DE1533297B1 - Aluminum alloy of high tensile strength and hardness and process for their heat treatment - Google Patents

Description

1 2

The invention relates to aluminum alloy containing a corresponding amount of zirconium. the struggles of high tensile strength and hardness and due to the simultaneous presence of water Heat treatment as a cast or wrought semi-finished product. fabric and zirconium, achieved improvement in mecha-es it was found that due to the simultaneous niche properties of the alloys with addition appropriately chosen proportionate avoidance of any formation of bubbles or cavities is excessive quantities surprising at zirconium and hydrogen to aluminum. Aluminum alloys that are less than 6 ecm and its alloys, which contain mechanical hydrogen per 100 g, can be cast Shafts of such alloys are to a considerable extent, without disturbing defects in the ingots are increased, as well as that a heat treatment result, but then there is no noteworthy Versolcher Alloys further improve the mechanical properties. These mechanical properties of the same causes and effect is on a hydrogen content in the range finally the mechanical properties of from 6 to 25 ecm per 100 g, as it is according to the invention castings made of such alloys are still prescribed, can be further improved by hot forming- The individual features and advantages of the invention

nen. Furthermore, it has been found that the mechanism, 15 can be seen from the following description on the basis of which these improvements of the mecha- the diagrams shown in the drawings, niche properties of such alloys compared to FIG. 1 shows the relationship between the alloys customary in the water trade with a comparable marriage material content and the Vickers hardness of aluminum mixer compositions, which result on the additional alloys containing 0.8% Zr and 0.5% Si after the interaction of aluminum with zirconium and ao a two-hour solution heat treatment at 400 ^° C .; Hydrogen based, also present in alloys F i g. 2 shows the relationship between the duration of the

containing other alloying elements such as manganese, solution heat treatment and Vickers hardness of aluminum-silicon, magnesium, nickel, copper, etc. Minium alloy with 0.8% Zr or with 0.8% Zr and By the invention, utilizing the 0.8% Si; Phenomena enumerated above aluminum alloys 25 F i g. 3 shows the dependence of the greatest Vickers on high tensile strength created, which only contain a proportionate amount of zirconium and hydrogen alloys with 0.8% Zr and H ₂ and 0.8% Zr, respectively, limited by the hardness of the solution annealing temperature of aluminum. The invention accordingly relates to 0.8% Si and H ₂ ;

Aluminum alloys containing 0.3 to 1.2% zirconium, Fig. 4 shows the relationship between the Vickers

6 to 25 cc of hydrogen per 100 g of alloy weight 30 and the solution-hardening of residual aluminum with aluminum permissible impurities corresponds alloys with 0.8% Zr, 0.5% Si and H ₂ or it with as well as those which additionally one or more 0.8% Zr, 0.5% Si, 1.0% Mn and H ₂ or with 0.8% Zr, the other alloying elements, namely 1.0 to 0.5% Si, 2.0 % Mn and H ₂ or with 0.8% Zr, 3% manganese, 0.1 to 1.5% silicon, 0.3 to 2.0% Ma-0.5% Si, 3.0% Mn and H ₈ , which after two hours of magnesium, 0.5 to 3.0% nickel and 1.0 to 4.0% copper 35 solution annealing in the one shown in the illustration. The invention also relates to lent temperatures that were cooled; drive for the production of such aluminum alloys F i g. 5 shows the dependency of the Vickers hardness

with the aim of improving their mechanical properties from the duration of the solution treatment at 400 ^{° C.} Aluminum alloys with 0.8% Zr, 0.5% Si and H ₂

The zirconium content of the alloys according to FIG. 40 or with 0.8% Zr, 0.5% Si, 1.0% Mn and H ₂ or the invention is therefore limited to a proportional amount of 0.8% Zr, 0.5 % Si, 2.0% Mn and H ₂ ; Fig. 6 shows the relationship between the tensile strengths of the alloys deteriorate if the strength and the zirconium content of aluminum-zirconium content exceeds this maximum value, alloys with 0.5% Si and H ₂ or with 0.5% Si, and because the effect of zirconium on the improvement 45 1.0% Mn and H ₂ , 0.5% Si, 2.0% Mn and H ₂ or improvement of the mechanical properties are only very low with 0.5% Si, 3.0% Mn and H ₂ after hot-forming, if the content thereof is below the minimum deformation of the castings;

at least 0.3%. F i g. 7 shows the relationship between the tensile strength

Basically, the art has been the view resistance and the zirconium content of alloys according to that the presence of hydrogen in The only important 5 ° Fig. 6 values with a hot-rolling degree of 55% at 400 ⁰ C quantities in aluminum alloy melts in hot rolling temperature.

such alloys have physical defects such as bubbles, FIG. 8 shows the dependence of the Vickers hardness on

