JP5069111B2 - Al-Si-Mg-Zn-Cu alloy for aerospace and automotive castings - Google Patents

Description

<Description of related applications>
This application claims the benefit of US Provisional Application No. 60 / 592,051, filed July 28, 2004, which is hereby incorporated by reference in its entirety.

<Field of Invention>
The present invention relates to an aluminum alloy, and more specifically to an aluminum casting alloy containing silicon (Si), magnesium (Mg), zinc (Zn), and copper (Cu).

<Background of the invention>
Aluminum castings are widely used in the aerospace and automotive industries for weight reduction. The most common cast alloy used is Al-Si ₇ -Mg, strength limit has been established. At present, E357 is the most commonly used Al-Si7-Mg alloy, and this cast material has a maximum tensile strength of 310 MPa (45,000 psi) and a tensile yield strength of 260 MPa (37 709 psi) and an elongation of 5% or more is guaranteed. In order to obtain lighter parts, it is necessary to verify the material properties of the design for higher strength and higher ductility materials.

  Various alternative alloys with higher strength exist and are registered. However, these alloys have potential problems in castability, corrosion potential, or fluidity, and it is not easy to solve these problems, so they are inferior in suitability for use. Therefore, there is a demand for an alloy having better mechanical properties than Al-Si7-Mg alloys such as E357, as well as good castability, corrosion resistance and other desired properties.

<Outline of the invention>
The present invention provides a novel AlSiMg alloy with improved mechanical properties, as well as shaped castings made from the AlSiMg alloy and a method for producing a shape casting from the AlSiMg alloy. The AlSiMg alloy composition of the present invention improves mechanical properties (for example, but not limited to, maximum tensile strength (UTS) and tensile yield strength (TYS)) over conventional AlSi7Mg alloys (eg, E357). Zn, Cu, and Mg are contained so that it may become a suitable ratio.

One aspect of the present invention is an aluminum cast alloy, the aluminum cast alloy of the present invention,
Si: 4% to 9%
Mg: 0.1-0.7%
Zn: 5% or less,
Fe: less than 0.15%,
Cu: less than 4%,
Mn: less than 0.3%,
B: Less than 0.05%
Ti: less than 0.15%,
The balance is essentially aluminum.

  In addition, said% is represented by weight% (wt%). In some embodiments of the present invention, the proportions of Zn, Cu and Mg are selected so as to obtain an AlSiMg alloy having improved strength characteristics compared to a conventional AlSi7Mg alloy (eg, E357). In one embodiment of the present invention, “improved strength characteristics” refers to an elongation equal to an E357 casting for a T6 grade investment casting for room temperature or high temperature applications as compared to an E357 casting made in the same manner. This means an increase or improvement of about 20% to 30% in tensile yield strength (TYS) and about 20% to 30% in ultimate tensile strength (UTS). .

    In some embodiments of the present invention, increasing the Cu content of the alloy can be achieved by increasing the maximum tensile strength (UTS) and tensile at room temperature (22 ° C.) and elevated temperature (100 ° C. to 250 ° C., preferably 150 ° C.). This is to increase the yield strength (TYS). Maximum tensile strength (UTS) and tensile yield strength (TYS) are generally understood to decrease with increasing temperature, but with Cu, compared to similar AlSiMg alloys not containing Cu, In general, it was found that the high-temperature strength characteristics were improved. In one embodiment of the present invention, the Cu content is kept to a minimum in order to increase the high temperature elongation. It should be further noted that the elongation (E) generally increases with increasing temperature.

  In some embodiments of the present invention, the choice of Cu and Mg content in the alloy is to improve the maximum tensile strength (UTS) and yield tensile strength (YTS) at room temperature (22 ° C.) and high temperature. To do. In some embodiments of the present invention, the inclusion of Zn can increase the elongation of alloys with compositions containing Cu and more Mg. In some embodiments of the present invention, the inclusion of Zn reduces the elongation of alloys with compositions containing Cu and less Mg. When Zn is contained, the elongation at room temperature is affected, but the same tendency is observed even at high temperatures.

