JPH03193837A - High temperature oxidation-resistant intermetallic compound ti-al series alloy - Google Patents

Abstract

PURPOSE:To manufacture the Ti-Al series alloy provided with high temp. oxidation resistance with good productivity by preparing an intermetallic compound Ti-Al series alloy contg. specified ratios of Nb and W. CONSTITUTION:An intermetallic compound Ti-Al series alloy contg., by atom, 0.05 to 3% Nb and 0.05 to 4% W, in which the content of Al is regulated to 40 to 52% is prepd. In this way, a Ti-Al series alloy member having excellent high temp. oxidation resistance can be obtd. with good productivity without requiring the application of a conventional surface treating method. Furthermore, the alloy is incorporated with at least one kind selected from <=3.5% V, <=4.5% C and <=1.25% Fe in addition to Nb and W, by which high specific strength can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION A0Object of the invention (1) Industrial application field The present invention is directed to a high temperature oxidation resistant intermetallic compound TtAI! , regarding alloys of the series.

(2) Conventional technology Intermetallic compound TiAf alloy (hereinafter referred to as TiA1!).

T i A I T i
s A three-phase alloy, TiAf-Ti3Af-TiAf
, three-phase alloys, etc. are known. This TiAf-based alloy is lightweight and has superior high-temperature oxidation resistance compared to Ti-based alloys, but compared to Ni-based alloys such as Inconel-713C, its high-temperature oxidation resistance has an oxidation weight gain of 5 to 5. 10 times worse.

Therefore, in order to improve the high-temperature oxidation resistance of TiAf-based alloys, N ion implantation method and Af
The surface layer is modified by surface treatment methods such as vapor deposition and A2 diffusion infiltration.

On the other hand, in terms of high temperature strength, TiAl1 alloy has 60
Inconel-713C under high temperature such as 0~900°C
Since it has a specific strength (the value obtained by dividing the breaking stress (generally tensile strength) by the density of the material) of the track and the like, it is expected to be used as a constituent material for heat-resistant members.

(3) Problems to be Solved by the Invention However, according to the surface treatment method described above, when the surface layer peels off due to the occurrence of cracks, etc., oxidation progresses from the peeled part, and the high temperature acid resistance of the TiAf alloy increases. There is a problem in that the chemical properties deteriorate significantly. Therefore, in order to solve these problems and improve productivity by eliminating surface treatment, TiAf! It is desired that the alloy itself has excellent high-temperature oxidation resistance.

On the other hand, in terms of high-temperature strength, when replacing Inconel-713C with a TiAffi alloy, the replacement must be made considerably larger than the Inconel-713C member, and therefore there is a demand for smaller size and lighter weight. Therefore, the density is equivalent to that of the conventional TiAl alloy, and the high strength TiAffi alloy, that is, the TiA with high specific strength.
j! There is a demand for the development of alloys based on these.

In view of the above, an object of the present invention is to provide the TiAf-based alloy, which itself has excellent high-temperature oxidation resistance.

Further, the present invention provides the TiAl material, which itself has excellent high temperature oxidation resistance and exhibits high specific strength at high temperatures.
The purpose is to provide a 1-series alloy.

B1 Structure of the Invention (1) Means for Solving the Problems The TtAj! according to the present invention! The system alloy is 0.05 atomic%
Above, 3 at% or less Nb, 0.05 at% or more,
The first characteristic is that it contains 4 atomic % or less of W and;

The TiAffi-based alloy according to the present invention includes Nb and i of 0.05 atomic % or more and 3 atomic % or less; W of 0.05 atomic % or more and 4 atomic % or less; V, 3.5 atomic % or less; .5
The second feature is that it contains at least one selected from C at % or less and Fe at 1.25 atomic % or less.

(2) Effect According to the first feature, TiA has excellent high-temperature oxidation resistance by containing specific amounts of Nb and W.
f-based alloys can be provided.

However, on the condition that Nb and W are used together, Nb
When the content is less than 0.05 atomic % and more than 3 atomic %, the high temperature oxidation resistance of the TiAf-based alloy deteriorates. On the other hand, under similar conditions, the W content was 0.05 at%
TiAff
The high temperature oxidation resistance of i-based alloys deteriorates.

