TW593710B - A method using physical vapor deposition to improve the high temperature oxidation resistance of gamma-titanium aluminides - Google Patents

Abstract

A method for forming a TiAl3 continuous intermetallic protective film on the surface of a titanium aluminide is particularly suitable for improving the high temperature oxidation resistance of the titanium aluminide. According to the invention, a titanium aluminide can be coated with an aluminum film having a suitable thickness by a physical vapor deposition process, e.g. sputtering, vapor deposition, etc. Furthermore, a high vacuum thermal treatment can be used to convert the aluminum film into a TiAl3 continuous intermetallic film, thereby improving the high temperature oxidation resistance thereof. Such a process is applicable on a component using a titanium aluminide material and being used in a high temperature environment, e.g. blades of a turbine engine, an exhaust valve for an automobile engine, etc.

Description

The plating method and the like of this patent will be appropriately combined with a subsequent layer of TiAl3, which is dense and protected. Because the surface and the surface expand each other, the investment is small, and the operation can be accurately controlled. The surface of the workpiece without a flat surface has a physical vapor phase. Deposition (PVD) sputtering method, evaporation = degree of aluminum coating deposited on the surface of titanium aluminum alloy, two plus ^ heat treatment, the production of titanium aluminum alloy surface, under the use of high temperature environment will form on the surface A layer of alumina inert film to improve high temperature and wide oxidation resistance will increase the adhesion of the aluminum coating to the substrate. The equipment has a short operating time, and the thickness of the coating, such as sputtering or evaporation, has good properties and uniform defects, and can completely cover the workpiece. At the same time, it has excellent texture after processing. < Brief description of the diagrams > The following is a brief description of the sputtering method chart in the present invention: The table shows important parameters of the sputtering process in the embodiment. The table shown in the second table is based on the oxidation curve of the third chart, calculated according to formula 1. After the δ aluminum coating thickness is subjected to a 600 pre-diffusion heat treatment for 24 hours, its: TkoAlw (or r-TiAl) oxidation rate constant Kp value The changes shown in the second table are based on the oxidation curve of the fourth graph, calculated according to Formula One = aluminum coating with a thickness of 3 has passed through 600. 〇 Pre-diffusion heat treatment at different times ^ > 7 A 1m oxidation rate constant κρ value changes. The figure shows the X-ray diffraction pattern of r—TyAiw metal after homogenization heat treatment.

593710

V. Description of the invention (4) The second picture is the X-ray diffraction pattern of the 7-Ti ”AIm metal surface sputtered with a 3 μπι aluminum ore layer. The second picture is the sputter deposition on the surface of T ^ ΑΙμ metal After the aluminum coatings of different thicknesses are subjected to a pre-diffusion heat treatment at a high vacuum of 600 ° C (below 3 x 10 to 7 torr) for 24 hours, they will be oxidized in air at a high temperature of 90 0 ° C for 80 hours. The relationship between weight gain and high temperature oxidation time.

The fourth picture shows that the 3 # m | Lu deposit is sputter-deposited on the 7-T A 1 ^ metal surface, and then passes through 600. (: The relationship between the weight increase per unit area and the high temperature oxidation time after high vacuum pre-diffusion heat treatment at different times, after 80 hours of oxidation in air at 90 ° C and 80 ° C. The fifth figure is at 7-Ti 5Q A15Q metal surface was plated with aluminum with different thicknesses and then subjected to high vacuum pre-diffusion heat treatment at 60 ° C for 24 hours. The temperature was maintained in a thermogravitic analysis (TGA) in air at 900 ° C. The analysis results after 70 hours. The sixth figure shows the X-ray diffraction pattern after depositing aluminum coatings of different thicknesses on the surface of Ti5QAl5Q intermetallic bonds and depositing aluminum coatings of different thicknesses, followed by high vacuum pre-diffusion heat treatment at 600 ° c for 24 hours. The seventh picture shows the sputter deposition of aluminum coatings of different thicknesses on the surface of r-Ti5GAl5G intermetallic metal, and then after 60 (rc high vacuum pre-diffusion heat treatment for 24 hours), it is oxidized in air at a high temperature of 900 ° C for 80 hours. X-ray diffraction pattern. <Detailed description of the invention> The following examples are used to explain the specific process of the invention in detail. This work selects r-tuIm titanium aluminum alloy metal alloy. This invention is applicable to these procedures.

