Precipitation strengthening AlCrFeNiV system high entropy alloy and manufacturing method thereof

Abstract

A precipitation strengthening AlCrFeNiV system high entropy alloy is composed of Al 0.30-0.60, Cr 0.20-0.89, Fe 0.60-1.20, Ni 1.50-3.50 and V 0.10-0.30 by weight ratio. The high entropy alloy is manufactured utilizing melting and casting, followed by deformation and heat treatment process.

Claims

1. A precipitation strengthening AlCrFeNiV system alloy denoted as Al.sub.aCr.sub.bFe.sub.cNi.sub.dV.sub.e, wherein a=0.38, b=0.69, c=0.60, d=2.12, e=0.17 or a=0.30-0.55, b=0.30-0.55, c=0.84-1.10, d=2.00-3.50, e=0.10-0.22, wherein the alloy is composed mainly with an FCC phase and further comprises an L1.sub.2 phase precipitated coherently with the FCC phase, and wherein the alloy has a yield strength and a tensile strength higher than 1200 MPa and 1300 MPa, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a comparison diagram of the X-ray diffraction (XRD) spectra of the high entropy alloys 1˜5 prepared in examples 1˜5.

(2) FIG. 2 is a scanning electron microscope image of the high entropy alloy 1 prepared in the example 1.

(3) FIG. 3 is a scanning electron microscope image of the high entropy alloy 2 prepared in the example 2.

(4) FIG. 4 is a scanning electron microscope image of the high entropy alloy 3 prepared in the example 3.

(5) FIG. 5 is a scanning electron microscope image of the high entropy alloy 4 prepared in the example 4.

(6) FIG. 6 is a scanning electron microscope image of the high entropy alloy 5 prepared in the example 5.

(7) FIG. 7 is a comparison diagram of the tensile stress-strain curves of the high entropy alloys 1˜5 prepared in examples 1˜5.

DETAILED DESCRIPTION

(8) The present invention will be further described below with reference to the accompanying drawings and specific examples. Wherein, the method is a conventional method unless otherwise specified, and the raw materials can be obtained from publicly available commercial approaches unless otherwise specified.

(9) In the following examples:

(10) The purity of the metal elements Al, Cr, Fe, Ni and V are all 99.9 wt. %;

(11) High purity argon: purity greater than 99.99 wt. %;

(12) High vacuum non-consumable arc melting furnace: DHL-400 type, Sky Technology Development Co., Ltd., Chinese Academy of Sciences;

(13) High vacuum arc melting and casting system: Shenyang Haozhiduo New Material Preparation Technology Co., Ltd.;

(14) A copper mold with a chamber having a rectangular cross section, and the size of the chamber is 50 mm×13 mm×50 mm (i.e., length×width×height).

(15) The mechanical property test and microstructure characterization of the high entropy alloys prepared in the examples were conducted as follows:

(16) (1) Phase analysis: The phase structure of the high entropy alloys was analyzed by a synchrotron-based high-energy X-ray diffraction technique, at the 11-ID-C beam line of the Advanced Photon Source, Argonne National Laboratory, USA. The wavelength λ of the high energy X-ray is 0.011725 nm;

(17) (2) Microstructure characterization: The microstructure of the high entropy alloys was characterized using the HITACHIS 4800 cold field emission scanning electron microscope.

(18) (3) Quasi-static tensile mechanical property test: The tensile mechanical property tests were carried out employing a CMT4305 universal electronic tensile testing machine at room temperature using a nominal strain rate of 1×10.sup.−3 s.sup.−1. The test specimens were machined to dog-bone shape with a gauge length of 10 mm, a width of 3.14 mm and a thickness of 1 mm according to the Chinese national standard (GB/T228.1-2010) “metallic materials tensile testing at ambient temperature”.