According to the second feature, by containing specific amounts of Nb and W and selectively containing specific amounts of VLC and Fe, it has excellent high temperature oxidation resistance and high specific strength at high temperatures. It is possible to provide a TiAl-based alloy that exhibits the following properties.

In this case, the reason for limiting the contents of Nb and W is the same as described above, but in particular, in the case of W, when the content exceeds 4 at %, the specific strength of the TiAf-based alloy decreases. Moreover, if the content of (■) exceeds 3.5 atomic %, the high temperature oxidation resistance of the TiAf-based alloy will be significantly deteriorated. Furthermore, the content of C is 4
．． When it exceeds 5 atom%, TiAj! The high-temperature oxidation resistance of the alloy is significantly deteriorated, and the specific strength is also significantly reduced.

Fe has extremely low elongation value TiAj! It has the function of imparting elongation to the alloy and improving its ductility, as well as improving its 0.2% yield strength. , Fe content is 1.2
When it exceeds 5 at %, the 0.2% yield strength decreases, and high temperature oxidation resistance also tends to deteriorate.

(3) Example Mainly composed of TiAl1-Ti3Af two-phase alloy, with N
By selectively adding B, W, V, and C, various types of TiAl-based alloys were manufactured by applying an arc melting method. Also T
i A I T i s A j! In the β two-phase alloy, a plurality of TiAA-based alloys were manufactured by the same method as described above while varying the content of 80.

A test piece was cut from each TiAffi alloy, and the tensile specific strength of each test piece was determined as the tensile strength at 800"C (X 10-" MP a -m3/kg
), and as a high-temperature oxidation resistance test, test pieces were left in still air at 900°C for 120 hours, and then the oxidation weight gain (x 10
-"kg/m") was determined.

The tensile specific strength of each test piece is Inconel-7
Equal to or greater than 13C, therefore 100XI
Q100XIQ-3/kg or more (preferably 120X
10-0-3 MPa-7 kg or more), and oxidation weight gain of approximately 60 x 10-"kg/m" or less was considered good.

Table 3 shows the chemical composition and tensile specific strength (X 10-"MP a・m3/
kg, same in each table below) and oxidation weight gain (X
10-3 kg/m'' (same in each table below).

Table 1 Invention Alloy 1 is the most excellent in terms of tensile specific strength and oxidation weight gain, and is the reference alloy for determining the composition in the present invention.

Other invention alloys 2 to 7 are An
The content of Ti is increased or decreased in accordance with the increase or decrease of the content of A2.

Comparative Example Alloy 8 is composed only of Ti and Al, and is the reference alloy for determining the composition in the Comparative Example, and other Alloys 9 to 11 have different Al contents based on Alloy 8. This is what I did.

Figure 1 shows the relationship between the A1 content and tensile specific strength of the invention alloys 1 to 7 and comparative example alloys 8 to 11, and Figure 2 shows the relationship between the Ai content and oxidation weight gain of these alloys 1 to 110. show.

As is clear from Table 1 and FIGS. 1 and 2, in the alloys 1 to 7 of the present invention, T i A,j! -Ti.

1 atomic % of Nb5W and C in the Aβ dual phase alloy and 1.5
To improve the specific tensile strength and high temperature oxidation resistance of the TiAl alloy by setting the content of A2 to 40 atomic % or more and 52 atomic % or less under the condition of adding atomic % of V. I can do it.

However, if the Al content is less than 40 atomic %, high temperature oxidation resistance will deteriorate, while if it exceeds 52 atomic %, the tensile specific strength will decrease.

Preferably, the Al content is 41 atomic % or more and 46 atomic % or less.

On the other hand, it is clear that none of Comparative Example Alloys 8 to 11 satisfies both tensile specific strength and high oxidation resistance.

Table ■ shows the invention alloys 1, 12 to 14 and comparative example alloy 8.
, 15.16, the chemical composition, tensile specific strength and oxidation weight gain are shown, respectively.

