DE1558457B1 - USE OF A TITANIUM ALLOY FOR THE MANUFACTURING OF HIGHLY STRESSED STRUCTURAL PARTS FOR JET ENGINES - Google Patents

Description

1 2

The invention relates to the use of a higher and the molybdenum and aluminum contents Titanium alloy for the production of highly stressed are lower than in the inventive construction parts to be used for jet engines. At one end alloy.

Material for such parts are particularly high. It is known that aluminum is used in amounts up to

Requirements in terms of strength, in particular 5 about 8% on the strength of titanium a favorable 0.2 limit, notched impact strength and creep strength influence and that tin and zirconium additives the at high temperatures. Furthermore, strength and creep rupture strength will further promote. It In particular, it has a low specific gravity and it has been found to be advantageous to use an aluminum compound Stability in the range from 400 to 600 ° C genium and tin content of no more than 6 or 2% calls. io, which also contains up to 4% zirconium

The titanium alloy to be used according to the invention can be used in order to obtain alloys with a good should in the hardened state a 0.2 limit of creep rupture strength. The strength of at least 95 kp / mm ² and a high notch impact type alloys meet today's requirements for toughness and time-gap strength at high temperatures, but not.

have ratures, as they are in structural parts of 15 The improvement in strength of such Ti-Al jet engines may occur. Sn-Zr alloys can be made by adding / J-stabi-

It is possible to achieve titanium alloys for the production of after lizing elements, the choice of which parts which remain ductile by welding are normally limited to those elements (German Auslegeschrift 1142 445), which are from 0.25 to the titanium opposite ^ -isomorphic. Of these EIe 7.5% aluminum and / or 0.25 to 16% tin and elements, molybdenum is most frequently added. In addition to one or more of the following elements, it is customary that the added molybdenum in the specified amounts: 0.25 to 5% bismuth or amount in alloys of the aforementioned type not indium, 0.1 to 10% niobium, tantalum or zirconium, 0.1 more than about 2%, because larger additives have up to 30% vanadium, 0.1 to 15% tungsten, 1 to a little disadvantageous effect on the creep strength, less than 2% iron or cobalt, 0.1 to 1 , 5% nickel, 0.1-25 It has now been found that the amount of molybdenum added to the Ti-Al-Sn-Zrbis 2.5 or 4 to 5% or 7.5% manganese, 0.1 to 2.5% alloys can be increased up to 6% or more than 5 up to 12.5%, optionally up to, provided that the zirconium-18% chromium, 0.1 to 2.5% or 5 to 15%, given also is increased to the same extent and that if up to 20% molybdenum, and furthermore up to 0.3% such alloys have good strength, stability oxygen, up to 0.3% carbon and up to 0 , 2% 3 ° and creep strength up to about 600 ° C, with nitrogen and the remainder at least 70% titanium. They can be hardened by a suitable heat treatment to a level of 0.2 limit of 140 kp / mm ² , which is known from the titanium alloys. It is only known that they are used for the production of parts. The joint achievement of a high level of creep are suitable, the tensile strength, hardenability and 0.2 limit after welding have remained so far, which is not important for the purpose of the present invention. On the other hand, stand for the feature of the invention.

According to the invention to be used material other It was found that high strength and

Above-mentioned properties in the foreground, over the creep rupture strength through relatively large accessories the known titanium alloy is not stated. sets of zirconium alone or molybdenum alone So it could not easily reach 40 foreseen. This is only possible if both whether and which titanium alloy from the known elements are available in larger quantities, th operation for the use according to the invention. According to the invention, the solution is provided

would be suitable for the purpose. Task using a titanium alloy with

Another well-known titanium alloy (Swiss

Patent 340 633) consists among other things of up to 45 5.5 to 7% aluminum,

10 ° / o aluminum, up to 8% tin, up to 10% zirconium, 5-3 1 ° / ₀ tin

0.02 to 0.3% oxygen, 0.02 to 0.2 _^0/0 is nitrogen, and - _'b · _{g0 /} zirconium

possible additions of up to 10% molybdenum, Vana-,, ",.,", ,,,,, ..

dium, niobium, tantalum individually or in groups, remainder ^{more than 3 to 6%} molybdenum,

Titanium. Of this titanium alloy, their high 50 0 to 0.35% are in total carbon,

Creep resistance at 400 to 500 ° C and their good hydrogen and nitrogen,

Known forgeability. Because the 0.2 limit at high residual titanium and unavoidable