  In some embodiments of the invention, the Cu content is 2% or less and the Zn content is in the range of about 3% to about 5%. Within this range, the higher the Zn content, the higher the maximum tensile strength (UTS) and the yield tensile strength (TYS) of the alloy. It has also been found that when the alloy of the present invention contains Zn, the maximum tensile strength (UTS) of the alloy is generally slightly reduced when the Cu concentration in the alloy exceeds 2%. In one embodiment, if the Cu content is greater than 2%, the Zn content is reduced to less than 3%. In one example, if the Cu content is greater than 2%, the Zn content may be 0%. In another embodiment of the invention, the selection of Cu, Zn and Mg content is done to increase elongation. In the alloy of the present invention, when the Zn content is less than 2.5 wt%, Mg has a positive effect (increase in elongation), and when the Zn content exceeds 2.5 wt%, it has a negative effect (elongation of elongation). Decline). In one embodiment of the present invention, the maximum tensile strength (UTS) of the alloy is increased by adding less than 0.5 wt% Ag.

  In some embodiments of the present invention, the choice of Mg, Cu and Zn concentrations is made to positively affect the quality index of the alloy at room temperature and elevated temperature. The quality index represents strength and elongation. Inclusion of Cu increases the strength of the alloy, but on the other hand, it lowers the elongation of the alloy, which may reduce the quality index of the alloy. In one embodiment, an inventive alloy that includes Cu and greater than 1 wt% Zn includes Mg to increase the quality index of the alloy. Furthermore, when the Mg content is high (eg, on the order of 0.6 wt%) and the Cu content is low (eg, less than 2.5 wt%), Zn increases the quality index.

  Inventive alloys are used for F, T5 or T6 heat treatment. In addition, the fluidity of the alloy is improved compared to E357.

Another aspect of the present invention is a shape casting, and the shape casting of the present invention comprises:
Si: 4% to 9%
Mg: 0.1-0.7%
Zn: 5% or less,
Fe: less than 0.15%,
Cu: less than 4%,
Mn: less than 0.3%,
B: Less than 0.05%
Ti: less than 0.15%,
The balance is essentially aluminum.

A further aspect of the invention is a method of producing a shape casting, the method of the invention comprising:
Si: 4% to 9%
Mg: 0.1-0.7%
Zn: 5% or less,
Fe: less than 0.15%,
Cu: less than 4%,
Mn: less than 0.3%,
B: Less than 0.05%
Ti: less than 0.15%,
The balance essentially aluminum,
Producing a molten metal mass that is

  One embodiment of the method of the present invention for producing an aluminum alloy product includes casting a molten metal mass into an aluminum alloy casting, such as investment casting, low pressure or gravity casting, permanent or semi-permanent mold casting, squeeze There are casting, die casting, directional casting or sand casting. The production method of the present invention includes providing a chill and a riser in the mold. In one embodiment of the invention, the molten metal mass is a thixotropic metal mass and the production of the aluminum alloy product includes semi-solid casting or forming.

<Detailed Description of the Invention>
Table 1 shows the composition of various alloys according to the present invention and a comparative conventional alloy E357. Various tests including mechanical property tests were conducted on the alloys shown in Table 1, and the test results are shown in FIGS.

  The values in Table 1 represent the various elements contained in the test sample in weight percent. The numerical values described in the leftmost alloy column are target values for copper and zinc contained in the alloy (except for the conventional alloy E357 in the last row).

  In Table 1, the actual content of Cu, Zn, Si, Mg, Fe, Ti, B, and Sr is shown by weight% for each sample.

  Samples having the compositions shown in Table 1 were cast with a unidirectional solidification test mold and examined for mechanical properties. Next, the obtained cast product was heat-treated according to T6 quality. Samples were taken from areas of different casting solidification rates. Thereafter, the tensile properties of the samples were evaluated at room temperature.

  FIG. 1a shows the tensile strength of an aluminum alloy sample. The aluminum alloy sample contains about 7% Si and about 0.5% Mg, and the concentrations of Cu and Zn are as described in the figure. The sample of FIG. 1 was coagulated at a rate of about 1 ° C./second. These samples had a dendrite arm spacing (DAS) of about 30 microns. It can be seen that the tensile strength of the alloy increases with increasing Zn concentration (the maximum Zn content in the test is about 3.61%). Similarly, it can be seen that the tensile strength increases with increasing Cu concentration (the maximum Cu content in the test is about 3%). Samples containing Cu and / or Zn showed higher strength than the conventional alloy E357.

