CN103160708B - Application of NiAl-2.5Ta-7.5Cr-20Co alloy as high-temperature self-lubricating material - Google Patents

Abstract

The invention discloses the application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high-temperature self-lubricating material. The alloy uses electrolytic Ni, metal Al, Cr, Ta and Co as raw materials, is melted in a vacuum electric arc furnace according to the ratio and cast into a round ingot. The alloy is used as a room-temperature to high-temperature self-lubricating material for sliding parts of a mechanism, and the abrasive material is SiC, Si ₃ N ₄ , Al ₂ O ₃ ceramic material or hard alloy. The load of the wear-resistant material is 10-20N, and the sliding speed is 0.2-0.5m/s. It is applied to the sliding parts of the mechanism under the condition of friction and wear under atmospheric conditions from room temperature to 600°C. Under this working condition, NiAl-2.5Ta-7.5Cr-20Co alloy has excellent long-lasting self-lubricating properties. The problem of the self-lubricating performance of the NiAl-based alloy from room temperature to 200°C and the self-lubricating performance of 500°C to 600°C is solved.

Description

Application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high temperature self-lubricating material

technical field

The invention relates to high-temperature self-lubricating application technology of nickel-aluminum-based composite materials, in particular to the application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high-temperature self-lubricating material.

Background technique

The intermetallic compound NiAl is an ideal high-temperature structural material, which has the advantages of high melting point (1640°C), high thermal conductivity (70-80W/m·K), low density (5.86g/cm ³ ) and excellent oxidation resistance. However, problems such as poor room temperature tensile plasticity, low room temperature fracture resistance, insufficient high temperature strength, and low high temperature creep resistance have always restricted the practical progress of NiAl as a structural component material. Over the years, from the perspective of alloying and preparing endogenous and exogenous composite materials, people have improved the high temperature creep resistance of NiAl alloys by adopting methods such as solid solution strengthening, second phase strengthening, and oxide dispersion strengthening (ODS). and room temperature fracture toughness. However, it is still difficult to meet the requirements for NiAl-based alloys to simultaneously achieve sufficient room temperature fracture toughness, creep strength comparable to superalloys, and 2% room temperature tensile plasticity. At present, NiAl has not been widely used as a high-temperature structural material and functional material, except that it is widely used as a coating material for Ni-based and Co-based superalloys.

Considering the natural compressive stress state under friction and wear conditions, the Institute of Metal Research, Chinese Academy of Sciences and Hunan University of Science and Technology studied in-situ endogenous NiAl-Al2O3-TiC composites, NiAl-Cr(Mo)-Ho-Hf eutectic alloys and Friction and wear properties of NiAl-Cr(Mo)-CrxSy composites. It was found that under the condition of friction and wear at room temperature, the tensile plasticity of the alloy becomes a secondary performance index compared with the hardness, strength, compression plasticity and work hardening ability, and its dry friction and wear is controlled by plastic deformation, which has good resistance Wear performance; under atmospheric and dry friction conditions, the alloy can produce good self-lubricating and wear-resistant effects in high-temperature friction and wear at 700 ° C to 900 ° C, and the friction coefficient and wear rate are lower than Ni-based self-lubricating alloys ( The alloy contains W, Mo, Co), and the self-lubricating properties are durable. In addition, the NiAl-Cr(Mo)-CrxSy composite material forms a CrxSy lubricating film on the friction surface at 200 ° C to 400 ° C, resulting in self-lubricating properties, which provides research ideas for the development of NiAl-based self-lubricating materials in a wider temperature range.

At present, if NiAl-based alloys are to be widely used as self-lubricating materials, three problems still need to be solved: ① self-lubricating performance from room temperature to 200 ℃; ② self-lubricating performance from 500 ℃ to 600 ℃; ③ self-lubricating performance at 1000 ℃. .

Contents of the invention

In order to overcome the defects in the prior art, the invention provides the application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high-temperature self-lubricating material.

The technical scheme that the present invention solves the problems of the technologies described above is:

Application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high-temperature self-lubricating material, NiAl-2.5Ta-7.5Cr-20Co alloy as a self-lubricating material for sliding parts of a mechanism from room temperature to 600 °C, and the abrasive material is SiC, Si ₃ N ₄ , Al ₂ O ₃ ceramic materials or cemented carbide.

The application of a NiAl-2.5Ta-7.5Cr-20Co alloy as a high-temperature self-lubricating material, the load of the wear-resistant material is 10-20N, the sliding speed is 0.2-0.5m/s, and it is applied from room temperature to 600°C in the atmosphere Mechanism sliding parts under friction and wear conditions.