Temperatures and the notched impact strength of these impurities

Titanium alloy and also the creep behavior

Temperatures above 400 ° C were not known, 55 was unable to produce highly stressed structures proposed for their suitability as a material for high-proportioning parts for jet engines, required structural parts for jet engines. A preferred alloy should be 6%

be closed. Aluminum, 2% tin, 4% zirconium, 4% molybdenum,

From U.S. Patents 3,061,427 and the remainder titanium and unavoidable impurities ent-049 425 are to be behaved differently from those according to the invention. The carbon content of the alloy, Turning titanium alloy composed of titanium, hydrogen and nitrogen does not make a total of over alloys known that at room temperature and 0.35%, with oxygen and nitrogen 0.15 and higher temperature good strength properties to -0.1% because of their tendency to relegate the alloys. With regard to notched impact strength, the 0.2 limit brittle, must not exceed. The relationship and creep rupture strength at higher temperatures. The contents of zirconium to molybdenum should be preferable the known titanium alloys, however, do not have to be 3: 2. The manufacture of this alloy erdie Values of the values to be used according to the invention follow the customary method, using titanium-titanium alloy. This is because their tin content was floating with the required amount of alloy

Mixes elements which, depending on the case, are added in elemental form or as master alloys, the mixture compressed and melted in a water-cooled copper crucible. The starting block thus formed is then formed into an electrode and melted off again. The manufacture of semi-finished products takes place then by heating the alloy ingots to a processing temperature and forging, rolling, Extrusion or drawing to produce the desired product (thin sheet, heavy plate, rod material, Wire, etc.).

If the prepared inventive use alloy as described above, and the product thus obtained is in the range of 890 to 950 ⁰ C solution annealed and air cooled, the 0.2-limit at room temperature in the range 95-97 kgf / mm ^2. If the alloy, as mentioned above, is solution annealed, air-cooled and then artificially aged at a temperature of 587 ° C., the 0.2 limit at room temperature, as can be seen from Table I, rises to 104 to 113 kp / mm ² . As can also be seen from Table I, after such a treatment, the alloy to be used according to the invention briefly shows a 0.2 limit of 74 kp / mm ² at 475 ° C., which drops to 53 kp / mm ^{2 at 587 ° C.} .

If the alloy to be used according to the invention is quenched in water after the solution heat treatment and then artificially aged in the range from 475 to 600 ° C., values for the 0.2 limit between 132 and 143 kp / mm ² result at room temperature.

The use of higher temperatures in the curing treatment is preferred because this increases lead to better elongation at break.

Table II shows that the notch tensile strength of the alloy after solution heat treatment, air cooling and artificial aging at 587 ° C has a value of 171 to 180 kp / mm ² for a Charpy V sample with a notch with the shape number ακ = 2, 8 has. In the creep test with notched specimens (shape number ακ = 2.8), the alloy is also able to withstand stresses of 154 and 161 kp / mm ² without breaking over a period of 5 hours (see Table II). In the notch resistance tests carried out for this purpose, the results of which are shown in Table II, samples were ^{exposed to a load of 127 kg / mm 2} for 5 hours and were then loaded at 5 hour intervals with an additional load of 7 kg / mm ² until they fractured . Column (8) shows the load values that the specimens withstood for 5 hours before breaking. In column (9) of Table II, the breaking loads and times are given after which the break took place. The good impact strength of the alloy Ti-6Al-2Sn-4Zr-4Mo according to Table II is an important part of the present invention.

From Table III it can be seen that the invention, has to be used in the alloy after solution heat treatment, air cooling and aging at 587 ° C an excellent creep rupture strength in the range of 400 to 600 ⁰ C and under tension at these temperatures, no decrease in expansion in a subsequent tensile test learns.

As can be seen from Table IV, further increases in the levels of zirconium and molybdenum result in amounts of up to 6% each to further improve the tensile strength properties.

Based on the results given in the tables, the alloy Ti-6Al-2Sn-6Zr-4Mo appears to give the optimum in terms of strength and toughness. In addition, the alloy Ti-6 also shows Al - 2Sn - 4Zr - 4Mo has good properties and is therefore a preferred composition.

Table I.

