CN108085529B - A kind of MAX phase strengthened zirconium titanium aluminum vanadium alloy and preparation method thereof - Google Patents

Abstract

A MAX phase-strengthened zirconium-titanium-aluminum-vanadium alloy, the ratio of various raw materials is: the mass fraction of zirconium is 20%-51%, the mass fraction of aluminum is 6%, the mass fraction of vanadium is 4%, and the MAX phase ( The mass fraction of Ti ₃ AlC ₂ ) is 0.5-2.0%, and the remaining mass fraction is titanium and unavoidable impurities. The invention mainly uses _ZrTiAlV series alloy as a matrix, adds pure _Ti3AlC2 obtained by SPS (plasma discharge sintering) method into the matrix, and passes through a non-consumable arc melting furnace to obtain a strengthened zirconium-titanium alloy. The invention can evenly distribute the MAX phase (Ti ₃ AlC ₂ ) which is not easy to be formed by directly adding carbon to the zirconium-titanium base alloy matrix; it utilizes the structural characteristics of the MAX phase (Ti ₃ AlC ₂ ) to add to the zirconium-titanium base alloy To achieve the purpose of refining the structure and improving the mechanical properties of the alloy; without the need for large heating furnaces and forging equipment, low-cost products can be obtained with a short manufacturing cycle.

Description

A kind of MAX phase strengthened zirconium titanium aluminum vanadium alloy and preparation method thereof

technical field

The invention relates to an alloy material and a preparation method thereof.

Background technique

Zirconium and titanium belong to the same main group in the mid-term table of elements. Zirconium alloys and titanium alloys have many similar characteristics, such as high strength, good corrosion resistance, good heat resistance, and good biocompatibility. Metal zirconium has the characteristics of small neutron absorption area, high corrosion resistance and high melting point (1860°C), which makes it widely used in the nuclear industry. Titanium alloy has the characteristics of high specific strength and excellent high temperature performance, and has been widely used in mechanical automation and aviation industry. With the continuous enrichment and development of zirconium-titanium alloys, zirconium-titanium alloys have gradually attracted attention as engineering structural materials, and their applications in many aspects, especially in the aerospace industry, are increasing.

The as-cast structure of zirconium-titanium-based alloys is coarse. In order to improve its mechanical properties, forging is usually used. In industry, the original coarse grains are generally refined through more than three times of piercing, so as to achieve the purpose of improving mechanical properties. However, this method requires a large heating furnace and forging equipment, and it is difficult to control the forging temperature. Before each forging, it is necessary to turn or grind the surface of the forging billet formed last time to remove the oxide layer on the surface. These additional processes will lead to an increase in the manufacturing cycle and cost of the zirconium-titanium-based alloy.

Contents of the invention

The object of the present invention is to provide a low-cost MAX phase (Ti ₃ AlC ₂ )-strengthened zirconium-titanium-aluminum-vanadium alloy and a preparation method thereof, which can be obtained without large-scale heating furnace and forging equipment and with a short production period. The invention mainly uses _ZrTiAlV series alloy as a matrix, adds pure _Ti3AlC2 obtained by SPS (plasma discharge sintering) method into the matrix, and passes through a non-consumable arc melting furnace to obtain a strengthened zirconium-titanium alloy.

1, the proportioning of the raw material of the zirconium-titanium-aluminum-vanadium alloy strengthened by the MAX phase of the present invention is: the mass fraction of zirconium is 20%-51%, the mass fraction of aluminum is 6%, the mass fraction of vanadium is 4%, the MAX phase ( The mass fraction of Ti ₃ AlC ₂ ) is 0.5-2.0%, and the remaining mass fraction is titanium and unavoidable impurities.