Table ■ Inventive alloys 12 to 14 have fixed contents of AI W, V, and C and different contents of Nb.
The content of is changing.

Comparative example alloy 15.16 is one in which only Nb is added and its content is changed, and the contents of Ti and A2 are set to be equal.

Figure 3 shows the invention alloys 1.12 to 14 and the comparative example alloy 8.
, 15.16, and Figure 4 shows the relationship between the Nb content and tensile specific strength of these alloys 1. 12-14.8.15
．． 16 shows the relationship between Nb content and oxidation weight gain of No. 16.

As is clear from Table 1 and Figures 3 and 4, in alloys 12 to 14 of the present invention, by setting the Nb content to 0.05 at% or more and 3 at% or less, TiA
The specific tensile strength and high temperature oxidation resistance of the j2 alloy can be improved.

When the content of Nb is less than 0.05 atomic % or more than 3 atomic %, the high temperature oxidation resistance of the TiAj2 alloy deteriorates.

In order to improve both the specific tensile strength and high temperature oxidation resistance of the TiAf alloy, it is preferable to set the Nb content to 0.5 at.% or more and 2 at.% or less.

On the other hand, it is clear that there is no Comparative Example Alloy 15.16 that satisfies both tensile specific strength and high temperature oxidation resistance.

Table ■ shows the invention alloys 1, 17 to 19 and comparative example alloy 8.
．． The chemical components, tensile specific strength and oxidation weight gain of 20 to 22 are shown, respectively.

Table ■ Invention alloys 17 to 19 are A/! , the contents of Nb, V, and C are fixed, and the content of W is changed, and T
The content of i is changing.

Comparative example alloy 20.21 is one in which W is added alone and its content is changed, and Ti and AI! The contents of , are set to be equal. Comparative example alloy 22 is
Invention alloys 17 to 19, except that W was not added.
It has a composition such as .

Figure 5 shows the invention alloys 1.17 to 19 and comparative example alloy 8.
．． Showing the relationship between W content and tensile specific strength of 20 to 22,
Further, FIG. 6 shows the relationship between the W content and oxidation weight gain of these alloys 1.8°17-22.

As is clear from Table 1, Figures 5 and 6, in the alloys 17 to 19 of the present invention, the W content is 2 atomic % or more,
By setting the content to 4 atomic % or less, the specific tensile strength and high-temperature oxidation resistance of the TiAf-based alloy can be improved.

However, if the W content is less than 0.05 atomic % or more than 4 atomic %, the high temperature oxidation resistance of the TiAj2 alloy deteriorates.

In order to improve both the tensile specific strength and high-temperature oxidation resistance of the TiAf-based alloy, the W content should be 0.5 at% or more,
It is preferable to set it to 2 atomic % or less.

On the other hand, it is clear that none of Comparative Example Alloys 20.21 satisfies both tensile specific strength and high temperature oxidation resistance. Furthermore, in the case of Comparative Example Alloy 22, high temperature oxidation resistance is significantly deteriorated due to the absence of W.

Table ■ shows the invention alloy 1.23 and comparative example alloy 8.24.
~26 chemical components, tensile specific strength and oxidation weight gain are shown, respectively.

Table 1 In Invention Alloy 23, the contents of Af, Nb, W, and C are fixed, and the content of ■ is changed, and the Ti content is changed accordingly.

Comparative Example Alloy 24.25 is one in which ``■'' is added alone and its content is changed, and the contents of Ti and /l are set to be equal. Further, Comparative Example Alloy 26 has a composition similar to that of Invention Alloy 23, except that the content of (1) was set to 4.5 atomic %.

Figure 7 shows the invention alloy 1.23 and the comparative example alloy 8.24.
Figure 8 shows the relationship between the ■ content and the tensile specific strength of Alloys 1, 8.23 to 26, and the oxidation weight gain.

As is clear from Table 1 and FIGS. 7 and 8, in Invention Alloy 23, by setting the content of 3 to 3 atomic %, TiAj! The specific tensile strength and high-temperature oxidation resistance of the alloy can be improved.

When the content of Ti and ■ exceeds 3.5 at%, Ti
The high temperature oxidation resistance of the Afi alloy deteriorates significantly.

