High-modulus Mg-Al-RE series alloy with uniformly distributed Al2RE phase and preparation method of high-modulus Mg-Al-RE series alloy

Abstract

The invention discloses a preparation method of a high-modulus Mg-Al-RE alloy with an Al2RE phase uniformly distributed, which comprises the following steps: 1) melting other magnesium alloy components except a high-purity aluminum component into a magnesium liquid state to obtain a molten magnesium liquid; (2) adding high-purity aluminum to the surface of the molten magnesium liquid in the step (1), pressing, stirring and melting to obtain a molten magnesium alloy; and (3) the molten magnesium alloy is rapidly cooled. The aluminum particles are added after the other magnesium alloy raw materials are melted, so that high-modulus Al-RE phase sedimentation of the magnesium alloy raw materials in the melting process is effectively avoided; besides, after the aluminum particles are put, the aluminum particles are slowly pressed down, the melt state is observed all the time, after the whole melt enters the white bright state, the melt is slightly stirred, then a stirring rod is pulled away, rapid water cooling is conducted, the melt heat preservation time is greatly shortened, and therefore sedimentation of a high-modulus Al-RE phase is reduced; and finally, the high-modulus Mg-Al-RE alloy with the high-modulus Al-RE phase uniformly distributed in the gravity direction is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnesium alloy materials, and particularly relates to a high modulus Mg-Al-RE alloy with uniformly distributed endogenous high modulus Al2RE phase and a preparation method thereof. Background Art

[0002] In recent years, transportation sectors such as aerospace, rail transit, and road transport have placed new demands on vehicle transport capabilities, requiring lighter weight, faster speeds, and greater load capacity. As the lightest metal structural material, magnesium alloys offer high specific strength and excellent vibration damping, making them the most promising lightweight material in the transportation sector. However, the insufficient modulus of conventional magnesium alloys (only 40-45 GPa) makes them unable to meet the high load-bearing capacity requirements of the new generation of vehicles, limiting their further application.

[0003] A key approach to improving the modulus of magnesium alloys is to rationally design alloying elements to introduce high-modulus secondary phases (such as Al₂RE and Si₃RE₅). This is also known as the intrinsic high-modulus phase approach. According to the law of mixing, a higher volume fraction of the high-modulus phase indicates a higher modulus for the magnesium alloy. Among the various high-modulus secondary phases, the Al₂RE phase requires the least atomic mass to form. Therefore, Mg-Al-RE alloys, as a key development area for high-modulus magnesium alloys, hold great potential for engineering applications.

[0004] However, the high-modulus Al2RE phase in magnesium alloys often exists in solid form during alloy preparation, and its density is greater than that of the magnesium melt. Therefore, the high-modulus Al2RE phase easily settles to the bottom of the magnesium melt, resulting in a large amount of high-modulus Al2RE phase enriched in the lower part of the obtained high-modulus magnesium alloy ingot and almost no high-modulus Al2RE phase in the upper part. In other words, the high-modulus Al2RE phase has poor distribution uniformity in the direction of gravity. Therefore, it is urgent to invent a method for preparing a high-modulus Mg-Al-RE alloy that improves the uniformity of the high-modulus Al2RE phase to meet the growing demand for transportation vehicles. Summary of the Invention

[0005] The present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, the main purpose of the present invention is to provide a method for preparing a high-modulus Mg-Al-RE alloy with a uniformly distributed Al2RE phase. This method aims to address the problem of poor uniformity of the high-modulus Al2RE phase in existing Mg-Al-RE alloys, which in turn leads to poor modulus of the magnesium alloy.

[0006] The present invention also provides a high modulus Mg-Al-RE alloy material.

[0007] The purpose of the present invention is achieved through the following technical solutions: A method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase comprises the following steps: 1) melting the other magnesium alloy components except the high-purity aluminum component into a magnesium liquid state to obtain a molten magnesium liquid; 2) adding high-purity aluminum to the surface of the molten magnesium in step 1), pressing down and stirring to melt, thereby obtaining a molten magnesium alloy; 3) Rapidly cooling the molten magnesium alloy to obtain a Mg-Al-RE alloy material.

