JP2729479B2 - Manufacturing method of aluminum alloy excellent in high temperature strength - Google Patents

Description

The present invention relates to a method for producing an aluminum alloy having excellent high-temperature strength. <Conventional technology and its problems> Aluminum materials that require high-temperature strength, including materials for pistons of internal combustion engines, include JIS standard AC8A and AC9A.
Although there are alloys such as AA standard A390, these alloys do not have very high service temperatures, and in recent years, studies to further improve the high-temperature strength by rapid solidification have been actively conducted. However, the rapid solidification method currently used uses a powdery or flake-like raw material from the viewpoint of cooling a rapidly solidified material used as a raw material as quickly as possible. Although the cooling rate of powder and flakes can be increased, the surface area is too large, so that impurities such as oxides adhering to the surface increase, and the subsequent hot forming step However, it was confirmed that the molded article itself could not be expected to have such a large improvement in strength because the area required to be closely bonded to the molded article became large. Of course, when taking measures such as cooling in an inert gas when obtaining powders or flakes, oxides on the surface are reduced, but they are more expensive and less effective. <Means for Solving the Problems> The present invention has been made to solve the above problems and to provide a method capable of easily producing a molded article having excellent high-temperature strength. Fe3 obtained by
An aluminum alloy having excellent high-temperature strength, wherein alloy fibers having a composition of 9% by weight and the balance of Al are used as a starting material, and the starting material is subjected to cold compression molding, drying, and then hot extrusion molding. Production method and Fe3 to 9% by weight obtained by melt spinning method and 10 to 25% by weight of Si, 1 to
5% by weight of Nn, 1 to 5% by weight of Ni, 1 to 5% by weight of Cu, 0.1 to
One or more kinds of Mg of 5% by weight and a balance of Al are used as a starting material, and the starting material is cold-compressed, dried, and then hot-extruded. This is a method for producing an aluminum alloy having excellent high-temperature strength. <Function> The method of the present invention is to provide an alloy fiber obtained by directly injecting a molten alloy into the atmosphere and rapidly cooling and solidifying the alloy as disclosed in Japanese Patent Application Laid-Open No. 59-82411 filed by the present applicant. There is a great feature in using as a starting material. The alloy fiber obtained in this way has a unique effect of the so-called rapidly solidified material in that each element, including Fe, forms a fine intermetallic compound by rapid solidification and improves the mechanical strength in a high temperature range. Of course, the difference is that the specific surface area is smaller than that of an ordinary powder or flake-like rapidly solidified material. Therefore, the amount of impurities adhering to the surface of oxides and the like is small, and the area that must be closely bonded to each other during the subsequent hot extrusion molding is also reduced accordingly, and the high-temperature strength of the obtained molded body is greatly improved. . The reasons for limiting the composition of the aluminum alloy used in the present invention are as follows. First, Fe forms a fine intermetallic compound by rapid solidification, is uniformly dispersed in a matrix, and improves mechanical strength in a high temperature range. However, if less than 3% by weight, its effect is not sufficient, and 9 Even if the content exceeds 10% by weight, the increase in high-temperature strength is small, and conversely, the elongation is reduced and workability deteriorates.
To 9% by weight. Next, Si, Mn, Ni, Cu,
For Mg, at least one of them is added depending on the application, and Si improves high temperature strength,
It is added to lower the coefficient of thermal expansion and improve wear resistance.
Such effects are hardly exhibited at less than 10% by weight,
Even if it exceeds 25% by weight, Mn and Ni form fine intermetallic compounds coexisting with Fe by rapid solidification, and increase the high-temperature strength. Even if it exceeds 10% by weight, improvement in high-temperature strength cannot be expected very much. Next, Cu has the effect of improving the room temperature and high temperature strength, but less than 1% by weight has little effect, and if it exceeds 5% by weight, the corrosion resistance and workability deteriorate. On the other hand, Mg has the effect of improving the room temperature strength. However, if the content is less than 0.1% by weight, the effect is small, and if it exceeds 5% by weight, the effect is not increased much and the processability is deteriorated. <Examples> Hereinafter, examples of the present invention will be described in detail along with comparative examples. An alloy having a composition as shown in Table 1 No. 1 to No. 14