This is clear from Comparative Example Alloy 26.

In order to improve both the tensile specific strength and high-temperature oxidation resistance of the TiAffi alloy, the content of
It is preferable to set it to 3 atomic % or less.

On the other hand, it is clear that there is no Comparative Example Alloy 24.25 that satisfies both tensile specific strength and high temperature oxidation resistance.

Table ■ shows the invention alloys 1, 27-30 and comparative example alloy 8.
．． The chemical components, tensile specific strength and oxidation weight gain of Nos. 31 to 33 are shown, respectively.

Table V Invention alloys 27-30 are A1. , Nb5W, the content of ■ is fixed and the content of C is changed, and accordingly T
The content of i is changing. However, the alloy 27 of the present invention does not contain C.

Comparative example alloy 31.32 is one in which C is added alone and its content is changed, and the contents of Ti and A1 are set to be equal. Comparative Example Alloy 33 is the Invention Alloy 2 except that the C content is set to 5 at%.
It has a composition of 7 to 30 and Roma.

Figure 9 shows the invention alloys 1, 27 to 30 and comparative example alloy 8.
, 31 to 33 show the relationship between C content and tensile specific strength,
Further, FIG. 10 shows the relationship between the C content and oxidation weight gain of these alloys 1,8°27-33.

As is clear from Table V5 and Figures 9 and 10, in alloys 28 to 30 of the present invention, by setting the C content to 2 at% or more and 4 at% or less, the tensile specific strength of the TiAf alloy is improved. and high temperature oxidation resistance can be improved.

When the content of Ti and C exceeds 4.5 at%, Ti
The tensile specific strength and high temperature oxidation resistance of Affi alloys deteriorate.

In order to improve both the tensile specific strength and high-temperature oxidation resistance of the TiAf-based alloy, the C content should be 0.5 at% or more,
It is preferable to set it to 3.5 atomic % or less.

However, even when C is not contained as in Invention Alloy 27, the specific tensile strength and high temperature oxidation resistance of the TiA1 alloy are relatively good.

On the other hand, it is clear that none of Comparative Example Alloys 31 to 33 satisfies both tensile specific strength and high temperature oxidation resistance.

The alloy of the present invention is mainly composed of a TiAffi-Tiz Al dual-phase alloy to which Nb, W, V, and C are selectively added. However, when Fe is added in addition to these additive elements, the elongation value decreases. It is possible to impart elongation to a TiA1-based alloy, which has an extremely low carbon content, to improve its ductility and to improve its 0.2% yield strength.

Table (2) shows the chemical composition, tensile specific strength, and oxidation weight gain of Invention Alloy 34.35 and Comparative Example Alloy 36.37 to which Fe was added.

Table ■ Inventive alloy 34.35 and comparative example alloy 36°37 are:
The Fe content was varied based on Invention Alloy 1, and the Al content was decreased as Fe was added.

From Table ■, by setting the Fe content to 1.25 at% or less, TiAj! It is possible to improve the tensile specific strength and high temperature oxidation resistance of the alloy.

Figure 11 shows TiAj! Figure 12 shows the relationship between Fe content and elongation in the alloy.
The relationship between content and 0.2% proof stress is shown.

11th. As is clear from FIG. 12, the Fe content is suitably 1.25 atomic % or less.

The alloy of the present invention has T iAI T is Aj! It is mainly a two-phase alloy to which Nb, W, V, C, and Fe are selectively added, but even when only Nb and W are added among these additive elements, TlAl-based alloy can improve the tensile specific strength and high temperature oxidation resistance of

Table (1) shows the chemical composition, tensile specific strength, and oxidation weight gain of Invention Alloys 38 to 43, respectively.

Table ■ Figure 13 shows the present invention alloys 38 to 40 and the comparative example alloy 8,
Figure 14 shows the relationship between the W content and tensile specific strength of alloys 38 to 40.8.15,
The relationship between the W content and oxidation weight gain of 20.21 is shown.

