Title:
Aluminum alloy having a nano-complex phase
Kind Code:
A1


Abstract:
An aluminum alloy includes manganese of about 1.1% to about 7.0% by weight, magnesium of about 0.1% to about 6.0% by weight, scandium of about 0.01% to about 1.5% by weight and the balance is essentially aluminum. Alloying elements of scandium, manganese and magnesium are added to form a columnar grain structure with a nano-complex phase in the aluminum alloy. Accordingly, the aluminum alloy has a high degree of physical and mechanical properties.



Inventors:
Hong, Wei-pirn (Taipei City, TW)
Chen, Chan-tung (Kaohsiung City, TW)
Application Number:
11/498840
Publication Date:
02/07/2008
Filing Date:
08/04/2006
Assignee:
ADVANCED MATERIAL SPECIALTY INC.
NELSON PRECISION CASTING CO., LTD.
Primary Class:
Other Classes:
420/542
International Classes:
C22C21/06
View Patent Images:



Primary Examiner:
YANG, JIE
Attorney, Agent or Firm:
Joe McKinney Muncy (Fairfax, VA, US)
Claims:
What is claimed is:

1. An aluminum alloy having a nano-complex phase, comprising: manganese of about 1.1% to about 7.0% by weight; magnesium of about 0.1% to about 6.0% by weight; scandium of about 0.01% to about 1.5% by weight; and the balance being essentially iron aluminum wherein additions of the scandium, the manganese and the magnesium produce a columnar grain structure with the nano-complex phase in the aluminum alloy.

2. The aluminum alloy having the nano-complex phase as defined in claim 1, further comprising silicon of about 0.01% to about 0.50% by weight, iron of about 0.01% to about 0.10% by weight, copper of about 0.01% to about 0.50% by weight, chromium of about 0.01% to about 0.50% by weight, nickel of about 0.01% to about 0.50% by weight and mixtures thereof.

3. The aluminum alloy having the nano-complex phase as defined in claim 1, further comprising titanium of about 0.01% to about 0.10% by weight, vanadium of about 0.01% to about 0.10% by weight, cobalt of about 0.01% to about 0.10% by weight, zinc of about 0.01% to about 0.10% by weight, zirconium of about 0.01% to about 0.10% by weight, niobium of about 0.01% to about 0.10% by weight, molybdenum of about 0.01% to about 0.10% by weight, yttrium of about 0.01% to about 0.10% by weight, tungsten of about 0.01% to about 0.10% by weight, lanthanum of about 0.01% to about 0.10% by weight and mixtures thereof.

4. The aluminum alloy having the nano-complex phase as defined in claim 1, wherein the columnar grain structure has a diameter ranging from 40 nm to 100 nm.

5. The aluminum alloy having the nano-complex phase as defined in claim 1, wherein the columnar grain structure has a length ranging from 0.2 μm to 1.0 μm.

6. The aluminum alloy having the nano-complex phase as defined in claim 1, wherein the nano-complex phase has a growth orientation substantially extending along its longitudinal direction.

7. The aluminum alloy having the nano-complex phase as defined in claim 1, wherein the aluminum alloy is used to manufacture golf club heads, golf club shafts or other club head members.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an aluminum alloy having a nano-complex phase. More particularly, the present invention relates to the aluminum alloy of Mn—Mg—Al that contains a predetermined amount of scandium (Sc) so as to facilitate formation of a columnar grain structure in the aluminum alloy with the nano-complex phase.

2. Description of the Related Art

Throughout the history of aluminum, various aluminum alloys have been made. Currently there are over 400 wrought aluminum and wrought aluminum alloys registered with the Aluminum Association. Aluminum alloys can be categorized into a number of groups based on the particular material's characteristics such as its ability to respond to thermal and mechanical treatment and the principal alloying element added to the aluminum alloy. The wrought aluminum alloys has a system of identification which is a 4-digit system known as the 4-digit wrought aluminum identification system.

In the 4-digit wrought aluminum identification system, the first digit (Xxxx) indicates the principal alloying element, which has been added to the aluminum alloy and is often used to describe the aluminum alloy series, i.e. 1000 series, 2000 series, 3000 series, up to 8000 series (see Table 1). The second digit (xXxx), if different from 0, indicates a modification of the specific alloy as well as modification times from 1 to 9, and the third and fourth digits (xxXX) are arbitrary numbers given to identify a specific alloy in the series. For example, the third and fourth digits (xxXX) in the past are registered with Aluminum Company of America (Alcoa).

