High-strength heat-resistant high-damping Mg-RE-Zn alloy ring piece and preparation method thereof

Abstract

The invention discloses a preparation method of a high-strength heat-resistant high-damping Mg-RE-Zn alloy ring piece, which comprises the following steps: firstly, preparing the Mg-RE-Zn alloy ring piece by adopting a centrifugal casting-ring rolling process, and then carrying out aging treatment to obtain the high-strength heat-resistant high-damping Mg-RE-Zn alloy ring piece. According to the preparation method, the alloy with a bimodal structure, 14H-LPSO and a large number of high-temperature-resistant beta'precipitated phases and Mg5RE phases is prepared through specific components in combination with a specific casting process and aging treatment, the mechanical performance and the damping performance are synergistically improved, and the alloy has the excellent mechanical performance and damping performance at the room temperature; wherein the tensile strength is 415 MPa, the yield strength is 328 MPa, and the ductility is 6.3%; the damping performance is that epsilon is equal to 0.001, Q-1 is equal to 0.026, meanwhile, the damping material also has excellent mechanical performance at the high temperature of 300 DEG C, the tensile strength is 268 MPa, the yield strength is 172 MPa, and the ductility is 22.0%.

Description

Technical Field

[0001] The invention belongs to the technical field of magnesium alloy material forming, and in particular relates to a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring and a preparation method thereof. Background Art

[0002] Magnesium and magnesium alloys are widely used in the aerospace field due to their high specific strength and excellent damping properties. The damping mechanism of Mg-RE-Zn alloy is dislocation damping mechanism, which makes it difficult to improve the mechanical properties and damping properties of Mg-RE-Zn alloy simultaneously. The DRX grains in the bimodal structure of Mg-RE-Zn alloy can effectively improve the mechanical properties of the material, and the 14H-LPSO phase and high dislocation density in the un-DRX grains can effectively maintain the damping properties of the alloy; this provides a new direction for the synergy of mechanical and damping properties of Mg-RE-Zn alloy.

[0003] Generally, magnesium alloys can be strengthened by refining the grains of magnesium alloys through large deformation, but this method will greatly reduce the damping performance of the alloy. This is because the dislocation density inside the small grains is small, and the small grains will shorten the distance between strong pinning points, making the dislocation movement amplitude smaller, which will reduce the energy absorbed by the dislocation movement, thereby reducing the damping performance of the alloy; and general large deformation is very difficult for large magnesium alloy structures. Therefore, the preparation of magnesium alloy rings with both high strength and high damping is a research hotspot and difficulty in the current technical field. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main purpose of the present invention is to provide a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring and a preparation method thereof, so as to achieve the effect of simultaneously improving the mechanical properties and damping properties of the Mg-RE-Zn alloy ring.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring comprises Mg, Zn and RE components, and its morphological characteristics are: comprising a bimodal structure, a 14H-LPSO phase and a Mg5RE phase.

[0007] Furthermore, the microstructure of the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring also includes a nano-β' precipitation phase.

[0008] The main purpose of the present invention is to provide a method for preparing high-strength, heat-resistant and high-damping Mg-RE-Zn alloy rings. First, the Mg-RE-Zn alloy rings are prepared by a centrifugal casting-ring rolling process, and then the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy rings are obtained by aging treatment.

[0009] In some specific embodiments, the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring comprises the following components in mass percentage: Zn: 1-2.7wt.%; RE: 10-15wt.%; wherein RE is Gd and Y elements, and the remainder is magnesium and unavoidable impurities.

[0010] Furthermore, the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring also includes Zr and / or Mn elements.

[0011] In some specific embodiments, the centrifugal casting-ring rolling process specifically comprises the following steps:

[0012] 1) Select appropriate centrifugal casting parameters according to the size of the annular billet, and the centrifugal casting is carried out under a protective gas atmosphere throughout the process;

[0013] 2) homogenizing the ring-shaped ingot before ring rolling;

[0014] 3) Selecting a suitable core roller size according to the inner diameter of the ring casting billet, and selecting the reduction amount and rolling speed according to the plastic deformation capacity of the alloy to obtain a ring after ring rolling;

[0015] 4) The rings are water cooled after ring rolling.