  FIG. 1b shows data similar to FIG. 1a, but the difference from that of FIG. 1a is that the dendrite arm spacing was about 64 microns due to the slow solidification rate of about 0.4 ° C./sec. That is. The sample with the maximum tensile strength was a sample of about 3% Cu and about 3.61% Zn. All of the samples shown in FIG. 1b contained Cu and / or Zn and were stronger than the conventional alloy E357.

  FIG. 2a shows the yield strength of the aluminum alloy sample. The aluminum alloy sample contains about 7% Si and about 0.5% Mg, and the concentrations of Cu and Zn are as described in the figure. These samples were coagulated at a rate of about 1 ° C./second. These samples had a dendrite arm spacing (DAS) of about 30 microns. The yield strength of the alloy increased remarkably with increasing Cu, and showed an increasing trend with increasing Zn. The sample with the maximum yield strength was a sample of about 3% Cu and about 4% Zn. All samples containing Cu or Zn showed yield strength greater than the conventional alloy E357.

  FIG. 2b shows data similar to FIG. 2a, except that the dendrite arm spacing was about 64 microns due to the slow solidification rate of about 0.4 ° C./sec. That is. The sample with the maximum yield strength was a sample of about 3% Cu and about 4% Zn. All samples containing Cu or Zn had higher yield strength than the conventional alloy E357.

  FIG. 3a shows the elongation data for the conventional alloy E357 and various alloys with added Cu and Zn. The solidification rate was 1 ° C./second and the dendrite arm spacing was about 30 microns. The alloys with the highest elongation were those with 0% Cu content. However, increasing the Zn concentration from 2% to about 4% increased the elongation. Alloys containing about 2% to 4% Zn exhibited greater elongation than the conventional alloy E357.

  FIG. 3b shows data similar to FIG. 3a, except that the dendrite arm spacing was about 64 microns due to the slow solidification rate of about 0.4 ° C./sec. That is. As described above, the alloy with 0% Cu content showed the largest elongation. However, alloys with 0% Cu and 2% to 4% Zn were only slightly inferior to E357 in terms of elongation. An alloy containing 2% to 4% of Zn is important in that the tensile strength and yield strength are superior to E357.

  FIG. 4 shows the results of casting with a fluidity mold. Similar to the above, the test was performed on aluminum alloys containing about 7% Si and about 0.5% Mg and having different contents of Cu and Zn. Most of the alloy of FIG. 4 contained Cu or Zn, and showed better fluidity than the conventional alloy E357. An alloy containing 3% Cu and 4% Zn showed the best fluidity. Flowability is important for shape castings because it affects the ability of the alloy to flow through small passages in the mold to supply liquid metal to all parts of the casting.

  FIG. 5 shows data relating to the quality index (Q) of the tested alloys. The quality index (Q) is a calculated index and includes maximum tensile strength (UTS) and logarithmic elongation (E). FIG. 5 shows a graph plotting the data of the two types of dendrite arm spacing described above. A sample having an arm interval of 30 microns is a sample having a cooling rate of 1 ° C./second, and a sample having an arm interval of 64 microns is a sample having a cooling rate of 0.4 ° C./second. As shown in FIG. 5, generally, the best quality factor (Q) is obtained for a sample having a high Zn concentration and a low Cu concentration.

  Table 2 shows various compositions of the alloys according to the present invention, and the concentrations of Cu, Mg and Zn were selected to provide improved mechanical properties at room temperature and elevated temperature. In Table 2, the contents of various elements of the tested samples are shown in% by weight. The balance of each alloy consists essentially of aluminum. Sr is included as a crystal refining material.

  Test pieces were prepared from samples having the above composition for mechanical property testing. The test piece was formed into a plate shape by investment casting. The cooling rate for investment casting was slower than about 0.5 ° C./second and the dendrite arm spacing (DAS) was on the order of about 60 microns or more. After casting, the test plate was heat treated to T6 temper. In general, T6 sorting includes solution heat treatment, quenching and artificial aging. The test plate was cut and examined for mechanical properties. Specifically, for a test piece including the alloy composition shown in Table 2, the maximum tensile strength (UTS) at room temperature (22 ° C.), the maximum tensile strength (UTS) at high temperature (150 ° C.), room temperature ( (22 ° C) tensile yield strength (TYS), high temperature (150 ° C) tensile yield strength (TYS), high temperature (150 ° C) elongation (E), room temperature (22 ° C) elongation (E ), Quality index (Q) at high temperature (150 ° C.), and quality index (Q) at room temperature (22 ° C.). The test results are shown in Table 3 below.

