JPH0441635A - Ti alloy with excellent heat resistance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a Ti alloy with excellent heat resistance, for example,
Ti is used in engine valves, jet engine components (compressor disks, turbine blades), industrial gas turbines, etc., which require heat resistance, high strength, and light weight (that is, high specific strength). T with excellent heat resistance, suitable for use in alloy parts business
This relates to i-alloy. (Prior art) Engine valves used in automobile reciprocating engines, compressor disks and turbine blades used in aircraft jet engines, turbine blades used in industrial gas turbines, etc., are made by increasing their combustion efficiency. One way to improve performance and fuel efficiency is to increase the combustion temperature, and therefore it is necessary to develop materials that can be used at higher temperatures. There is also a demand for further weight reduction. Conventionally, heat-resistant Ti alloys have been used as materials that are relatively lightweight and have the required strength and heat resistance. For example, Ti-6A Bun-4V (AlS 4695) and Ti-6Al-2Sn-4Ti-6A. (AlS 4976), Ti-6Ti-6AJ2-2
Sn-4Zr-2, ISi, Tj-5, 8Alt-4
Sn-3,5Zr-0,7Nb-0,5Zr-0,35
Examples include Si-0,15C (#Opening/Closing No. 59-89744). And these are both α+β type Ti-A, l-V
The main material is Ti-AKL-5n-Zr based alloy or Niγα type alloy, and if necessary, β such as Mo, Nb, V, etc.
A stabilizing element is added. (Problems to be Solved by the Invention) The conventional heat-resistant Ti alloys described above are considerably lighter than heat-resistant steels and heat-resistant alloys containing a large amount of Nf, and have reasonable strength and heat resistance. As mentioned above, in order to improve the combustion efficiency of automobile and aircraft engines, industrial gas turbines, etc., there is a tendency to increase the combustion temperature, so further improvements in #thermal properties are desired. There was a problem. (Object of the Invention) The present invention has been made in view of such conventional problems, and aims to further improve the heat resistance of conventional heat-resistant Ti alloys with high specific strength. The purpose is

[Structure of the invention]

