JPH03166331A - Heat-resistant conductive aluminum alloy - Google Patents

Abstract

PURPOSE:To obtain the Al alloy having same strength to that of a conventional heat-resistant conductive aluminum alloy and having remarkably excellent heat resistance without deteriorating its electrical conductivity too much by incorporating specified amounts of Ni and Fe into Al. CONSTITUTION:The heat-resistant Al alloy contains, by weight, <1.6 to 6.0% Ni, <0.8 to <2.0% Fe and the balance Al. In this alloy, Ni forms an eutectic structure of which NiAl3 is dispersed into a matrix to improve its strength and heat resistance. As for the content of Ni, in the case of <=1.6%, the heat resistance is made insufficient, and in the case of >6.0%, a dendrite phase of NiAl3 primary crystals is crystallized out not only to deteriorate the workability but also to increase the deterioration of the ductility and electric conductivity. Furthermore, Fe reinforces the Al matrix and moreover improves the strength. But, as for its content, in the case of <=0.8%, the above effect is made insufficient, and in the case of <=2.0%, the deterioration of its electrical conductivity increases.

Description

[Detailed description of the invention] The present invention relates to a heat-resistant aluminum alloy for conductive use,
In particular, conventional conductive heat-resistant aluminum alloy (Alt-Zt
The purpose of the present invention is to provide an aluminum alloy conductor that has strength equivalent to that of aluminum alloys) and excellent heat resistance without significantly reducing conductivity.

Conventionally, solid solution type heat-resistant aluminum alloys that utilize the solid solution 2' heat resistance mechanism of Al-2R alloys have been used for power transmission lines that require heat resistance, but in recent years, with the increase in power demand, improvements in heat resistance have been used. has become required. In response to this, a heat-resistant conductive aluminum alloy with an increased amount of solid solution 2 and a high heat-resistant conductive aluminum alloy that utilizes the heat-resistant mechanism of precipitated Zr instead of the heat-resistant mechanism of solid solution Zr have been developed.

However, an increase in the amount of solid solution Zr leads to a decrease in electrical conductivity, and in order to utilize the heat resistance mechanism of precipitated Zr, it is necessary to
Because it requires long-term heat treatment at a temperature of 450°C,
It had the disadvantage of high cost. Furthermore, the usable heating temperature of these alloys when energized is about 300° C., and further improvement in heat resistance is strongly desired.

In view of this, as a result of various studies, the present invention has developed a heat-resistant aluminum alloy for conductive use that has strength equivalent to that of conventional heat-resistant aluminum alloys for conductive use, and has far superior heat resistance without significantly reducing conductivity. This is what I did.

That is, the alloy of the present invention has a Nil. It is characterized by containing more than 6vj% (hereinafter vj% is simply abbreviated as %) and 6.0% or less, more than 0.8% and less than 2.0% Fe, and the balance consisting of Al and normal impurities. be.

However, the reason why the alloy composition is limited as described above in the present invention is as follows.

The Ni content was limited to more than 1.6% and less than 6.0% because Ni was added to the Al matrix. The purpose is to improve strength and heat resistance as a eutectic structure in which the metal is dispersed, but if the content is less than 1.6%, the heat resistance will be insufficient, and if it exceeds 6.0%, the initial content will be present in the metal structure. Akira N
This is because the dendrite phase of iAA' is crystallized, which not only impairs workability but also greatly reduces ductility and electrical conductivity. Moreover, the Fe content exceeds 0.8%2. The reason for limiting the content to less than 0% is to strengthen the matrix by adding Fe and further improve the strength, but if the content is less than fl. This is because if it is less than 8%, the effect is insufficient, and if it is more than 2.0%, the conductivity will decrease significantly.

The alloy of the present invention has the above composition, but in order to manufacture it, it is made into a rough drawn wire by normal continuous or semi-continuous casting and hot rolling, and then cold drawn to obtain the desired wire diameter. After that, heat treatment may be performed.

The conditions for heat treatment after cold wire drawing are IO
It is desirable to heat at a temperature of Q~400°C for 0.5~10 hours. Note that such heating is effective for adjusting strength and conductivity as well as imparting heat resistance, but even if the temperature is below 100°C or the treatment time is less than 0.5 hours, the electrical conductivity will not recover and the heat resistance will deteriorate. Moreover, even if the temperature exceeds 4H°C or the treatment time exceeds 10 hours, the strength decreases significantly.

The present invention will be described in detail below with reference to Examples.

Melt electrical aluminum ingot with a purity of 99.8%, and add Al to it.
-6% Fe master alloy and Al-10% Ni master alloy were added to produce an alloy having the composition shown in Table 1, which was cast and hot-rolled using a belt-and-wheel type continuous casting mill to have a diameter of 8.0 mm.
A rough wire of
It was processed into a line of m.

After heating this wire at various temperatures, the conductivity and
Tensile strength and lO% softening temperature were measured.

Comparing these results with conventional Al-Zr alloys, the first
Also listed in the table.

Note that the 10% softening temperature is the temperature at which the strength decreases by 10% after one hour of heat treatment.

As is clear from Table 1, the alloy of the present invention (Nal~6) has an electrical conductivity of 56% or more and a tensile strength of 17. 5 kg/m or more,
It exhibits characteristics with a tθ% softening temperature of 39Q℃ or higher, and is superior to conventional alloys (
It can be seen that compared to Nα11), it has the same strength without much reduction in conductivity, and has far superior heat resistance.

On the other hand, as can be seen from the comparative alloys (Na7 to 10), those outside the composition range of the present invention alloys are inferior in electrical conductivity, tensile strength, and heat resistance. The heat resistance was not improved, and the strength was not improved in the comparative alloy 9 with a low Fe content, and the electrical conductivity was significantly reduced in both the comparative alloy 8 with a high N1 content and the comparative alloy Nα10 with a high Fe content.

As described above, according to the present invention, it is possible to obtain an alloy that has strength equivalent to that of conventional heat-resistant aluminum alloys, has far superior heat resistance without significantly reducing conductivity, and is suitable for use in power transmission lines, etc. This has the remarkable effect of increasing power transmission capacity.

Claims (1)

[Claims] (1) Ni exceeding 1.6wt% and 6.0wt% or less, F
e Contains more than 0.8wt% and less than 2.0wt%, the remainder A
A heat-resistant aluminum alloy for conductive use consisting of l and normal impurities.