The NiAl-2.5Ta-7.5Cr-20Co alloy is used as a high-temperature self-lubricating material, and the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co composite material is 0.24-0.27.

When the NiAl-2.5Ta-7.5Cr-20Co alloy is used as a high-temperature self-lubricating material, a Co oxide lubricating film is formed on the friction surface of the NiAl-2.5Ta-7.5Cr-20Co composite material.

The beneficial effects of the present invention are: 1. the NiAl-2.5Ta-7.5Cr-20Co alloy structure of the present invention is made up of NiAl, Cr, Cr2Ta and Co3Ta phase, in the process of friction and wear, the oxide lubricating film of Co is self-formed on the friction surface, Since the lubricating film has self-healing properties in friction and wear, it has long-lasting self-lubricating properties from room temperature to 600°C. The problem of the self-lubricating performance of the NiAl-based alloy from room temperature to 200°C and the self-lubricating performance of 500°C to 600°C is solved. ② The NiAl-2.5Ta-7.5Cr-20Co alloy of the present invention can be matched with ceramic materials such as SiC, Si ₃ N ₄ and Al ₂ O ₃ and hard alloy respectively, and has a wide range of applications. ③ The present invention uses NiAl-2.5Ta-7.5Cr-20Co alloy as a self-lubricating material, which is a NiAl-based alloy added with Ta, Cr and Co as strengthening elements. The alloy has excellent compressive strength, plasticity and hardness at room temperature to 600°C. Under the wear condition where the load is compressive stress, the friction and wear performance from room temperature to 600°C shows excellent self-lubricating performance, and the friction coefficient is 0.24-0.27.

Description of drawings

Fig.1 SEM morphology of NiAl-2.5Ta-7.5Cr-20Co alloy.

Figure 2 (b).X diffraction pattern of NiAl-2.5Ta-7.5Cr-20Co alloy.

Fig. 3 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at room temperature.

Fig. 4 Morphology of lubricating film on friction surface of NiAl-2.5Ta-7.5Cr-20Co alloy at room temperature.

Fig. 5 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 100 °C.

Fig. 6 Morphology of lubricating film on the friction surface of NiAl-2.5Ta-7.5Cr-20Co alloy at 100 °C.

Fig. 7 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 200 °C.

Fig. 8 Morphology of lubricating film on NiAl-2.5Ta-7.5Cr-20Co alloy friction surface at 200 °C.

Fig. 9 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 300 °C.

Fig.10 Morphology of lubricating film on friction surface of NiAl-2.5Ta-7.5Cr-20Co alloy at 300℃.

Fig. 11 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 400 °C.

Fig.12 Morphology of lubricant film on NiAl-2.5Ta-7.5Cr-20Co alloy friction surface at 400℃.

Fig. 13 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 500 °C.

Fig. 14 Morphology of lubricating film on NiAl-2.5Ta-7.5Cr-20Co alloy friction surface at 500 °C.

Fig. 15 Variation trend of friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at 600 °C.

Fig. 16 Morphology of lubricant film on NiAl-2.5Ta-7.5Cr-20Co alloy friction surface at 600 °C.

detailed description

The present invention will be described in detail below in conjunction with specific embodiments.

The practical application method of the present invention is implemented according to the following steps:

1. Fix the NiAl-2.5Ta-7.5Cr-20Co alloy block sample on the lower sample fixture, fix the ceramic or hard alloy ball on the upper sample fixture, and place it in the electric heating furnace to raise the temperature at a rate of 20°C/ Minutes, after the temperature rises to the set temperature, keep warm for 2 minutes, load, and the upper sample shaft drives the ceramic or hard alloy ball to rotate to start friction and wear.

2. The load is 10-20N, the sliding speed is 0.2-0.5m/s, the friction and wear test temperature is room temperature-600℃, dry friction in the atmosphere.

Table 1 Friction coefficient of NiAl-2.5Ta-7.5Cr-20Co alloy at different temperatures

temperature room temperature 100°C 200℃ 300℃ 400°C 500℃ 600°C NiAl-2.5Ta-7.5Cr-20Co 0.27 0.24 0.25 0.25 0.26 0.25 0.25 NiAl-2.5Ta-7.5Cr 0.36 0.34 0.41 0.43 0.45 0.48 0.52

As shown in Table 1, at different temperatures, it can be seen that the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy is 0.24-0.27.

As shown in Figure 1, the NiAl-2.5Ta-7.5Cr-20Co alloy structure consists of NiAl, Cr, Cr2Ta and Co3Ta phases.