[0016] In certain specific embodiments, the centrifugal casting parameters in step 1) are determined according to the following conditions: when the outer diameter of the ring Rout / Rin≤1.15, the rotation speed is calculated using the Konstantinov formula; when the outer diameter of the ring Rout / Rin≥1.15, the rotation speed is calculated using the gravity coefficient formula.

[0017] In some specific embodiments, the protective gas in step 1) is a mixed gas of CO2 and SF6, wherein the SF6 gas content does not exceed 1%.

[0018] In some specific embodiments, the homogenization treatment parameters in step 2) are 400-520° C. for 8-12 h.

[0019] In some specific embodiments, the ring is subjected to aging treatment after water cooling, and the aging treatment conditions are: aging treatment at 200-230° C. for 30-60 hours.

[0020] The preparation method of the present application can obtain large Mg-RE-Zn alloy rings with a size of Φ300-3000mm, excellent room temperature mechanical properties, damping properties and 300°C high temperature mechanical properties.

[0021] Compared with the prior art, the present invention has at least the following advantages:

[0022] 1) The preparation method provided by the present invention generates a large amount of 14H-LPSO phase by adding RE and Zn elements to the alloy; by adopting the centrifugal casting-ring rolling process, the 14H-LPSO phase inside the larger un-DRX grains of the alloy will be kinked, and the small-angle grain boundary at the edge of the kink band will be transformed into a large-angle grain boundary, resulting in fine recrystallization. At the same time, grains will be broken during the ring rolling process, and the volume fraction of fine grains will increase with the increase of deformation; finally, a large number of fine grains are distributed along the grain boundaries of the un-DRX grains, presenting a bimodal structure; at the same time, through the casting-ring rolling process, a large amount of dispersed high-temperature resistant Mg5RE phase is generated inside the alloy; and combined with the subsequent aging treatment, a large amount of nano-scale β' precipitation phase can be further precipitated; that is, the preparation method of the present invention, through specific components, combined with specific casting processes and aging treatments, generates a large alloy ring including a bimodal structure, 14H-LPSO, a large amount of high-temperature resistant precipitation phase Mg5RE and β' precipitation phase, thereby synergistically improving the mechanical and damping properties.

[0023] 2) The Mg-RE-Zn alloy provided by the present invention has excellent mechanical properties and damping properties at room temperature, wherein the tensile strength is 415MPa, the yield strength is 328MPa, and the elongation is 6.3%; the damping property is ε=0.001, Q -1 =0.026, which is much larger than the standard of high damping alloy (ε=0.001, Q -1 >0.01); at the same time, it also has excellent mechanical properties at a high temperature of 300°C, including a tensile strength of 268MPa, a yield strength of 172MPa, and an elongation of 22.0%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below.

[0025] Figure 1 The bimodal microstructure diagram and OM photograph of un-DRX grains of the Mg-6Gd-5Y-1Zn-0.4Zr alloy ring prepared in Example 2 of the present invention; wherein (a) is a bimodal microstructure diagram; (b) is an OM photograph of un-DRX grains;

[0026] Figure 2 TEM photos of the 14H-LP SO phase, β' precipitation phase (a) and Mg5RE phase (b) of the Mg-6Gd-5Y-1Zn-0.4Zr alloy ring prepared in Example 2 of the present invention;

[0027] Figure 3The room temperature mechanical properties diagram and high temperature mechanical properties diagram of the Mg-6Gd-5Y-1Zn-0.4Zr alloy ring prepared in Example 2 of the present invention; wherein (a) is a room temperature mechanical properties diagram; (b) is a 300°C high temperature mechanical properties diagram;

[0028] Figure 4 The damping performance diagram and GL curve of the Mg-6Gd-5Y-1Zn-0.4Zr alloy ring prepared in Example 2 of the present invention; wherein, (a) is the damping performance diagram; and (b) is the GL curve. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0030] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0031] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0032] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0033] In the following embodiments, the Mg-RE-Zn raw materials are Mg-6Gd-5Y-1Zn-0.4Zr and Mg-8.9Gd-3.9Y-1.3Zn-0.8Mn alloys, which can be purchased through commercial channels or obtained through conventional preparation methods.