TABLE 1
Wrought Aluminum Alloy Designation System
Alloy SeriesPrincipal Alloying Element
10XX99.0% Minimum Aluminum
20XXCopper
30XXManganese
40XXSilicon
50XXMagnesium
60XXMagnesium and Silicon
70XXZinc
80XXOther Elements
90XXNew Alloy

In general, aluminum alloys are divided into two groups of heat treatable alloy and non-heat treatable alloy. The 20XX series, 40XX series, 60XX series and 70XX series are heat treatable aluminum alloys; the 10XX series, 30XX series and 50XX series non-heat treatable aluminum alloys. The heat treatable aluminum alloys acquire their optimum mechanical properties through a process of thermal treatment. The heat treatable aluminum alloy can be designed to have a higher degree of hardness or tensile strength by means of the process of precipitation hardening heat treatment. By way of example, 7075-type aluminum alloy is treated at a temperature in a range of about 115 degrees centigrade to about 125 degrees centigrade for 22 hours to 26hours.

TABLE 2
Mechanical Properties of Aluminum Alloy
TensileYielding Strength
Alloy SeriesStrength (kg/mm2)(kg/mm2)Elongation (%)
10805.5–9.51.530.0
201442.025.014.0
300520.0–25.017.0 2.0
305224.0–31.018.03.0–10.0
606130.025.010.0
707554.048.0 8.0

An aluminum-scandium alloy, as described in U.S. Pat. No. 5,597,529, entitled “ALUMINUM-SCANDIUM ALLOYS,” is directed to a modification of Aluminum Association alloy 6061 which has a composition of (0.4-0.8), Si-0.7 Fe-(0.15-0.4) Cu-0.15 Mn-(0.8-1.2) Mg-(0.04-0.35) Cr-0.25 Zn-0.15 Ti. The modified alloy essentially removes chromium from the 6061 alloy and adds scandium in its place to obtain enhanced properties. This modified alloy generally comprises about (0.2-1.8) Si-(0.2-0.8) Mn-(0.4-1.4) Mg-(0.02-10.0) Sc, and is substantially free of chromium.

Another aluminum-scandium alloy described in U.S. Pat. No. 5,597,529 is further directed to a modification of Aluminum Association alloy 2319 which has a composition of 0.2 Si-0.3 Fe-(5.8-6.8) Cu-(0.2-0.4) Mn-0.02 Mg-0.1 Zn-(0.05-0.15) V-(0.1-0.25) Zr-(0.1-0.2) Ti. The modified alloy essentially adds scandium to the 2319 alloy to obtain enhanced properties. This modified alloy generally comprises about (2.0-10.0) Cu-(0.02-10.0) Sc.

Another aluminum-scandium alloy described in U.S. Pat. No. 5,597,529 is further directed to a modification of Aluminum Association alloy 5356 which has a composition of 0.25 Si-0.4 Fe-0.1 Cu-(0.05-0.2) Mn-(4.5-5.5) Mg-(0.05-0.2) Cr-0.1 Zn-(0.06-0.2) Ti. The modified alloy essentially adds scandium to the 5356 alloy to obtain enhanced properties. This modified alloy generally comprises about (2.7-6.0) Mg-(0.02-10.0) Sc.

Another aluminum-scandium alloy described in U.S. Pat. No. 5,597,529 is further directed to a modification of Aluminum Association alloy 4043 which has a composition of (4.5-6.0) Si-0.8. Fe-0.3 Cu-0.05 Mn-0.05 Mg-0.1 Zn-0.2 Ti. The modified alloy essentially adds scandium to the 4043 alloy to obtain enhanced properties. The modified alloy generally comprises about (3.0-15.0) Si-(0.02-10.0) Sc.

As mentioned above, the modified alloy may add a greater amount of scandium to alloy 6061, alloy 2319, alloy 5356 and alloy 4043. However, scandium is a high-cost metal. While the addition of scandium to the alloy may have an effect on the very high degree of mechanical property, it is generally considered to be too expensive for use as an ordinary alloyed material. Hence, there is a need for reducing the amount of scandium and increasing the amount of low-cost metals for achieving the alloy at a relatively reasonable cost.