[0008] In some specific embodiments, the Mg-Al-RE alloy material comprises the following components by mass percentage: Al: 6-14%, RE: 10-25%, the content of unavoidable impurity elements ≤ 0.03%, and the balance being Mg.

[0009] In some specific embodiments, before step 1), the components of the Mg-Al-RE alloy material are pretreated by baking at 150-250° C. for 10-30 min.

[0010] In certain specific embodiments, the melting process conditions in step 1) are: completely melting at 720-760° C. under a protective atmosphere to obtain molten magnesium liquid.

[0011] In some specific embodiments, the protective atmosphere is a mixed atmosphere of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1.

[0012] In some specific embodiments, the pressing process parameters in step 2) are: the pressing speed of the high-purity aluminum into the magnesium liquid is 2 to 10 mm / s.

[0013] In some specific embodiments, when the entire area of the molten magnesium alloy in the melting container turns bright white, stirring is started to disperse the molten magnesium alloy for 5-20 seconds.

[0014] Furthermore, the melting container is a steel crucible; In certain specific embodiments, the high-purity aluminum is in solid granular form with a particle size of 0.5-1.5 mm and is pre-wrapped with high-purity aluminum foil.

[0015] As the same inventive concept, the present invention also provides a high modulus Mg-Al-RE alloy material.

[0016] Compared with the prior art, the present invention has at least the following advantages: 1) The preparation method of the present invention effectively avoids the precipitation of the high modulus Al2RE phase during the melting process of the magnesium alloy raw materials by adding aluminum particles after the remaining magnesium alloy raw materials are melted. In addition, after the aluminum particles are added, the aluminum particles are slowly pressed downward and the melt state is constantly observed. The reaction progress of the high modulus Al2RE phase is judged by the degree of downward expansion of the white bright area of the melt. After the entire melt enters the white bright state, it is slightly stirred and then the stirring rod is removed and rapidly water-cooled. This greatly shortens the melt holding time, thereby reducing the precipitation of the high modulus Al2RE phase, and ultimately obtains a high modulus Mg-Al-RE alloy in which the high modulus Al2RE phase is uniformly distributed in the direction of gravity.

[0017] 2) The preparation method of the present invention significantly improves the melting rate of Al and the formation rate of the high modulus Al2RE phase by replacing the aluminum block with aluminum particles, providing a basic guarantee for avoiding the precipitation of the high modulus Al2RE phase during the melting process of the magnesium alloy raw material.

[0018] 3) The preparation method of the present invention has easy-to-obtain raw materials, a simple process, high repeatability, and great promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention, the following briefly introduces the drawings required for the specific embodiments or the description of the prior art.

[0020] Figure 1 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 1 of the present invention; Figure 2 This is a scanning electron image of the microstructure of the lower portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 1 of the present invention; Figure 3 This is a scanning electron image of the microstructure of the upper portion of the Mg-8Al-13Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 2 of the present invention; Figure 4 This is a scanning electron image of the microstructure of the lower portion of the Mg-8Al-13Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 2 of the present invention; Figure 5 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 3 of the present invention; Figure 6 This is a scanning electron image of the microstructure of the lower portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 3 of the present invention; Figure 7This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 4 of the present invention; Figure 8 This is a scanning electron image of the microstructure of the lower portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 4 of the present invention; Figure 9 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 5 of the present invention; Figure 10 This is a scanning electron image of the microstructure of the lower portion of the Mg-6Al-10Y alloy ingot with uniform distribution of high modulus Al2Y phase in Example 5 of the present invention; Figure 11 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 1 of the present invention; Figure 12 This is a scanning electron image of the microstructure of the lower part of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 1 of the present invention; Figure 13 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 2 of the present invention; Figure 14 This is a scanning electron image of the microstructure of the lower part of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 2 of the present invention; Figure 15 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 3 of the present invention; Figure 16 This is a scanning electron image of the microstructure of the lower part of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 3 of the present invention; Figure 17 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 4 of the present invention; Figure 18 This is a scanning electron image of the microstructure of the lower part of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 4 of the present invention; Figure 19 This is a scanning electron image of the microstructure of the upper portion of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 5 of the present invention; Figure 20This is a scanning electron image of the microstructure of the lower part of the Mg-6Al-10Y alloy ingot with uneven distribution of high modulus Al2Y phase in Comparative Example 5 of the present invention; DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are merely illustrative and non-restrictive, and should not be used to limit the scope of protection of the present invention.