Example 1

(19) The specific preparation steps of the high entropy alloy Al.sub.0.38Cr.sub.0.69Fe.sub.0.6Ni.sub.2.12V.sub.0.17 (hereinafter referred to as high entropy alloy 1) are as follows:

(20) (1) Raw material preparation: The pure metals Al, Cr, Fe, Ni and V were grinded to remove oxides and other impurities on the surfaces using sandpapers with a grinding machine, and were then successively cleaned with acetone and ethanol by ultrasonic cleaning machines to obtain clean metal elements. Afterwards, the pure metals were accurately weighed according to the chemical formula of the high entropy alloy in this example for a total mass of 80 g.

(21) (2) Melting: The cleaned pure metals were stacked inside the water-cooled copper crucible of the high vacuum non-consumable arc melting furnace from bottom to top according to the order of their respective melting points from low to high. Then the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas as protective gas. The pure Ti ingot was first melted to further reduce the oxygen content in the furnace chamber, and then the melting of the alloy was carried out with a melting current ranging from 20 A to 500 A. During the melting process, electromagnetic stirring was used to homogenize the alloy. After the alloy ingot was cooled, the alloy ingot was flipped and remelted for 4 times to obtain a master alloy ingot.

(22) (3) Casting: The master alloy ingot was placed in the high vacuum arc melting and casting apparatus, and the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas. Under the protection of argon, the master alloy ingot was heated to 1600° C. with a melting current ranging from 20 A to 500 A. After the master alloy ingot was completely melted, the liquid alloy was cast into a copper mold and cooled to obtain a high entropy alloy ingot.

(23) (4) Solution treatment: The high entropy alloy ingot was cleaned with acetone by ultrasonic cleaning machines, and then vacuum-sealed and filled with argon. The high entropy alloy ingot was heated to 1200° C. at a heating rate of 10° C./min in a furnace, and held at that temperature for 24 h. Thereafter, the sample was taken out and water quenched to obtain a solid solution state high entropy alloy.

(24) (5) Deformation treatment: The solid solution state high entropy alloy was deformed by rolling at room temperature by multi-pass rolling with 0.5 mm reduction in each pass and a rolling speed of 0.1 m/s for a total deformation of 70%, thereby obtaining a rolled high entropy alloy.

(25) (6) Aging treatment: The rolled high entropy alloy was subjected to heat treatment for 10 h at 700° C., and then air-cooled to obtain the high entropy alloy 1.

(26) It can be seen from the XRD spectrum shown in FIG. 1 that the prepared high entropy alloy 1 is composed of FCC phase and L1.sub.2 phase. As can be seen from the SEM image shown in FIG. 2, the prepared high entropy alloy 1 is composed of two regions of A and B and the average grain size is 0.7 μm. Region A is the matrix FCC phase, and region B is a region where the FCC phase and the L1.sub.2 phase are alternately arranged. According to the results of the quasi-static tensile mechanical property tests in FIG. 7 and Table 1, the prepared high entropy alloy 1 possesses a tensile yield strength of 1426 MPa, a tensile strength of 1609 MPa and an elongation of 10% at room temperature.

Example 2

(27) The specific preparation steps of the high entropy alloy Al.sub.0.6Cr.sub.0.84Fe.sub.1.2Ni.sub.3V.sub.0.24 (hereinafter referred to as high entropy alloy 2) are as follows:

(28) (1) Raw material preparation: The pure metals Al, Cr, Fe, Ni and V were grinded to remove oxides and other impurities on the surfaces using sandpapers with a grinding machine, and were then successively cleaned with acetone and ethanol by ultrasonic cleaning machines to obtain clean metal elements. Afterwards, the pure metals were accurately weighed according to the chemical formula of the high entropy alloy in this example for a total mass of 80 g.

(29) (2) Melting: The cleaned pure metals are stacked inside the water-cooled copper crucible of the high vacuum non-consumable arc melting furnace from bottom to top according to the order of their respective melting points from low to high. Then the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas as protective gas. The pure Ti ingot was first melted to further reduce the oxygen content in the furnace chamber, and then the melting of the alloy was carried out with a melting current ranging from 20 A to 500 A. During the melting process, electromagnetic stirring was used to homogenize the alloy. After the alloy ingot was cooled, the alloy ingot was flipped and remelted for 4 times to obtain a master alloy ingot.