2. The preparation method of the above-mentioned MAX phase-strengthened zirconium-titanium-aluminum-vanadium alloy:

(1) Material preparation: MAX phase (Ti ₃ AlC ₂ ) is obtained by SPS (plasma discharge sintering) to obtain pure Ti ₃ AlC ₂ , crushed, and placed in absolute ethanol with zirconium titanium aluminum vanadium (ZrTiAlV) alloy system respectively, with Ultrasonic vibration cleaning, drying and weighing according to the proportion;

(2) Ingot casting: put the raw materials mentioned in step (1) into a vacuum non-consumable melting furnace for 8 times of melting, the vacuum degree during melting is 2.0×10 ^-2 Pa, and the melting current is kept at 300A, each time The smelting time of each sample is 2 minutes. After each smelting is completed, wait for the high-temperature red hot color of the ingot to fade away, and then proceed to the next smelting to ensure that a zirconium-titanium alloy ingot with uniform composition is obtained;

Compared with the prior art, the present invention has the following advantages:

1. It can evenly distribute the MAX phase (Ti ₃ AlC ₂ ) which is not easy to be formed by directly adding carbon into the zirconium-titanium-based alloy matrix.

2. Utilize the structural characteristics of the MAX phase (Ti ₃ AlC ₂ ) to add to the zirconium-titanium-based alloy to achieve the purpose of refining the structure and improving the mechanical properties of the alloy.

3. Low-cost products can be obtained with a short manufacturing cycle without the need for large-scale heating furnaces and forging equipment.

Description of drawings

Fig. 1 is the X-ray diffractogram of embodiment 1-4 of the present invention smelting alloy rolling state;

Fig. 2 is the SEM topography figure of embodiment 1-4 of the present invention as-cast;

Fig. 3 is a rolling state transmission electron microscope image of Example 4 of the present invention.

Explanation of the contents of the above drawings:

Figure 1 shows that as the addition of MAX phase (Ti ₃ AlC ₂ ) increases, the peak position of Ti ₃ AlC ₂ can be gradually observed in the XRD peak spectrum, and the peak intensity of pyrolyzed TiC can also be observed.

Figure 2 shows that as the addition of MAX phase (Ti ₃ AlC ₂ ) increases, the matrix structure is refined, and strip-shaped MAX phase (Ti ₃ AlC ₂ ) precipitates can be seen at 2% addition.

Fig. 3 shows that SAED data verified that there is MAX phase (Ti ₃ AlC ₂ ) in the composition of the precipitated phase.

Detailed ways

Embodiment 1 (comparative example)

Cut 63.5g of forged 20Zr (Ti-20Zr-6Al-4V), put it in absolute ethanol, clean it with ultrasonic vibration, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times, the vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the melting time of each sample is 2 minutes. After each melting is completed, wait for the high-temperature red color of the ingot to fade before proceeding to the next melting. An alloy ingot with uniform composition is obtained.

A compression rod with a height of 10 mm and a diameter of 5 mm was cut from the ingot on a wire cutting machine, and the scale was removed from the surface with sandpaper, and its compression mechanical properties were tested on an instron5982 mechanical property testing machine. The specific experimental data are shown in Table 1.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 2

Cut 63.9g of forged 20Zr (Ti-20Zr-6Al-4V) and SPS (plasma discharge sintering) to obtain 0.33g of pure Ti ₃ AlC ₂ phase, crush it, put it in absolute ethanol, and vibrate with ultrasonic waves After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

A compression rod with a height of 10 mm and a diameter of 5 mm was cut from the ingot on a wire cutting machine, and the scale was removed from the surface with sandpaper, and its compression mechanical properties were tested on an instron5982 mechanical property testing machine. The specific experimental data are shown in Table 1.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 3

Cut 63.2g of forged 20Zr (Ti-20Zr-6Al-4V), SPS (plasma discharge sintering) to obtain 0.64g of pure Ti ₃ AlC ₂ phase, mash it, put it in absolute ethanol, and use ultrasonic vibration After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

A compression rod with a height of 10 mm and a diameter of 5 mm was cut from the ingot on a wire cutting machine, and the scale was removed from the surface with sandpaper, and its compression mechanical properties were tested on an instron5982 mechanical property testing machine. The specific experimental data are shown in Table 1.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 4