Page 7 593710 V. Description of the invention (7) After covering and pre-diffusion heat treatment of two vacuums, it can effectively slow the local temperature oxidation of r. T l50 A lw. In addition, the thicker the aluminum coating, the better the high-temperature oxidation resistance of the treated metal. 9 0 0. (: High temperature oxidation curve after 2 hours, its oxidation rate is the formula following the parabolic oxidation:, = —Kpt + c ⑴ Formula f ω is the weight increase per unit area, t is the oxidation time, κρ is the secondary oxidation rate constant (Parabolic oxide rate coiistant). Ρ · Kofstad, High Temperature Corrosion, Elsevier ^ HfeiencePub · Ltd ·, 1 998, p. 164] Using the curves of the formula, aluminum coatings with different thicknesses can be calculated. The individual and thorium values after 24 hours of bulk treatment. Dimetallic kappa value; written description: fKp, as shown in the second table. As can be seen from the second table, its thickness decreases as the thickness of the layer increases. The degree of mouth is limited; the value of ΛΤΙ is not significant, which indicates that Cheng Ren's increased oxidation resistance when the thickness of the coating reaches 3 // m, and the value of Shiqi Dingding / M soil after sputtering is 4,899 mg2 / 2 The reduction of leaf bleaching properties can be reduced / cm hr, 诘], and the risk is from 0.0 to 709 mg2. The reduction is about 7%, and the high temperature and oxygen resistance of 6 Strong # means that titanium-aluminum metal & emulsification is significantly improved. And when aluminum plating chip Go to pay, its κρ value is 3.2e_4 mg2 / cmhr, when the dryness reaches 5 when the L value is 15,000th of the L value, the minus and the value are unsputtered κ values, which shows its financial oxidation effect The number of levels above makes the titanium and aluminum media all belong to ## 化. According to the present examples, it is necessary to significantly improve the metal's resistance to lice. When the thickness reaches 5 V 111, '* ^ ^ ^ and the strength will increase with the increase of the thickness of the film. "Because of the internal stress of the film, nr Μ passes 600t high true 593710. V. Description of the invention ( 8)

The empty pre-diffusion heat treatment 24 has a small amount of atmosphere as a function of stress, which results in oxidation resistance after the treatment. For product application examples, you can choose the surface of the test piece. In this standard, the surface of the hand piece will not have a good surface quality. Its κρ value is about 80 hours after untreated. ; And without treatment 'will produce and lose metallic luster on the surface. After an hour, the aluminum coating of some test strips may be slightly peeled off due to heat, which makes the surface of the test strip exposed by the base material uneven, and also affects the surface requirements. The choice of texture and metallic luster is required. 3 // m The above 5 // m aluminum plating layer is deposited at a thickness of 60 (TC high-vacuum pre-diffusion place, peeling occurs, and the appearance of the treated test piece can be seen from the table. The thickness is 3 // m. At 7% of the film, the surface energy of the store still maintains the 7-Ti ^ Also dielectric metal material after pre-diffusion treatment at a high temperature of 90 (rc), and the layer is easily peeled off and discontinuous white oxide in about 5 hours. The fourth figure shows the thickness of k-g-μ deposited in the Luqian layer at 7-150 ° F, 150 ° F, 150 ° F, 48 ° F, 60hr, and 72hr. 〇 Oxidation in the air for 80 days: Vacuum pre-expansion ^ After heat treatment, the relationship diagram of oxidation time at 900 ℃ at high temperature. ^ ^ After that, the unit weight increase and high temperature weight increase are not more than 0.9 cycles. It can be seen that the unit area of each curve is significantly different. Using the formula (丨 / CIfl2, and varying It is not clear from the third table that the calculated Kp value of 3 / zm is as shown in the third table. The increase in the physical time and the steaming and heterochain layer will not have the Kρ value with the pre-diffusion heat. The κρ value was changed from 0.0 0 70 9 mg2 / ^. The pre-diffusion treatment time for 24 hours and its 72 hours κρ values were all 〇〇〇Γ, while 36 hours, 48 hours, 60 hours and P 7Q9 mS2 / cm Near hr, even if the difference is greatest

593710 V. Description of the invention (9), 6-10 = 0,00856 of Rishou, there is still only a slight increase. This may be because there is a slight amount of oxygen in the 二 if, so with the pre-diffusion heat treatment, try The surface of the sheet and the oxygen formed the result of the oxide. The ^^ 60 C: pre-diffusion treatment time has no significant effect on the oxidation resistance of ^ / 50 5G intermediary metal coated with 3 # m aluminum coating on the surface, so when considering the economic benefits, it is necessary to choose the cost The shortest time is the store. But you can do static continuous oxidation experiments in the air of Thermogravitic Analysis (TGA) II / / JDL / v. The fifth figure is the analysis diagram of the deposit of different thicknesses on the surface of r-II metal, and then subjected to r = I air pre-diffusion heat treatment for 24 hours, using a thermogravimetric analyzer at Λ temperature for 70 hours. It can be seen from the fifth graph that the increase in the thickness of the single # A / decreases as the thickness of the aluminum coating increases. When the thickness is 71, the oxidation resistance is the best. The 900 ° C static constant in the fifth figure and the 90th generation dynamic cycle oxidation experiment in the third figure have 4 2 @ η:, and the κρ values are also in the same range, which further proves that when the property is 4 ΐ to 3 "m At the above time, “Ming Jie Metal has excellent high temperature anti-emulsification effect. In titanium alloy metal φ X ^ _

