of . If the total content of B and/or P is less than o, o o s%, the effect will be small, and if it exceeds 0.5%, it will not be effective in improving the damping ability, and will impair castability and mechanical properties. . The total content of B and/or P in the alloy of the present invention is between 0.00 and 0.00. %, preferably 0.07 to 0.3%.

Next, in the alloy of the present invention, N a + C; I in the impurity
The reason for limiting the Sr content will be described. Al
It is preferable that the amount of impurities contained therein be as small as possible, but a total amount of about /,j% is usually acceptable.

However, among the impurity elements, N 2+ C (T and Sr easily form compounds with the above-mentioned B and P, inhibiting the addition effect of B and P, making the sJ phase fine and granular, and reducing the damping ability. Therefore, the content of Na30I
:) In or less, preferably 20 ppm or less, Ca 70 r) 1 m or less, preferably! rOp
pm or less, Sl-/ 3-01')I)m or less, okoshiguba/θoppm or less, and Na, Ca.

The total content of Sr and Sr shall be 20 ppm or less.

Other common impurities included in Al include Z n
+ Sn, P l-1, etc., but for Z n, it is usually about /%, and for Sn, Pb, etc., the total is 0,
/% is allowed.

The alloy of the present invention is used as a casting alloy.

Specifically, it is used for various castings such as die casting, metal mold casting, sand casting, and precision casting, and exhibits good vibration-proofing performance. The heat treatment after casting can be carried out without any problem as long as the shape of the S particles and other compound particles does not change due to granulation or the like.

As mentioned above, the alloy according to the present invention is made by controlling the additive elements.
111 to form a large number of complex-shaped flaky S1 phases, and has excellent damping ability.

〔Example〕

Next, embodiments of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Examples/~/〃 and Comparative Examples/~3- Alloy A-8 having the composition shown in Table/ was melted in an inert atmosphere in a high-frequency melting furnace, and then cast into a mold to a thickness of 10 mm.
A cast plate with a width of 200 mm and a height of 700 mm was produced.

Next, the cast plate was cut to a length of 07+1711
, width 10mm, thickness,! A test piece of the shell was prepared and used to measure the damping capacity.

The attenuation capacity was measured using the mechanical impedance method.
The resonant frequencies ranged from ~3000H2. Show your results! Shown below.

Table 2 also shows the results of microscopic observation of the shape of the S phase.

table! As is clear from Table 2, the alloy of the present invention has a flaky S1 phase with a complicated shape and has excellent damping ability.

〔Effect of the invention〕

Since the aluminum alloy of the present invention has excellent damping ability, VT
Casting that requires vibration-proofing properties such as bases and housings for CD players, head cases for floppy discs, automobile transmission cases, covers, cylinders, and other electronic equipment, OA equipment, automobile parts, and precision mechanical parts. It can be suitably used as a material for parts.

Patent applicant: Kasei Naoetsu Co., Ltd. Representative Patent Attorney Hase - Others/names

Claims (1)

[Claims] (1) In terms of weight percentage, [1] 8 to 20% of Si, [2] 0.1 to 5% of Cu and/or Mg in total, [3] Group consisting of Fe, Ni, Ti, Mn, and Sb. A total of 0.1 to 3% of at least one element selected from
and [4] 0.005 to 0.5% of P and/or B in total,
The content of Na, Ca, and Sr in the impurities is 30 ppm or less, 70 ppm or less of Ca, and 150 ppm or less of Sr, respectively, and the content of Na, Ca, and Sr is An aluminum alloy for casting having excellent vibration damping properties, characterized in that the total content is 150 ppm or less.