Cut 63.4g of forged 20Zr (Ti-20Zr-6Al-4V) and SPS (plasma discharge sintering) to obtain 1.29g of pure Ti ₃ AlC ₂ phase, crush it, put it in absolute ethanol, and use ultrasonic vibration After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

A compression rod with a height of 10 mm and a diameter of 5 mm was cut from the ingot on a wire cutting machine, and the scale was removed from the surface with sandpaper, and its compression mechanical properties were tested on an instron5982 mechanical property testing machine. The specific experimental data are shown in Table 1.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 5

Cut 63.4g of forged 30Zr (Ti-30Zr-6Al-4V) and SPS (plasma discharge sintering) to obtain 1.29g of pure Ti ₃ AlC ₂ phase, crush it, put it in absolute ethanol, and use ultrasonic vibration After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 6

Cut 63.4g of forged 40Zr (Ti-40Zr-6Al-4V), SPS (plasma discharge sintering) to obtain 1.29g of pure Ti ₃ AlC ₂ phase, crush it, put it in absolute ethanol, and use ultrasonic vibration After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Example 7

Cut 63.4g of forged 51Zr (Ti-51Zr-6Al-4V), SPS (plasma discharge sintering) to obtain 1.29g of pure Ti ₃ AlC ₂ phase, mash it, put it in absolute ethanol, and use ultrasonic vibration After cleaning, dry it with a hair dryer, and place it in a non-consumable vacuum arc melting furnace for repeated melting 8 times. The vacuum degree is 2.0×10 ^-2 Pa, the melting current is kept at 300A, and the sample melting time is 2 minutes. Each melting is completed. Afterwards, wait for the high-temperature red color of the ingot to recede before proceeding to the next smelting. An alloy ingot with uniform composition is obtained.

Then put the zirconium-titanium-aluminum-vanadium alloy ingot into the muffle furnace and heat it to 950°C, keep it warm for 30 minutes, and then transfer the alloy ingot to a two-roll flat rolling mill within 20 seconds for multi-pass rolling deformation; the first rolling After the production is completed, keep the temperature at 950°C for 5 minutes, and then carry out the second rolling deformation within 20s. In this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature.

Product performance testing:

Cutting from ingot with wire cutting For thin slices, grind the surface of the thin slices from coarse to fine, place them in absolute ethanol, clean them with ultrasonic waves for 30 minutes, and dry them with a hair dryer at low temperature. The processed sample is analyzed by DSC to obtain the starting temperature and ending temperature of the phase transformation of the alloy.

(1) hot-rolled state stretching

Due to the small size of the ingot, it is impossible to cut the tensile sample, so it is hot-rolled to obtain a flat alloy sample. Before rolling, the initial thickness is measured with a vernier caliper. According to the deformation amount of 70%, the rolled The final thickness, and divide the difference between the two by the amount of pressing each time. The hot rolling machine presses down 1.62mm each time to get the number of times of hot rolling. After the first time, adjust the amount of pressing each time to achieve For hot rolling requirements, put the as-cast alloy into the muffle furnace and heat the muffle furnace to 950°C for 30 minutes, then quickly transfer the alloy ingot to a two-roll flat rolling mill for multi-pass rolling deformation; After the first rolling is completed, keep the above temperature for 5 minutes, and then quickly carry out the second rolling deformation, and in this cycle, the amount of pressing each time is controlled at 9-11% of the initial thickness of the alloy ingot, and finally the deformation of the alloy ingot reaches More than 70%; After the last deformation, place the alloy plate in the air to cool to room temperature. The rolling temperature is controlled in the near α/α+β area, and the rolling temperature is determined according to the DSC curve. The rolled alloy is cut into standard tensile samples with a wire cutting machine. The properties are: σ _b ≥ 1204MPa, σ _0.2 ≥ 1075MPa, part δ ≥ 7.39%. The uniaxial tensile test at room temperature is carried out on the instron5982 mechanical property testing system, the tensile speed is: 0.375mm/min, and the length change of the sample during the stretching process is tracked and measured with an extensometer.