Still, there is a need for forming a columnar grain structure in the aluminum alloy such that the mechanical strength of the aluminum alloy can be increased without being treated in the process of heat treatment. To this end, the principal alloying elements added to the aluminum alloy may be changed or adjusted for gaining a higher degree of mechanical strength.

As is described in greater detail below, the present invention intends to provide an aluminum alloy having a nano-complex phase through the addition of alloying elements. The aluminum alloy adds a small amount of scandium and a greater amount of low-cost metal which can facilitate formation of the nano-complex phase. The addition of the alloying elements may produce a uniform columnar grain structure in the aluminum alloy in precipitation during solidification in such a way as to mitigate and overcome the above problem.

SUMMARY OF THE INVENTION

The primary objective of this invention is to provide an aluminum alloy having a nano-complex phase, wherein predetermined amounts of scandium (Sc), manganese (Mn) and magnesium (Mg) are added to the aluminum alloy to form a columnar grain structure with the nano-complex phase. Accordingly, the mechanism properties of the aluminum alloy are improved or enhanced.

The secondary objective of this invention is to provide the aluminum alloy having the nano-complex phase, wherein predetermined amounts of scandium (Sc), manganese (Mn) and magnesium (Mg) are added to the aluminum alloy to form the nano-complex phase. The nano-complex phase of the aluminum alloy may be treated through a process of heat treatment for adjusting a growth orientation along its longitudinal direction. Accordingly, the mechanism properties of the aluminum alloy are further improved or enhanced.

Another objective of this invention is to provide the aluminum alloy having the nano-complex phase, wherein the aluminum alloy adds a small amount of scandium and a greater amount of manganese. Accordingly, the aluminum alloy is achieved at a relatively reasonable cost.

The aluminum alloy in accordance with an aspect of the present invention includes manganese of about 1.1% to about 7.0% by weight, magnesium of about 0.1% to about 6.0% by weight, scandium of about 0.01% to about 1.5% by weight and the balance is essentially aluminum. Alloying elements of scandium, manganese and magnesium are added to form a columnar grain structure with a nano-complex phase in the aluminum alloy. Accordingly, the aluminum alloy has a high degree of physical and mechanical properties.

In a separate aspect of the present invention, the aluminum alloy includes silicon of about 0.01% to about 0.50% by weight, iron of about 0.01% to about 0.10% by weight, copper of about 0.01% to about 0.50% by weight, chromium of about 0.01% to about 0.50% by weight, nickel of about 0.01% to about 0.50% by weight and mixtures thereof.

In a further separate aspect of the present invention, the aluminum alloy includes titanium of about 0.01% to about 0.10% by weight, vanadium of about 0.01% to about 0.10% by weight, cobalt of about 0.01% to about 0.10% by weight, zinc of about 0.01% to about 0.10% by weight, zirconium of about 0.01% to about 0.10% by weight, niobium of about 0.01% to about 0.10% by weight, molybdenum of about 0.01% to about 0.10% by weight, yttrium of about 0.01% to about 0.10% by weight, tungsten of about 0.01% to about 0.10% by weight, lanthanum of about 0.01% to about 0.10% by weight and mixtures thereof.

In a yet further separate aspect of the present invention, the columnar grain structure has a diameter ranging from 40 μm to 100 μm.

In a yet further separate aspect of the present invention, the columnar grain structure has a length ranging from 0.2 μm to 1.0 μm.

In a yet further separate aspect of the present invention, the nano-complex phase has a growth orientation substantially extending along its longitudinal direction.

In a yet further separate aspect of the present invention, the aluminum alloy is used to manufacture golf club heads, golf club shafts or other club head members.

Further scope of the applicability of the present invention will become apparent from the detailed description given. hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a photomicrograph of a cross section of an aluminum alloy having a nano-complex phase in accordance with a preferred embodiment of the present invention, with a magnification of 15,000 times, illustrating a columnar grain structure (encircled portion) along a longitudinal direction thereof; and

FIG. 2 is a photomicrograph of a cross section of the aluminum alloy having the nano-complex phase in accordance with the preferred embodiment of the present invention, with a magnification of 15,000 times, illustrating a columnar grain structure (encircled portion) along a cross-sectional direction thereof.

