High-damping mg-ce-la alloy, method for preparing same, and use thereof

Abstract

The application discloses a high-damping Mg-Ce-La alloy, characterized by comprising the following components in percentage by mass: Ce: 0.1-0.6%, La: 0.1-0.6%, the balance being Mg and inevitable impurities, wherein the atomic ratio of Ce / La is 0.5-2.0. The application further discloses a preparation method of the high-damping Mg-Ce-La alloy. By adding La and Ce in a specific ratio in Mg and limiting the atomic ratio of La and Ce, Mg 12 Ce phase is generated in the magnesium alloy, but Mg 12 La phase is not generated, La preferentially dissolves in the Mg 12 Ce phase lattice, the morphology of the second phase is changed, and the dispersed Mg 12 Ce second phase is formed, the magnesium matrix is greatly purified, the alloy has excellent low-strain-stage damping performance, the alloy has a high-density parallel dislocation, the dislocation can generate greater hysteresis strain under alternating stress, more vibration energy is consumed, and the strain-independent damping performance of the alloy can be directly improved.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, specifically to a high-damping Mg-Ce-La alloy and its preparation method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of modern industry, aerospace, and transportation, noise pollution caused by mechanical vibration has become an increasingly serious environmental problem. The development and application of high-damping materials is an effective way to reduce vibration and noise. Magnesium and its alloys, as the lightest structural metal materials, have high specific strength, high specific elastic modulus, and excellent intrinsic damping performance, and have broad application prospects in fields that require both lightweighting and vibration and noise reduction.

[0004] Current research on the damping properties of magnesium alloys shows that reducing the solute atom content in the magnesium matrix can effectively improve the damping performance of the alloy in the low-strain stage. In Mg-Ce alloys, adding a third alloying element with a significantly different electronegativity from Ce can cause Ce to preferentially cooperate with this element to form Mg. 12 The precipitation of the Ce second phase reduces the Ce solute atom content in the matrix, purifies the matrix phase, and improves the damping performance of the alloy in the low strain stage. La and Ce have a large difference in electronegativity and a strong mutual repulsion effect, resulting in a significant purification effect. However, existing research lacks sufficient understanding of the high damping mechanism of Mg-Ce-La alloys, especially the systematic study of the relationship between the alloy's microstructure and damping performance under specific heat treatment processes; current research on high-damping magnesium alloys mainly focuses on the high strain amplitude region (ε≥10). -3 The damping performance of the alloy is considered, but the ability of the alloy to enter a high damping state under low strain amplitude conditions is ignored, which makes it difficult to meet the vibration reduction requirements of engineering components under low amplitude service conditions. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention provides a high-damping Mg-Ce-La alloy and its preparation method. Therefore, the main objective of this invention is to comprehensively utilize the strong mutual repulsion effect of Ce-La to purify the matrix and increase the average dislocation line length L between weak pin roll points by high-density parallel dislocation arrangement. C The synergistic effect of three mechanisms—extra energy dissipation at the nanotwin semi-coherent interface—achieves excellent damping performance across the entire strain range, including both low and high strain regions.

[0006] The objective of this invention is achieved through the following technical solution: A high-damping Mg-Ce-La alloy comprising, by mass percentage: Ce: 0.1-0.6%, La: 0.1-0.6%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 0.5-2.0.

[0007] In some specific embodiments, the microstructure of the high-damping Mg-Ce-La alloy includes an α-Mg matrix and Mg... 12 Ce phase, and including high-density parallel dislocation structures.

[0008] As part of the same inventive concept, this invention also provides a method for preparing a high-damping Mg-Ce-La alloy, comprising the following steps: 1) According to the formula requirements, the magnesium alloy raw materials are smelted to obtain magnesium alloy melt; 2) The magnesium alloy melt from step 1) is quenched to obtain a magnesium alloy ingot; 3) The magnesium alloy ingots are heat-treated sequentially to obtain the high-damping Mg-Ce-La alloy.

[0009] In some specific embodiments, the high-damping Mg-Ce-La alloy comprises the following components: Ce: 0.1-0.6%, La: 0.1-0.6%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 0.5-2.0.

[0010] In some specific embodiments, the smelting in step 1) specifically involves: placing pure Mg into a crucible and heating it to melt under the protection of a protective gas. After the pure Mg has completely melted, Mg-La master alloy and Mg-Ce master alloy are added to the crucible in sequence for smelting. After all the alloy raw materials have melted, the surface slag is removed, and the mixture is stirred evenly to obtain a magnesium alloy melt.

[0011] In some specific embodiments, the protective gas in step 1) is a mixture of CO2 and SF6 in a volume ratio of 99.5:0.5.

