METHOD FOR PREPARING NANO SPHERICAL OXIDE DISPERSION STRENGTHENING PHASE

Abstract

A method for preparing a nano spherical oxide dispersion strengthening phase using a micron oxide is proposed for the first time. First, a micron oxide is used as a raw material to prepare a nano oxide with a completely amorphous structure/matrix alloy composite powder by mechanical ball milling in stages. In the first stage, ball milling is performed, causing the oxide to break and transform in structure, and achieving nano-sizing and completely amorphization, to prepare a composite powder with a completely amorphous structure nano oxide uniformly distributed in the matrix alloy powder; and in the second stage, the composite powder obtained in the first stage and the remaining matrix alloy powder are uniformly mixed by ball milling. Then, the uniformly mixed powder is sequentially subjected to hot forming, hot rolling, and heat treatment, to obtain a nano spherical oxide dispersion strengthened alloy.

Claims

1. A method for preparing a nano spherical oxide dispersion strengthening phase, comprising: mixing a micron oxide with a matrix alloy powder, and preparing a composite powder with a uniformly distributed amorphous nano oxide by a mechanical ball milling in a plurality of stages, in a first stage of the plurality of stages, mixing and ball milling the micron oxide with a part of the matrix alloy powder to prepare a composite powder with a completely amorphous structure nano oxide particles uniformly distributed in the matrix alloy powder, in a second stage of the plurality of stages, uniformly mixing the composite powder obtained in the first stage with a remaining part of the matrix alloy powder by the mechanical ball milling; and sequentially subjecting a uniformly mixed composition powder obtained in the second stage to a hot forming, a hot rolling, and a heat treatment, to prepare the nano spherical oxide dispersion strengthened alloy.

2. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, wherein the nano spherical oxide dispersion strengthening phase comprises at least one selected from the group consisting of Y.sub.2O.sub.3, TiO, Y.sub.2TiO.sub.3, Y.sub.2TiO.sub.7, Y—Cr—O, and Y—W—O; a size of the nano spherical oxide dispersion strengthening phase is less than or equal to 100 nm; and the matrix alloy powder is one selected from the group consisting of a Fe—Cr—W—Ti or Fe—Cr—W alloy, a nickel-based superalloy, a copper alloy, and a high-entropy alloy.

3. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, comprising: using an oxide powder as a first raw material and an ahoy powder as a second raw material; mixing and ball milling the first raw material with a part of the second raw material to obtain the composite powder with the completely amorphous structure nano oxide particles; mixing the composite powder with a remaining part of the second raw material by the mechanical ball milling, to obtain the uniformly mixed composite powder; subjecting the uniformly mixed composite powder to the hot forming to prepare a nano-oxide dispersion strengthened alloy; and subjecting the nano-oxide dispersion strengthened alloy to the hot rolling and an annealing heat treatment, to obtain a nano spherical oxide-phase dispersion strengthened alloy, wherein a mass ratio of the first raw material to the part of the second raw material is 1:0-10), and a mass ratio of the first raw material to the second raw material is (0.5-5):(99.5-95); the oxide powder of the first raw material is at least one selected from the group consisting of Y.sub.2O.sub.3 and TiO.sub.2; and the alloy powder of the second raw material is one selected from the group consisting of a Fe—Cr—W—Ti or Fe—Cr—W alloy, a nickel-based superalloy, a copper alloy, and a high-entropy alloy.

4. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 3, wherein a particle size of the oxide powder of the first raw material is less than 10 μm; and a particle size of the alloy powder of the second raw material is less than or equal to 150 μm.

5. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, wherein the hot forming is one selected from the group consisting of a powder extrusion, a powder forging, and a hot isostatic pressing.

6. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, wherein a temperature of the hot rolling is a common rolling temperature of a matrix alloy, a total deformation is greater than 40%, and wherein the temperature of the hot rolling with a Fe—Cr—W—Ti or Fe—Cr—W alloy as the matrix alloy is 950-1050° C.

7. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, wherein an annealing heat treatment is a vacuum annealing heat treatment; an annealing temperature is greater than T.sub.xC°, and an annealing time is 1-3 h; and the T.sub.x is a crystallization temperature of an amorphous oxide of a raw material.

8. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, comprising the following steps: step 1: weighing a powder material according to a mass ratio of a first raw material to a second raw material of (0.5-5):(99.5-95); taking milling balls according to a mass ratio of a total mass of the powder material to a mass of the milling balls of 1:(10-20), and filling the first raw material, a part of the second raw material, and the milling balls into a milling can, and then sealing the milling can, wherein the milling balls with diameters of 18-22 mm, 14-16 mm, 9-11 mm, 7-8.5 mm, 4.5-5.5 mm, and 2.5-3.5 mm are compatible according to a mass ratio of (1-2):(1-2):(1-2):(1-2):(1-2):(1-2); and a mass ratio of the first raw material to the part of the second raw material is 1:(1-10); step 2: vacuumizing the milling can, and then filling the milling can with an inert gas; step 3: installing the milling can filled with the inert gas in step 2 into a planetary ball milling machine to perform the mechanical ball milling, wherein parameters of the mechanical ball milling comprise a milling time of 60-120 h, and a milling rotating speed of 200-300 r/min; step 4: after the mechanical ball milling is completed, sieving a powder under an inert gas atmosphere in a glovebox to obtain the composite powder with the uniformly distributed amorphous nano oxide; step 5: mixing the composite powder and a remaining part of the second raw material and filling into the milling can, filling the milling balls, and then installing the milling can into the planetary ball milling machine to perform the mechanical ball milling, to obtain the composite powder with the completely amorphous structure nano oxide particles, wherein during a preparation of the composite powder with the completely amorphous structure nano oxide particles by the mechanical ball milling, a mass ratio of a total mass of the powder material to a mass of the milling balls is 1:(5-10), and the parameters of the mechanical ball milling comprise a milling time of 20-40 h, and a milling rotating speed of 200-300 r/min; and step 6: sequentially subjecting the composite powder with the completely amorphous structure nano oxide particles to the hot forming, the hot rolling, and the heat treatment, to prepare the nano spherical oxide dispersion strengthened alloy.

9. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 8, wherein two gas nozzles are disposed on a lid of a milling can for vacuumizing and filling with an inert gas after sealing; a protective gas is the inert, gas, such as helium, argon, or a mixed gas of the argon and the helium, a purity of the protective gas is 99.99 wt. %, and an oxygen content of the protective gas is less than 0.0001 wt. %; and a ball milling machine is a vertical planetary ball milling machine or an omni directional planetary ball milling machine, and a revolution direction and a rotation direction are changed every 25-35 min during the mechanical ball milling.

10. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 1, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2o.sub.3 alloy, the elongation is greater than 11.50%.

11. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 2, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O 3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

12. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 3, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-140-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%, and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

13. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 4, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

14. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 5, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

15. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 6, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%, when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%, and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

16. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 7, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

17. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 8, wherein when a prepared product is a Fe-14Cr-3W-0411-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 12.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-14Cr-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

18. The method for preparing the nano spherical oxide dispersion strengthening phase according to claim 9, wherein when a prepared product is a Fe-14Cr-3W-0.4Ti-1.0Y.sub.2O.sub.3 alloy, an elongation is greater than 17.50%; when the prepared product is a Fe-14Cr-3W-0.4Ti-1.5Y.sub.2O.sub.3 alloy, the elongation is greater than 12.00%; and when the prepared product is a Fe-140-3W-0.4Ti-2.0Y.sub.2O.sub.3 alloy, the elongation is greater than 11.50%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 presents a TEM image showing the microstructure of an alloy prepared in Example 1.

[0047] FIG. 2 to FIG. 4 present TEM images showing a nano oxide strengthening phase extracted from an alloy prepared in Example 1.

[0048] FIG. 5 presents a TEM image showing the microstructure of an alloy prepared in Example 2.

[0049] FIG. 6 presents a TEM image showing an oxide strengthening phase extracted from an alloy prepared in Comparative Example 3.

[0050] FIG. 1 shows that the nano spherical oxide is uniformly distributed.

[0051] FIG. 2. to FIG. 4 show that the nano oxide strengthening phase is spherical. FIG. 2 shows a multi-scale distribution of the nano oxide strengthening phase in the alloy.

[0052] FIG. 5 shows the fine grain and uniformly distributed nano spherical oxide in the

[0053] FIG. 6 shows that the oxide strengthening phase is irregular.