From the molten state, it was injected into the atmosphere by rapid cooling and solidification by the method described in JP-A-59-82411 to obtain an alloy fiber having an average fiber diameter of 100 μm. After pre-forming this alloy fiber to 50mmφ × 110mmL by cold compression (filling rate about 70%),
Dry at 0 ° C for 2 hours.
A 20 mmφ round bar was produced by hot extrusion at a temperature of ° C. (extrusion ratio 6.2). These extruded materials were heated at 300 ° C. for 72 hours and then cooled to room temperature to prepare high-temperature tensile test pieces, which were subjected to a tensile test at 300 ° C. to determine the mechanical properties. Table 2 shows the results. For No. 15 to No. 17 as conventional alloys, they were melted in a graphite crucible, subjected to a prescribed molten metal treatment, made into an ingot in a mold, subjected to T6 treatment, and then subjected to the same high-temperature tensile Table 2 shows the results of the test. Table 1 shows that the alloy of the present invention
No.1 and No.2 of Al-Fe composition and No.12 and N
In order to compare o13, a graph showing the relationship between tensile strength and elongation was prepared from Table 2 as shown in FIG. From this graph, No. 1 which is 5% by weight of Fe and No. 2 which is 8% by weight of Fe, which are claims of the present invention, and Comparative Example
When No. 12 having 2% by weight of Fe is compared with No. 13 having 10% by weight of Fe, the tensile strength of No. 12 is significantly reduced,
In the case of 13, even if Fe is increased from 8% by weight to 10% by weight, the tensile strength does not increase so much and conversely the elongation decreases significantly.
When considering the deterioration of workability by increasing the Fe weight%, it is reasonable to set the range of Fe 3 to 9 wt%. Next, No. 3 to No. 11 of the present invention in which another alloy component was further added to the Al-Fe alloy system, No. 13 and No. 14 as comparative alloys, and No. 15 to No. 17 as conventional alloys. In order to compare the above, a graph showing the relationship between tensile strength and elongation was created from Table 2 as shown in FIG. Further, No. 6, No. 7, No. 8 having the same composition of 17% by weight of Si, 4.5% by weight of Cu, and 0.6% by weight of Mg other than Fe and Comparative Example No. 14 were connected by a solid line. As a result, when the comparative alloy No. 14 having 0.2% by weight of Fe was compared with the alloys Nos. 6 to 8 of the present invention, it was found that the tensile strength was significantly reduced. In addition, it was found that in the conventional alloys No. 15 to No. 17, both the tensile strength and the elongation were lower than those of the alloy of the present invention and the comparative alloy. When other alloy components are further added to the Al-Fe alloy, the mechanical properties of strength and elongation are slightly inferior to those of the Al-Fe alloy, but the wear resistance and the coefficient of thermal expansion are reduced by the addition of Si. Improvements have been made. <Effects of the Invention> As described above, according to the method of the present invention, since the alloy fiber obtained by the melt spinning method is used as a starting material, the characteristics as a rapidly solidified material can be maintained while the molding is sufficiently maintained. Impurities contained in the body can be reduced as much as possible, and the advantage that the area which must be in close contact bonding is small is utilized, and as a result, a molded article excellent in high-temperature strength can be obtained. Further, the method of the present invention also has the advantage that by changing the conditions of melt spinning, an alloy fiber having an arbitrary diameter and an aspect ratio can be obtained, so that a molded article having various properties can be obtained according to the use of the final product. Have.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the relationship between tensile strength and elongation of an Al—Fe alloy of the present invention and a comparative example. FIG. 2 is a graph showing the relationship between the tensile strength and the elongation of the Al-Fe alloy of the present invention in which other alloy components are further added, the comparative example, and the conventional alloy.

Claims (1)

(57) [Claims] Fe3-9% by weight obtained by melt spinning method, balance A
(1) A method for producing an aluminum alloy having excellent high-temperature strength, comprising using an alloy fiber having a composition of 1 as a starting material, subjecting the starting material to cold compression molding, drying, and then performing hot extrusion. 2. Fe3 to 9% by weight obtained by the melt spinning method;
~ 25 wt% Si, 1-5 wt% Mn, 1-5 wt% Ni, 1 ~
An alloy fiber having a composition of 5% by weight of Cu, 0.1 to 5% by weight of Mg, and the balance of Al and a balance of Al is used as a starting material. A method for producing an aluminum alloy having excellent high-temperature strength, comprising performing cold extrusion.