[0022] When expressing a certain amount, concentration or other value or parameter in the form of a range, preferred range, or preferred upper and lower numerical limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper range limits or preferred numerical values with any lower range limit or preferred numerical value, without considering 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.

[0023] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0024] The materials, methods, and examples herein are illustrative and, unless otherwise indicated, are not to be construed as limiting.

[0025] In the following embodiments, the high modulus performance of the magnesium alloy material is demonstrated by testing the main properties of each test sample respectively; the main properties tested in this application include elastic modulus, alloy composition, etc.

[0026] 1) Elastic modulus test; The elastic modulus test is carried out using a resonance frequency and damping analyzer and the ultrasonic resonance method in accordance with the dynamic method specified in GB / T 22315; 2) Alloy composition test The alloy composition of the samples was tested using X-ray fluorescence spectrometer.

[0027] Example 1 This embodiment provides a method for preparing a high modulus Mg-6Al-10Y magnesium alloy with improved uniformity of distribution of an intrinsic high modulus Al2RE phase, comprising the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrapping the high-purity aluminum obtained in step 2 with high-purity aluminum foil for use; 4) placing the steel crucible prepared in step 3) and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride at a volume ratio of 99:1), heating the crucible to a temperature of 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted, thereby obtaining molten magnesium; 5) placing the high-purity aluminum wrapped in high-purity aluminum foil described in step 3) onto the surface of the molten magnesium solution described in step 4), and pressing down the high-purity aluminum wrapped in high-purity aluminum foil using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 6) constantly observing the pressing process in step 5), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium liquid with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 7) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 6) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot having a high modulus endogenous Al2Y phase uniformly distributed in the gravity direction. The ingot is polished, cleaned, and dried before use.

[0028] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this example are shown in Figure 2. Figure 1 and Figure 2 As shown, compared Figure 1 and Figure 2 It can be seen that the high modulus Al2Y phase is densely distributed in the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot, indicating that the high modulus Al2Y phase is uniformly distributed in the direction of gravity.

[0029] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot and measured using X-ray fluorescence spectrometry to reveal the following compositions: Mg-5.2Al-8.5Y and Mg-5.4Al-9.1Y. This indicates minimal compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by only 0.2% and Y content by only 0.6%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 50.9 GPa and 51.1 GPa, respectively, differing by only 0.2 GPa.

[0030] Example 2 This embodiment provides a method for preparing a high modulus Mg-8Al-13Y magnesium alloy with improved uniformity of distribution of an intrinsic high modulus Al2RE phase, which comprises the following steps: 1) Selected Mg-8Al-13Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-8Al-13Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrapping the high-purity aluminum obtained in step 2) with high-purity aluminum foil for use; 4) placing the steel crucible prepared in step 3) and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride at a volume ratio of 99:1), heating the crucible to a temperature of 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted, thereby obtaining molten magnesium; 5) placing the high-purity aluminum wrapped in high-purity aluminum foil described in step 3) onto the surface of the molten magnesium solution described in step 4), and pressing down the high-purity aluminum wrapped in high-purity aluminum foil using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 6) constantly observing the pressing process in step 5), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium alloy with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 7) The steel crucible and the high modulus Mg-8Al-13Y alloy obtained in step 6) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-8Al-13Y alloy ingot having a high modulus endogenous Al2Y phase uniformly distributed in the gravity direction. The ingot is then polished, cleaned, and dried before use.

[0031] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-8Al-13Y alloy ingot prepared in this example are shown in Figure 2. Figure 3 and Figure 4 As shown, compared Figure 3 and Figure 4 It can be seen that the high modulus Al2Y phase is densely distributed in the upper and lower parts of the high modulus Mg-8Al-13Y alloy ingot, indicating that the high modulus Al2Y phase is uniformly distributed in the direction of gravity.

