JPH09310160A - High strength and high ductility aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high strength and high ductility aluminum alloy excellent in mechanical properties, ductility and workability by finely dispersing compounds having a regular icosahedral aperiodic structure crystallized out as primary crystals into aluminum or supersaturated solid solution aluminum. SOLUTION: An aluminum alloy of peritectic reaction series is formed into a high strength and high ductility aluminum alloy by a rapid solidifying method. The compounds having a regular icosahedral aperiodic structure are formed of quasi-crystals and are composed of icosahedron phases, regular decagon phases or the approximate crystal phases thereto, and the grain size is regulated to >=1000nm. The ratio of the quasi-crystals contained in the structure is regulated to >=90%, and the ratio of the elements to be added is regulated to <10%. The quasi-crystals crystallized out as primary crystals are finely dispersed to form the structure, which imparts ductility thereto and improves its workability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aluminum alloy containing a quasicrystal in its structure and having excellent strength and ductility.

[0002]

2. Description of the Related Art As an aluminum alloy of this type having high strength and high heat resistance and containing a quasicrystal in its structure, Japanese Patent Laid-Open No.
The ones disclosed in JP-A-268528 and JP-A-7-238336 are known. Aluminum alloys containing quasicrystals in the structure disclosed in these publications are produced by rapid solidification method to form an alloy having a fine crystal structure, and the obtained alloys are subjected to heat treatment, or hot working such as compaction and extrusion. Is performed to precipitate a quasicrystal from the fine crystal structure.

[0003]

However, in an aluminum alloy containing a quasicrystal precipitated from a fine crystal structure, the quasicrystal is precipitated at the grain boundary of the fine crystal,
Even if it has high strength and high heat resistance, the alloy itself is brittle and has problems in ductility and workability. Therefore, the present invention has a structure in which a quasicrystal crystallized as a primary crystal is finely dispersed in aluminum or a supersaturated solid solution aluminum, so that the peculiarity and the structure of the structure generated at the interface between the fine crystal and the quasicrystal are dispersed. It is an object of the present invention to improve the state and impart ductility, thereby improving workability and providing an aluminum alloy excellent in strength and ductility.

[0004]

The present invention relates to an aluminum alloy comprising a main element aluminum and an additive element containing at least a quasicrystal forming element, the structure of which is a positive crystal which is crystallized as a primary crystal in aluminum or supersaturated solid solution aluminum. It is a high-strength, high-ductility aluminum alloy in which a compound having an icosahedral aperiodic structure is finely dispersed. The compound having the regular icosahedral aperiodic structure is a quasicrystal, and the quasicrystal has an icosahedral, I
Phase), a regular decagonal phase (decagonal, D phase), or an approximate crystal thereof.

The alloy of the present invention does not cause quasicrystals to be precipitated, but in a peritectic reaction system alloy system such as Al-Mn, Al-Cr, or Al-V system, the quasicrystals are used as primary crystals by the rapid solidification method. It can be produced by crystallization and using Al as the residual liquid. That is, before the residual liquid is solidified, quasicrystals are crystallized and finely dispersed in the residual liquid, and then the residual liquid is solidified.
Due to the disordered atomic arrangement and solidification morphology of the quasicrystal, an alloy having a high interfacial strength between the quasicrystal and aluminum can be obtained. Furthermore, the residual liquid Al does not have a clear grain boundary and can be made into a single crystal, and it is possible to improve the mechanical properties and to provide an alloy with excellent ductility and workability. it can. Further, the existence of the quasi-crystal particles independently in the structure makes it possible to provide an alloy having high toughness.

The solidification method applicable to the present invention includes a single roll method, a twin roll method, a rotating submerged spinning method, various atomizing methods, a liquid quenching method such as a spray method, a sputtering method,
There are mechanical alloying method, mechanical gliding method, various die casting methods, etc. For these methods,
10 ² to 10 ⁴ K / se, although it varies slightly depending on the alloy composition
It can be manufactured at a cooling rate of about c. Further, the alloy of the present invention obtained by the above solidification method can be made into a solidified material such as an extruded material or a forged material by performing thermal control so as to maintain the obtained structure, and at a low temperature. It is also suitable for high-speed superplasticity, and also suitable for the production of solidified materials of various complex shapes. Since the alloy of the present invention has high ductility at room temperature, it can be cold forged as well as hot forged.

The volume ratio and grain size of the quasicrystal can be controlled by quenching conditions, composition control, processing conditions and the like. With this, the characteristics can be controlled. Quasicrystal grain size is 1000 nm
The following can provide an alloy having more excellent strength characteristics.

[0008] In the above, the quasicrystal contained in the alloy structure preferably has a volume ratio of 20 to 70%. 20
If it is less than%, excellent mechanical properties cannot be obtained, and 7
If it exceeds 0%, embrittlement of the alloy is caused, and there is a possibility that the obtained material cannot be sufficiently processed. Further, in the present invention, a composition having a high solute concentration of 90 at% or more of aluminum provides a tensile strength of 600 MPa or more and a ductility of 5% or more. Further, the rigidity is high, and a value of 30 GPa / ρ or more can be obtained.

The present invention consists of a main element (Al) and an additional element. In addition to the quasi-crystal forming element, which is an essential element, an additional element is added, and an element different from this is added to a ternary system or more. By using an alloy, it is possible to provide an alloy having more excellent characteristics.