From the above data in Table 3, regression of tensile yield strength (TYS) at room temperature (22 ° C), maximum tensile strength (UTS) at room temperature (22 ° C), elongation (E) at room temperature (22 ° C) The model is as follows.
TYS (MPa) at room temperature (22 ° C.) = 322.04-25.9466 * Mg (wt%) + 19.5276 Cu (wt%) − 4.8189 Zn (wt%) + 1.5766 Si (wt%) + 19.08 Mg (wt%) Zn (wt%)-2.1535 Cu (wt%) Zn (wt%)-119.57Sr (wt%)
UTS (MPa) at room temperature (22 ° C.) = 373.188−71.5565 * Mg (wt%) + 14.5255Cu (wt%) − 6.0743Zn (wt%) + 4.557444Si (wt%) + 23.212Mg (wt%) Zn (wt%) -3,4964 Cu (wt%) Zn (wt%) + 79.2381 Sr (wt%)
E (%) at room temperature (22 ° C.) = 7.119-11.548 * Mg (wt%) − 1.055 Cu (wt%) − 0.117 Zn (wt%) + 0.739 Si (wt%) − 0 .801 Mg (wt%) Zn (wt%) + 0.173 Cu (wt%) Zn (wt%) + 16.903 Sr (wt%).

From the above data in Table 3, tensile yield strength (TYS) at high temperature (150 ° C), maximum tensile strength (UTS) at high temperature (150 ° C), elongation (E) at high temperature (150 ° C) and high temperature A regression model of the quality index (Q) at (150 ° C.) is obtained as follows.
TYS (MPa) at high temperature (150 ° C.) = 279.465 + 29.792 * Mg (wt%) + 14.0 Cu (wt%) + 0.4823 Zn (wt%) − 0.503 Si (wt%) + 6.566 Mg (wt %) Zn (wt%)-1.998Cu (wt%) Zn (wt%)-3.686Sr (wt%)
UTS (MPa) at high temperature (150 ° C.) = 293.3 + 15.723 * Mg (wt%) + 18.32 Cu (wt%) + 0.441 Zn (wt%) + 1.264 Si (wt%) + 9.811 Mg (wt%) ) Zn (wt%)-37344 Cu (wt%) Zn (wt%)-145.682 Sr (wt%)
E (MPa) = 13.575-20.454 * Mg (wt%)-1.672Cu (wt%)-4.812Zn (wt%) + 1.184Si (wt%) + 8.138Mg at high temperature (150 ° C.) (wt%) Zn (wt%) + 0.014 Cu (wt%) Zn (wt%) -26.65 Sr (wt%)
Q (MPa) at high temperature (150 ° C.) = 447.359-138.331 * Mg (wt%) − 0.4181 Cu (wt%) − 65.285 Zn (wt%) + 14.36 Si (wt%) + 130 .69 Mg (wt%) Zn (wt%)-6.043 Cu (wt%) Zn (wt%) + 405.71 Sr (wt%)

  Regression models of maximum tensile strength (UTS) at high temperature (150 ° C), elongation (E) at high temperature (150 ° C), and quality index (Q) at high temperature (150 ° C) are shown in Figs. Plotted.

  The graph of FIG. 6 plots the maximum tensile strength (UTS) (MPa) at high temperature (150 ° C.) as a function of increasing Zn concentration (wt%) for alloy compositions with different Mg and Cu concentrations. It is. Specifically, the reference line (15) is a plot of the present alloy containing about 0.6 wt% Mg and about 3 wt% Cu, and the reference line (20) is about 0.5 wt% Mg and Cu. The alloy of the present invention containing about 3 wt% is plotted, and the reference line (25) is a plot of the alloy of the present invention containing about 0.6 wt% Mg and about 2 wt% Cu. Is a plot of an alloy of the present invention containing about 0.5 wt% Mg and about 2 wt% of Cu, and the reference line (35) is a plot of an alloy of the present invention containing about 0.6 wt% Mg and about 1 wt% Cu. The reference line (40) is a plot of the present alloy containing about 0.5 wt% Mg and about 1 wt% Cu, and the reference line (45) contains about 0.6 wt% Mg. , Cu of 0 wt% is plotted, and the reference line (50) is about 0.5 wt. %, The alloy of the present invention which is Cu 0 wt% is plotted.