[0034] In the following preparation method, the centrifugal casting parameters in step 1) are determined according to the following conditions: when the outer diameter of the ring Rout / Rin≤1.15, the rotation speed is calculated using the Constantinov formula; when the outer diameter of the ring Rout / Rin≥1.15, the rotation speed is calculated using the gravity coefficient formula;

[0035] Example 1

[0036] This embodiment provides a method for preparing a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring (Mg-8.9Gd-3.9Y-1.3Zn-0.8Mn), which specifically includes the following steps:

[0037] 1) According to the size of the ring casting billet R 外=250mm, R 内 =200mm(R 外 / R 内 ≥1.15), the centrifugal casting speed is calculated by the gravity coefficient formula to be 550r / min, and the centrifugal casting is carried out in an atmosphere of a mixed gas of CO2 and SF6, wherein the SF6 gas content does not exceed 1%;

[0038] 2) The ring casting was homogenized at 515°C for 12 hours before ring rolling;

[0039] 3) Selecting a suitable core roll size according to the inner diameter of the ring casting billet, the alloy ring rolling reduction is 40%, the single pass reduction is 10%, the ring rolling feed speed is 0.8 mm / min, and the ring piece after ring rolling is obtained;

[0040] 4) The ring after ring rolling is placed in water for water cooling, and after the ring is cooled, it is placed at 210° C. for aging treatment for 48 hours to obtain a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring.

[0041] Example 2

[0042] This embodiment provides a method for preparing a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring (Mg-6Gd-5Y-1Zn-0.4Zr), which specifically includes the following steps:

[0043] 1) According to the size of the ring casting: R 外 =175mm, R 内 =125mm(R 外 / R 内 ≥1.15), the centrifugal casting speed is calculated by the gravity coefficient formula to be 660r / min; the centrifugal casting is carried out in a mixed gas atmosphere of 99% CO2 and 1% SF6;

[0044] 2) The ring casting was homogenized at 510°C for 8 hours before ring rolling;

[0045] 3) Selecting a suitable core roll size according to the inner diameter of the ring casting billet, the alloy ring rolling reduction is 60%, the single pass reduction is 10%, the ring rolling feed speed is 0.8 mm / min, and the ring piece after ring rolling is obtained;

[0046] 4) The ring after ring rolling is placed in water for water cooling, and after the ring is cooled, it is placed at 200° C. for aging treatment for 48 hours to obtain a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring.

[0047] Example 3

[0048] This embodiment provides a method for preparing a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring (Mg-6Gd-5Y-1Zn-0.4Zr), which specifically includes the following steps:

[0049] 1) According to the size of the ring casting billet R 外 =175mm, R 内 =125mm(R 外 / R 内 ≥1.15), the centrifugal casting speed is calculated by the gravity coefficient formula to be 660r / min, and the centrifugal casting is carried out in an atmosphere of a mixed gas of CO2 and SF6, wherein the SF6 gas content does not exceed 1%;

[0050] 2) The ring casting was homogenized at 510°C for 8 hours before ring rolling;

[0051] 3) Selecting a suitable core roll size according to the inner diameter of the ring casting billet, the alloy ring rolling reduction is 40%, the single pass reduction is 10%, the ring rolling feed speed is 0.8 mm / min, and the ring piece after ring rolling is obtained;

[0052] 4) The ring after ring rolling is placed in water for water cooling, and after the ring is cooled, it is placed at 200° C. for aging treatment for 48 hours to obtain a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring.

