High-modulus Mg-Al-RE alloys with uniform Al2RE phase distribution and their preparation methods

Abstract

The application discloses a preparation method of high-modulus Mg-Al-RE series alloy with uniformly distributed Al2RE phase, and comprises the following steps: 1) melting other magnesium alloy components except 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 step 1), and then pressing and stirring the molten magnesium liquid to obtain a molten magnesium alloy; and 3) rapidly cooling the molten magnesium alloy.The application effectively avoids the high-modulus Al-RE phase from being precipitated in the melting process of the magnesium alloy raw material by adding aluminum particles after the melting of the remaining magnesium alloy raw material is completed; in addition, after the aluminum particles are added, the aluminum particles are slowly pressed, the molten state is observed at any time, the stirring rod is removed and rapid water cooling is conducted after slightly stirring when the whole molten body enters a white bright state, the molten body holding time is greatly shortened, the precipitation of the high-modulus Al-RE phase is reduced, and finally the high-modulus Mg-Al-RE series alloy with the high-modulus Al-RE phase uniformly distributed in the direction of gravity is obtained.

Description

Technical Field

[0001] This invention belongs to the field of magnesium alloy materials technology, specifically relating to a high-modulus Mg-Al-RE alloy with uniformly distributed endogenous high-modulus Al2RE phase and its preparation method. Background Technology

[0002] In recent years, the transportation sectors, including aerospace, rail transit, and road transport, have placed new demands on vehicle transport capabilities, namely lighter weight, higher speed, and greater load-bearing capacity. Magnesium alloys, as the lightest metallic structural material, possess high specific strength and good vibration damping properties, making them the most promising lightweight material in the transportation field. However, the insufficient modulus of traditional magnesium alloys (only 40-45 GPa) makes it difficult to meet the high load-bearing capacity requirements of next-generation vehicles, limiting the further application of magnesium alloys.

[0003] One important method to improve the modulus of magnesium alloys is to rationally design alloying elements to introduce high-modulus second phases (such as Al2RE phase, Si3RE5 phase, etc.), also known as the endogenous high-modulus phase method. According to the mixing principle, the higher the volume fraction of the high-modulus phase, the higher the modulus of the magnesium alloy. Among the many high-modulus second phases, the Al2RE phase requires the least amount of atoms to form, therefore, Mg-Al-RE alloys have great potential for engineering applications as a key focus in the development of high-modulus magnesium alloys.

[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 molten magnesium. Therefore, the high-modulus Al2RE phase easily settles at the bottom of the molten magnesium, resulting in a large accumulation of high-modulus Al2RE phase in the lower part of the high-modulus magnesium alloy ingot while the upper part has almost none. In other words, the high-modulus Al2RE phase exhibits poor uniformity in the gravitational direction. Therefore, there is an urgent need to develop a method for preparing high-modulus Mg-Al-RE alloys that improves the uniformity of the high-modulus Al2RE phase to meet the growing demand for transportation vehicles. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide a method for preparing high-modulus Mg-Al-RE alloys with uniform Al2RE phase distribution, thereby addressing the problem of poor uniformity of the high-modulus Al2RE phase in existing Mg-Al-RE alloys, which leads to poor magnesium alloy modulus.

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

[0007] The objective of this invention is achieved through the following technical solution: A method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution includes the following steps: 1) Melt the magnesium alloy components other than the high-purity aluminum component into a molten magnesium state to obtain molten magnesium liquid; 2) Add high-purity aluminum to the surface of the molten magnesium liquid in step 1), press down and stir to melt, and obtain molten magnesium alloy; 3) Rapidly cool the molten magnesium alloy to obtain Mg-Al-RE alloy materials.

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

[0009] In some specific embodiments, the process further includes pretreatment of each component of the Mg-Al-RE alloy material by baking at 150-250°C for 10-30 minutes before step 1).

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

[0011] In some specific embodiments, the protective atmosphere is a mixture 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 ~ 10 mm / s.

[0013] In some specific embodiments, when the entire area of ​​the molten magnesium alloy in the molten 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 some specific embodiments, the high-purity aluminum is a granular solid with a particle size of 0.5-1.5 mm, and is pre-treated by wrapping it with high-purity aluminum foil.