  Referring to the graph depicted in FIG. 6 and the data listed in Table 3, the Cu concentration of the alloy is about 2 wt% as shown by the alloy of the reference line (15) (20) (25) (30). As the above increases, it can be seen that the inclusion of Zn has a negative effect on the maximum tensile strength (UTS) of the alloy at high temperatures. Also, as shown in the reference line (35) (40) (45) (50) alloy, when the Cu concentration of the alloy decreases to less than about 2 wt%, the Zn content is the maximum tensile strength of the alloy at high temperatures. It turns out that it has a positive effect on (UTS). Although not wishing to be bound by theory, the negative effect of Zn on the strength of alloys with high Cu content is that particles formed by the interaction of Zn and Cu are solution heat treated in the T6 heat treatment step. It is thought that it does not dissolve in the inside. Particles that do not dissolve are considered to reduce the strength and elongation properties of the casting.

  With further reference to FIG. 6, in some embodiments of the present invention, the alloy containing 0.6 wt% Mg, as shown in the alloys of baseline (15) (25) (35) (45), It shows that the maximum tensile strength (UTS) at a high temperature is larger than that of an alloy having a similar composition of (20), (30), (40) and (50) with an Mg concentration on the order of about 0.5 wt%.

  The graph depicted in FIG. 7 plots the elongation (%) at high temperature (150 ° C.) as a function of increasing Zn concentration (wt%) for alloy compositions having different Mg and Cu concentrations. Specifically, the reference line (55) is a plot of an alloy of the present invention containing about 0.6 wt% Mg and about 3 wt% Cu, and the reference line (60) is about 0.5 wt% Mg and Cu. The alloy of the present invention containing about 3 wt% is plotted, and the reference line (65) is a plot of the alloy of the present invention containing about 0.6 wt% Mg and about 2 wt% Cu. Is a plot of an alloy of the present invention containing about 0.5 wt% Mg and about 2 wt% of Cu, and the reference line (75) is a plot of an alloy of the present invention containing about 0.6 wt% Mg and about 1 wt% Cu. The reference line (80) is a plot of the present alloy containing about 0.5 wt% Mg and about 1 wt% Cu, and the reference line (85) contains about 0.6 wt% Mg. , Cu of the present invention is plotted with 0 wt%, and the reference line (90) is about 0.5 wt. %, The alloy of the present invention which is Cu 0 wt% is plotted.

  Referring to the graph depicted in FIG. 7 and the data listed in Table 3, it can be seen that increasing the Cu concentration of the inventive alloy has a negative effect on the elongation of the alloy. For example, referring to the reference line (55) (65) (75) (85) where the Mg concentration is 0.6 wt%, it can be seen that the elongation of the alloy decreases as the Cu content increases. Moreover, it is shown that the Cu concentration has the same effect on the alloy indicated by the reference lines (60) (70) (80) (90) where the Mg concentration is about 0.5 wt%.

  Referring further to Table 3 and FIG. 7, in one embodiment of the present invention, when the Zn content of the inventive alloy increases, as shown by the reference lines (60) (70) (80) (90), Mg It can be seen that when the content is small (for example, on the order of 0.5 wt%), the elongation of the alloy is increased. In one embodiment of the present invention, when the Zn content of the invention alloy increases, the Mg content increases (for example, 0.6 wt%) as indicated by the reference lines (55) (65) (75) (85). It is understood that the elongation of the alloy is reduced. When the Zn content is greater than 2.5 wt%, Mg has a positive effect on elongation, and when the Zn content is less than 2.5 wt%, it has a negative effect on elongation. For example, referring to the reference line (55) (60) where the Cu content in the alloy is equal to 3.0 wt%, when the Zn content in the alloy is 2.5 wt% or more, the Mg concentration is reduced from 0.5 wt% to 0 wt%. When it increases to .6 wt%, the quality index (Q) improves. Furthermore, the Mg concentration has a similar effect on alloys with less than 3.0 wt% Cu.