[0053] Characterization and performance test examples:

[0054] This application takes Example 2 as an example to characterize and test the prepared high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring, specifically:

[0055] 1) Characterization of tissue morphology

[0056] Test method: This test example characterizes the microstructure of the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring prepared in Example 2. Figure 1 ) and TEM images ( Figure 2): The Mg-RE-Zn alloy in the present application contains a bimodal structure, Mg5RE phase, β' precipitation phase and 14H-LPSO phase, and the specific formation reason is: during the centrifugal casting-ring rolling process, the 14H-LPSO phase inside some larger un-DRX grains will be kinked, and the small-angle grain boundaries at the edge of the kink band will be transformed into large-angle grain boundaries, resulting in fine recrystallization. At the same time, grains will also be broken during the ring rolling process, and the volume fraction of fine grains will increase with the increase of deformation; finally, a large number of fine grains are distributed along the grain boundaries of un-DRX grains, showing a bimodal structure; in addition, during the rolling process, the high-temperature resistant Mg5RE phase will also be broken and finally dispersed in the Mg matrix. In addition, a large number of nano-scale β' precipitation phases will be produced during the aging process, so that the alloy maintains a high strength at room temperature and high temperature.

[0057] 2) Mechanical properties test

[0058] Test method:

[0059] The present application uses a CMT5105 universal testing machine to test the mechanical properties (room temperature and 300°C high temperature) of the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring prepared in Implementation 2. The test results are shown in Tables 1 and Figure 3 As shown:

[0060] Table 1 Mechanical properties of Mg-6Gd-5Y-1Zn-0.4Zr under different test conditions

[0061]

[0062] From the data in Table 1, it can be seen that the Mg-RE-Zn alloy in the present application has excellent room temperature mechanical properties and damping properties, and also has excellent high temperature resistant mechanical properties.

[0063] 3) Damping performance test

[0064] Test method: The damping performance of the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring prepared in Example 2 was tested using a DMA850 dynamic thermal mechanical analyzer. The test results are shown in Table 2 and Figure 4 As shown:

[0065] Table 2 Damping properties of Mg-6Gd-5Y-1Zn-0.4Zr

[0066]

[0067] From the data in Table 2, it can be seen that the Mg-RE-Zn alloy in the present application has excellent damping performance after centrifugal casting, that is, the Mg-RE-Zn alloy in the present application, during the centrifugal casting-ring rolling process, the 14H-LPSO phase inside the un-DRX grains in the alloy can effectively improve the damping performance of the alloy, thereby making the damping performance of the alloy far exceed the standard of high damping alloy (ε = 0.001, Q -1 >0.01).

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring, characterized in that: It includes Mg, Zn and RE components, and its morphological characteristics include: bimodal structure, 14H-LPSO phase and Mg5RE phase.

2. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 1, characterized in that: Mg-RE-Zn alloy rings were prepared by centrifugal casting-ring rolling process.

3. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 2, characterized in that: The high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring comprises the following components in mass percentage: Zn: 1-2.7wt.%; RE: 10-15wt.%; wherein RE is Gd and Y elements, and the remainder is magnesium and inevitable impurities.

4. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 1 or 2, characterized in that: The centrifugal casting-ring rolling process specifically comprises the following steps: 1) Select appropriate centrifugal casting parameters according to the size of the annular billet, and the centrifugal casting is carried out under a protective gas atmosphere throughout the process; 2) homogenizing the ring-shaped ingot before ring rolling; 3) Selecting a suitable core roller size according to the inner diameter of the ring casting billet, and selecting the reduction amount and rolling speed according to the plastic deformation capacity of the alloy to obtain a ring after ring rolling; 4) The rings are water cooled after ring rolling.

5. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 4, characterized in that: The centrifugal casting parameters in step 1) are determined according to the following conditions: when the outer diameter of the ring Rout / Rin≤1.15, the rotation speed is calculated using the Konstantinov formula; when the outer diameter of the ring Rout / Rin≥1.15, the rotation speed is calculated using the gravity coefficient formula.

6. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 5, characterized in that: The protective gas in step 1) is a mixed gas of CO2 and SF6, wherein the SF6 gas content does not exceed 1%.

7. The method for preparing the high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 6, characterized in that: The parameters of the homogenization treatment in step 2) are homogenization treatment at 400-520° C. for 8-12 hours.

8. The method for preparing a high-strength, heat-resistant and high-damping Mg-RE-Zn alloy ring according to claim 4, characterized in that: The invention also includes performing aging treatment on the water-cooled ring, wherein the conditions of the aging treatment are: Place at 200-230℃ for aging treatment for 30-60h.

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