[0015] As part of the same inventive concept, this 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 high-modulus Al2RE phase during the melting process of magnesium alloy raw materials by adding aluminum particles after the other magnesium alloy raw materials have been melted. In addition, after adding aluminum particles, the aluminum particles are slowly pressed down and the melt state is constantly observed. The reaction process of high-modulus Al2RE phase is judged by the degree of downward expansion of the bright white area of ​​the melt. After the melt enters the bright white state, the stirring rod is removed and the melt is rapidly water-cooled after a little stirring. This greatly shortens the heat preservation time of the melt, thereby reducing the precipitation of high-modulus Al2RE phase. Finally, a high-modulus Mg-Al-RE alloy in which the high-modulus Al2RE phase is uniformly distributed in the direction of gravity is obtained.

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

[0018] 3) The preparation method of the present invention uses simple and readily available raw materials, has a simple process, high repeatability, and has great value for promotion and application. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a scanning electron microscope image of the upper part 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 microscope image of the lower part 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 microscope image of the upper part 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 microscope image of the lower part 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 microscope image of the upper part 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 microscope image of the lower part 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 microscope image of the upper part 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 microscope image of the lower part 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 microscope image of the upper part 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 microscope image of the lower part 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 microscope image of the upper 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 12 This is a scanning electron microscope image 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 microscope image of the upper 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 14 This is a scanning electron microscope image 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 microscope image of the upper 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 16 This is a scanning electron microscope image 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 microscope image of the upper 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 18 This is a scanning electron microscope image 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 microscope image of the upper part 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 microscope image 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 Implementation

[0021] 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.

[0022] 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.

[0023] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0024] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

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

[0026] 1) Elastic modulus test; The elastic modulus was tested using a resonant frequency and damping analyzer and the ultrasonic resonance method, in accordance with the dynamic method specified in GB / T 22315. 2) Alloy composition testing The alloy composition of the sample was determined using X-ray fluorescence spectrometry.

[0027] Example 1 This embodiment provides a method for preparing high-modulus Mg-6Al-10Y magnesium alloy with improved uniformity of endogenous high-modulus Al2RE phase distribution, which includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrap the high-purity aluminum obtained in step 2 with high-purity aluminum foil for later use; 4) Place the steel crucible described in step 3) and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted to obtain molten magnesium liquid. 5) Place the high-purity aluminum wrapped in high-purity aluminum foil from step 3) onto the surface of the molten magnesium liquid in step 4), and use a graphite stirring rod to press down the high-purity aluminum wrapped in high-purity aluminum foil at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 6) Observe the pressing process described in step 5) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium liquid with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 7) Take the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 6) out of the resistance furnace and perform rapid water cooling to obtain a high-modulus Mg-6Al-10Y alloy ingot with a high-modulus endogenous Al2Y phase uniformly distributed in the gravity direction. After grinding, cleaning the surface and drying, it can be put into use.

[0028] The scanning electron microscope images of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this embodiment are shown below. Figure 1 and Figure 2 As shown, comparison Figure 1 and Figure 2 It can be seen that the high-modulus Al2Y phase is densely distributed in both 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 parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-5.2Al-8.5Y and Mg-5.4Al-9.1Y, respectively. This indicates that the compositional difference between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot is minimal, with only a 0.2% difference in Al content and a 0.6% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy were measured using ultrasonic resonance, yielding values ​​of 50.9 GPa and 51.1 GPa, respectively, a difference of only 0.2 GPa.

[0030] Example 2 This embodiment provides a method for preparing high-modulus Mg-8Al-13Y magnesium alloy with improved uniformity of endogenous high-modulus Al2RE phase distribution, which includes the following steps: 1) Selected Mg-8Al-13Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-8Al-13Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrap the high-purity aluminum obtained in step 2) with high-purity aluminum foil for later use; 4) Place the steel crucible described in step 3) and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted to obtain molten magnesium liquid. 5) Place the high-purity aluminum foil wrapped in the high-purity aluminum foil from step 3) onto the surface of the molten magnesium liquid in step 4), and use a graphite stirring rod to press down the high-purity aluminum foil wrapped in the high-purity aluminum foil at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 6) Observe the pressing process described in step 5) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium alloy with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 7) Take the steel crucible and high-modulus Mg-8Al-13Y alloy obtained in step 6) out of the resistance furnace and perform rapid water cooling to obtain a high-modulus Mg-8Al-13Y alloy ingot with a high-modulus endogenous Al2Y phase uniformly distributed in the gravity direction. After grinding, cleaning the surface and drying, it can be put into use.