[0012] In some specific embodiments, the cold quenching in step 2) specifically refers to: quenching the magnesium alloy melt in step 1) in cold water to obtain a magnesium alloy ingot.

[0013] In some specific embodiments, the heat treatment in step 3) is performed at a temperature of 400-500°C for 12 hours.

[0014] Furthermore, the heat treatment temperature described in step 3) is 500°C.

[0015] In some specific embodiments, the process also includes cleaning and drying the magnesium alloy raw materials before melting in step 1), and coating the inner wall of the crucible with boron nitride.

[0016] Compared with the prior art, the present invention has at least the following advantages: 1) The high-damping Mg-Ce-La alloy of the present invention, by adding a specific proportion of La and Ce to Mg and simultaneously limiting the atomic ratio of La to Ce, allows Mg to be generated in the magnesium alloy. 12 Ce phase, without the formation of Mg 12 La, a rare earth intermetallic compound (Mg, Ce, La); taking advantage of the strong mutual repulsion effect arising from the electronegativity difference between La and Ce, La preferentially dissolves in Mg. 12 In the Ce phase lattice, the morphology of the second phase is changed to form dispersed Mg. 12 The Ce second phase significantly purifies the magnesium matrix, giving the alloy excellent damping properties in the low strain stage; even after heat treatment at 400℃ for 12 h, a distinct network of Mg can still be observed. 12 Ce, at ε=10 -4 Time Q -1 =0.018, reaching a high damping state; 2) The high-damping Mg-Ce-La alloy of the present invention has high-density parallel dislocations. The highly ordered parallel dislocations greatly reduce the mutual intersection and pinning between dislocations, improve dislocation mobility, and weaken or even eliminate the pinning effect caused by dislocation entanglement. Moreover, the high density of dislocations means that there are more dislocation segments that can participate in bowing reciprocating motion, and the parallel state ensures the high mobility of dislocations in the low strain stage. Therefore, under alternating stress, dislocations can generate greater hysteresis strain and consume more vibration energy, which can directly improve the strain-independent damping performance of the alloy. 3) The preparation method of the high-damping Mg-Ce-La alloy provided by the present invention uses simple raw materials, containing only Mg, Ce and La elements, and only two processes: resistance furnace melting and heat treatment. The manufacturing process is simple, the cost is controllable, the repeatability is high, and it is suitable for widespread application. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 The images show the SEM morphology of the high-damping Mg-Ce-La alloys prepared in Examples 1-3 of this invention. Figure 2 The strain damping curves of the alloys prepared in Examples 1-3 and Comparative Examples 1-3 are shown. Figure 3 The image shows a TEM image of the high-damping Mg-Ce-La alloy prepared in Example 3. Figure 4The SEM morphology image of the alloy prepared for Comparative Example 1 is shown. Figure 5 The SEM morphology image of the alloy prepared for Comparative Example 2 is shown. Figure 6 SEM morphology characterization image of the alloy prepared in Comparative Example 3; Figure 7 This is the solid solution curve of the Mg-Ce-Al alloy. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0020] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0021] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0022] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0023] In the following embodiments, the magnesium alloy raw materials used are pure Mg and intermediate alloys Mg-30 wt.%Ce and Mg-20 wt.%La. Before smelting, the aforementioned magnesium alloy raw materials need to be cleaned and dried, and the inner wall of the crucible is coated with boron nitride.

[0024] The test methods used in the following embodiments include: The damping performance of the Mg-Ce-La alloy is demonstrated by testing the main properties of each test sample separately; the main properties tested in this application include appearance morphology, damping, etc.

[0025] 1) Damping performance test The strain damping performance was measured using a dynamic mechanical analyzer (DMA850). The test conditions were as follows: single cantilever mode; sample size was a rectangular strip of 40 mm × 5 mm × 2 mm; the surface of the damping test sample needed to be polished with 200 grit, 400 grit, 600 grit, 800 grit, and 1000 grit sandpaper. Next, experiments were conducted on the damping properties of the alloy: under normal temperature conditions, the strain was 1.0 × 10⁻⁶. -5Change to 2.0×10 -3 The damping performance (Q) at a vibration frequency (f) of 1.0 Hz was measured. -1 ); Example 1