DETAILED DESCRIPTION OF THE EMBODIMENTS

EXAMPLE 1

Fe-14Cr-3W-0.4Ti-1.5Y.SUB.2.O.SUB.3 .(wt. %) alloy

[0054] A preparation process is as follows:

[0055] Step 1: A total of 300 g of 60 g of a Y.sup.2O.sub.3 powder and 240 g of a gas-atomized Fe-14Cr-3W-0.4Ti (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1:4, and filled into a milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 μm, and the particle size of the Y.sub.2O.sub.3 powder was less than or equal to 10 μm. According to the ball-to-powder mass ratio of 10:1, 3000 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0056] Step 2: The milling can was sealed, and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0057] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 300 r/min, and a mechanical ball milling time of 60 h. The revolution and rotation directions were changed once per 30 mm during ball milling.

[0058] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the ODS powder E.

[0059] Step 5: A total of 1850 g of 150 g of the ODS powder E and the pre-alloyed iron-based powder was filled into the milling can, milling balls were supplemented according to the specification of the milling balls in step 1 to ensure that the ball-to-powder mass ratio is 10:1, and the milling can was sealed and vacuumized, and then was installed into the vertical planetary ball milling machine to perform mechanical ball milling. The mechanical ball milling parameters were set as follows: a rotating speed of 300 r/min, and a mechanical ball milling time of 40 h. The final ODS composite powder is obtained.

[0060] Step 6: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was carried out at an extrusion temperature of 850° C., an extrusion speed of 15 mm/s, and an extrusion ratio of 10:1. Then the as-extruded alloy was hot rolled at a temperature of 850 ° C., a rolling speed of 0.36 m/s, and a total deformation of 80%. Final, the hot-rolled alloy was heat treated at a temperature of 950° C. for 1 h, and air cooled, to obtain the nano spherical oxide dispersion strengthened iron-based alloy.

[0061] FIG. 1 to FIG. 4 show that the ODS iron-based alloy obtained in this example has a multi-scale spherical strengthening phase with a size of 2 nm to 100 nm, multi-scale fine grains, its tensile strength reaches 1578 MPa at room temperature and 622 MPa at 700° C., and its elongation is 12.85% at room temperature.

EXAMPLE 2

Fe-14Cr-3W-0.4Ti-1.0Y.SUB.2.O.SUB.3 .(wt. %) Alloy

[0062] A preparation process is as follows:

[0063] Step 1: A total of 300 g of 75 g of a Y.sub.2O.sub.3 powder and 225 g of a gas-atomized Fe-14Cr-3W-0.4Ti (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1:3, and filled into a milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 μm, and the particle size of the Y.sub.2O.sub.3 powder was less than or equal to 10 μm. According to the ball-to-powder ratio of 12:1, 3600 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0064] Step 2: The milling can was sealed and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0065] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 280 r/min, and a mechanical ball milling time of 120 h. The revolution and rotation directions were changed once per 30 min during ball milling.

[0066] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the ODS powder F.

[0067] Step 5: A total of 3750 g of 150 g of the ODS powder F and 3600 g of the remaining pre-alloyed iron-based powder was mixedly filled into the milling can, milling balls were supplemented according to the specification of the milling balls in step 1 to ensure that the ball-to-powder mass ratio is 10:1, the milling can was sealed and vacuumized, and then was installed into the vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 280 r/min, and a mechanical ball milling time of 30 h. The final ODS composite powder is obtained.

[0068] Step 6: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was carried out at an extrusion temperature of 950° C., an extrusion speed of 25 min/s, and an extrusion ratio of 11:1. Then the as-extruded alloy was hot rolled at a temperature of 950° C., a rolling speed of 0.36 m/s, and a total deformation of 60%. Final, the hot-rolled alloy was heat treated at a temperature of 1050° C. for 1 h, and air cooled, to obtain the nano spherical oxide dispersion strengthened iron-based alloy.

[0069] FIG. 5 shows that the ODS iron-based alloy obtained in this example has a multi-scale spherical strengthening phase with a size of 2 nm to 100 nm, and multi-scale fine grains, the oxide is completely transformed into amorphous solid, thereby achieving completely amorphization. The tensile strength of the ODS iron-based alloy reaches 1621 MPa at room temperature and 613 MPa at 700° C., the elongation is 12.13% at room temperature.

EXAMPLE 3

Fe-14Cr-3W-0.4Ti-2.0Y.SUB.2.O.SUB.3 .(wt. %) alloy

[0070] A preparation process is as follows:

[0071] Step 1: A total of 600 g of 100 g of a Y.sub.2O.sub.3 powder and 500 g of a gas-atomized Fe-14Cr-3W-0.4Ti (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1:5, and filled into a milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 μm, and the particle size of the Y.sub.2O.sub.3 powder was less than or equal to 10 μm. According to the ball-to-powder ratio of 15:1, 9000 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0072] Step 2: The milling can was sealed and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0073] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 260 r/min, and a mechanical ball milling time of 80 h. The revolution and rotation directions were changed once per 30 min during ball milling.