[0031] The scanning electron microscope images of the upper and lower parts of the high-modulus Mg-8Al-13Y alloy ingot prepared in this embodiment are shown below. Figure 3 and Figure 4 As shown, comparison Figure 3 and Figure 4 It can be seen that the high-modulus Al2Y phase is densely distributed in both 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 parts of the high-modulus Mg-8Al-13Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the compositions to be Mg-7.3Al-12.3Y and Mg-7.5Al-12.6Y, respectively. This indicates that the compositional difference between the upper and lower parts of the obtained high-modulus Mg-8Al-13Y alloy ingot is minimal, with only a 0.2% difference in Al content and a 0.3% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-8Al-13Y alloy were measured using ultrasonic resonance, yielding values ​​of 54.2 GPa and 54.9 GPa, respectively, a difference of only 0.7 GPa.

[0033] Example 3 This embodiment provides a method for preparing high-modulus Mg-6Al-10Y magnesium alloys with improved uniformity of endogenous high-modulus Al2RE phase distribution. It is basically the same as Example 1, except that in step 1), the selected high-purity aluminum particles have a particle size of 1.5 mm, which includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1.5 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrap the high-purity aluminum obtained in step 2 with high-purity aluminum foil for later use; 4) Place the steel crucible described in step 3) and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 760 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted to obtain molten magnesium liquid. 5) Place the high-purity aluminum wrapped in high-purity aluminum foil from step 3) onto the surface of the molten magnesium liquid in step 4), and use a graphite stirring rod to press down the high-purity aluminum wrapped in high-purity aluminum foil at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 6) Observe the pressing process described in step 5) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium liquid with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 7) Take the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 6) out of the resistance furnace and perform rapid water cooling to obtain a high-modulus Mg-6Al-10Y alloy ingot with a high-modulus endogenous Al2Y phase uniformly distributed in the gravity direction. After grinding, cleaning the surface and drying, it can be put into use.

[0034] The scanning electron microscope images of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this embodiment are shown below. Figure 5 and Figure 6 As shown, comparison Figure 5 and Figure 6 It can be seen that the high-modulus Al2Y phase is densely distributed in both 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 parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-5.1Al-8.2Y and Mg-5.9Al-9.3Y, respectively. This indicates that the compositional difference between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot is minimal, with only a 0.8% difference in Al content and a 1.1% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy were measured using ultrasonic resonance, yielding values ​​of 50.7 GPa and 51.2 GPa, respectively, a difference of only 0.5 GPa.

[0036] Example 4 This embodiment provides a method for preparing high-modulus Mg-6Al-10Y magnesium alloys with improved uniformity of endogenous high-modulus Al2RE phase distribution. It is basically the same as Example 1, except that the pressing speed in step 5) is 2 mm / s, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrap the high-purity aluminum obtained in step 2 with high-purity aluminum foil for later use; 4) Place the steel crucible described in step 3) and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 720 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted to obtain molten magnesium liquid. 5) Place the high-purity aluminum foil wrapped in the high-purity aluminum foil from step 3) onto the surface of the molten magnesium liquid in step 4), and use a graphite stirring rod to press down the high-purity aluminum foil wrapped in the high-purity aluminum foil at a speed of 2 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 6) Observe the pressing process described in step 5) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium liquid with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 7) Take the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 6) out of the resistance furnace and perform rapid water cooling to obtain a high-modulus Mg-6Al-10Y alloy ingot with a high-modulus endogenous Al2Y phase uniformly distributed in the gravity direction. After grinding, cleaning the surface and drying, it can be put into use.

[0037] The scanning electron microscope images of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this embodiment are shown below. Figure 7 and Figure 8 As shown, comparison Figure 7 and Figure 8 It can be seen that the high-modulus Al2Y phase is densely distributed in both 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 parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the compositions to be Mg-5.7Al-8.8Y and Mg-5.8Al-9.1Y, respectively. This indicates that the compositional difference between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot is minimal, with only a 0.1% difference in Al content and a 0.3% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy were measured using ultrasonic resonance, yielding values ​​of 51.0 GPa and 51.1 GPa, respectively, a difference of only 0.1 GPa.