[0026] This embodiment provides a method for preparing a high-damping Mg-Ce-La alloy, including the following steps: (1) Alloy smelting: The raw materials for alloy preparation are pure Mg and intermediate alloys Mg-30 wt.%Ce and Mg-20 wt.%La; under protective gas, pure Mg blocks are placed in a crucible and placed together in a smelting resistance furnace, and the heating temperature of the smelting resistance furnace is set to 720℃; after the pure Mg blocks in the crucible have completely melted, Mg-La and Mg-Ce intermediate alloys are added, and the temperature is maintained for 20 minutes. After the pure Mg blocks and intermediate alloys have completely melted, the alloy melt is slag-removed and mechanically stirred to make the composition of the alloy melt uniform. (2) Casting: The alloy melt from step (1) was left to stand at 720℃ for 3 min and then quenched in cold water to obtain the as-cast Mg-Ce-La alloy; The high-damping Mg-Ce-La alloy comprises the following components: Ce: 0.3%, La: 0.3%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 1.0.

[0027] The properties of the as-cast Mg-Ce-La alloy prepared in this embodiment were characterized by the following tests: Appearance and morphology: The appearance and morphology of the as-cast Mg-Ce-La alloy prepared in this embodiment were tested by scanning electron microscopy (SEM), and the results are as follows. Figure 1 EDS spot scan analysis results show that the prepared alloys are all composed of α-Mg and Mg. 12 Ce phase, Mg in Mg-Ce-La alloys 12 The Ce phase is distributed in a continuous network. Damping performance: This application presents damping tests on the prepared as-cast Mg-Ce-La alloy, and the results are as follows: Figure 2 As shown in the figure, the strain amplitude of this Mg-Ce-La at room temperature is ε=10. -3 At that time, the damping value reached 0.095.

[0028] Example 2

[0029] This embodiment provides a method for preparing a high-damping Mg-Ce-La alloy. The composition ratio is the same as that in Example 1, and the preparation method is basically the same as that in Example 1. The difference is that after obtaining the as-cast Mg-Ce-La alloy, the as-cast Mg-Ce-La alloy is heat-treated at 400℃ and held for 12 hours to obtain the heat-treated (400℃) Mg-Ce-La alloy.

[0030] Characterization tests were performed on the Mg-Ce-La alloy after heat treatment (400℃) in this embodiment: The morphology of the heat-treated Mg-Ce-La alloy prepared in this embodiment was tested by scanning electron microscopy (SEM), and the results are as follows. Figure 1 As shown in b and b1, after heat treatment at 400℃ for 12 h, the Mg in the Mg-Ce-La alloy... 12 The Ce phase still exhibits a network distribution, but it is not continuous, indicating that Mg... 12 The Ce phase precipitate was successfully dissolved into the matrix; This application conducted damping tests on the Mg-Ce-La alloy after heat treatment at 400℃ for 12 h in this embodiment, and the results are as follows. Figure 2 As shown, from Figure 2 It can be seen that the strain amplitude of the Mg-Ce-La alloy at room temperature is ε=10. -3 At that time, the damping value reaches 0.100, ε=10. -4 At that time, the damping value reached 0.018.

[0031] Example 3

[0032] This embodiment provides a method for preparing a high-damping Mg-Ce-La alloy. The composition ratio is the same as that in Example 1, and the preparation method is basically the same as that in Example 1. The difference is that after obtaining the alloy ingot, the alloy is heat-treated at 500°C and held for 12 hours to obtain the heat-treated (500°C) Mg-Ce-La alloy.

[0033] Characterization tests were performed on the Mg-Ce-La alloy after heat treatment (500℃) in this embodiment: The morphology of the heat-treated Mg-Ce-La alloy prepared in this embodiment was tested by scanning electron microscopy (SEM), and the results are as follows. Figure 1 As shown in c and c1, after heat treatment at 500℃ for 12 h, the solid solution content of alloying elements increases accordingly, and the Mg content in the Mg-Ce-La alloy increases. 12 The Ce phase was transformed into a diffuse blocky distribution; This application conducted damping tests on the Mg-Ce-La alloy after heat treatment at 500℃ for 12 h in this embodiment, and the results are as follows: Figure 2 As shown, the first critical strain ε of the Mg-Ce-La alloy after heat treatment at 500℃ for 12 h is... cr1 = 5.41×10 -5 , in 10 -5 At that time, the damping value was 0.002; when the strain increased to 10... -4 At this point, the Mg-Ce-La alloy has a damping value of 0.023, reaching a high-damping state, and at 10 -3 At this point, the damping value is 0.127, indicating that the alloy has excellent damping performance throughout the full strain stage.

[0034] In addition, TEM tests were performed on the Mg-Ce-La alloy after heat treatment at 500℃ for 12 h in this embodiment, and the results are as follows. Figure 3 As shown, the Mg-Ce-La alloy after heat treatment at 500℃ for 12 h exhibits high-density parallel dislocations and nanotwin semi-coherent interfaces. The parallel dislocations reduce dislocation intersections and pinning, and increase the average dislocation segment length L between weak pinning points. C .