(Means for Solving the Problems) The Ti alloy with excellent heat resistance according to the present invention has the following properties by weight:
Al: 10% or less, Sn: 15% or less. #Mold is defined as a structure containing one or more of Zr: 15% or less, Ga: 0.01 to 15%, and the remainder consisting of Ti and impurities, and in an embodiment, Al. The Sn, Zr, and Ga contents are AlL+ (S n/3)+ (Zr/6)+(Ga/
2) 515% AR+ (Sn/3)+ (Zr/6)+Ga≧5
% relationship, and the same (1% by weight in the embodiment, A text = 8% or less, Sn+15% or less, Z
r: Contains one or more of 15% or less, further includes Ga: 0.01 to 10%, and the remainder consists of Ti and impurities, and Al. The Sn, Zr, and Ga contents are: A writer (S n/3) + (Zr/6) + (Ga/2)
510% A Bunju (S n/3) + (Z r/6) + Ga≧6%
The configuration satisfies the relationship , and the same (in the embodiment, V , N b , T a , Cr , Mo
,W. Further contains one or more of Mn, Fe, Co, Ni, and Cu (V/1.5) + (Nb/3.6) + (Ta/4.5) + (Cr70.64) +Mo+
(W/2.6)+ (Mn10.64n+ (F
elo, 35) + (Colo, 7) + (
The configuration satisfies the relationship of N ilo , 9) + (Cu/1.3)≦7%, and the same (in the embodiment, C,
It is characterized by a structure containing one or more of Sf, S, Y, and REM in a total of 1% or less, and solves the conventional problems described above with the structure of the Ti alloy with excellent heat resistance. It is used as a means to do so. Next, the reason for limiting the composition range (wt%) of the Ti alloy with excellent heat resistance according to the present invention will be explained. Sentence A: 10% or less Ai is an effective element for solid solution strengthening of the α phase, so
One or more of these are contained along with Sn and Zr, but if the AQ content is too large, it will form Ti3 All compounds and reduce ductility, so it is necessary to keep it at 10% or less. , it is preferable to set it to 8% or less as necessary. Sn: 15% or less Sn is an effective element for solid solution strengthening of the α phase.
One or more of these are contained together with Al and Zr, but if the Sn content is too large, Ti3Sn compounds will be formed and the ductility will be reduced, so it is necessary to keep it at 15% or less. . Zr: 15% or less Zr is an effective element for solid solution strengthening of the α and β phases, so one or more of these are included together with AlSn, but if the Zr content is too high, the β phase will be strengthened. As the amount of
It is necessary to keep it below 5%. Ga: 0.0l-15% Ga is an effective element for solid-solution strengthening the α phase and improving the heat resistance of Ti alloys, so it is contained at 0.01% or more to obtain this effect. However, Ga
If the content is too large, Ti3Ga compounds will be formed and the ductility will be reduced, so it needs to be 15% or less, and if necessary, it is preferably 10% or less. AJ1+ (S n/3) + (Z r/6) + (Ga
/2) ≦15% In order to ensure the necessary ductility in consideration of the solid solubility limit of the α phase when the elements of A, Sn, Zr, and Ga are appropriately added in combination, the above steps must be taken. It is desirable that the content of each element be 15% or less, and more preferably 10% or less if necessary. A, Q+ (Sn/3) + (Zr/6)+G
a≧5% When each element of Al, Sn, Zr, and Ga is appropriately added in combination, in order to ensure the necessary high temperature strength, the relationship between the above elements should be 5% or more. It is desirable that the content be 6% or more, and it is even more desirable that the content be 6% or more, if necessary. V Nb, Ta, Cr, Mo, W, Mn. One or more of Fe, Co, Ni, and Cu These elements are effective for solid solution strengthening of the β phase and improving heat treatability, and are an element group effective for improving short-time strength. Therefore, it is also desirable to add one or more of these as necessary. In this case, (V/1.5)+ (Nb/3.6)+
(Ta/4.5)+ (Crlo, 64)+M
o+ (W/2 .6)+ (Mn10 .64)
+ (Fe10.35)+ (Co10.7)+
(Ni10.9) + (Cu/1.3) In the MO equivalent relationship, if this value exceeds 7%, the amount of β phase will increase and the creep characteristics will deteriorate. Even if one or more of the elements are added, it is desirable that the amount is 7% or less based on the above relationship. Among the above elements, Nb, Ta, and Mo have a slow diffusion rate in Ti; It is particularly effective in improving creep properties, and is also highly effective in improving oxidation resistance. One or more of C, Si, S, Y, REM (one or more rare earth elements) These elements form inclusions or compounds with impurities in Tf or Ti. , are a group of elements effective for improving creep strength, so it is also desirable to add one or more of these as necessary. However, if the content is too large, the manufacturability will deteriorate and the ductility will also decrease, so even if added, it is desirable that the total amount of one or more of these types is 1% or less. Ti: Remainder Ti is lightweight, has excellent heat resistance and corrosion resistance, and provides high specific strength, so it was designated as the remainder. (Function of the invention) Since the Ti alloy according to the present invention has the above-described structure, by adding an appropriate amount of type 1 or type 2 of A, Sn, and Zr to Ti, α phase can be formed. In addition, by adding an appropriate amount of Zr, the β phase is also solid solution strengthened, and by adding an appropriate amount of Ga, the α phase is solid solution strengthened and the heat resistance is improved. Ti has excellent heat resistance and corrosion resistance as well as high specific strength.
The heat resistance of the alloy has been further improved, and V, Nb
, Ta, Cr, Mo, W, Mn, Fe. By containing one or more of Co, Ni, and Cu as necessary, the β phase is solid solution strengthened, heat treatability is improved, and short-time strength is improved.
Creep strength can be further improved by containing one or more of C, Sf 2 , S, Y, and REM as necessary. (Actual trip example) Ti alloys having the chemical composition shown in Table 1 were produced by plasma melting, and ingots with a diameter of LOOmm were obtained for each ingot, which was then bloomed at 1150°C and then forged at 1000°C. A 20 mm square bar material was obtained by stretching. Next, after solution treatment was performed just below the β transus temperature (Tβ-20°C), an aging treatment was performed at 635°C to obtain a test material. Next, the room temperature tensile properties (0.2% proof stress, drawing), 600°C tensile properties (0.2% proof stress, drawing), and temperature = 600°C, stress 20.4 kgf/m of each sample material were determined.
The creep characteristics were investigated for m2 and time = 100 hours. These results are also shown in Table 1. As shown in Table 1, the alloy of the present invention has high-temperature tensile properties, high-temperature (600°C) tensile properties, and high-temperature (600°C) tensile properties.
It was found that the creep properties were good, and the high temperature properties showed good values, especially when compared with a comparative alloy to which no Ga was added, indicating that the alloy had excellent heat resistance. Also, AlL+ (S n/3)+ (Z r15)+
The alloy No. 17, which has a large value (G a / 2), does not have very good ductility, so
Since cracks occurred during forging under the forging and drawing conditions of this example, it was recognized that it was necessary to consider the forging and drawing conditions.

【Effect of the invention】

The Ti alloy according to the present invention contains, in weight percent, one or more of the following: A = 10% or less, Sn + 15% or less, Zr: 15% or less, and further Ga: 0.01 to 15%.
In the conventional heat-resistant Ti alloy with high specific strength,
It is possible to further improve its heat resistance, and for example, it brings about a remarkable effect that it can cope with the tendency of increasing combustion temperature to improve the combustion efficiency of various combustion engines.

Claims (5)

[Claims] (1) Contains one or more of the following in weight%: Al: 10% or less, Sn: 15% or less, Zr: 15% or less, further contains Ga: 0.01 to 15%, and the balance is Ti Ti has excellent heat resistance and is characterized by consisting of impurities.
alloy. (2) Al, Sn, Zr, Ga content is Al+(Sn/3)+(Zr/6)+(Ga/2)≦15% Al+(Sn/3)+(Zr/6)+Ga≧5 The Ti alloy with excellent heat resistance according to claim 1, which satisfies the relationship of %. (3) In weight%, Al: 8% or less, Sn: 15% or less,
Zr: Contains one or more of 15% or less,
Furthermore, it contains Ga: 0.01 to 10%, and the remainder consists of Ti and impurities, and the content of Al, Sn, Zr, and Ga is Al+(Sn/3)+(Zr/6)+(Ga/2)≦10 % Al+(Sn/3)+(Zr/6)+Ga≧6% Ti alloy with excellent heat resistance. (4) further contains one or more of V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, (V/1.5)+(Nb/3. 6) +(Ta/4.5)+(Cr/0.64) +Mo+(W/2.6)+(Mn/0.64)+(Fe
/0.35)+(Co/0.7)+(Ni/0.9)+(Cu/1.3)≦7% of claim 1, 2, or 3. Ti alloy with excellent heat resistance as described in . (5) One or two of C, Si, S, Y, REM
The Ti alloy with excellent heat resistance according to claim 1, 2, 3, or 4, which contains at least 1% of Ti alloys in total.