[0039] Example 5 This embodiment provides a method for preparing high-modulus Mg-6Al-10Y magnesium alloys with improved uniformity of endogenous high-modulus Al2RE phase distribution. It is basically the same as Example 1, except that the stirring time in step 6) is 10 seconds. The method includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and wrap the high-purity aluminum obtained in step 2 with high-purity aluminum foil for later use; 4) Place the steel crucible described in step 3) and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 720 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted to obtain molten magnesium liquid. 5) Place the high-purity aluminum wrapped in high-purity aluminum foil from step 3) onto the surface of the molten magnesium liquid in step 4), and use a graphite stirring rod to press down the high-purity aluminum wrapped in high-purity aluminum foil at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 6) Observe the pressing process described in step 5) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium liquid with the graphite stirring rod for 10 seconds and then remove the graphite stirring rod. 7) Take the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 6) out of the resistance furnace and perform rapid water cooling to obtain a high-modulus Mg-6Al-10Y alloy ingot with a high-modulus endogenous Al2Y phase uniformly distributed in the gravity direction. After grinding, cleaning the surface and drying, it can be put into use.

[0040] The scanning electron microscope images of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this embodiment are shown below. Figure 9 and Figure 10 As shown, comparison Figure 9 and Figure 10 It can be seen that the high-modulus Al2Y phase is densely distributed in both 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 parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the compositions to be Mg-5.3Al-8.8Y and Mg-5.7Al-9.1Y, respectively. This indicates that the compositional difference between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot is minimal, with only a 0.4% difference in Al content and a 0.3% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy were measured using ultrasonic resonance, yielding values ​​of 50.8 GPa and 51.1 GPa, respectively, a difference of only 0.3 GPa.

[0042] Comparative Example 1 This comparative example provides a magnesium alloy preparation example that does not use the method of the present invention, which is basically the same as Example 1, except that aluminum granules are replaced with aluminum blocks, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, in block form, 99.995% purity; high-purity aluminum, in block form, 99.995% purity; Mg-30Y master alloy, in block form, containing 70% Mg and 30% Y. 2) Polish the oxide layer on the surface of the high-purity magnesium, high-purity aluminum and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum and Mg-30Y master alloy at 200℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, and place the steel crucible and the high-purity magnesium and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted. 4) After the high-purity aluminum from step 2) is added to the completely molten magnesium liquid from step 3), use a graphite stirring rod to press down the high-purity aluminum at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 5) Observe the pressing process described in step 4) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium alloy with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 6) Remove the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 5) from the resistance furnace and rapidly water-cool them to obtain the high-modulus Mg-6Al-10Y alloy ingot obtained by the traditional preparation method. After grinding, cleaning the surface and drying, it can be put into use.

[0043] Scanning electron micrographs of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown below. Figure 11 and Figure 12 As shown, comparison 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 direction of gravity.

[0044] Furthermore, samples were taken from the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-1.4Al-2.3Y and Mg-8.5Al-16.0Y, respectively. This indicates a significant difference in composition between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot, with a 7.1% difference in Al content and a 13.7% difference in Y content. Simultaneously, the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy were measured using ultrasonic resonance, yielding values ​​of 48.0 GPa and 56.9 GPa, respectively, a difference of 8.9 GPa.

[0045] Comparative Example 2 This comparative example provides a magnesium alloy preparation example that does not use the method of the present invention, which is basically the same as Example 1, except that the pressing speed is not performed according to the method of the present invention, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrap the high-purity aluminum granules obtained in step 2) with high-purity aluminum foil, place the steel crucible and the high-purity magnesium and Mg-30Y master alloy inside into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1), turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) When the high-purity aluminum granules wrapped in the high-purity aluminum foil in step 2) are added into the completely molten magnesium liquid in step 3), the high-purity aluminum is pressed down 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) Observe the pressing process described in step 4) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium alloy with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 6) Remove the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 5) from the resistance furnace and rapidly water-cool them to obtain the high-modulus Mg-6Al-10Y alloy ingot obtained by the traditional preparation method. After grinding, cleaning the surface and drying, it can be put into use.

[0046] Scanning electron micrographs of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown below. Figure 13 and Figure 14 As shown, comparison 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 direction of gravity.