  The graph depicted in FIG. 8 is a plot of the quality index (Q) at high temperature (150 ° C.) as a function of Zn content for the AlSiMg alloys of the present invention with different concentrations of Cu and Mg. Specifically, the reference line (95) is a plot of an alloy of the present invention containing about 0.5 wt% Mg and about 3 wt% Cu, and the reference line (100) is about 0.5 wt% Mg and Cu. The alloy of the present invention containing about 2 wt% is plotted, and the reference line (105) is a plot of the alloy of the present invention containing about 0.5 wt% Mg and about 1 wt% Cu. Is a plot of an alloy of the present invention containing about 0.6 wt% Mg and about 2 wt% of Cu, and the reference line (75) is a plot of an alloy of the present invention containing about 0.6 wt% Mg and about 1 wt% Cu. The reference line (120) is a plot of the alloy of the present invention containing about 0.5 wt% Mg and 0 wt% Cu, and the reference line (125) is about 0.6 wt% Mg and Cu The alloy according to the present invention containing about 1 wt% is plotted, and the reference line (85) is about 0.6 Mg. Include t%, it plots the invention alloy is Cu0wt%, baseline (130) includes Mg of about 0.6 wt%, is a plot of the present invention alloy is Cu0wt%. As described above, the quality index (Q) is a calculated index, and includes the maximum tensile strength (UTS) and the logarithmic elongation (E).

Referring to the data of FIG. 8 and Table 3, the alloys of the present invention generally increase the maximum tensile strength (UTS) and / or the tensile yield strength (TYS) as the Cu content increases. However, on the other hand, the elongation may be lowered to lower the quality index (Q) of the alloy. Mg generally has a positive effect on the quality index of the alloy of the present invention containing Cu and Zn (however, the Zn content is 1.2 wt% or more). For example, referring to the reference line (95) (105) where the Cu concentration is 3.0 wt%, when the Zn content is 1.2 wt% or more, the Mg concentration is changed from 0.5 wt% to 0.6 wt%. It can be seen that the quality index (Q) improves as the value increases. Further, the Mg concentration indicates that the same effect is obtained even for an alloy having a Cu concentration of less than about 3.0 wt%. In some embodiments of the present invention, an AlSiMg alloy with a high Cu concentration (e.g., an alloy indicated by the reference lines (95) (100) (105) (120)) has a quality index (Q ) Value decreases.
Decrease. In some embodiments of the present invention, as indicated by the reference lines (115) (125) (130), the Mg content is on the order of about 0.6 wt% and the Cu content is less than about 2.5 wt%. When the content is small, the quality index (Q) of the alloy is improved by containing Zn.

  The alloy compositions listed in Table 3 are examples of invention alloys, and the invention is not limited thereto, and all compositions having the components and ranges recited in the claims are not limited to the invention. Is within the range. Further examples of alloy compositions that are within the scope of the present invention are shown in the table of FIG. FIG. 9 includes tensile yield strength (TYS), maximum tensile strength (UTS), elongation (E), and quality index (Q) for alloys of the illustrated composition, where TYS, UTS, E, and Q are It was obtained from a T6 quality test sample at room temperature (22 ° C.).

  The last row of the table in FIG. 9 shows the alloy composition, mechanical properties at room temperature (22 ° C.) (Tensile Yield Strength (TYS), Maximum Tensile) for specimens of T357 graded E357 alloy produced by investment casting. Strength (UTS), elongation (E) and quality index (Q)). The E357 alloy is a conventional alloy and is included for comparison. Still referring to FIG. 9, E357 has a maximum tensile strength (UTS) at 22 ° C. of 275 MPa and an elongation (E) of about 5%. At a temperature of about 150 ° C., the investment casting of E357 and the T6 graded sample have a maximum tensile strength (UTS) of 260 MPa, a tensile yield strength (TYS) of 250 MPa, an elongation (E) of about 7%, and a quality index ( Q) is 387 MPa.

  In one embodiment of the present invention, the aluminum alloy of the present invention comprises Si: 4% to 9%, Mg: 0.1 to 0.7%, Zn: less than 5%, Fe: less than 0.15%, Cu: Less than 4%, Mn: less than 0.3%, B: less than 0.05%, Ti: less than 0.15%, compared with the T357 heat-treated product of investment casting compared to the E357 cast product produced in the same way The maximum tensile strength (UTS) at 150 ° C. is 20% to 30% greater.