Example 1

In this embodiment, the wear temperature is room temperature, the abrasive part is SiC ceramics, the load is 20N, the sliding speed is 0.2m/s, the wear time is 0.5h, and the sliding distance is 360m. The NiAl-2.5Ta-7.5Cr-20Co alloy block sample is fixed on the lower sample fixture, and the SiC ceramic material is fixed on the upper sample fixture, loaded, and the upper sample shaft drives the SiC ball sample to rotate to start friction and wear.

As shown in Figure 2, the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 1 is carried out with the wear test. The initial friction coefficient is about 0.26, and the friction coefficient increases slightly as the wear progresses. After 7 minutes of wear , the coefficient of friction remains stable, and the measured average coefficient of friction is 0.27.

As shown in Figure 3, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 1 shows that a relatively smooth and complete oxide lubricating film is formed on the friction surface, and the lubricating film has slight peeling characteristics .

Example 2

In this embodiment, the wear temperature is 100°C, the abrasive part is Si ₃ N ₄ ceramics, the load is 20N, the sliding speed is 0.3m/s, the wear time is 1.25h, and the sliding distance is 1350m. The NiAl-2.5Ta-7.5Cr-20Co alloy block sample is fixed on the lower sample holder, and the Si ₃ N ₄ ceramic material is fixed on the upper sample holder, and placed in a heating electric furnace with a heating temperature of 100°C and a heating rate of 20°C/min, after the temperature rises to 100°C, keep warm for 2min, load, the upper sample shaft drives the Si ₃ N ₄ ball sample to rotate and start friction and wear, and cool to room temperature in the air after stopping.

As shown in Fig. 4, the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 2 remains stable with the progress of the wear test, and the measured average friction coefficient is 0.24.

As shown in Figure 5, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 2 shows that a smooth and even oxide lubricating film is formed on the friction surface.

Example 3

In this embodiment, the wear temperature is 200°C, the abrasive part is Si ₃ N ₄ ceramics, the load is 15N, the sliding speed is 0.5m/s, the wear time is 1.25h, and the sliding distance is 2250m. The NiAl-2.5Ta-7.5Cr-20Co alloy bulk sample was fixed on the lower sample fixture, and the Si ₃ N ₄ ceramic ball was fixed on the upper sample fixture, and placed in a heating electric furnace at a heating temperature of 200°C and a heating rate of 20°C/min, after the temperature rises to 200°C, keep warm for 2min, load, the upper sample shaft drives the Si ₃ N ₄ ceramic balls to rotate and start friction and wear, and cool to room temperature in the air after stopping.

As shown in Fig. 6, the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 3 remains stable with the progress of the wear test, and the measured average friction coefficient is 0.25.

As shown in Figure 7, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 3 shows that a flat, smooth and complete oxide lubricant film is formed on the friction surface, and the lubricant film has a small amount of dots and Lumpy flaking features.

Example 4

In this example, the wear temperature is 300°C, the abrasive part is Al ₂ O ₃ ceramics, the load is 20N, the sliding speed is 0.4m/s, the wear time is 1.25h, and the sliding distance is 1800m. The NiAl-2.5Ta-7.5Cr-20Co alloy block sample was fixed on the lower sample holder, and the _Al2O3 ceramic ball was fixed _on the upper sample holder, and placed in a heating electric furnace at a heating temperature of 300 °C and a heating rate of 20°C/min, after the temperature rises to 300°C, keep warm for 2min, load, the upper sample shaft drives the Al ₂ O ₃ ceramic balls to rotate and start friction and wear, and cool to room temperature in the air after stopping.

As shown in Fig. 8, the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 4 maintained a stable state around 0.24 as the wear test progressed, and the measured average friction coefficient was 0.25.

As shown in Figure 9, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 4 shows that a flat, smooth and complete oxide lubricant film is formed on the friction surface, and the lubricant film has a small amount of dots and Lumpy flaking features.

Example 5

In this embodiment, the wear temperature is 400°C, the abrasive part is YG8 cemented carbide, the load is 10N, the sliding speed is 0.3m/s, the wear time is 1.25h, and the sliding distance is 1350m. The NiAl-2.5Ta-7.5Cr-20Co alloy block sample is fixed on the lower sample fixture, and the cemented carbide is fixed on the upper sample fixture, and placed in a heating electric furnace with a heating temperature of 400°C and a heating rate of 20°C/ Minutes, after the temperature rises to 400 ° C, keep warm for 2 minutes, load, the upper sample shaft drives the carbide ball sample to rotate and start friction and wear, and cool to room temperature in the air after stopping.

As shown in FIG. 10 , the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 5 remained stable with the progress of the wear test, and the measured average friction coefficient was 0.26.

As shown in Figure 11, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 5 shows that a smooth and flat oxide lubricating film is formed on the friction surface, and the lubricating film has a small amount of dots and blocks. peeling characteristics.