Tensile properties of an alloy Ti - 6 Al - 2 Sn - 4 Zr - 4 Mo at room temperature (RT)

and elevated temperatures

Heat treatment Attempt
temperature (D (2) (3) (4) Modulus of elasticity
10 * kp / mm ² ° C kp / mm ² kp / mm ² % % 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... RT 121 113 41 16 1.16 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... RT 120 111 43 16 1.12 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... 420 96 77 62 19th 0.98 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... 475 91 74 65 19th 0.92 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... 530 82 68 73 16 0.78 890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK * ... 587 69 53 80 9 0.82 945 ° C / 1 hour - LK RT 112 97 49 18th 1.07 945 ° C / 1 hour - LK RT 111 95 43 17th 1.03 945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC RT 114 104 41 17th 1.22 945 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK .... RT 118 107 41 16 1.18 945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC 420 91 71 66 19th 0.86 945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC 475 89 70 66 19th 0.96 945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC 530 84 68 72 16 0.88 945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC 587 69 57 82 20th 0.76 945 ° C / lh water cooling RT 124 106 15th 12th 0.94 Footnotes at the end of Table I.

Table I continued

C / l Heat treatment Attempt
temperature
⁰ C (D
kp / mm ² (2)
kp / mm ² (3)
7 » (4) Modulus of elasticity
10 * kp / mm ² 945 ^c C / l Hour — water cooling RT 127 108 13th 11th 0.95 945 ^c C / l Hrs - water cooling + 457 ° C / 2 hrs. RT 158 138 2 3 1.12 945 ^c C / l Hrs - water cooling + 457 ° C / 4 hrs. RT 156 139 0.9 1 1.10 (5) 945 ^c C / l Hrs - water cooling + 457 ° C / 8 hrs. RT 154 138 0.8 1 1.15 (5) 945 ° C / l Hrs - water cooling + 457 ° C / 16 hrs. RT 158 134 3 1 1.38 (5) 945 ° c / i Hrs - water cooling + 565 ° C / 2 hrs. RT 156 138 4th 3 1.16 945 ° C / l Hrs - water cooling + 565 ° C / 4 hrs. RT 160 143 10 5 1.21 945 ° C / l Hrs - water cooling + 565 ° C / 8 hrs. RT 155 140 9 4th 1.19 945 ° C / l Hrs - water cooling + 565 ° C / 16 hrs. RT 148 132 9 4th 1.24 945 ° C / l Hrs - water cooling + 587 ° C / 2 hrs. RT 152 139 12th 4th 1.12 945 ° C / l Hrs - water cooling + 587 ° C / 8 hrs. RT 146 137 12th 4th 1.22 945 ° C / l Hours - LK + 475 ° C / 4 hours - LK RT 118 98 17th 12th 1.22 945 ° C / l Hours - LK + 565 ° C / 4 hours - LK RT 116 98 16 11th 1.21 945 ° Hours - LK + 565 ° C / 4 hours - LK RT 115 102 15th 12th 1.28

* LK = air cooling.

(1) tensile strength.

(2) 0.2 limit.

(3) Constriction of the fracture.

(4) Elongation at break (gauge length Z ₀ = 4rf).

(5) Broken areas outside the measuring length.

Table II
Notch properties of Ti - 6 Al - 2 Sn - 4 Zr - 4 Mo alloy

Heat treatment

Notch tensile test (6)
kp / mm ² Shape number
αχ 180 2.8 171 2.8 174 2.8 179 2.8

Notch stand test
Tool life (7)

(8th)

endured

(9)
broken after

Notched impact test

(10) mkp

890 ° C / 1 hour - LK * + 587 ⁰ C / 8 hours - LK *

890 ° C / 1 hour - LK * + 587 ° C / 8 hours - LK *

945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC

945 ° C / 1 hour - SC + 587 ° C / 8 hours - SC

5 hours
at 161 kp / mm ²

5 hours
at 161 kp / mm ²

5 hours
at 161 kp / mm ²

5 hours
at 154 kp / mm ²

30 sec.
at 168 kp / mm ²

5 sec.
at 168 kp / mm ²

2 min.
at 168 kp / mm ²

51 min.
at 161 kp / mm ²

2.07 2.01 2.37 2.07

* LK = air cooling. (6) Notched Tensile Strength.

(J) Samples were exposed to a load of 127 kp / mm ² for 5 hours and were then subjected to an additional load of 7 kp / mm ² at 5 hour intervals until they fractured. In column

(8) shows the load values that the specimens withstood for 5 hours before breaking, and in column

(9) the breaking loads and times after which the breakage occurred are given. (10) Notched impact strength (Charpy V sample)

Table III
Yield strength and strength of a Ti - 6 Al - 2 Sn - 4 Zr - 4 Mo alloy

Heat treatment

Creep test

temperature

Load! Time
kp / mm ² ; Hours.

strain

Strength properties at 20 ⁰ C after standing test

(D
kp / mm ²

(2)
kp / mm ²

(3) (4)