[0047] Furthermore, samples were taken from the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-1.1Al-1.9Y and Mg-9.2Al-17.0Y, respectively. This indicates a significant difference in composition between the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, with an 8.1% difference in Al content and a 15.1% difference in Y content. Simultaneously, ultrasonic resonance analysis revealed the elastic moduli of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy to be 47.5 GPa and 57.8 GPa, respectively, a difference of 10.3 GPa.

[0048] Comparative Example 3 This comparative example provides a magnesium alloy preparation example that does not use the method of the present invention, which is basically the same as Example 1, except that the stirring is not performed according to the stirring time described in the method of the present invention, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrap the high-purity aluminum granules obtained in step 2) with high-purity aluminum foil, place the steel crucible and the high-purity magnesium and Mg-30Y master alloy inside into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1), turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) When the high-purity aluminum granules wrapped in the high-purity aluminum foil in step 2) are added into the completely molten magnesium liquid in step 3), the high-purity aluminum is pressed down 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) Observe the pressing process described in step 4) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium alloy with the graphite stirring rod for 120 seconds and then remove the graphite stirring rod. 6) Remove the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 5) from the resistance furnace and rapidly water-cool them to obtain the high-modulus Mg-6Al-10Y alloy ingot obtained by the traditional preparation method. After grinding, cleaning the surface and drying, it can be put into use.

[0049] Scanning electron micrographs of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown below. Figure 15 and Figure 16 As shown, comparison 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 direction of gravity.

[0050] Furthermore, samples were taken from the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed their compositions to be Mg-2.3Al-4.4Y and Mg-8.6Al-15.0Y, respectively. This indicates a significant difference in composition between the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, with a 6.3% difference in Al content and a 10.6% difference in Y content. Simultaneously, ultrasonic resonance analysis revealed the elastic moduli of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy to be 49.0 GPa and 55.9 GPa, respectively, a difference of 6.9 GPa.

[0051] Comparative Example 4 This comparative example provides a magnesium alloy preparation example that does not use the method of the present invention, which is basically the same as Example 1, except that the rapid water cooling described in the method of the present invention is not performed, and includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium and Mg-30Y master alloy obtained in step 2) into a steel crucible, wrap the high-purity aluminum granules obtained in step 2) with high-purity aluminum foil, place the steel crucible and the high-purity magnesium and Mg-30Y master alloy inside into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1), turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium and Mg-30Y master alloy are completely melted; 4) When the high-purity aluminum granules wrapped in the high-purity aluminum foil in step 2) are added into the completely molten magnesium liquid in step 3), the high-purity aluminum is pressed down 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) Observe the pressing process described in step 4) at all times. When the entire area of ​​the molten magnesium alloy in the steel crucible turns bright white, stir the molten magnesium alloy with the graphite stirring rod for 20 seconds and then remove the graphite stirring rod. 6) Cool the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 5) in a resistance furnace to obtain a high-modulus Mg-6Al-10Y alloy ingot prepared by the traditional method. After grinding, cleaning and drying, it can be put into use.

[0052] Scanning electron micrographs of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown below. Figure 17 and Figure 18 As shown, comparison 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 direction of gravity.

[0053] Furthermore, samples were taken from the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-1.2Al-2.1Y and Mg-9.5Al-17.0Y, respectively. This indicates a significant difference in composition between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot, with an 8.3% difference in Al content and a 14.9% difference in Y content. Simultaneously, ultrasonic resonance analysis revealed the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy to be 47.2 GPa and 57.3 GPa, respectively, a difference of 10.1 GPa.