(2) As-cast compression: Cut the as-cast alloy into a compressed cylinder with a height-to-diameter ratio of about 2:1 with a wire cutting machine. The oxide layers on the bottom and sides were sanded off with sandpaper. The compression test at room temperature was carried out on an instron5982 mechanical property testing system at a compression speed of 0.1800mm/min. An extensometer was used to track and measure the length change of the sample during the compression process. It was found that after adding the MAX phase (Ti ₃ AlC ₂ ), the structure of the alloy changed. In addition to the original structure of the matrix, the MAX phase (Ti ₃ AlC ₂ ) could also be observed in stripes, and a small amount of Ti ₃ AlC ₂ was pyrolyzed. TiC. And the microstructure of the matrix is refined, achieving the effect of strengthening the mechanical properties of the zirconium-titanium-based alloy. Generally, if carbon is directly added, it is difficult to obtain Ti ₃ AlC ₂ in the in-situ formation reaction during smelting, and it is easier to obtain Ti ₂ AlC/Ti ₃ AlC. Therefore, the present invention directly adds the MAX phase (Ti ₃ AlC ₂ ), which can effectively solve the problem that the MAX phase (Ti ₃ AlC ₂ ) is not easily formed. Moreover, in the non-consumable vacuum melting furnace, the ingredients can be homogenized through 8 times of melting.

Table 1 The test results of the mechanical properties of the alloy of the present invention with the increase of MAX phase (Ti ₃ AlC ₂ )

Numbering alloy state Compressive strength (MPa) Compression ratio(%) hardness Example 1 cast state 1647.0 8.7 391.39 Example 2 cast state 1727.0 10.9 388.06 Example 3 cast state 1682.0 9.0 384.21 Example 4 cast state 1848.0 7.1 451.33

It can be seen from Table 1 that when the MAX phase (Ti ₃ AlC ₂ ) is added by 2%, namely Example 4, its compressive strength and hardness increase significantly.

Claims (2)

1. a kind of zirconium titanium aluminum vanadium alloy that MAX phase is strengthened, it is characterised in that: the proportion of various raw material are as follows: zirconium mass fraction is 20%-51%, the mass fraction of aluminium are 6%, and the mass fraction of vanadium is 4%, Ti₃AlC₂Mass fraction be 0.5-2.0%, remain Remaining mass fraction is titanium and inevitable impurity；

Zirconium titanium aluminum vanadium alloy that the MAX phase is strengthened the preparation method comprises the following steps:

(1) it stocks up: Ti₃AlC₂Pure Ti is obtained using spark plasma sintering₃AlC₂, smash to pieces, set respectively with ZrTiAlV alloy system It in dehydrated alcohol, is cleaned up with ultrasonic oscillation, is weighed according to the ratio after drying；

(2) ingot casting: raw material described in step (1) are put into vacuum non-consumable smelting furnace melting 8 times, vacuum degree when melting It is 2.0 × 10^-2Pa, melting electric current are maintained at 300A, and each each sample smelting time is 2min, after each melting is completed, It waits the red heat color of ingot casting high temperature to decorporate, then carries out melting next time.

2. the zirconium titanium aluminum vanadium alloy preparation method that the MAX phase of claim 1 is strengthened, it is characterised in that:

(1) it stocks up: Ti₃AlC₂Pure Ti is obtained using spark plasma sintering₃AlC₂, smash to pieces, set respectively with ZrTiAlV alloy system It in dehydrated alcohol, is cleaned up with ultrasonic oscillation, is weighed according to the ratio after drying；

(2) ingot casting: raw material described in step (1) are put into vacuum non-consumable smelting furnace melting 8 times, vacuum degree when melting It is 2.0 × 10^-2Pa, melting electric current are maintained at 300A, and each each sample smelting time is 2min, after each melting is completed, It waits the red heat color of ingot casting high temperature to decorporate, then carries out melting next time.