[0035] Comparative Example 1 This comparative example provides a method for preparing a Mg-Ce alloy, the composition of which is basically the same as that of Example 3, except that La is not added. The preparation method is the same as that of Example 3, specifically: The Mg-Ce alloy comprises the following components: Ce: 0.3%, with the balance being Mg and unavoidable impurities.

[0036] This application describes the performance characterization test of the Mg-Ce alloy prepared in this comparative example; The morphology of the heat-treated Mg-Ce alloy prepared in this comparative example was tested by scanning electron microscopy (SEM), and the results are as follows: Figure 4 As shown, after heat treatment at 500℃ for 12 h, the solid solution content of alloying elements increased accordingly, and the second phase of the Mg-Ce alloy was transformed into a dispersed blocky distribution. Its damping test results are as follows Figure 2 As shown in the figure, the strain amplitude of Mg-Ce at room temperature is ε=10. -3 At that time, the damping value reached 0.142, ε=10. -4 At that time, the damping value reached 0.003.

[0037] Comparative Example 2 This comparative example provides a method for preparing a Mg-Ce-Al alloy, which is the same as the method in Example 3, except that the component ratios are different. Specifically: The high-damping Mg-Ce-Al alloy comprises the following components: Ce: 1.7%, Al: 0.33%, with the balance being Mg and unavoidable impurities.

[0038] This application performs performance characterization tests on the Mg-Ce-Al alloy prepared in this comparative example; The morphology of the heat-treated Mg-Ce-Al alloy prepared in this comparative example was tested by scanning electron microscopy (SEM), and the results are as follows: Figure 5 As shown, after heat treatment at 500℃ for 12 h, the second phase of the Mg-Ce-Al alloy is a dispersed blocky distribution. Damping test results as follows Figure 2 As shown, the strain amplitude of Mg-Ce-Al at room temperature is ε=10. -3 At this point, the damping value reaches 0.147, indicating a high-damping state under high strain, while at low strain ε=10. -4 The damping value is only 0.004.

[0039] Comparative Example 3 This comparative example provides a method for preparing a Mg-Ce-Nd alloy, the composition of which is basically the same as that in Example 3, except that La is replaced with Nd. The preparation method is the same as that in Example 3, specifically: The Mg-Ce alloy comprises the following components: Ce: 0.3%, Nd: 0.3%, with the balance being Mg and unavoidable impurities.

[0040] This application characterizes the properties of the Mg-Ce-Nd alloy prepared in this comparative example. The morphology of the heat-treated Mg-Ce-Nd alloy prepared in this comparative example was tested by scanning electron microscopy (SEM), and the results are as follows: Figure 6 As shown, after heat treatment at 500℃ for 12 h, the solid solution content of Mg-Ce-Nd alloy elements increases accordingly, and the second phase in the Mg-Ce-Nd alloy exhibits a parallel blocky distribution.

[0041] Damping test results as follows Figure 2 As shown, the strain amplitude of Mg-Ce-Nd at room temperature is ε=10. -3 At this point, the damping value reaches 0.128, indicating a high-damping state under high strain, while at low strain, ε=10. -4 The damping value is only 0.003.

[0042] As can be seen from the morphology of Comparative Examples 1-3, the SEM characterization of the alloys in the comparative examples shows that the second phase is distributed in a dispersed (parallel) blocky manner, but the composition and morphology are significantly different from those of the examples. This indicates that the absence of La or its substitution by other elements in the Mg-Ce alloys cannot significantly reduce the stacking fault energy of the matrix, which is not conducive to plane slip and the formation of high-density parallel dislocations; moreover, the distribution of the second phase is scattered or discontinuous, lacking the conditions to induce the generation of parallel dislocations; at the same time, the damping test shows that the damping value under low strain is significantly lower than that of the examples, which also indirectly shows the influence of the high-density parallel dislocation structure in the alloy of this application on the damping value under low strain.

[0043] This application also conducted room temperature mechanical property tests on the alloys prepared in Examples 1-3 and Comparative Examples 1-3, and the test results are shown in Table 1: Table 1. Room temperature mechanical properties of the alloys prepared in the embodiments and comparative examples of the present invention. As can be seen from the table above, compared with Comparative Examples 1-3, Examples 1-3 have higher strength, with room temperature tensile strength reaching about 120~150MPa and yield strength reaching about 80MPa. This is mainly because the Mg-Ce-La alloy achieves a good balance between strength and plasticity due to its dispersed blocky structure. As can be seen from the performance test results of Implementation 1-3 and Comparison 1-3 above, under specific element combinations and specific preparation processes, the combined effect of high-density parallel dislocations and nanotwin structures enables the Mg-Ce-La alloy to have excellent damping performance in the low strain stage and to be in a high damping state throughout the entire test strain range.