[0074] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the ODS powder G.

[0075] Step 5: A total of 2500 g of 300 g of the ODS powder & and 2200 g of the pre-alloyed iron-based powder was mixedly filled into the milling can, milling balls were supplemented according to the specification of the milling balls in step 1 to ensure that the ball-to-powder mass ratio is 10:1, the milling can was sealed and vacuumized, and then was installed into the vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 260 r/min, and a mechanical ball milling time of 20 h. The ODS composite powder H is obtained.

[0076] Step 6: A total of 1250 g of 150 g of the ODS composite powder H and 1100 g of the pre-alloyed iron-based powder was filled into the milling can, and the foregoing operations were repeated for mechanical ball milling with unchanged parameters, to obtain the final ODS composite powder.

[0077] Step 7: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was conducted at an extrusion temperature of 950° C., an extrusion speed of 15 mm/s, and an extrusion ratio of 12:1. Then the as-extruded alloy was hot rolled at a temperature of 950° C., a rolling speed of 0.36 m/s, and a total deformation of 80%. Final the hot-rolled alloy was heat treated at a temperature of 1050° C. for 1 h, and air cooled, to obtain the nano spherical oxide dispersion strengthened iron-based alloy.

[0078] The ODS iron-based alloy obtained in this example has a multi-scale spherical strengthening phase uniformly dispersed in the matrix and with a size of 2 nm to 500 nm, and its grain is multi-scale fine grain, the tensile strength reaches 1688 MPa at room temperature and 632 MPa at 700° C., and the elongation is 12.05% at room temperature.

COMPARATIVE EXAMPLE 1

Fe-14Cr-3W-0.4Ti-1.5Y.SUB.2.O.SUB.3 .(wt. %) Alloy

[0079] A preparation process is as follows:

[0080] Step 1: A total of 300 g of a Y.sub.2O.sub.3 powder and a gas-atomized Fe-14Cr-3W-0.4Ti (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1.5:98.5, and filled into a milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 and the particle size of the Y.sub.2O.sub.3 powder was less than 10 μm. According to the ball-to-powder ratio of 10:1, 3000 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0081] Step 2: The milling can was sealed and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0082] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 300 r/min, and a mechanical ball milling time of 60 h. The revolution and rotation directions were changed once per 30 min during ball milling.

[0083] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the ODS powder I.

[0084] Step 5: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was carried out at an extrusion temperature of 850° C., an extrusion speed of 15 mm/s, and an extrusion ratio of 10:1. Then the as-extruded alloy was hot rolled at a temperature of 850° C., a rolling speed of 0.36 m/s, and a total deformation of 80%. Final, the hot-rolled alloy was heat treated at a temperature of 950° C. for 1 h, and air cooled, to obtain the nano oxide dispersion strengthened iron-based alloy.

[0085] In the ODS iron-based alloy obtained in this comparative example, the final oxide morphology is irregular, The size of the strengthening phase in the obtained ODS iron-based alloy is greater than 0.5 μm, and the tensile strength of the obtained ODS iron-based alloy can reach 1255 MPa at room temperature and 408 MPa at 700° C., and the elongation is 7.23% at room temperature.

COMPARATIVE EXAMPLE 2

Fe-14Cr-3W-0.4Ti-1.0Y.SUB.2.O.SUB.3 .(wt. %) Alloy

[0086] A preparation process is as follows:

[0087] Step 1: 75 g of a Y powder was weighed and filled into a milling can. The particle size of the Y.sub.2O.sub.3 powder was less than 10 μm. According to the ball-to-powder ratio of 10:1, 750 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0088] Step 2: The milling can was sealed and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0089] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. The mechanical ball milling parameters were set as follows: a rotating speed of 300 r/min, and a mechanical ball milling time of 60 h. The revolution and rotation directions were changed once per 30 min during ball milling,

[0090] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the oxide powder J.

