JPH03120334A - Low thermal expansion aluminum alloy having excellent extrudability - Google Patents

Abstract

PURPOSE:To reduce the thermal expansion coefficient in the Al alloy and to improve its extrudability by specifying Si, Mg, Ni and Al as well as Cu, Fe, etc. CONSTITUTION:The Al alloy is formed from the compsn. constituted of, by weight, 8 to 13% Si, 0.3 to 1% Mg, 1.5 to 8% Ni and the balance Al, or in addition to this, furthermore with one or more kinds among 0.1 to 1% Cu, 0.01 to 0.5% Fe, 0.0001 to 0.002% Sr, 0.001 to 0.1% Ti, etc. The above alloy has a low thermal expansion coefficient and furthermore has excellent extrudability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a low thermal expansion aluminum alloy with excellent extrudability, which is used, for example, in rotors of automobile superchargers.

2. Description of the Related Art Parts that undergo thermal cycles, such as the rotor of a supercharger in an automobile, are required to be made of a material with a small coefficient of thermal expansion. As a low thermal expansion aluminum alloy that meets these requirements, A4032 etc.
fi-eutectic Si based alloys are known.

Problems that the invention aims to solve However, in this type of alloy, St.

Due to the large amount of Cu%Mg contained, the extrusion properties are poor and it is difficult to obtain an extruded molded material with a complicated shape, which limits its use.

In view of the above-mentioned problems, the present invention aims to provide an aluminum alloy with improved extrudability and a small coefficient of thermal expansion.

Means for Solving the Problems The inventors conducted extensive experiments and research based on the above objectives, and found that it was possible to improve both extrusion characteristics and low thermal expansion characteristics by devising alloy components. We have come to the knowledge that this is the case, and have completed this invention based on this knowledge.

Therefore, this invention is basically based on St:8. 0 to 13. 0wt%Mg: 0.3
~1.0wt% Ni: 1. The gist of the invention is a low thermal expansion aluminum alloy with excellent extrudability, containing 5 to 8.0 wt%, with the remainder consisting of aluminum and unavoidable impurities.

Furthermore, the present invention also targets aluminum alloys to which various elements are added to improve the properties, and aluminum alloys with Si: 8.0 to 13
．． 0vt%, Mg: 0.3-1.0wt%, Ni:
1. 5-8. In addition to the content of 0 wt%, Cu:0. 1 ~1. 0wt% Fe: 0. 01~0. 5wt%Sr:
0.0001-0.002wt%Tt: 0.00
1-01 lwt% Mn: 0.01-0.5 wt% Cr: 0.01-0. lwt% Zn: 0.01-0. The purpose of the present invention is to provide a low thermal expansion aluminum alloy containing one or more of 1 wt% V: 0.01 to 0.05 wt%, the balance being aluminum and unavoidable impurities, and having excellent extrudability.

St reduces the coefficient of thermal expansion and contributes to improving wear resistance. 8. In order to sufficiently reduce the coefficient of thermal expansion. It is necessary to contain 0 wt% or more. If the content is further increased, the coefficient of thermal expansion can be further lowered, but if the content exceeds 13 wt%, the extrudability will be inhibited, making it impossible to obtain an extruded molded material with a complicated shape. As a result, the range of applications will be limited. Therefore, the permissible range of its content is 8
．． It should be 0-13.0wt96. The most preferred range is 9.0 to 11.0 wt%.

Mg contributes to improving mechanical strength. Mg
The content of is 0. If it is less than 3 wt%, the required high strength cannot be imparted to the alloy.

However, since Mg has the property of inhibiting a decrease in the coefficient of thermal expansion, if it is contained in an excessive amount exceeding 1.0 wt%, not only will the coefficient of thermal expansion increase, but also the extrusion processability will decrease. Therefore, the permissible range of its content is 0. 3-1
．． 0wt%, the most suitable range is 0.4-0.8w
It is in the range of t%.

Like Si, Ni also reduces the coefficient of thermal expansion and contributes to improving wear resistance. If the Ni content is less than 1.5 νt%, it is not possible to provide the alloy with the required wear resistance, and it is insufficient to reduce the coefficient of thermal expansion that has increased due to the addition of Mg. 0
If the content exceeds wt%, the hollow extrudability will be inhibited, and the range of applications will be restricted. Therefore, the permissible range of its content is 1.5 to 8.0 wt%, most preferably 2.0 to 6.0 wt%. It is in the range of 5wt%.