[0032] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-8Al-13Y alloy ingot and measured using X-ray fluorescence spectrometry to reveal their compositions: Mg-7.3Al-12.3Y and Mg-7.5Al-12.6Y. This indicates minimal compositional differences between the upper and lower portions of the resulting high-modulus Mg-8Al-13Y alloy ingot, with Al content differing by only 0.2% and Y content by only 0.3%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-8Al-13Y alloy were 54.2 GPa and 54.9 GPa, respectively, differing by only 0.7 GPa.

[0033] Example 3 This embodiment provides a method for preparing a high modulus Mg-6Al-10Y magnesium alloy with improved uniformity of distribution of an intrinsic high modulus Al2RE phase. The method is substantially the same as that of Example 1, except that the particle size of the selected high-purity aluminum particles in step 1) is 1.5 mm. The method comprises the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1.5 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrapping the high-purity aluminum obtained in step 2 with high-purity aluminum foil for use; 4) placing the steel crucible prepared in step 3) and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride at a volume ratio of 99:1), heating the crucible to a temperature of 760° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted, thereby obtaining molten magnesium; 5) placing the high-purity aluminum wrapped in high-purity aluminum foil described in step 3) onto the surface of the molten magnesium solution described in step 4), and pressing down the high-purity aluminum wrapped in high-purity aluminum foil using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 6) constantly observing the pressing process in step 5), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium liquid with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 7) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 6) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot having a high modulus endogenous Al2Y phase uniformly distributed in the gravity direction. The ingot is polished, cleaned, and dried before use.

[0034] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this example are shown in Figure 2. Figure 5 and Figure 6 As shown, compared Figure 5 and Figure 6 It can be seen that the high modulus Al2Y phase is densely distributed in the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot, indicating that the high modulus Al2Y phase is uniformly distributed in the direction of gravity.

[0035] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot and measured using X-ray fluorescence spectrometry to reveal the following compositions: Mg-5.1Al-8.2Y and Mg-5.9Al-9.3Y. This indicates minimal compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by only 0.8% and Y content by only 1.1%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 50.7 GPa and 51.2 GPa, respectively, differing by only 0.5 GPa.

[0036] Example 4 This embodiment provides a method for preparing a high modulus Mg-6Al-10Y magnesium alloy with improved uniformity of distribution of an intrinsic high modulus Al2RE phase. The method is substantially the same as that of Example 1, except that the pressing speed in step 5) is 2 mm / s. The method comprises the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrapping the high-purity aluminum obtained in step 2 with high-purity aluminum foil for use; 4) placing the steel crucible prepared in step 3) and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride at a volume ratio of 99:1), heating the crucible to a temperature of 720° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted, thereby obtaining molten magnesium; 5) placing the high-purity aluminum wrapped in high-purity aluminum foil described in step 3) onto the surface of the molten magnesium solution described in step 4), and pressing down the high-purity aluminum wrapped in high-purity aluminum foil using a graphite stirring rod at a speed of 2 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 6) constantly observing the pressing process in step 5), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium liquid with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 7) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 6) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot having a high modulus endogenous Al2Y phase uniformly distributed in the gravity direction. The ingot is polished, cleaned, and dried before use.

[0037] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this example are shown in Figure 2. Figure 7 and Figure 8 As shown, compared Figure 7 and Figure 8 It can be seen that the high modulus Al2Y phase is densely distributed in the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot, indicating that the high modulus Al2Y phase is uniformly distributed in the direction of gravity.

[0038] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot and measured using X-ray fluorescence spectrometry to reveal their compositions: Mg-5.7Al-8.8Y and Mg-5.8Al-9.1Y. This indicates minimal compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by only 0.1% and Y content by only 0.3%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 51.0 GPa and 51.1 GPa, respectively, differing by only 0.1 GPa.