0 /

/O

Modulus of elasticity 10 ⁴

'/ o kp / mm ²

890 ° C / 1 hour - LK + 587 ⁰ C / 8 hours - LK *

890 ° C / 1 hour - LK + 587 ⁰ C / 8 hours - LK *

890 ° C / 1 hour - LK + 587 ° C / 8 hours - LK *

890 ° C / 1 hour - LK + 587 ⁰ C / 8 hours - LK *

89O ° C / 1 hour - LK + 587 ⁰ C / 8 hours - Lk *

945 ° C / 1 hour - LK + 587 ° C / 8 hours - LK

945 ° C / 1 hour - LK + 587 ° C / 8 hours - LK

945 ° C / 1 hour - LK + 587 ° C / 8 hours - LK

945 ° C / 1 hour - LK + 587 ° C / 8 hours - LK

945 ° C / l hour + LK 587 ⁰ C / 8 hour LK

* LK = air cooling.
(1) tensile strength.

425

540

540

590

49

21

10

150

150

21 150

150

590 12th 150 425 49 150 540 21 150 540 21 150 590 10 150 590 12th 150

0.108 0.505 0.583 6.985 j 4.036 0.083 0.330 0.366 0.630 1.726

(2) 0.2 limit.

(3) Constriction of the fracture.

122
120
120
114
113
114
119
119
114.5

114.5

112
114
112
110
100
103
108
110
107
108

42 16 36 '16

1.14 1.10 1.21

41j 17

29 14 j 1.17

28 j 13 '1.14

38 17 j 1.21

19 y 14! 1.23 1.38 1.22 1.23

37 17th 31 16 30th 16

(4) Elongation at break (gauge length Z ₀ = Ad).

Table IV

Tensile strength properties at room temperature of Ti - 6 Al - 2 Sn - 6 Zr - 4 Mo- and Ti - 6 Al - 2 Sn - 6 Zr - 6 Mo alloys

alloy Mon 900 ° Heat treatment • cy (D (2) (3) (4) Modulus of elasticity
• 10 ⁴
kp / mm ² Ti-6 Al-2 Sn-6 Zr-4 Mon 900 ° C / 1 hr - LK * + 587
8 hours - LK ⁰ C / 137 134 39 15th 1.15 Ti-6 Al-2 Sn-6 Zr-4 Mon 945 ° C / 1 hr - LK * + 587
8 hours - LK ° C / 137 135 42 17th 1.19 Ti - 6 Al - 2 Sn - 6 Zr - 4 Mon 945 ° C / 1 hr - LK * + 587
8 hours - LK ° c / 134 127 38 16 1.16 Ti - 6 Al - 2 Sn- 6 Zr- 4 Mon 860 C / 1 hr - LK * + 587
8 hours - LK c / 131 122 36 16 1.13 Ti - 6 Al - 2 Sn- 6 Zr- 6 Mon 860 ⁰ C / 1 hour - LK + 587 °
8 hours - LK c / 134 124 26th 19th 1.15 Ti-6A1-2Sn-6Zr-6 Mon 920 ³ C / 1 hour - LK + 587 °
8 hours - LK c / 135 126 26th 13th 1.18 Ti-6 Al-2 Sn-6 Zr-6 Mon 920 ³ C / 1 hour - LK + 587 °
8 hours - LK c / 134 124 27 14th 1.19 Ti-6 Al-2 Sn-6 Zr-6 ³ C / 1 hour - LK + 587 °
8 hours - LK 132 123 23 13th 1.15

* LK = air cooling.
(1) Tensile strength (kp / mm ² ).

(2) 0.2 limit (kp / mm ² ).

(3) Constriction of the fracture (%)

(4) Elongation at break [gauge length I ₀ = 4d] (%)

109527/154

Claims (3)

9 10 patent claims · as a material for the production of highly stressed structural parts for jet engines. 1. Using a titanium alloy with 2. Use of a titanium alloy of the claim 1 specified composition of 6% 5.5 to 7% aluminum, 5 aluminum, 2% tin, 4% zirconium, 4% molyb-1.5 to 3% tin, Danish, the remainder titanium and unavoidable impurities-3 to 8% zirconium, for the claim 1 stated purpose,
more than 3 to 6% molybdenum, 3. Use of emef. Titanium alloy of the im An-0 up to 0.35% in total of carbon, according to the '"composition, where Oxygen and nitrogen, io the ratio of their contents of zirconium to The remainder is titanium and unavoidable molybdenum such as 3: 2, for the impurities in claim 1 called purpose.