The specific composition is represented by the general formula: AlbalQaMb.
(However, Q: Mn, Cr, V, Ti, Nb, Mo, T
at least one element selected from a and W, M: at least one selected from transition elements excluding quasi-crystal forming elements (Q elements), rare earth elements including Y, and misch metal (Mm)
Is an element of the species, a and b are in atomic percentage 0.5 ≦ a
≦ 10, 0 ≦ b <9.5). The Q and M elements are additive elements, the Q element is a quasicrystal forming element, and the M element is another additive element.

Q element is Mn, Cr, V, Ti, Nb, M
At least one element selected from o, Ta, and W is an element indispensable for forming a quasicrystal, as described above. Further, by combining these elements with the M element described later, quasicrystals can be more easily produced and the thermal stability of the alloy structure is improved.

The M element is a transition element other than the quasicrystal forming element (Q element), a rare earth element containing Y, and a misch metal (M
m), which is at least one element, specifically, Sc, Fe, Co, Ni, Cu, Y, Zr, Pd,
Ag, Hf, Os, Ir, Pt, Au, Ce, Pr, N
d, Eu, Gd, Tb, Dy, Ho, Er, Yb, L
u and Mm. By adding these elements,
It is more effective in improving the mechanical properties and thermal stability of the alloy.

In the above general formula, a is 0.5 to 10 at% and b is 0 to 9.5 at% in atomic percent (provided that
Each of the ranges (excluding 9.5) is limited so that an alloy having excellent mechanical properties, ductility, and workability, which is the object of the present invention, can be provided within this range.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below based on Examples. Example 1 An aluminum-based alloy powder having a composition (atomic ratio) represented by Al ₉₃ Mn ₅ Co ₂ was produced by a gato atomizer. After filling the prepared aluminum-based alloy powder into a metal capsule, degassing was performed to produce an extruded billet. This billet is heated to 360 to 600 ° C. by an extruder.
Extrusion was carried out at the temperature of 10 to obtain an extruded material.

Comparative Example 1 An alloy having the same composition as in Example 1 was manufactured in the same manner as above. The extruded material obtained was heat-treated at 600 ° C. for 30 minutes.
The structure of Example 1 and Comparative Example 1 was observed by TE.
It was performed by M observation (transmission electron microscope observation).

The alloy (extruded material) of Example 1 has a structure in which quasicrystals crystallized as primary crystals are finely dispersed in an Al single crystal (remainder) in which no grain boundaries exist, and the quasicrystals The size was 1000 nm or less. On the other hand, the alloy after heat treatment (extruded material) of Comparative Example 1 had a structure in which a large number of intermetallic compounds composed of fine Al ₆ Mn were present (precipitated) in fine Al crystals. Next, Example 1 and Comparative Example 1
Was investigated for its mechanical properties. Table 1 shows the results.

[0017]

[Table 1]

According to Table 1, the alloy of the present invention (the alloy of Example 1) is superior to the alloy of Comparative Example 1 in mechanical properties such as strength (at room temperature) and ductility (at room temperature).
It turns out that it is excellent. Further, for the compositions shown in Table 2, the strength, ductility and other mechanical properties at room temperature were examined in the same manner as above. The results are shown in Table 2.

[0019]

[Table 2]

Table 2 shows that the alloy of the present invention has excellent mechanical properties such as strength and ductility. The results of the above examples show that the alloy of the present invention has a tensile strength of 600 MPa or more at room temperature and a ductility of 5% or more. Although not shown, the rigidity is 30
An excellent value of GPa / ρ or more can be obtained.

[0021]

As described above, the alloy of the present invention has a structure in which quasicrystals crystallized as primary crystals are finely dispersed in aluminum or supersaturated solid solution aluminum, whereby fine crystals and quasicrystals are obtained. It is possible to provide an aluminum alloy having improved peculiarity generated at the interface of (1) and the dispersed state of the structure and imparted with ductility, thereby improving workability, and having excellent mechanical properties such as strength, ductility and workability.

Claims (6)

[Claims] 1. An aluminum alloy comprising a main element aluminum and an additive element containing at least a quasicrystal forming element, the structure of which is a regular icosahedron aperiodic structure crystallized as a primary crystal in aluminum or supersaturated solid solution aluminum. A high-strength, high-ductility aluminum alloy, characterized in that the compound contained therein is finely dispersed. 2. The high-strength, high-ductility aluminum alloy according to claim 1, wherein the aluminum alloy is a peritectic reaction type alloy system and is produced by a rapid solidification method. 3. A compound having a regular icosahedron aperiodic structure is a quasicrystal, and the quasicrystal is an icosahedral phase.
dral, I phase), regular decagonal phase (decagonal,
The high-strength according to claim 1, which is a D phase) or an approximate crystal phase thereof, and has a grain size of 1000 nm or less.
High ductility aluminum alloy. 4. The quasicrystal contained in the tissue has a volume ratio of 2
The high-strength, high-ductility aluminum alloy according to claim 1, which is 0 to 70%. 5. The high-strength, high-ductility aluminum alloy according to claim 1, wherein the main element, aluminum, is 90% or more, and the additive element, is less than 10%. 6. An aluminum alloy having the general formula: Albal
QaMb (however, Q: Mn, Cr, V, Ti, Nb,
At least one element selected from Mo, Ta, W,
M: at least one element selected from transition elements excluding quasicrystal forming elements (Q elements), rare earth elements including Y, and misch metal (Mm), and a and b are 0.5 ≦ a in atomic percent The high-strength, high-ductility aluminum alloy according to claim 1, which has a composition represented by ≦ 10, 0 ≦ b <9.5).