Figure 15 shows the present invention alloys 41 to 43 and comparative example alloy 8,
16 shows the relationship between the W content and the tensile specific strength of alloys 41 to 43.8 and 20.21, and FIG. 16 shows the relationship between the W content and oxidation weight gain of these alloys 41 to 43.8 and 20.21.

As is clear from Table 1 and Figures 13 to 16, in the present invention alloys 38 to 43, the Nb content was reduced to 0.05.
By setting the W content in the range of 0.05 atomic % or more and 4 atomic % or less, the tensile specific strength and high temperature acid resistance of the Ti/L alloy can be improved. It is possible to improve both chemical properties.

Comparative Example Alloy 8 does not contain Nb and W, and Comparative Example Alloy 15 contains only 2 atomic % of Nb, and Comparative Example Alloy 2
0.21 contains only W at 1 atomic % and 2 atomic %, respectively, but both tensile specific strength and high temperature oxidation resistance are inferior to Invention Alloys 38 to 43.

Effects of the C0 Invention According to the invention described in claim (1), by specifying the contents of Nb and W as described above, it is possible to provide the TiAl alloy having excellent high temperature oxidation resistance. This makes it unnecessary to apply conventional surface treatment methods and TiAj! The productivity of alloy-based members can be improved.

According to the invention described in claim (2), the contents of Nb and W are specified as described above, and the content of V
, C, and Fe as described above, the TiAj! has excellent high-temperature oxidation resistance and exhibits high specific strength at high temperatures. system alloy, thereby making it unnecessary to apply conventional surface treatment methods and Tj1! It is possible to improve the productivity of alloy-based members and to make the members smaller and lighter.

[Brief explanation of drawings]

1st. FIG. 2 is a graph showing the relationship between Affi content, tensile specific strength, and oxidation weight gain; FIG. 4 is a graph showing the relationship between Nb content, tensile specific strength, and oxidation weight gain. Fig. 6 is a graph showing the relationship between W content, tensile specific strength and oxidation weight gain; Fig. 7; Fig. 8 is a graph showing the relationship between content, tensile specific strength and oxidation weight gain; 10th
The figure is a graph showing the relationship between C content, tensile specific strength, and oxidation weight gain, Figure 11 is a graph showing the relationship between Fe content and elongation, and Figure 12 is a graph showing the relationship between Fe content and 0.2% proof stress. Graph showing the relationship, 13th. Figure 14 shows Nb content of 2 at%
Graph showing the relationship between W content, tensile specific strength, and oxidation weight gain in 15th. FIG. 16 is a graph showing the relationship between Nb content, W content, tensile specific strength, and oxidation weight gain at 3 atomic %. Figure 2 A2 content (atomic %) Figure 1 AIl content (atomic %) Figure 4 Nb content (atomic %) Figure 6 W content (atomic %) Figure 3 Nb content (atomic %) Figure 5 W content (atomic %) Figure 8 ■ Content (atomic %) Figure 10 C content (atomic %) Figure 7 ■ Content (atomic %) Figure 9 C content (atomic %) Fig. 12 Fe content (atomic %) Fig. 14 W content (atomic %) (N b -2 atomic %) Fig. 11 Fe content (atomic %) Fig. 13 W content (atomic %) (N b -2 atomic %) Figure 16 W content (atomic %) (N b = 3 atomic %) Figure 15 W content (atomic %) (Nb = 3 atomic %)

Claims (3)

[Claims] (1) 0.05 atomic % or more and 3 atomic % or less of Nb;
．． A high-temperature oxidation-resistant intermetallic compound TiAl-based alloy, characterized in that it contains at least 0.05 atom % and at most 4 atom % of W; (2) 0.05 atomic % or more and 3 atomic % or less Nb;
．． 05 at% or more and 4 at% or less of W; 3.5 at%
V not more than 4.5 at%, C not more than 4.5 at% and 1.25 at%
High temperature oxidation resistant intermetallic compound TiAl characterized by containing at least one selected from the following Fe and;
system alloy. (3) The high-temperature oxidation-resistant intermetallic compound TiAl alloy according to item (1) or (2), wherein the Al content is set to 40 at % or more and 52 at % or less.