Pores and pinholes in castings. the manganese and silicon content of aluminum fact, it has in practice been very alloys containing 0.8% Zr and H important proved after two hours of _2, by appropriate measures to solution annealing of the castings 55 at 400 ⁰ C; prevent hydrogen in molten alu- F i g. 9 shows the relationship between the tensile alloys in quantities greater than 1 ecm per strength and the zirconium content of aluminum alloy weight is present or alloys with a content of 0.5% Si, 1% Ni, larger amounts of hydrogen precipitated and different contents of H ₂ after two hours. In contrast, in the alloys is 60 solution annealing at 400 ⁰ C and after hot rolling in accordance with the invention just the one of the hydrogen% at 400 ⁰ C with 55 degree of reduction; absolutely necessary alloying elements and FIG. 10 shows the relationships between the tensile strength of 6 to 25 ecm per 100 g of alloy strength and the zirconium content of aluminum weight. It has been shown that even with alloys containing 0.5% Si, 2.0% nickel and various hydrogen content of the alloy of 25 cc per 65 which levels of H ₂ after two hours Lösungsg from this healthy blocks poured annealing is at 400 ⁰ C or after hot rolling in the can that have no disturbing defects such as bubbles or the same temperature with 55% degree of rolling. Pinholes, if the alloy is from Fig. 1 at the same time. 1 it can be seen that alloys whose

Hydrogen content is less than 6 ecm per 100 g alloy weight, have significantly less favorable hardness values and that at more than 25 ecm H ₂ per 100 g the hardness values are lower again, which means that the hydrogen content prescribed according to the invention is in the range from 6 to 25 ecm each 100 g leads to surprising results.

As the values shown in FIG. 2 show, the addition of silicon to an aluminum alloy according to the invention accelerates the hardening process. For example, at a ^{solution annealing temperature of 450 °} C., 260 minutes are required for the silicon-free alloy in order to achieve the maximum value of the hardness, but only 60 minutes for the silicon-containing alloy. As a result, the addition of silicon as a third alloying element reduces the duration of the solution heat treatment.

According to Fig. 3, the maximum hardness is at 400 ° C Solution annealing temperature is reached and higher hardness values are achieved with Si-containing alloys than with silicon-free alloys.

F i g. 4 it can be seen that the absolute value of the hardness increases as the manganese content increases.

F i g. 5 shows that with an increase in the manganese content, the annealing time to achieve the maximum value the hardness decreases.

From Fig. 6 it can be seen, inter alia, that with a zirconium content in the range from 0.8 to 1.0% gives the highest tensile strength.

In Fig. 7 confirms the practically applicable range of the zirconium content between 0.3 and 1.2%.

From FIG. 8 is an interaction of the manganese and silicon content on hardness and a maximum hardness value at 0.3 to 1.2% Si and 2.0% Mn, can be seen.

From the F i g. 9 (1% Ni) and FIG. 10 (2% Ni) it can be seen that the tensile strength of castings, as in the previous cases, can be increased considerably by hot rolling. Regarding the zirconium content the tensile strength reaches its maximum value at around 1% Zr. However, in the case of undeformed alloys that contain 2.0% nickel achieved the highest tensile strength at 0.6% Zr. As results from the diagram, show alloys according to the invention with nickel as an alloying element similar tensile strength values as the alloys described above.

In the following, the effects of adding zirconium and hydrogen will now be different commercially available aluminum alloys for their mechanical properties using Tables 1 to 6 are explained.

Table 1 shows the chemical composition of two alloys, one of which (Example K) is a significant Amount and the other (example S) contains only a small amount of hydrogen.

Table 2 shows the mechanical properties of these alloys according to the various in the Treatments given in the table and indicates that the hydrogen-containing alloy is in the as-cast state has only a slightly higher tensile strength and hardness, d. i.e., the effect of the hydrogen content and zirconium is relatively small, but this effect after a two-hour solution heat treatment increases significantly at 400 ° C. Also from Table 2 is the effect of hot deformation on tensile strength and elongation of an alloy containing hydrogen can be seen.

Of Tables 3 and 4 containing similar examples, Table 3 shows the chemical compositions of aluminum alloys with zirconium, manganese, silicon and hydrogen and Table 4 the mechanical properties of these alloys in different states. Table 4 shows that the effect of adding hydrogen without subsequent heat treatment is not so significant is like after a two hour solution heat treatment

ίο at 400 ⁰ C, after which tensile strength and hardness increase to about double and still a useful elongation remains. The effect of hot deformation on tensile strength and especially elongation is particularly remarkable.

Tables 5 and 6 refer to similar examples of a number of aluminum alloys, which contain copper, magnesium and silicon, or those of the duralumin type.

Table 5 shows the chemical compositions of these alloys. The alloys according to the examples P and R contain 0.46% and 0.28% zirconium and 15 to 20 ecm of hydrogen per 100 g of alloy weight in addition to the normal alloy elements. The alloys according to Examples Q and S contain the same proportional amounts of the alloying elements as those according to Examples P and R, with the exception that the hydrogen content is only of the order of magnitude of that which is commercially available Aluminum alloys, d. i.e., only 1.5 to 2.0 ecm per 100 g.