  In a preferred embodiment of the present invention, the inventive alloy having a Cu content of 2 wt% or less and a Zn content of 3 wt% to 5 wt is compared with the E357 cast product manufactured in the same manner in the investment cast T6 heat treated product. The maximum tensile strength (UTS) at 150 ° C. is 10% to 20% greater.

  In another preferred embodiment of the present invention, the alloy containing more than 2 wt% Cu and not containing Zn is 150 ° C. in the investment cast T6 heat treated product compared to the E357 cast product produced in the same way. Maximum tensile strength (UTS) at 20% to 30% greater.

  Alloys having high tensile yield strength (TYS) and high maximum tensile strength (UTS) include Si: about 7%, Mg: about 0.45 to about 0.55%, Cu: about 2-3%, An alloy containing Zn: 0% is preferable.

  Alloys having high tensile yield strength (TYS) and high maximum tensile strength (UTS) include Si: about 7%, Mg: about 0.55 to about 0.65%, Cu: less than 2%, Zn: Alloys containing 3% to 5% are preferred.

  As an alloy having good strength and elongation, an alloy containing Si: about 7%, Mg: about 0.5%, Cu: trace amount, Zn: about 4% is preferable.

  As an alloy having good fluidity, an alloy containing Si: about 7%, Mg: about 0.5%, Cu: about 3%, Zn: about 4% is preferable.

  The above data suggests a group of cast alloys having various desirable properties. Depending on the application, the preferred properties vary.

  The alloys of the present invention can be cast into useful products by investment casting, low pressure or gravity casting, permanent or semi-permanent mold casting, squeeze casting, high pressure die casting or sand casting.

  While examples of the present invention have been illustrated, many modifications and other embodiments will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover such modifications and embodiments as fall within the spirit and scope of the invention.

For a sample obtained by unidirectionally solidifying an aluminum alloy containing Si: about 7%, Mg: about 0.5% and having different Zn and Cu contents at a rate of 1 ° C./second, the tensile strength at room temperature It is a graph which shows data. Tensile strength at room temperature of a sample obtained by unidirectionally solidifying an aluminum alloy containing Si: about 7% and Mg: about 0.5% and having different Zn and Cu contents at a rate of 0.4 ° C./second It is a graph which shows the data of length. For samples obtained by unidirectionally solidifying aluminum alloys containing Si: about 7%, Mg: about 0.5% and different Zn and Cu contents at a rate of 1 ° C./second, the yield strength at room temperature It is a graph which shows data. Yield strength at room temperature of a sample obtained by unidirectionally solidifying an aluminum alloy containing Si: about 7% and Mg: about 0.5% and having different Zn and Cu contents at a rate of 0.4 ° C./second It is a graph which shows the data of length. Elongation data at room temperature is obtained for a sample obtained by unidirectionally solidifying an aluminum alloy containing Si: about 7% and Mg: about 0.5% and having different Zn and Cu contents at a rate of 1 ° C / second. It is a graph to show. For samples obtained by unidirectionally solidifying aluminum alloys containing Si: about 7%, Mg: about 0.5% and different Zn and Cu contents at a rate of 0.4 ° C./second, the elongation at room temperature It is a graph which shows data. It is a graph which shows the result of a fluidity | liquidity test about the sample of aluminum alloy which contains Si: about 7%, Mg: about 0.5%, and content of Zn and Cu differs. It is a graph which shows the quality parameter | index based on the maximum tensile strength and elongation at room temperature about the sample of aluminum alloy which contains Si: about 7%, Mg: about 0.5%, and content of Zn and Cu differs. . For specimens of 7Si-Mg-Cu-Zn alloy produced by investment casting and T6 heat treatment, the concentration of Mg, Cu and Zn affects the maximum tensile strength (UTS) at high temperature (about 150 ° C) It is a graph which shows an influence. FIG. 7 shows the influence of Mg, Cu and Zn concentration on elongation (E) at high temperature (about 150 ° C.) for a specimen of 7Si—Mg—Cu—Zn alloy produced by investment casting and T6 heat treatment. It is a graph. Regarding the test piece of 7Si-Mg-Cu-Zn alloy manufactured by investment casting and T6 heat treatment, the effect of Mg, Cu and Zn concentration on the quality index (Q) at high temperature (about 150 ° C) It is a graph to show. It is a table | surface containing the alloy of this invention and the conventional alloy (E357) for a comparison, Comprising: About the sample of each alloy composition manufactured by performing investment casting and T6 heat processing, the maximum tensile strength in high temperature (150 degreeC) ( UTS), tensile yield strength (TYS), elongation (E) and quality index (Q) data are shown.