DETAILED DESCRIPTION OF THE INVENTION

An aluminum alloy having a nano-complex phase in accordance with a preferred embodiment of the present invention includes major elements of Aluminum (Al), manganese (Mn) and magnesium (Mg). In the preferred embodiment, the aluminum alloy includes manganese of about 1.1% to about 7.0% by weight, magnesium of about 0.1% to about 6.0% by weight and the balance is essentially aluminum. The aluminum alloy acquires a mechanical property of toughness according to an amount of aluminum addition. The addition of manganese enhances the aluminum alloy to possess a high degree of hardness. Also, the addition of magnesium further enhances the aluminum alloy to possess a high degree of strength and corrosion resistance.

Referring now to FIGS. 1 and 2, the aluminum alloy in accordance with the preferred embodiment of the present invention further includes scandium of about 0.01% to about 1.5% by weight. The addition of scandium may produce uniform distribution and nucleation of columnar grain structures in the aluminum alloy in precipitation during solidification, as best shown in encircled portions in FIGS. 1 and 2. The nano-complex phase is formed in the uniform columnar grain structure. The columnar grain structure has a diameter ranging from 40 nm to 100 nm, and a length ranging from 0.2 μm to 1.0 μm that constitute the nano-complex phase. It would be desire that the amount of manganese ranging from 1.1 wt % to 7.0 wt % can facilitate formation of the columnar grain structure in the aluminum alloy.

In a preferred embodiment, when solidified, the aluminum alloy is treated in a heat treatment process so as to adjust major growth orientations of the nano-complex phase of the aluminum alloy substantially extending along their longitudinal directions. It would be desire that the heat treatment process can ensure the diameters of the grains within the nano sizes. Advantageously, the heat treatment can significantly increase physical and mechanical properties of the modified aluminum alloy.

In addition, the modified aluminum alloy of the present invention may further include alloying elements, silicon (Si), iron (Fe), copper (Cu), chromium (Cr), nickel (Ni) and mixtures for example, without departing from the scope and spirit of the present invention. In a preferred embodiment, the aluminum alloy includes silicon of about 0.01% to about 0.50% by weight, iron of about 0.01% to about 0.10% by weight, copper of about 0.01% to about 0.50% by weight, chromium of about 0.01% to about 0.50% by weight, nickel of about 0.01% to about 0.50% by weight and mixtures thereof. Consequently, the additions of these alloying elements can further enhance physical and mechanical properties of the modified aluminum alloy.

In addition to the foregoing, the modified aluminum alloy of the present invention may further include other alloying elements, titanium (Ti), vanadium (V), cobalt (Co), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), yttrium (Y), tungsten (W), lanthanum (La) and mixtures for example, without departing from the scope and spirit of the present invention. In a preferred embodiment, the aluminum alloy includes titanium of about 0.01% to about 0.10% by weight, vanadium of about 0.01% to about 0.10% by weight, cobalt of about 0.01% to about 0.10% by weight, zinc of about 0.01% to about 0.10% by weight, zirconium of about 0.01% to about 0.10% by weight, niobium of about 0.01% to about 0.10% by weight, molybdenum of about 0.01% to about 0.10% by. weight, yttrium of about 0.01% to about 0.10% by weight, tungsten of about 0.01% to about 0.10% by weight, lanthanum of about 0.01% to about 0.10% by weight and mixtures thereof. Consequently, the additions of these alloying elements can further enhance physical and mechanical properties of the modified aluminum alloy.

The differences of mechanical properties between the modified aluminum alloy and the conventional aluminum alloys are set forth in Table 3. In Table 3, the mechanical properties typically include data of tensile strength, yielding strength and elongation. The mechanical properties of the conventional aluminum alloys (representing three different alloys) and the modified aluminum alloy. of the present invention are compared, according to data in Table 3.

TABLE 3
Comparison Table for Mechanical Properties of the modified
aluminum alloy and conventional aluminum alloys
Mechanical Property
Tensile StrengthYielding StrengthElongation
Alloy Type(ksi*)(ksi*)(%)
Low-Carbon Steel583225
1025**
A356 T640306
A357 Cast O-T6245353
Embodiment57429
*ksi = 103 psi.
**Hot Rolled Low-Carbon Steel.