[0044] Comparative Example 4 This comparative example provides a method for preparing a Mg-Ce-La alloy. The component ratios are basically the same as in Example 3, except for the different ratios of Ce and La. The preparation method is the same as in Example 3, specifically: The high-damping Mg-Ce-La alloy comprises the following components: Ce: 0.5%, La: 0.2%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 2.5.

[0045] Comparative Example 5 This comparative example provides a method for preparing a Mg-Ce-La alloy. The component ratios are basically the same as in Example 3, except for the different ratios of Ce and La. The preparation method is the same as in Example 3, specifically: The high-damping Mg-Ce-La alloy comprises the following components: Ce: 0.2%, La: 0.6%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 0.34.

[0046] Depend on Figure 7 As shown in the Mg-Ce-La ternary solid solubility curves, when the Ce / La atomic ratio is high (Comparative Example 4, Ce / La = 2.5), the molar content of Ce far exceeds the solid solubility limit for the corresponding amount of La, resulting in a large amount of coarse Mg. 12 The Ce phase precipitates disorderedly, and the La content is insufficient to alter the second phase morphology through mutual repulsion, resulting in limited matrix purification. When the Ce / La atomic ratio is low (Comparative Example 5, Ce / La = 0.34), the molar content of La exceeds that shown in the solid solubility curve, and La tends to precipitate itself to form Mg. 12 La phase, rather than solid dissolved into Mg 12 Ce lattice leads to the formation of a mixed second phase, which also makes it impossible to achieve dispersed Mg. 12 Ce second phase enhances the effect of matrix purification.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A high-damping Mg-Ce-La alloy, characterized in that, It comprises the following components by mass percentage: Ce: 0.1-0.6%, La: 0.1-0.6%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 0.5-2.

0.

2. The high-damping Mg-Ce-La alloy according to claim 1, characterized in that, The microstructure of the high-damping Mg-Ce-La alloy includes an α-Mg matrix and Mg... 12 Ce phase, and high-density parallel dislocation structure.

3. A method for preparing a high-damping Mg-Ce-La alloy, characterized in that, Includes the following steps: 1) According to the formula requirements, the magnesium alloy raw materials are smelted to obtain magnesium alloy melt; 2) The magnesium alloy melt from step 1) is quenched to obtain a magnesium alloy ingot; 3) The magnesium alloy ingots are heat-treated sequentially to obtain the high-damping Mg-Ce-La alloy.

4. The method for preparing the high-damping Mg-Ce-La alloy according to claim 3, characterized in that, The high-damping Mg-Ce-La alloy comprises the following components: Ce: 0.1-0.6%, La: 0.1-0.6%, with the balance being Mg and unavoidable impurities, wherein the Ce / La atomic ratio is 0.5-2.

0.

5. The method for preparing the high-damping Mg-Ce-La alloy according to claim 3, characterized in that, The smelting process described in step 1) is as follows: pure Mg is placed in a crucible and heated to melt under the protection of a protective gas. After the pure Mg has completely melted, Mg-La master alloy and Mg-Ce master alloy are added to the crucible in sequence for smelting. After all the alloy raw materials have melted, the surface slag is removed, and the mixture is stirred evenly to obtain a magnesium alloy melt.

6. The method for preparing the high-damping Mg-Ce-La alloy according to claim 5, characterized in that, The protective gas mentioned in step 1) is a mixture of CO2 and SF6 in a volume ratio of 99.5:0.

5.

7. The method for preparing the high-damping Mg-Ce-La alloy according to claim 6, characterized in that, The cold quenching described in step 2) specifically involves quenching the magnesium alloy melt from step 1) in cold water to obtain a magnesium alloy ingot.

8. The method for preparing the high-damping Mg-Ce-La alloy according to claim 7, characterized in that, The heat treatment in step 3) is performed at a temperature of 400-500℃ for 12 hours.

9. The method for preparing the high-damping Mg-Ce-La alloy according to claim 8, characterized in that, The heat treatment temperature described in step 3) is 500℃.

10. The method for preparing the high-damping Mg-Ce-La alloy according to claim 3, characterized in that, It also includes cleaning and drying the magnesium alloy raw materials before melting in step 1), and coating the inner wall of the crucible with boron nitride.

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