(30) (3) Casting: The master alloy ingot was placed in the high vacuum arc melting and casting apparatus, and the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas. Under the protection of argon, the master alloy ingot was heated to 1600° C. with a melting current ranging from 20 A to 500 A. After the master alloy ingot was completely melted, the liquid alloy was cast into a copper mold and cooled to obtain a high entropy alloy ingot.

(31) (4) Solution treatment: The high entropy alloy ingot was cleaned with acetone by ultrasonic cleaning machines, and then vacuum-sealed and filled with argon. The high entropy alloy ingot was heated to 1200° C. at a heating rate of 10° C./min in a furnace, and held at that temperature for 24 h. Thereafter, the sample was taken out and water quenched to obtain a solid solution state high entropy alloy.

(32) (5) Deformation treatment: The solid solution state high entropy alloy was deformed by rolling at room temperature by multi-pass rolling with 0.5 mm reduction in each pass and a rolling speed of 0.1 m/s for a total deformation of 70%, thereby obtaining a rolled high entropy alloy.

(33) (6) Aging treatment: The rolled high entropy alloy was subjected to heat treatment for 1 h at 600° C., and then air-cooled to obtain the high entropy alloy 2.

(34) It can be seen from the XRD spectrum shown in FIG. 1 that the prepared high entropy alloy 2 is composed of FCC phase and L1.sub.2 phase. As can be seen from the SEM image shown in FIG. 3, the prepared high entropy alloy 2 is composed of two regions of A and B and the average grain size is 1.3 μm. region A is the matrix FCC phase, and region B is a region where the FCC phase and the L1.sub.2 phase are alternately arranged. According to the results of the quasi-static tensile mechanical property tests in FIG. 7 and Table 1, the prepared high entropy alloy 2 possesses a tensile yield strength of 1228 MPa, a tensile strength of 1353 MPa and an elongation of 1.8% at room temperature.

Example 3

(35) The specific preparation steps of the high entropy alloy Al.sub.0.5Cr.sub.0.55FeNi.sub.2.5V.sub.0.2 (hereinafter referred to as high entropy alloy 3) are as follows:

(36) (1) Raw material preparation: The pure metals Al, Cr, Fe, Ni and V were grinded to remove oxides and other impurities on the surfaces using sandpapers with a grinding machine, and were then successively cleaned with acetone and ethanol by ultrasonic cleaning machines to obtain clean metal elements. Afterwards, the pure metals were accurately weighed according to the chemical formula of the high entropy alloy in this example for a total mass of 80 g.

(37) (2) Melting: The cleaned pure metals were stacked inside the water-cooled copper crucible of the high vacuum non-consumable arc melting furnace from bottom to top according to the order of their respective melting points from low to high. Then the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas as protective gas. The pure Ti ingot was first melted to further reduce the oxygen content in the furnace chamber, and then the melting of the alloy was carried out with a melting current ranging from 20 A to 500 A. During the melting process, electromagnetic stirring was used to homogenize the alloy. After the alloy ingot was cooled, the alloy ingot was flipped and remelted for 4 times to obtain a master alloy ingot.

(38) (3) Casting: The master alloy ingot was placed in the high vacuum arc melting and casting apparatus, and the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas. Under the protection of argon, the master alloy ingot was heated to 1600° C. with a melting current ranging from 20 A to 500 A. After the master alloy ingot was completely melted, the liquid alloy was cast into a copper mold and cooled to obtain a high entropy alloy ingot.

(39) (4) Solution treatment: The high entropy alloy ingot was cleaned with acetone by ultrasonic cleaning machines, and then vacuum-sealed and filled with argon. The high entropy alloy ingot was heated to 1200° C. at a heating rate of 10° C./min in a furnace, and held at that temperature for 24 h. Thereafter, the sample was taken out and water quenched to obtain a solid solution state high entropy alloy.