[0039] Example 5 This embodiment provides a method for preparing a high modulus Mg-6Al-10Y magnesium alloy with improved uniformity of distribution of an intrinsic high modulus Al2RE phase. The method is substantially the same as that of Example 1, except that the stirring time in step 6) is 10 seconds. The method comprises the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrapping the high-purity aluminum obtained in step 2 with high-purity aluminum foil for use; 4) placing the steel crucible prepared in step 3) and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride at a volume ratio of 99:1), heating the crucible to a temperature of 720° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted, thereby obtaining molten magnesium; 5) placing the high-purity aluminum wrapped in high-purity aluminum foil described in step 3) onto the surface of the molten magnesium solution described in step 4), and pressing down the high-purity aluminum wrapped in high-purity aluminum foil using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 6) constantly observing the pressing process in step 5), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium liquid with the graphite stirring rod for 10 seconds and then removing the graphite stirring rod; 7) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 6) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot having a high modulus endogenous Al2Y phase uniformly distributed in the gravity direction. The ingot is polished, cleaned, and dried before use.

[0040] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this example are shown in Figure 2. Figure 9 and Figure 10 As shown, compared Figure 9 and Figure 10 It can be seen that the high modulus Al2Y phase is densely distributed in the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot, indicating that the high modulus Al2Y phase is uniformly distributed in the direction of gravity.

[0041] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot and measured using X-ray fluorescence spectrometry to reveal the following compositions: Mg-5.3Al-8.8Y and Mg-5.7Al-9.1Y. This indicates minimal compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by only 0.4% and Y content by only 0.3%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 50.8 GPa and 51.1 GPa, respectively, differing by only 0.3 GPa.

[0042] Comparative Example 1 This comparative example provides an example of preparing a magnesium alloy without using the method of the present invention. The method is basically the same as Example 1, except that the aluminum particles are replaced with aluminum blocks, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid block, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, placing the steel crucible and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1), heating the steel crucible to a temperature of 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) After the high-purity aluminum in step 2) is added to the completely molten magnesium liquid in step 3), the high-purity aluminum is pressed downward using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 5) constantly observing the pressing process in step 4), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium alloy with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 6) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 5) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot prepared by a conventional method. The ingot is polished, cleaned, and dried before use.

[0043] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown in Figure 2. Figure 11 and Figure 12 As shown, compared Figure 11 and Figure 12 It can be seen that the high modulus Al2Y phase is scattered in the upper part of the high modulus Mg-6Al-10Y alloy ingot and densely distributed in the lower part, indicating that the high modulus Al2Y phase is severely unevenly distributed in the gravity direction.

[0044] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot, and the specific compositions were determined by X-ray fluorescence spectrometry: Mg-1.4Al-2.3Y and Mg-8.5Al-16.0Y, respectively. This indicates significant compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by 7.1% and Y content by 13.7%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 48.0 GPa and 56.9 GPa, respectively, a difference of 8.9 GPa.

[0045] Comparative Example 2 This comparative example provides an example of preparing a magnesium alloy without using the method of the present invention. The comparative example is substantially the same as Example 1, except that the pressing is not performed at the pressing speed described in the method of the present invention. The comparative example includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrapping the high-purity aluminum pellets obtained in step 2) with high-purity aluminum foil, placing the steel crucible and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1), heating the steel crucible to 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) After the high-purity aluminum pellets wrapped in high-purity aluminum foil in step 2) are added to the completely molten magnesium liquid in step 3), the high-purity aluminum pellets are pressed downward using a graphite stirring rod at a speed of 20 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 5) constantly observing the pressing process in step 4), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium alloy with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 6) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 5) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot prepared by a conventional method. The ingot is polished, cleaned, and dried before use.

[0046] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown in Figure 2. Figure 13 and Figure 14 As shown, compared Figure 13 and Figure 14 It can be seen that the high modulus Al2Y phase is scattered in the upper part of the high modulus Mg-6Al-10Y alloy ingot and densely distributed in the lower part, indicating that the high modulus Al2Y phase is severely unevenly distributed in the gravity direction.

[0047] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot, and the specific compositions were determined by X-ray fluorescence spectrometry: Mg-1.1Al-1.9Y and Mg-9.2Al-17.0Y, respectively. This indicates significant compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by 8.1% and Y content by 15.1%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 47.5 GPa and 57.8 GPa, respectively, a difference of 10.3 GPa.