[0091] Step 5: A total of 4000 g of 40 g of the oxide powder J obtained in step 4 and 3960 g of the gas-atomized Fe-14Cr-3W-0.4Ti. (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1:99, and milling balls were supplemented according to the specification of the milling balls in step 1 to ensure that the ball-to-powder mass ratio is 10:1, and filled into the milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 μm, and the foregoing steps were repeated for mechanical ball milling, to obtain the final ODS composite powder.

[0092] Step 6: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was carried out at an extrusion temperature of 1200° C., an extrusion speed of 15 mm/s, and an extrusion ratio of 8:1. Then the as-extruded alloy was hot rolled at a temperature of 950° C., a rolling speed of 0.35 m/s, and a total deformation of 80%. Final, the hot-rolled alloy was heat treated at a temperature of 1050° C. for 1 h, and air cooled, to obtain the nano oxide dispersion strengthened alloy.

[0093] In the ODS iron-based alloy obtained in this comparative example, the oxide is not completely amorphized, the final oxide morphology is irregular, the size of the strengthening phase in the obtained ODS iron-based alloy is greater than 0.8 μm, the tensile strength of the obtained ODS iron-based alloy is 1295 MPa at room temperature and 423 MPa at 700° C., and the elongation is 6.30% at room temperature.

COMPARATIVE EXAMPLE 3

Fe-14Cr-3W-0.4Ti-2.0Y.SUB.2.O.SUB.3 .(wt. %) Alloy

[0094] A preparation process is as follows:

[0095] Step 1: A total of 300 g of 50 g of a Y.sub.2O.sub.3 powder and 250 g of a gas-atomized Fe-14Cr-3W-0.4Ti (wt. %) pre-alloyed iron-based powder was weighed according to a mass ratio of 1:5, and filled into a milling can. Wherein the particle size of the pre-alloyed iron-based powder was less than or equal to 150 μm, and the particle size of the Y.sub.2O.sub.3 powder was less than or equal to 10 μm. According to the ball-to-powder mass ratio of 5:1, 1500 g of milling balls with diameters of 20 mm, 15 mm, 10 mm, 8 mm, 5 mm, and 3 mm respectively according to a mass ratio of 1:1:1:1:1:1 was weighed and filled into the milling can.

[0096] Step 2: The milling can was sealed and vacuumized to a vacuum level less than or equal to 0.1 Pa, and then filled with high-pure argon.

[0097] Step 3: The milling can was installed into a vertical planetary ball milling machine to perform mechanical ball milling. The mechanical ball milling parameters were set as follows: a rotating speed of 180 r/min, and a mechanical ball milling time of 40 h. The revolution and rotation directions were changed once per 30 min during ball milling.

[0098] Step 4: After the mechanical ball milling is completed, the powder was sieved under an inert gas atmosphere in a glovebox to obtain the ODS powder K.

[0099] Step 5: A total of 1250 g of 150 g of the ODS powder K and 1100 g of the pre-alloyed iron-based powder was mixedly filled into the milling can, milling balls were supplemented according to the specification of the milling balls in step 1 to ensure that the ball-to-powder mass ratio is 5:1, the milling can was sealed and vacuumized, and installed into the vertical planetary ball milling machine to perform mechanical ball milling. Wherein the mechanical ball milling parameters were set as follows: a rotating speed of 160 r/min, and a mechanical ball milling time of 10 h. The final ODS composite powder is obtained.

[0100] Step 6: The foregoing composite powder was filled into a pure-iron can, and hot extrusion was conducted at an extrusion temperature of 1200° C., an extrusion speed of 15 mm/s, and an extrusion ratio of 8:1. Then the as-extruded alloy was hot rolled at a temperature of 950° C., a rolling speed of 0.35 m/s, and a total deformation of 80%. Final, the hot-rolled alloy was heat treated at a temperature of 1050° C. for 1 h, and air cooled, to obtain the nano oxide dispersion strengthened alloy.

[0101] FIG. 6 shows that in the ODS iron-based alloy obtained in this comparative example, the oxide is not amorphized, the final oxide morphology is irregular, the size of the strengthening phase in the obtained ODS iron-based alloy is greater than 1.1 μm, the tensile strength of the obtained ODS iron-based alloy is 978 at room temperature and 333 MPa at 700° C., and the elongation is 5.78% at room temperature.

[0102] It can be understood that the foregoing implementations are merely exemplary implementations used to illustrate the principle of the present disclosure, but the present disclosure is not limited thereto. In the art, various modifications and improvements can be made without departing from the idea and essence of the present disclosure, and these modifications and improvements shall fall within the protection scope of the present disclosure.