(40) (5) Deformation treatment: The solid solution state high entropy alloy was deformed by rolling at room temperature by multi-pass rolling with 0.5 mm reduction in each pass and a rolling speed of 0.1 m/s for a total deformation of 60%, thereby obtaining a rolled high entropy alloy.

(41) (6) Aging treatment: The rolled high entropy alloy was subjected to heat treatment for 1 h at 600° C., and then air-cooled to obtain the high entropy alloy 3.

(42) It can be seen from the XRD spectrum shown in FIG. 1 that the prepared high entropy alloy 3 is composed of FCC phase and L1.sub.2 phase. As can be seen from the SEM image shown in FIG. 4, the prepared high entropy alloy 3 is composed of two regions of A and B and the average grain size is 1.2 μm. Region A is the matrix FCC phase, and region B is a region where the FCC phase and the L1.sub.2 phase are alternately arranged. According to the results of the quasi-static tensile mechanical property tests in FIG. 7 and Table 1, the prepared high entropy alloy 3 possesses a tensile yield strength of 1307 MPa, a tensile strength of 1393 MPa and an elongation of 2.0% at room temperature.

Example 4

(43) The specific preparation steps of the high entropy alloy Al.sub.0.4Cr.sub.0.32Fe.sub.0.8Ni.sub.2V.sub.0.16 (hereinafter referred to as high entropy alloy 4) are as follows:

(44) (1) Raw material preparation: The pure metals Al, Cr, Fe, Ni and V were grinded to remove oxides and other impurities on the surfaces using sandpapers with a grinding machine, and were then successively cleaned with acetone and ethanol by ultrasonic cleaning machines to obtain clean metal elements. Afterwards, the pure metals were accurately weighed according to the chemical formula of the high entropy alloy in this example for a total mass of 80 g.

(45) (2) Melting: The cleaned pure metals were stacked inside the water-cooled copper crucible of the high vacuum non-consumable arc melting furnace from bottom to top according to the order of their respective melting points from low to high. Then the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas as protective gas. The pure Ti ingot was first melted to further reduce the oxygen content in the furnace chamber, and then the melting of the alloy was carried out with a melting current ranging from 20 A to 500 A. During the melting process, electromagnetic stirring was used to homogenize the alloy. After the alloy ingot was cooled, the alloy ingot was flipped and remelted for 4 times to obtain a master alloy ingot.

(46) (3) Casting: The master alloy ingot was placed in the high vacuum arc melting and casting apparatus, and the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas. Under the protection of argon, the master alloy ingot was heated to 1600° C. with a melting current ranging from 20 A to 500 A. After the master alloy ingot was completely melted, the liquid alloy was cast into a copper mold and cooled to obtain a high entropy alloy ingot.

(47) (4) Solution treatment: The high entropy alloy ingot was cleaned with acetone by ultrasonic cleaning machines, and then vacuum-sealed and filled with argon. The high entropy alloy ingot was heated to 1250° C. at a heating rate of 10° C./min in a furnace, and held at that temperature for 24 h. Thereafter, the sample was taken out and water quenched to obtain a solid solution state high entropy alloy.

(48) (5) Deformation treatment: The solid solution state high entropy alloy was deformed by rolling at room temperature by multi-pass rolling with 0.5 mm reduction in each pass and a rolling speed of 0.1 m/s for a total deformation of 70%, thereby obtaining a rolled high entropy alloy.

(49) (6) Aging treatment: The rolled high entropy alloy was subjected to heat treatment for 5 h at 600° C., and then air-cooled to obtain the high entropy alloy 4.

(50) It can be seen from the XRD spectrum shown in FIG. 1 that the prepared high entropy alloy 4 is composed of FCC phase and L1.sub.2 phase. As can be seen from the SEM image shown in FIG. 5, the prepared high entropy alloy 4 is composed of two regions of A and B and the average grain size is 0.8 μm. Region A is the matrix FCC phase, and region B is a region where the FCC phase and the L1.sub.2 phase are alternately arranged. According to the results of the quasi-static tensile mechanical property tests in FIG. 7 and Table 1, the prepared high entropy alloy 4 possesses a tensile yield strength of 1204 MPa, a tensile strength of 1318 MPa and an elongation of 4.4% at room temperature.