In this invention, in addition to the addition of Si, Mg and Ni, Cu:0. 1 ~1. 0wt% Fe: 0. 01~0. 5wt%Sr;
0.0001-0.002wt%Ti:0. OO1~0
, 1νt% Mn: 0. 01~0. 5wt%Cr: 0.
01~0. 1wt96Zn: 0.01~0. lw
t% V: Contains one or more of o, ox to 0.05 wt%.

These contribute to improving mechanical properties.

Cu contributes to improving the strength of the aluminum alloy. If the content is less than 0.1 wt%, the required high strength cannot be given to the alloy, and 1.0 νt%
Even if the content exceeds 100%, a proportional increase in the strength improvement effect cannot be expected, and containing more than that is essentially meaningless.

Fe lowers the coefficient of thermal expansion and is 0.0
If the content is less than 1 wt%, the effect is poor, and if the content exceeds 0.5 wt%, no proportional increase in the effect can be expected, and the content of more than 0.5 wt% is essentially meaningless.

Sr is an effective element for refining S1 grains, and 0
．． If it is less than 0.0001 wt%, the effect will be poor;
Even if the content exceeds 0.002 wt %, no particular enhancement of the above effect can be expected, and the content in excess of this is essentially meaningless.

TiSMn, Cr, Zn and V are effective elements for refining the crystal grains of the alloy and stabilizing the structure.
: 0,001wt%, Mn:Q.

01wt%, Cr: 0.01wt%, Zn: 0.01w
t%, V: less than 0.01 wt%, the above effects are poor,
On the contrary, Ti: 0.1wt%, Mn: 0.5wt%, Cr:
0.1wt%, Zn: 0.1wt%, V: 0.05νt
Even if the content exceeds 5%, not only will the above-mentioned effects not be particularly enhanced, but the number of items to be sold will increase.

Effects of the Invention As is clear from the examples below, the aluminum alloy according to the present invention has a much lower coefficient of thermal expansion and excellent extrudability compared to the conventional A4032 alloy. .

Example Aluminum alloy billet with the composition shown in Table 1 (diameter 1
50#III, length 300#IIl+) was cast in a conventional manner, and the billet was homogenized at 490°C for 5 hours, then billet preheating temperature 510''C5 extrusion speed 0, 1
Under the conditions of yrtx/see, as shown in Figure 1,
Both sides are bulged, and the bulges on both sides (1) (1)
and a hole (la) in each middle part (2).
(la) A hollow extruded material with a cross-sectional shape having the shape of (2a) (width L of the extruded material: 90 rtms, outer diameter R1 of both bulges: 25 mm, same inner diameter R220111111, thickness t of the middle part: 25 m, hole in the middle part Inner diameter R3: 15
IIn) was extruded and the extrudability was evaluated. The result is the second
Shown in the table.

Subsequently, the thermal expansion coefficient and mechanical properties of the extruded material after T6 treatment were investigated. The results are also shown in Table 2.

[Hereinafter, blank spaces] As can be seen from the results in Table 2 above, the aluminum alloy of the present invention has superior extrusion properties and low thermal expansion properties, as well as superior mechanical properties, compared to the conventional A4032 alloy. It was also excellent.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the extruded material. that's all

Claims (2)

[Claims] (1) Contains Si: 8.0 to 13.0 wt% Mg: 0.3 to 1.0 wt% Ni: 1.5 to 8.0 wt%, with the balance consisting of aluminum and unavoidable impurities, and has excellent extrudability. Low thermal expansion aluminum alloy. (2) Contains Si: 8.0 to 13.0 wt%, Mg: 0.3 to 1.0 wt%, Ni: 1.5 to 8.0 wt%, and further Cu: 0.1 to 1.0 wt% Fe: 0.01-0.5wt% Sr: 0.0001-0.002wt% Ti: 0.001-0.1wt% Mn: 0.01-0.5wt% Cr: 0.01-0.1wt% Zn: A low thermal expansion aluminum alloy with excellent extrudability, containing one or more of 0.01 to 0.1 wt% V: 0.01 to 0.05 wt%, with the remainder consisting of aluminum and inevitable impurities.