[0054] Comparative Example 5 This comparative example provides a magnesium alloy preparation example that does not use the method of the present invention. It is basically the same as Example 1, except that the high-purity aluminum particles are not added after the raw materials other than the aluminum component are completely melted according to the method of the present invention. The method includes the following steps: 1) Selected Mg-6Al-10Y alloy smelting materials: including high-purity magnesium, blocky solid, purity 99.995%; high-purity aluminum, granular solid, particle size 1 mm, purity 99.995%; Mg-30Y master alloy, blocky solid, containing 70% Mg and 30% Y. 2) Polish the oxide layer of the high-purity magnesium and Mg-30Y master alloy selected in step 1), weigh them according to the required Mg, Al and Y element content of Mg-6Al-10Y alloy, and bake the weighed high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy at 200 ℃ for 30 min until completely dry. 3) Place the high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy obtained in step 2) into a steel crucible. Place the steel crucible and the high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy inside it into an electric resistance furnace and introduce a protective atmosphere (a mixture of carbon dioxide and sulfur hexafluoride with a volume ratio of 99:1). Turn on the heating to make the temperature inside the steel crucible reach 740 ℃ and hold it until the high-purity magnesium, high-purity aluminum granules and Mg-30Y master alloy are completely melted. 4) After the raw materials described in step 3) are completely melted, use a graphite stirring rod to slowly press down at a speed of 5 mm / s until the graphite stirring rod touches the bottom of the steel crucible. 5) Stir the molten magnesium alloy with the graphite stirring rod for 20 seconds, then remove the graphite stirring rod; 6) Remove the steel crucible and high-modulus Mg-6Al-10Y alloy obtained in step 5) from the resistance furnace and rapidly water-cool them to obtain the high-modulus Mg-6Al-10Y alloy ingot obtained by the traditional preparation method. After grinding, cleaning the surface and drying, it can be put into use.

[0055] Scanning electron micrographs of the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot prepared in this comparative example are shown below. Figure 19 and Figure 20 As shown, comparison 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 direction of gravity.

[0056] Furthermore, samples were taken from the upper and lower parts of the high-modulus Mg-6Al-10Y alloy ingot, respectively. X-ray fluorescence spectroscopy revealed the specific compositions to be Mg-0.9Al-1.8Y and Mg-11.0Al-19.3Y, respectively. This indicates a significant difference in composition between the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy ingot, with an Al content difference of only 10.1% and a Y content difference of 17.5%. Simultaneously, ultrasonic resonance analysis revealed the elastic moduli of the upper and lower parts of the obtained high-modulus Mg-6Al-10Y alloy to be 46.5 GPa and 58.9 GPa, respectively, a difference of 12.4 GPa.

[0057] In summary, as can be seen from the comparative examples and comparative embodiments, the high-modulus Mg-Al-Y alloy ingots prepared using the method of the present invention have similar Al and Y element contents in the upper and lower parts, comparable Al2Y phase contents, and essentially consistent elastic moduli in the upper and lower parts. In contrast, the high-modulus Mg-Al-Y alloy ingots prepared without the method of the present invention show significant differences in Al and Y element contents between the upper and lower parts, with the Al2Y phase concentrated in the lower part of the ingot and scattered in the upper part, resulting in large differences in elastic moduli. 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, obtaining high-quality high-modulus Mg-Al-RE alloys.

[0058] 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 method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution, characterized in that, Includes the following steps: 1) Melt the magnesium alloy components other than the high-purity aluminum component into a molten magnesium state to obtain molten magnesium liquid; 2) Add high-purity aluminum to the surface of the molten magnesium liquid in step 1), press down and stir to melt, and obtain molten magnesium alloy; 3) The molten magnesium alloy is rapidly cooled to obtain a Mg-Al-RE alloy material; wherein the Mg-Al-RE alloy material comprises the following components by mass percentage: Al: 6-14%, RE: 10-25%, unavoidable impurity element content ≤0.03%, and the balance is Mg; the pressing process parameters in step 2) are: the pressing speed of the high-purity aluminum into the magnesium liquid is 2 ~10 mm / s; when the entire area of ​​the molten magnesium alloy in the molten container turns white and bright, stirring is started to disperse the molten magnesium alloy for 5-20s; and the high-purity aluminum is in granular solid form.

2. The method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution according to claim 1, characterized in that, It also includes pretreatment before step 1), where each component of the Mg-Al-RE alloy material is baked at 150 ~ 250℃ for 10 ~ 30 min.

3. The method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution according to claim 1, characterized in that, The melting process conditions described in step 1) are: complete melting at 720-760℃ under a protective atmosphere to obtain molten magnesium liquid.

4. The method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution according to claim 3, characterized in that, The protective atmosphere is a mixture of carbon dioxide and sulfur hexafluoride in a volume ratio of 99:

1.

5. The method for preparing a high-modulus Mg-Al-RE alloy with uniform Al2RE phase distribution according to claim 4, characterized in that, The high-purity aluminum has a particle size of 0.5-1.5 mm and is pre-treated by wrapping it with high-purity aluminum foil.

6. A high-modulus Mg-Al-RE alloy material prepared by the preparation method according to any one of claims 1-5.

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