Claims (26)

% By weight
Si : 6.803 % to 9 %,
Mg : 0.1% to 0.7 %,
Zn : 3 % to 5 %,
Fe : less than 0.15%,
Cu : less than 2.0%,
Ag: 0.504% or less,
Mn : less than 0.3%,
B: 0 less than .05%,
Ti : less than 0.15%,
An aluminum casting alloy consisting of the balance aluminum and inevitable impurities . Cu is Ru 1.0 wt% or less der, aluminum casting alloy according to claim 1. Mg is 0.55 to 0.65 wt%, of claim 2 aluminum cast alloy. Mg is 0.45 to 0.55 wt%, aluminum casting alloy according to claim 1. The aluminum cast alloy of claim 1 having strength properties at least 10% higher than an E357 alloy casting. % By weight
Si : 6.803 % to 9 %,
Mg : 0.1% to 0.7 %,
Zn : 3 % to 5 %,
Fe : less than 0.15%,
Cu : less than 2.0%,
Ag: 0.504% or less,
Mn : less than 0.3%,
B: 0 less than .05%,
Ti : less than 0.15%,
Shape casting consisting of the balance aluminum and inevitable impurities . The shape casting according to claim 6 , which has been heat-treated in a T5 state or a T6 state. Cu is below 1.0 wt% or less, the shape casting of claim 7. Maximum tensile strength at high temperature of the heat-treated shape castings T6 state is at least 10% larger heard from casting that has been treated in the same way from the E357 alloy, shape castings according to claim 7 or 8. The shape casting of claim 9 , wherein the high temperature is in the range of 100C to 250C. M g is from .45 to 0.5 5 wt%, claim 6 or 7 shaped castings. Shape casting heat treatment T6 condition, the maximum tensile strength at high temperature, at least 20% larger listening than castings were processed in the same way from the E357 alloy, the shape casting of claim 11. The shape casting of claim 12 , wherein the high temperature is in the range of 100C to 250C. A method for producing a shape casting of an aluminum alloy comprising: (a) at weight percent,
Si : 6.803 % to 9 %,
Mg : 0.1% to 0.7 %,
Zn : 3% to 5 %,
Fe : less than 0.15%,
Cu: less than 2.0%,
Ag: 0.504% or less,
Mn : less than 0.3%,
B: 0 less than .05%,
Ti : less than 0.15%,
Remaining aluminum and inevitable impurities
And (b) forming an aluminum alloy product from the molten metal lump, and a method for producing an aluminum alloy shape casting. Aluminum alloy products are formed by investment casting, low pressure casting or gravity casting, permanent mold casting or semi-permanent casting, squeeze casting, die casting, unidirectional casting, or sand casting, and casting molten metal ingots into aluminum alloy castings. 15. The method of claim 14 , comprising: Prepare a mold with chill and riser,
Casting a molten metal mass in the mold to form an aluminum alloy product;
16. The method of claim 15 , further comprising: The method of claim 14 , further comprising heat treating the casting to a T5 state or a T6 state. The method of claim 14 or 17 M g is 0.45 to 0.55 wt%. Cu is 1.0 wt% or less, The method of claim 14 or 17. 15. The method of claim 14 , wherein the molten metal mass comprises a thixotropic metal mass, and forming the aluminum alloy product comprises semi-solid casting or forming. Aluminum casting alloy, 0 .5 ° C. / sec is cooled at a slower rate than the aluminum casting alloy according to claim 1. The aluminum casting alloy of claim 1, wherein the aluminum casting alloy has a dendrite arm spacing of 60 microns or more. Shape castings, 0 .5 ° C. / sec is cooled at a slower rate than the shape casting of claim 6. The shape casting of claim 6 , wherein the shape casting has a dendrite arm spacing of 60 microns or more. 15. The method of claim 14 , comprising cooling the molten metal mass at a rate slower than 0.5 ° C / second. 15. The method of claim 14 , wherein the molten metal mass has a dendrite arm spacing of 60 microns or greater.

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