Table 6 shows the tensile strength, hardness and elongation of these alloys after the following different treatments:
Treatment 1: hot rolling at 52o ⁰ C and the degree of reduction of 55%, quenching to room temperature (RT) after 30 minutes long holding at 520 ⁰ C metal temperature, after artificial aging at 165 ° C. Treatment 2: hot rolling at 52o ⁰ C (55% degree of reduction ), Quenching to RT after holding at 52O ⁰ C metal temperature for 30 minutes, cold rolling with 8% degree of rolling, artificial aging at 165 ° C. Treatment 3: Hot rolling at 500 ° C (55% degree of rolling) after holding at 500 ⁰ C metal temperature for 30 minutes, Quenching to RT and artificial aging at 165 ⁰ C.

Treatment 4: hot rolling at 470 ⁰ C (55% degree of reduction), 30 minutes long holding at 47o ⁰ C metal temperature, quenching to RT and artificial aging at 165 ° C.

It is clear from Table 6 that the tensile strength of aluminum alloy with the usual low hydrogen content in the range of 40 to 44 kp / mm ² after cold forming is 45 kp / mm ² , whereas the tensile strength of alloys according to the invention is 45 to 50 kp / mm ² is, the maximum value of the tensile strength for an alloy with 0.46% zirconium and 15 to 20 ecm of hydrogen per 100 g and after treatment 2 is achieved.

_6o table 1
Chemical compositions of
alloys with zirconium, silicon and Zr Chemical composition
Si I Cu I Fe I Al 0.013
0.012 0.04
0.02 rest
rest Aluminum-
Hydrogen. Alloy
65 tion 0.75
0.76 0.16
0.10 %
H _a (ccm / 100g) K
L. 18 to 22
2

Table 2 Mechanical properties of aluminum alloys with zirconium, silicon and hydrogen.

State

As-cast state

Solution heat treated for 2 hours at 400 ° C

Hot rolled at 400 ° C

alloy

Mechanical properties

Tensile strength I elongation kp / mm ² I%

12.6
8.1

20.2
9.5

23.8
15.8

30th
40

HardnessHV kp / mm ²

43 27

10 73 28 33 25th 78 36 58

Table 3 Chemical composition of aluminum alloys with zirconium, manganese, silicon and hydrogen.

alloy

Zr

Mn

Chemical composition% Si I Fe I Cu

Al

H ₂ (ccm / 100g)

0.76 0.70

1.90 1.98

0.52 0.51

0.03
0.02

0.005
0.004

Rest rest

14 to 22 1.5

Table 4 Mechanical composition of aluminum alloys with zircomum, manganese, silicon and hydrogen.

State alloy Mechanism
tensile strenght
kp / mm ² ; hey properties
Elongation I hardness HV
% j kp / mm ² 57
44 As-cast state M.
N 17.2
12.9 12th
15th 84
52 2 hours at 400 ° C
solution annealed M.
N 25.8
14.0 10
32 99
54 Hot rolled at 400 ° C M.
N 32.8
17.9 17th
43

Table 5 Chemical composition of duralumin type alloys containing Zr and hydrogen.

alloy Cu Mn Chemical composition Ni Mg Si % Zr Al H ₂ (ccm / 100g) 3.90 2.93 0.95 0.60 1.45 0.46 rest 15 to 20 P. 3.85 2.95 0.90 0.55 1.50 0.47 rest 1.5 Q 3.87 2.93 0.96 0.51 1.33 0.28 rest 14 to 19 R. 3.92 2.90 0.96 0.55 1.30 0.29 rest 2.0 S.

Table 6 Tensile strength of duralumin type alloys containing Zr and hydrogen.

Treatment
art P. alloy
QIR 45.4 S. Tensile strength (kp / mm ² ) 48.1 1 48.7 43.8 46.7 43.0 2 50.3 44.2 46.0 45.0 3 47.0 42.7 44.4 4th 49.5 40.0 39.6

Claims (4)

Patent claims: 1. Aluminum alloy of high tensile strength and hardness, characterized in that they contain 0.3 to 1.2% zirconium and 6 to 25 ecm hydrogen at room temperature and normal pressure per 100 g alloy weight, the remainder contains aluminum including permissible admixtures. 2. Aluminum alloy of high tensile strength and hardness according to claim 1, characterized in that that they also have one or more of the other alloying elements, namely 1.0 to 3.0% manganese, Contains 0.1 to 1.5% silicon, 0.3 to 2.0% magnesium, 0.5 to 3.0% nickel and 1.0 to 4.0% copper. 3. A method for the heat treatment of castings made of aluminum alloys according to claim 1 or 2, characterized in that the castings are at 350 for 10 minutes to 48 hours Solution annealed up to 450 ° C and then quenched to room temperature in water, oil or air will. 4. A method for heat treatment of wrought aluminum alloys according to claim 1 or 2, characterized in that the castings are subjected to hot deformation in the temperature range from 400 to 520 ⁰ C, then quenching at room temperature in air, oil or water and optionally artificial aging. For this purpose 2 sheets of drawings 009 513/122