[0048] Comparative Example 3 This comparative example provides an example of preparing a magnesium alloy without using the method of the present invention. The comparative example is substantially the same as Example 1, except that the stirring time described in the method of the present invention is not followed, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrapping the high-purity aluminum pellets obtained in step 2) with high-purity aluminum foil, placing the steel crucible and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1), heating the steel crucible to 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) After the high-purity aluminum pellets wrapped in high-purity aluminum foil in step 2) are added to the completely molten magnesium liquid in step 3), the high-purity aluminum pellets are pressed downward using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 5) constantly observing the pressing process in step 4), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium alloy with the graphite stirring rod for 120 seconds and then removing the graphite stirring rod; 6) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 5) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot prepared by a conventional method. The ingot is polished, cleaned, and dried before use.

[0049] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown in Figure 2. Figure 15 and Figure 16 As shown, compared Figure 15 and Figure 16 It can be seen that the high modulus Al2Y phase is scattered in the upper part of the high modulus Mg-6Al-10Y alloy ingot and densely distributed in the lower part, indicating that the high modulus Al2Y phase is severely unevenly distributed in the gravity direction.

[0050] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot, and the specific compositions were determined by X-ray fluorescence spectrometry: Mg-2.3Al-4.4Y and Mg-8.6Al-15.0Y, respectively. This indicates significant compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by 6.3% and Y content by 10.6%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 49.0 GPa and 55.9 GPa, respectively, a difference of 6.9 GPa.

[0051] Comparative Example 4 This comparative example provides an example of preparing a magnesium alloy without using the method of the present invention. The comparative example is substantially the same as Example 1, except that the rapid water cooling described in the method of the present invention is not used for cooling. The comparative example includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrapping the high-purity aluminum pellets obtained in step 2) with high-purity aluminum foil, placing the steel crucible and the high-purity magnesium and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1), heating the steel crucible to 740° C. and maintaining the temperature until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) After the high-purity aluminum pellets wrapped in high-purity aluminum foil in step 2) are added to the completely molten magnesium liquid in step 3), the high-purity aluminum pellets are pressed downward using a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 5) constantly observing the pressing process in step 4), and when the entire area of the molten magnesium alloy in the steel crucible turns bright white, stirring the molten magnesium alloy with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 6) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 5) are cooled in a resistance furnace to obtain a high modulus Mg-6Al-10Y alloy ingot prepared by a conventional method. The ingot is polished, cleaned, and dried before use.

[0052] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown in Figure 2. Figure 17 and Figure 18 As shown, compared Figure 17 and Figure 18 It can be seen that the high modulus Al2Y phase is scattered in the upper part of the high modulus Mg-6Al-10Y alloy ingot and densely distributed in the lower part, indicating that the high modulus Al2Y phase is severely unevenly distributed in the gravity direction.

[0053] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot, and the specific compositions were determined by X-ray fluorescence spectrometry: Mg-1.2Al-2.1Y and Mg-9.5Al-17.0Y, respectively. This indicates significant compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with Al content differing by 8.3% and Y content by 14.9%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 47.2 GPa and 57.3 GPa, respectively, a difference of 10.1 GPa.

[0054] Comparative Example 5 This comparative example provides an example of magnesium alloy preparation without using the method of the present invention. The method is basically the same as Example 1, except that the high-purity aluminum particles are not added after the raw materials except the aluminum component are completely melted as described in the method of the present invention. The method includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, solid block, purity 99.995%; high-purity aluminum, solid granules, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, solid block, containing 70% Mg and 30% Y; 2) Grinding the surface oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weighing the Mg, Al, and Y elements required for the Mg-6Al-10Y alloy, and baking the weighed high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy at 200°C for 30 minutes until completely dry; 3) placing the high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy obtained in step 2) into a steel crucible, placing the steel crucible and the high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy therein into a resistance furnace and introducing a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:1), heating the steel crucible to a temperature of 740° C. and maintaining the temperature until the high-purity magnesium, high-purity aluminum particles, and Mg-30Y master alloy are completely melted; 4) After the raw materials in step 3) are completely melted, slowly press down with a graphite stirring rod at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible; 5) stirring the molten magnesium alloy with the graphite stirring rod for 20 seconds and then removing the graphite stirring rod; 6) The steel crucible and the high modulus Mg-6Al-10Y alloy obtained in step 5) are removed from the resistance furnace and rapidly water-cooled to obtain a high modulus Mg-6Al-10Y alloy ingot prepared by a conventional method. The ingot is polished, cleaned, and dried before use.