Example 6

In this embodiment, the wear temperature is 500°C, the abrasive part is Si ₃ N ₄ ceramics, the load is 15N, the sliding speed is 0.5m/s, the wear time is 1.25h, and the sliding distance is 2250m. The NiAl-2.5Ta-7.5Cr-20Co alloy bulk sample was fixed on the lower sample fixture, and the Si ₃ N ₄ ceramic ball was fixed on the upper sample fixture, and placed in an electric heating furnace with a heating temperature of 500 °C and a heating rate of 20°C/min, after the temperature rises to 500°C, keep warm for 2min, load, the upper sample shaft drives the Si ₃ N ₄ ceramic balls to rotate and start friction and wear, and cool down to room temperature in the air after stopping.

As shown in FIG. 12 , the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 6 remained stable with the progress of the wear test, and the measured average friction coefficient was 0.25.

As shown in Figure 13, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 6 shows that a flat, smooth and complete oxide lubricant film is formed on the friction surface, and the lubricant film has a small amount of dots and Lumpy flaking features.

Example 7

In this example, the wear temperature is 600°C, the abrasive part is Al ₂ O ₃ ceramics, the load is 20N, the sliding speed is 0.4m/s, the wear time is 1.25h, and the sliding distance is 1800m. The NiAl-2.5Ta-7.5Cr-20Co alloy block sample was fixed on the lower sample holder, and the Al ₂ O ₃ ceramic ball was fixed on the upper sample holder, and placed in a heating electric furnace at a heating temperature of 600°C and a heating rate of 60°C/min, after the temperature rises to 600°C, keep warm for 2min, load, the upper sample shaft drives the Al ₂ O ₃ ceramic balls to rotate and start friction and wear, and cool down to room temperature in the air after stopping.

As shown in Figure 14, the friction coefficient of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 7 progressed with the wear test. The friction coefficient was initially about 0.23. After 6 minutes of wear, the friction rose to around 0.25 and remained stable. The average coefficient of friction was measured to be 0.25.

As shown in Figure 15, the friction surface morphology of the NiAl-2.5Ta-7.5Cr-20Co alloy in Example 7 shows that a smooth, smooth and complete oxide lubricating film is formed on the friction surface, and the lubricating film has a small amount of dots and Lumpy flaking features.

The result of embodiment shows, the present invention adopts NiAl-2.5Ta-7.5Cr-20Co alloy as self-lubricating wear-resistant material, and NiAl-2.5Ta-7.5Cr-20Co alloy can be combined with ceramics such as SiC, Si ₃ N ₄ or Al ₂ O ₃ Material and cemented carbide pairing, the load is 10-20N, the sliding speed is 0.2-0.5m/s, and it is applied to the sliding parts of the mechanism under the condition of friction and wear under the atmospheric condition of room temperature to 600°C. Under this working condition, NiAl-2.5Ta-7.5Cr-20Co alloy has excellent long-lasting self-lubricating properties and wear resistance.

Claims (5)

1. NiAl-2.5Ta-7.5Cr-20Co alloy is as an application for high temperature self-lubricating composite, it is characterized in that: NiAl-2.5Ta-7.5Cr-20Co alloy, as mechanism slips parts, is applied to room temperature to 600 DEG C self-lubricating material, is SiC, Si to mill part material ₃n ₄or Al ₂o ₃stupalith or Wimet.

2. a kind of NiAl-2.5Ta-7.5Cr-20Co alloy as described in claim 1 is as the application of high temperature self-lubricating composite, it is characterized in that: the load of high-abrasive material is 10 ~ 20N, sliding velocity is 0.2 ~ 0.5 m/s, is in the mechanism slips parts of frictional wear operating mode under being applied to room temperature to 600oC atmospheric condition.

3. a kind of NiAl-2.5Ta-7.5Cr-20Co alloy as described in claim 1, as the application of high temperature self-lubricating composite, is characterized in that: the frictional coefficient of NiAl-2.5Ta-7.5Cr-20Co matrix material is 0.24 ~ 0.27.

4. a kind of NiAl-2.5Ta-7.5Cr-20Co alloy as described in claim 1, as the application of high temperature self-lubricating composite, is characterized in that: the friction surface of NiAl-2.5Ta-7.5Cr-20Co matrix material forms oxide compound lubricant film.

5. a kind of NiAl-2.5Ta-7.5Cr-20Co alloy as described in claim 4, as the application of high temperature self-lubricating composite, is characterized in that: the oxide compound lubricant film of the friction surface formation of NiAl-2.5Ta-7.5Cr-20Co matrix material is the oxide compound lubricant film of Co.