In comparison with the conventional alloys of A356 T6 and A357 Cast O-T62, the modified aluminum alloy of the present invention has a significant increase in each of mechanical properties of tensile strength, yielding strength and elongation, as can be seen from Table 3. In comparison with the conventional alloys of hot rolled low-carbon steel (low-carbon steel 1025), the modified aluminum alloy of the present invention still has a significant increase in yielding strength even if there is a decrease in elongation. Furthermore, the tensile strength of the modified aluminum alloy is similar to that of the hot rolled low-carbon steel (low-carbon steel 1025). The modified aluminum alloy, however, possesses an adequate degree of elongation due to the improvement compared to the conventional aluminum alloy (A356 T6 and A357 Cast O-T62) These results indicate that the additions of the relatively smaller amount of scandium (0.01 wt % to 1.5 wt %) and the relatively greater amount of manganese (1.1 wt % to 7.0 wt %) improve the mechanical properties of the modified aluminum alloy. Consequently, the modified aluminum alloy of the present invention is suitable for manufacturing sport equipments, such as golf club heads, golf club shafts or other club head members (e.g. club weight members).

In FIGS. 1 and 2, two photomicrographs, with a magnification of 15,000 times, of an aluminum alloy having a columnar grain structure (encircled portion) along longitudinal and cross-sectional directions thereof in accordance with a preferred embodiment of the present invention are illustrated. It is apparent from FIGS. 1 and 2, the addition of the designated amount of scandium and magnesium may produce uniform distribution and nucleation of columnar grain structures in the aluminum alloy in precipitation during solidification. Subsequently, the modified aluminum alloy may be treated through a process of heat treatment for adjusting a growth orientation along its longitudinal direction such that diameters of the grain structure can be maintained within nano sizes. Furthermore, the aluminum alloy may be modified to maintain mechanical properties similar to those of the low-carbon steel even if the elongation of the modified aluminum alloy is lower than that of low-carbon steel. Nonetheless, the elongation of the modified aluminum alloy is still greater than that of alloy A356 T6 or alloy A357 Cast O-T62 such that the modified aluminum alloy is suitable for manufacturing golf club heads, golf club shafts or other club head members. Yet furthermore, the modified aluminum alloy possesses a greater degree of corrosion resistance.

The compositions, the nano-complex phase and manufacturing cost of the modified aluminum alloy and the conventional aluminum alloys are set forth in Table 4. In Table 4, the compositions of the aluminum alloy include scandium, manganese and magnesium.

TABLE 4
Comparison Table for Compositions, Nano-Complex Phase
and Manufacturing Cost of Conventional Aluminum Alloy
and Modified Aluminum Alloy of the Present Invention
Nano-
ScMnComplex
Alloy Type(wt %)*(wt %)**Mg (wt %)PhaseCost
Modified Alloy<1.5%1.1%–7.0%0.1%–6.0%ExcellentLow
Conventional>1.5%<1.1%0.1%–6.0%NoneHigh
Alloy
*high-cost metal
**low-cost metal

The modified aluminum alloy adds a small amount of scandium and a greater amount of magnesium for facilitating formation of the nano-complex phase, as can be seen from Table 4. The conventional aluminum alloy cannot produce a nano-complex phase due to the fact that the amount of magnesium is smaller than 1.1 wt %. In addition to this, the conventional aluminum alloy cannot reduce the manufacturing cost due to the fact that the amount of scandium is greater than 1.5 wt %. In the preferred embodiment, the modified aluminum alloy adds a smaller amount of scandium (i.e. smaller than 1.5 wt %) and a greater amount of magnesium (i.e. greater than 1.1 wt %). Advantageously, the modified aluminum alloy possesses improved mechanical properties and also reduces manufacturing cost by using a greater amount of low-cost metal.

It will be apparent from the aforementioned discussions that the conventional aluminum alloy adds a smaller amount of magnesium that cannot facilitate the formation of the nano-complex phase of scandium in the aluminum alloy during solidification. Conversely, the modified aluminum alloy has an increase in the predetermined amount of magnesium (i.e. low-cost metal), a decrease in the predetermined amount of scandium (i.e. high-cost metal) such that a columnar grain structure is formed in the nano-complex phase. Advantageously, such a modified aluminum alloy. possesses a high degree of mechanical properties and also reduces the manufacturing cost.

Although the invention has been described in detail with reference to its presently preferred embodiment, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims.