CN108677073A - A kind of high-strength wrought magnesium alloys and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength deformed magnesium alloy and a preparation method thereof. The magnesium alloy is composed of Mg, Mn and low-content Sr, and the mass percentages of each component are Mn: 0.01-3%, Sr 0.5-1.5 %, the balance is magnesium and unavoidable impurities. In the Mg‑Sr‑Mn ternary system, Sr only reacts with Mg to form Mg ₁₇ Sr ₂ , but does not react with Mn. The phase composition of the alloy is: α‑Mg, elemental Mn phase and Mg ₁₇ Sr ₂ phase , the preparation process adopts a simple smelting-extrusion process, the obtained magnesium alloy material has good strength and toughness, the preparation process is simple, the composition is simple, the cost is low, and it has good industrialization prospects.

Description

A kind of high-strength wrought magnesium alloy and its preparation method

technical field

The invention relates to the field of magnesium alloy metal materials, in particular to a high-strength deformed magnesium alloy and a preparation method thereof.

Background technique

Magnesium and magnesium alloys are currently the lightest metal structural materials, with low density, high specific strength and specific stiffness, good damping and shock absorption, good thermal conductivity, good electromagnetic shielding effect, excellent machining performance, stable parts size and easy recycling, etc. Advantages, it has many years of history in industries such as aviation, aerospace, automobiles, computers, electronics, communications and home appliances. In recent years, the continuous improvement of lightweight and environmental protection requirements for automobiles and the increasingly tight energy have stimulated people's interest in magnesium. Therefore, a large number of new wrought magnesium alloys have become research hotspots. It is precisely because of such low cost and good comprehensive performance that magnesium alloys have been given great attention, and a lot of research has been carried out on this. Adding a small amount of different elements to the common Mg-Mn series magnesium alloy can increase the elongation without reducing the strength. Although the strength and plasticity of rare earth-containing magnesium alloys are very good, because of its high price and limited resources, we choose a low-priced alkali metal element strontium.

Yang Mingbo and others disclosed a Mg-Sr-Mn series heat-resistant magnesium alloy and its preparation method (the publication number is CN107739938 A). Although the alloy system of this patent involves Mg-Sr-Mn, it needs to add Sc, Nd , Sm, Zn, Ca, Zr and other elements, the composition is complex, the cost is high, there are α-Mg, Mg17Sr2, α-Mn, Mg ₁₂ Nd, Mg ₄₁ Sm ₅ and Mn ₂ Sc phases, and the second phase is in a large amount Mg ₁₇ Sr ₂ and α-Mn are the main components, and Mn ₂ Sc is the supplementary phase. This is because Mg ₁₇ Sr ₂ has good high temperature resistance, but its mechanical properties are not good. The tensile strength is only 135~186MPa, and the yield strength It is only 119~162MPa, which cannot meet the demand for high mechanical properties such as 3C product shells, leisure products, medical load-bearing structures, and aerospace components.

Contents of the invention

In view of the deficiencies of the prior art above, the purpose of the present invention is to provide a high-strength wrought magnesium alloy and a preparation method thereof, so as to solve the problems of high cost and poor strength of the existing wrought magnesium alloy.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: a high-strength wrought magnesium alloy, comprising the following components in mass percentage: Mn 0.01-3%, Sr 0.5-1.5%, and the balance is magnesium and unavoidable impurities.

In the ternary alloy phase diagram of the Mg-Mn-Sr magnesium alloy prepared by the present invention, Sr only reacts with Mg to form Mg ₁₇ Sr ₂ , and does not react with Mn, so the phase composition of the Mg-Mn-Sr alloy is: α-Mg, elemental Mn phase and Mg ₁₇ Sr ₂ phase, among which elemental Mn can play the role of recrystallization heterogeneous nucleation point in the process of plastic processing of deformed magnesium alloys, promote recrystallization and refine grains; Mg ₁₇ Sr Phase ₂ not only refines the as-cast grains, but also acts as a heterogeneous nucleation site for recrystallization, further refining the microstructure of the deformed alloy. Therefore, the Mg-Mn-Sr deformed alloy has the characteristics of fine grains and excellent strength.

More importantly, the design and regulation of the alloy composition is based on the different ratios of the Mg-Sr phase and the elemental Mn two second phases in the Mg-Sr-Mn ternary alloy. It is mainly achieved by precisely controlling the low content of Sr. This is because although Sr can obviously refine the grain size, when the Sr content reaches 0.7wt.%, the grain size will not decrease obviously and basically remain unchanged. Change. In addition, when the Sr content increases, the second phase, Mg ₁₇ Sr ₂ , will obviously increase. Although a large amount of Mg ₁₇ Sr ₂ phase can improve the heat resistance of magnesium alloys, the crack source will be obvious during the stretching process. increase, leading to a decrease in mechanical properties.

A method for preparing a high-strength wrought magnesium alloy, comprising the following steps:

1) Raw material preparation: use pure magnesium ingots, magnesium-strontium master alloys, and magnesium-manganese master alloys as raw materials, perform mechanical grinding (remove the surface oxide layer), and calculate the ingredients according to the mass percentage of the above-mentioned high-strength deformed magnesium alloys;

2) Smelting: Preheat pure magnesium, magnesium-strontium master alloy and magnesium-manganese master alloy at 300°C for 30 minutes, then place the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ to make it Completely melt to obtain a magnesium melt. After the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, and fully stirred for 3~ 6min, when the temperature rises to 700~740℃, keep warm for 10~20min, then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 300°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the surface scale of the magnesium alloy ingot obtained in step 3), and then preheat it at 200~350°C for 1.5~3.0h, and then coat the surface of the magnesium alloy ingot with magnesium An alloy lubricant, using an extrusion die to hot-extrude the magnesium alloy profile at 250-400°C to obtain a magnesium alloy rod.

In the present invention, all the Sr elements of the Mg-Sr-Mn ternary alloy form compounds with Mg, and are not in solid solution in Mg, and the Mg-Sr phase can promote particle-stimulated nucleation during extrusion, providing a large number of nucleation points, while The solid solubility of Mn element in the Mg matrix is extremely low and does not react with Sr, so the deformation resistance between the lattices is very low, and it has good forming ability, which is beneficial to achieve lower temperature and faster deformation speed. Prepare deformed profiles, so it can be directly extruded without solution treatment before extrusion, and the operation is simple.

Further, the extrusion ratio in the hot extrusion is 10:1-80:1, and the extrusion speed is 0.5-3 m/min.

Compared with the prior art, the present invention has the following beneficial effects:

1. The Mg-Mn-Sr wrought magnesium alloy proposed by the present invention is based on the Mg-Mn alloy by adding precisely controlled content of strontium element to improve the comprehensive performance of the magnesium alloy. It is found that strontium does not react with manganese in the phase diagram of the magnesium-manganese-strontium ternary alloy, but only reacts with magnesium to form the second phase of Mg ₁₇ Sr ₂ , and precipitates the α-Mn phase on the magnesium matrix. By adding a low content of strontium, on the one hand, the supercooling degree of the alloy solution is increased, on the other hand, the extremely low solid solubility in magnesium leads to grain refinement, and a small amount of Mg ₁₇ Sr ₂ is generated second The phase serves as the substrate for heterogeneous nucleation during the extrusion process, which not only reduces the size of the grains, but also avoids the increase in the number of obvious crack sources during the stretching process, thereby significantly improving the strength and plasticity of the magnesium alloy. . In addition, the Mn element can provide sufficient recrystallization nucleation points during the alloy deformation process, which can effectively refine the recrystallization grains and further improve the mechanical properties of the deformed magnesium alloy.

2. The raw materials used in the present invention are only magnesium, manganese and strontium, the composition is simple, the price is low, the simple smelting-extrusion process is adopted, no solid solution treatment is required, it can be used directly, the preparation process is simple, the preparation efficiency is high, and energy saving . The elongation of the prepared Mg-Sr-Mn magnesium alloy material can reach 19.69%, the tensile strength can reach 255~350MPa, and the yield strength can reach 228~339MPa. It has good strength and toughness, and is suitable for 3C product shells and leisure products. Load-bearing structures and aerospace parts, etc., and the material has good biocompatibility, adjustable degradation speed and mechanical properties, can be used as medical materials, and has good industrialization prospects.

Description of drawings

Fig. 1 is the mechanical property curve of the denatured magnesium alloy prepared by embodiment 1 ~ 3;

Fig. 2 is the mechanical property curve of the denatured magnesium alloy prepared by embodiment 4～6;

Fig. 3 is the mechanical property curve of the denatured magnesium alloy prepared in Examples 7-9.

Detailed ways

The present invention will be described in further detail below in conjunction with embodiment. It should be noted that the purity of industrially pure magnesium described in the following examples is above 99%; the magnesium-manganese master alloy and the magnesium-strontium master alloy are added in the form of Mg-5Mn and Mg-30Sr.

Example 1

1) Raw material preparation: use pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 2.0%; Sr: 0.5%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, then completely melt the pure magnesium ingot at 720°C under the protection of a mixed gas of SF ₆ and CO ₂ to obtain magnesium Melt, after the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, fully stirred for 3 minutes, and when the temperature rises to At 700°C, after holding for 10 minutes, remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 2

1) Raw material preparation: use pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 2.0%; Sr: 1.0%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, then completely melt the pure magnesium ingot at 740°C under the protection of a mixed gas of SF ₆ and CO ₂ to obtain magnesium Melt, after raising the temperature of the magnesium melt to 720°C and stabilizing it, add the preheated magnesium-manganese master alloy and magnesium-strontium master alloy into the completely melted magnesium melt, and fully stir for 3-6 minutes. When the temperature rises to 700~740℃, keep warm for 10~20min, then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 3

1) Raw material preparation: take pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 2.0%; Sr: 1.5%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, and then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ Obtain the magnesium melt, after the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, fully stirred for 6 minutes, when the temperature When the temperature rises to 720°C, keep it warm for 20 minutes, and then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 4

1) Raw material preparation: use pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 1.0%; Sr: 0.5%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, and then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ Obtain the magnesium melt, after the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, fully stirred for 6 minutes, when the temperature When the temperature rises to 720°C, keep warm for 10 minutes, then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 5

1) Raw material preparation: use pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 1.0%; Sr: 1.0%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, and then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ The magnesium melt is obtained, and after the temperature of the magnesium melt is raised to 720° C. to be stable, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, fully stirred for 3 to 6 minutes, When the temperature rises to 740°C, keep warm for 10 minutes, and then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 6

1) Raw material preparation: use pure magnesium ingot, Mg-5Mn and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 1.0%; Sr: 1.5%; the balance is Mg;

2) Melting: Preheat pure magnesium, Mg-5Mn and Mg-30Sr at 300°C for 30 minutes, and then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ Obtain the magnesium melt, after the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, fully stirred for 5 minutes, when the temperature When the temperature rises to 720°C, keep it warm for 20 minutes, and then remove the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 7

1) Raw material preparation: take pure magnesium ingot and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 0.01%; Sr: 0.5%; the balance is Mg;

2) Melting: Preheat pure magnesium and Mg-30Sr at 300°C for 30 minutes, then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ to obtain a magnesium melt After raising the temperature of the magnesium melt to 720°C and stabilizing it, add the preheated magnesium-strontium master alloy into the completely melted magnesium melt and stir it for 5 minutes. When the temperature rises to 720°C, keep it warm for 20 minutes. , get rid of the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 8

1) Raw material preparation: use pure magnesium ingot and Mg-30Sr as raw materials, and weigh the following components by weight percentage: Mn: 0.01%; Sr: 1.0%; the balance is Mg;

2) Melting: Preheat pure magnesium and Mg-30Sr at 300°C for 30 minutes, then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ to obtain a magnesium melt After raising the temperature of the magnesium melt to 720°C and stabilizing it, add the preheated magnesium-strontium master alloy into the completely melted magnesium melt and stir it for 5 minutes. When the temperature rises to 720°C, keep it warm for 20 minutes. , get rid of the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

Example 9

1) Raw material preparation: take pure magnesium ingot and Mg-30Sr as raw materials, and weigh the following ingredients by weight percentage: Mn: 0.01%; Sr: 1.5%; the balance is Mg;

2) Melting: Preheat pure magnesium and Mg-30Sr at 300°C for 30 minutes, then completely melt the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ to obtain a magnesium melt After raising the temperature of the magnesium melt to 720°C and stabilizing it, add the preheated magnesium-strontium master alloy into the completely melted magnesium melt and stir it for 5 minutes. When the temperature rises to 720°C, keep it warm for 20 minutes. , get rid of the scum on the surface to obtain a pure magnesium alloy melt;

3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling;

4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 310° C. for 2 hours, and then coat the surface of the magnesium alloy ingot with a magnesium alloy lubricant, The magnesium alloy ingot was hot-extruded at 300° C. using an extrusion die with an extrusion ratio of 25:1 and an extrusion speed of 0.91.2 m/min to obtain a magnesium alloy rod.

2. Performance verification

GB/T 228.1:2010 standard was used to design tensile specimens, and the tensile rate was 1.5 mm/s. The magnesium alloys prepared in Examples 1-9 were tested. The results are shown in Figures 1-2 and Table 1.

Table 1

Example mn Sr Mg Tensile strength (MPa) Yield strength (MPa) Elongation Example 1 2.0% 0.5% margin 316 300 17.38% Example 2 2.0% 1.0% margin 348 335 9.45% Example 3 2.0% 1.5% margin 350 339 8.91% Example 4 1.0% 0.5% margin 287 270 18.32% Example 5 1.0% 1.0% margin 297 283 15.7% Example 6 1.0% 1.5% margin 327 312 10.31% Example 7 0.01% 0.5% margin 255 228 19.69% Example 8 0.01% 1.0% margin 289 278 12.24% Example 9 0.01% 1.5% margin 308 270 12.62%

The results show that the tensile strength of the Mg-Al-Mn magnesium alloy material prepared by the present invention can reach 255 ~ 350MPa, and the yield strength can reach 228 ~ 339MPa. It can be seen that compared with similar products, the comprehensive mechanical properties of the magnesium alloy material of the present invention are better than those of similar products. There has been a big improvement. It is suitable for 3C product shells, load-bearing structures for leisure products, and aerospace parts, etc., and the material has good biocompatibility, adjustable degradation speed and mechanical properties, and can also be used as a medical material, with good industrialization prospects.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention. within the scope of protection.

Claims (4)

1. A high-strength wrought magnesium alloy, characterized in that it comprises the following components by mass percentage: Mn 0.01-3%, Sr 0.5-1.5%, and the balance is magnesium and unavoidable impurities. 2. The high-strength wrought magnesium alloy according to claim 1, characterized in that it comprises the following components in mass percentage: Mn 1.0-2.0%, Sr 1.0-1.5%, and the balance is magnesium and unavoidable impurities. 3. A method for preparing a high-strength wrought magnesium alloy, comprising the following steps: 1) Raw material preparation: use pure magnesium ingots, magnesium-strontium master alloys, and magnesium-manganese master alloys as raw materials, and perform mechanical grinding according to the composition of the high-strength wrought magnesium alloy described in any one of claims 1-2. Calculate ingredients; 2) Smelting: Preheat pure magnesium, magnesium-strontium master alloy and magnesium-manganese master alloy at 300°C for 30 minutes, then place the pure magnesium ingot at 720~740°C under the protection of a mixed gas of SF ₆ and CO ₂ to make it Completely melt to obtain a magnesium melt. After the temperature of the magnesium melt is raised to 720°C and stabilized, the preheated magnesium-manganese master alloy and magnesium-strontium master alloy are added to the completely melted magnesium melt, and fully stirred for 3~ 6min, when the temperature rises to 700~740℃, keep warm for 10~20min, then remove the scum on the surface to obtain a pure magnesium alloy melt; 3) Casting: pour the magnesium alloy melt obtained in step 2) into a mold preheated to 320°C, and obtain a magnesium alloy ingot after cooling; 4) Extrusion processing: remove the oxide skin on the surface of the magnesium alloy ingot obtained in step 3), and then preheat it at 200~350°C for 1.5~3.0h, and then coat the surface of the magnesium alloy ingot with Magnesium alloy lubricant, using an extrusion die to hot-extrude the magnesium alloy ingot at 250-400°C to obtain a magnesium alloy rod; the extrusion ratio in the hot-extrusion is 10:1-80:1, The extrusion speed is 0.5~3 m/min. 4. The method for preparing a high-strength deformed magnesium alloy according to claim 3, wherein the extrusion ratio in the hot extrusion is 15:1 to 30:1, and the extrusion speed is 0.5 to 1.5 m/min.