The structure is also different. Aluminium denier π "Different from Lu, the higher the amount of oxide produced, the easier it will be to smi the surface: the better it is, because the resistance of the metal containing ml3 to the metal. ^„, S?. The rolling property is better than 7 -ΉΑ1 is much better. In this example of Λbismuth, the T-Tl50Al50 metal substrate and its surface will pass through a high vertical space of 60 0 t: and also: 7 ^ ^ coating surface coating, ^ ^ Α Τ A § ^ ^ Al3 /, the picture shows γ-Τ ι ^ ΑΙμ metal surface sputtering

Page 12 593710 V. Description of the invention (10) --- X-ray diffraction pattern after depositing different thickness plating layers and high vacuum pre-diffusion heat treatment at 600 ° c for 24 hours. The figure clearly shows that the diffraction peak intensity of the TiAl3 phase increases with the increase of the thickness of the aluminum coating. On the contrary, the diffraction peak intensity of the base ^ r -Ti ^ AlsG decreases with the increase of the thickness of the aluminum coating ^ Low, when the thickness reaches 5 // in, all become the diffraction peaks of T i A13, and the diffraction peaks of the substrate are not seen at all. This means that when the thickness of the aluminum coating is more than 3 # m, the τ 丨 A intermediary metal will be completely formed after pre-diffusion treatment on the interface with the substrate, which also proves why it will be excellent in high temperature cyclic oxidation experiments. Resistance to oxidation. In the seventh figure, aluminum alloys of different thicknesses are deposited on the 7-Tiw A 1 ^ metal surface by sputtering, and then passed through 600. (: High-vacuum pre-diffusion heat treatment for 24 hours and then, after 90 hours of oxidation in air at 900 ° C, the light diffraction pattern. The picture shows the untreated r-Ti ^ Aiw dielectric metal material at 90 ( After rc oxidation, a large amount of TiO2 oxide is formed on the surface, and its diffraction peak intensity decreases with the increase of the thickness of the pure aluminum coating. When the thickness reaches 3 Am or more, the TiO2 phase can hardly be seen. Diffraction peaks; the diffraction peaks of the ALA phase will increase significantly with the increase of the thickness of the aluminum coating, and the intensity of the diffraction peaks will also increase. This X-ray, ·: ^ 射 图 ^ / means 7-Τ "ο A 15 ° intermetallic material and titanium-aluminum intermetal with an aluminum coating below 3 m. After 90 (TC air oxidation for 80 hours, the surface is mainly formed of non-dense, discontinuous, easily peelable and non-protective Ti〇2 white. Oxidation layer. After high-temperature oxidation of titanium-aluminum intermetals with an aluminum plating layer of more than 3 // m, a dense, continuous and anti-oxidation A 込 〇 "durable layer" is mainly formed.

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Claims (1)

593710 VI. Scope of patent application. A method for rewinding “aluminum-based metal 'high temperature oxidation resistance” by physical vapor deposition method includes at least the following steps: (1) providing titanium-aluminum metal; and (2) combining the above钬 Aluminum metal is subjected to a physical vapor deposition surface treatment to deposit a thin film of appropriate thickness on the surface of the metal. The thickness of the thin film layer ranges from 3 μm to 20; and (3) the above titanium aluminum metal Vacuum heat treatment is performed to form a continuous Ti A13 intermetallic layer on the surface to improve its high temperature oxidation resistance. The temperature range of vacuum heat treatment is between 200 ° C ~ 650 ° C, and the processing time is more than 0 · 1 hour. 2. A method for improving the high-temperature oxidation properties of a metallurgical metal by physical vapor deposition as described in item 1 of the scope of the patent application, wherein the above-mentioned “aluminum-based metal is an r-Ti5 () Al5 () phase The composition (atomic ratio) of aluminum alloy or 7-rich titanium aluminum alloy is in the range of T60A14 [] to Ti4GAl6G. 3_ A method for improving the high-temperature oxidation resistance of titanium-aluminum-based metals by physical vapor deposition as described in item 1 of the scope of patent application, wherein the physical vapor deposition method includes a sputtering method, an evaporation method, and other physical vapor deposition methods One of the methods is to discard the weight 0 4, as described in item 1 of the scope of the patent application, a method for improving the high temperature resistance of titanium-aluminum-based metal by physical vapor deposition, wherein the optimal treatment time for vacuum heat treatment is 2 4 hours. Page 15