[0055] The scanning electron microstructures of the upper and lower parts of the high modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown in Figure 2. Figure 19 and Figure 20 As shown, compared Figure 19 and Figure 20 It can be seen that the high modulus Al2Y phase is scattered in the upper part of the high modulus Mg-6Al-10Y alloy ingot and densely distributed in the lower part, indicating that the high modulus Al2Y phase is severely unevenly distributed in the gravity direction.

[0056] Furthermore, samples were taken from the upper and lower portions of the high-modulus Mg-6Al-10Y alloy ingot, and the specific compositions were determined by X-ray fluorescence spectrometry: Mg-0.9Al-1.8Y and Mg-11.0Al-19.3Y, respectively. This indicates significant compositional differences between the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy ingot, with the Al content differing by only 10.1% and the Y content by 17.5%. Ultrasonic resonance analysis also revealed that the elastic moduli of the upper and lower portions of the resulting high-modulus Mg-6Al-10Y alloy were 46.5 GPa and 58.9 GPa, respectively, a difference of 12.4 GPa.

[0057] In summary, the comparative examples and comparative examples show that the upper and lower parts of the high modulus Mg-Al-Y alloy ingots obtained using the preparation method of the present invention have similar Al and Y element contents, comparable Al2Y phase contents, and basically consistent elastic moduli, while the upper and lower parts of the high modulus Mg-Al-Y alloy ingots prepared without using the method of the present invention have huge differences in Al and Y element contents, the Al2Y phase is enriched in the lower part of the ingot and scattered in the upper part of the ingot, and the elastic modulus is greatly different. This fully demonstrates that the preparation method of the present invention can effectively improve the uniformity of the distribution of the endogenous high modulus Al2RE phase and obtain high-quality high modulus Mg-Al-RE alloys.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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 description of the present invention.

Claims

1. A method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase, characterized in that: The steps include: 1) melting the other magnesium alloy components except the high-purity aluminum component into a magnesium liquid state to obtain a molten magnesium liquid; 2) adding high-purity aluminum to the surface of the molten magnesium in step 1), pressing down and stirring to melt, thereby obtaining a molten magnesium alloy; 3) Rapidly cooling the molten magnesium alloy to obtain a Mg-Al-RE alloy material.

2. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 1, characterized in that: The Mg-Al-RE alloy material comprises the following components by mass percentage: Al: 6-14%, RE: 10-25%, the content of unavoidable impurity elements ≤ 0.03%, and the balance being Mg.

3. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 1, characterized in that: The method further comprises pre-treating the components of the Mg-Al-RE alloy material by baking them at 150-250° C. for 10-30 minutes before step 1).

4. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 1, characterized in that: The melting process conditions in step 1) are: completely melting at 720-760° C. under a protective atmosphere to obtain molten magnesium liquid.

5. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 4, characterized in that: The protective atmosphere is a mixed atmosphere of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:

1.

6. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 4, characterized in that: The pressing process parameters in step 2) are as follows: the pressing speed of the high-purity aluminum into the magnesium liquid is 2 to 10 mm / s.

7. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 1, characterized in that: When the entire area of the molten magnesium alloy in the melting container turns into a bright white state, stirring is started to disperse the molten magnesium alloy for 5-20 seconds.

8. The method for preparing a high modulus Mg-Al-RE alloy with uniformly distributed Al2RE phase according to claim 1, characterized in that: The high-purity aluminum is in a granular solid state with a particle size of 0.5-1.5 mm and is pre-wrapped with high-purity aluminum foil.

9. A high modulus Mg-Al-RE alloy material prepared according to the preparation method according to any one of claims 1 to 8.

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