Example 5

(51) The specific preparation steps of the high entropy alloy Al.sub.0.5Cr.sub.0.37FeNi.sub.3.18V.sub.0.21 (hereinafter referred to as high entropy alloy 5) are as follows:

(52) (1) Raw material preparation: The pure metals Al, Cr, Fe, Ni and V were grinded to remove oxides and other impurities on the surfaces using sandpapers with a grinding machine, and were then successively cleaned with acetone and ethanol by ultrasonic cleaning machines to obtain clean metal elements. Afterwards, the pure metals were accurately weighed according to the chemical formula of the high entropy alloy in this example for a total mass of 80 g.

(53) (2) Melting: The cleaned pure metals were stacked inside the water-cooled copper crucible of the high vacuum non-consumable arc melting furnace from bottom to top according to the order of their respective melting points from low to high. Then the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas as protective gas. The pure Ti ingot was first melted to further reduce the oxygen content in the furnace chamber, and then the melting of the alloy was carried out with a melting current ranging from 20 A to 500 A. During the melting process, electromagnetic stirring was used to homogenize the alloy. After the alloy ingot was cooled, the alloy ingot was flipped and remelted for 4 times to obtain a master alloy ingot.

(54) (3) Casting: The master alloy ingot was placed in the high vacuum arc melting and casting apparatus, and the furnace chamber was evacuated to 2.5×10.sup.−3 Pa and filled with high purity argon gas. Under the protection of argon, the master alloy ingot was heated to 1600° C. with a melting current ranging from 20 A to 500 A. After the master alloy ingot was completely melted, the liquid alloy was cast into a copper mold and cooled to obtain a high entropy alloy ingot.

(55) (4) Solution treatment: The high entropy alloy ingot was cleaned with acetone by ultrasonic cleaning machines, and then vacuum-sealed and filled with argon. The high entropy alloy ingot was heated to 1250° C. at a heating rate of 10° C./min in a furnace, and held at that temperature for 24 h. Thereafter, the sample was taken out and water quenched to obtain a solid solution state high entropy alloy.

(56) (5) Deformation treatment: The solid solution state high entropy alloy was deformed by rolling at room temperature by multi-pass rolling with 0.5 mm reduction in each pass and a rolling speed of 0.1 m/s for a total deformation of 75%, thereby obtaining a rolled high entropy alloy.

(57) (6) Aging treatment: The rolled high entropy alloy was subjected to heat treatment for 1 h at 700° C., and then air-cooled to obtain the high entropy alloy 5.

(58) It can be seen from the XRD spectrum shown in FIG. 1 that the prepared high entropy alloy 5 is composed of FCC phase and L1.sub.2 phase. As can be seen from the SEM image shown in FIG. 6, the prepared high entropy alloy 5 is composed of two regions of A and B and the average grain size is 1.2 μm. Region A is the matrix FCC phase, and region B is a region where the FCC phase and the L1.sub.2 phase are alternately arranged. According to the results of the quasi-static tensile mechanical property tests in FIG. 7 and Table 1, the prepared high entropy alloy 5 possesses a tensile yield strength of 1407 MPa, a tensile strength of 1490 MPa and an elongation of 3.6% at room temperature.

(59) TABLE-US-00001 TABLE 1 Yield strength Tensile strength Elongation Sample No. (σ.sub.0.2/MPa) (σ.sub.b/MPa) (%) High entropy alloy 1 1283 1377 2.2 High entropy alloy 2 1228 1353 1.8 High entropy alloy 3 1307 1393 2.0 High entropy alloy 4 1260 1396 3.1 High entropy alloy 5 1407 1490 3.6

(60) To sum up, the foregoing is only the preferred embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent substitutions, improvement, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.