Nanotitanium reinforced magnesium-based alloy and its preparation method and mechanical device

Abstract

The application relates to the alloy preparation technical field, and discloses a nano-titanium reinforced magnesium-based alloy, a preparation method thereof and mechanical equipment. The disclosed preparation method of the nano-titanium reinforced magnesium-based alloy comprises the following steps: uniformly dispersing nano-titanium particles in paraffin to obtain a paraffin preform; heat-treating the paraffin preform to remove part of the paraffin to obtain a dewaxing preform; the mass ratio of the nano-titanium particles to the paraffin in the dewaxing preform is 1:0.3-0.8; adding the dewaxing preform into a semi-solid magnesium alloy melt to uniformly stir and mix, so that the paraffin attached to the surface of the nano-titanium particles completely escapes from the melt to obtain a mixed melt; pouring casting after the temperature of the mixed melt is increased by 50-80 DEG C to obtain the nano-titanium reinforced magnesium-based alloy. The disclosed nano-titanium reinforced magnesium-based alloy is prepared by using the above preparation method. The disclosed mechanical equipment is prepared by using the above magnesium-based alloy. The preparation method provided by the application can uniformly disperse the nano-titanium in the magnesium-based alloy, and obtain a composite magnesium-based alloy material with good mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of alloy preparation technology, and more specifically, to nano-titanium reinforced magnesium-based alloys, their preparation methods, and mechanical equipment. Background Technology

[0002] To improve the mechanical properties of magnesium-based alloys, nano-titanium particles can be added. However, due to the large specific surface area and high surface activity of nano-titanium particles, and the influence of van der Waals forces and electrostatic forces, they easily agglomerate into molten magnesium alloys when directly added. Furthermore, because the density of nano-titanium particles differs significantly from that of magnesium alloys, they also tend to settle after addition. Therefore, directly adding nano-titanium particles to molten magnesium alloys is unlikely to achieve a performance enhancement effect. Thus, achieving a strengthening effect by adding nano-titanium particles to magnesium alloys presents considerable challenges.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide nano-titanium reinforced magnesium-based alloys, their preparation methods, and mechanical equipment, aiming to improve at least one of the problems mentioned in the background art.

[0005] This invention is implemented as follows:

[0006] In a first aspect, the present invention provides a method for preparing a nano-titanium-reinforced magnesium-based alloy, comprising:

[0007] Pre-waxing: The paraffin pre-wax containing uniformly dispersed nano-titanium particles is heat-treated under a first protective atmosphere until some of the paraffin is removed to obtain a dewaxed pre-wax; the mass ratio of nano-titanium particles to paraffin in the paraffin pre-wax is 1:1 to 2; the mass ratio of nano-titanium particles to paraffin in the dewaxed pre-wax is 1:0.3 to 0.8.

[0008] Alloy mixing: Under a second protective atmosphere, the dewaxed preform is added to the semi-solid magnesium alloy melt and stirred until it is uniformly mixed, so that the paraffin attached to the surface of the nano-titanium particles completely escapes from the melt to obtain a mixed melt.

[0009] Casting: After raising the temperature of the mixed melt by 50-80℃, the nano-titanium-reinforced magnesium-based alloy is obtained by casting.

[0010] In an optional implementation, the process further includes the following steps prior to the preform dewaxing step:

[0011] Under an inert gas protective atmosphere, nano-titanium particles and paraffin wax are mixed evenly at 100-120°C in a mass ratio of 1:1 to 2 to obtain a preform.

[0012] Optionally, the inert gas is argon;

[0013] Optionally, the mixing is performed at a rotating speed of 35-45 rpm for 1.5-2.5 hours.

[0014] In an optional embodiment, the mixing is performed under the condition of ultrasonic treatment, the frequency of the ultrasonic wave is 10-30 KHz, and the power is 200-400 W.

[0015] In an optional embodiment, the particle size of the nano-titanium particles in the paraffin preform is 1-600 nm, and preferably 50-200 nm.

[0016] In an optional embodiment, the heat treatment is performed by placing the paraffin preform in a 380-420 ℃ environment for 28-32 min, and then heating to 530-570 ℃ for 55-65 min.

[0017] In an optional embodiment, the dewaxing preform added to the semi-solid magnesium alloy melt is a granular material.

[0018] During the process of adding the dewaxing preform to the semi-solid magnesium alloy melt, the stirring speed is 300-500 r / min, and the stirring mode is unidirectional stirring.

[0019] After the dewaxing preform is added to the semi-solid magnesium alloy melt, forward and reverse stirring or variable speed stirring is adopted, the stirring speed is 300-1200 r / min, and the stirring time is 10-60 min to obtain a mixed melt.

[0020] Optionally, the alloy mixing step is performed in a melting device, and the melting device is maintained in a micro-positive pressure state of ≤0.03 MPa during the alloy mixing step.

[0021] In an optional embodiment, during the casting step, the process of increasing the temperature of the mixed melt to 600-720 ℃ is performed under the condition of stirring at a rotating speed of 400-1000 r / min.

[0022] Optionally, the temperature increasing rate during the temperature increasing process is 10-30 ℃.

[0023] Optionally, during the alloy mixing step, the semi-solid magnesium alloy melt is obtained by heating a magnesium alloy to complete melting and then reducing the temperature to 550-650 ℃.

[0024] In an optional embodiment, the first protective atmosphere is an argon atmosphere.

[0025] Optionally, the second protective atmosphere is an argon atmosphere, or a mixed atmosphere of carbon dioxide and sulfur hexafluoride.

[0026] In a second aspect, the present application provides a nano-titanium reinforced magnesium-based alloy prepared by the method according to any one of the preceding embodiments.

[0027] In a third aspect, the present application provides a mechanical device made of the nano-titanium reinforced magnesium-based alloy as described in the foregoing embodiments.

[0028] The present application has the following beneficial effects:

[0029] The preparation method of the nano-titanium reinforced magnesium-based alloy obtained by the above design can effectively avoid the problem of agglomeration of nano-titanium particles which is not easy to disperse uniformly when nano-titanium is directly added to the magnesium alloy melt, and the nano-titanium particles are added together with the paraffin wax. The paraffin wax can completely escape from the melt at high temperature and will not introduce impurities into the magnesium alloy. Therefore, the preparation method provided in the present application can prepare a reinforced magnesium-based alloy with uniformly dispersed nano-titanium. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained from these drawings without creative labor.

[0031] Figure 1 SEM image of the composite material prepared for Example 1;

[0032] Figure 2 SEM image of the composite material prepared for Example 2;

[0033] Figure 3 SEM image of the composite material prepared for Example 3;

[0034] Figure 4 SEM image of the composite material prepared for Example 4;

[0035] Figure 5 SEM image of the composite material prepared for Comparative Example 1;

[0036] Figure 6 SEM image of the composite material prepared for Comparative Example 2;

[0037] Figure 7 SEM image of the composite material prepared for Comparative Example 3. DETAILED DESCRIPTION

[0038] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not specified, the conventional products that can be purchased in the market are adopted.

[0039] The nano-titanium reinforced magnesium-based alloy and the preparation method and the mechanical equipment thereof provided by the embodiments of the present application are described in detail below.

[0040] The preparation method of the nano-titanium reinforced magnesium-based alloy provided by the embodiments of the present application comprises:

[0041] Pre-preform dewaxing: the paraffin preform uniformly dispersed with nano-titanium particles is heat treated under the first protective atmosphere until part of the paraffin is removed to obtain a dewaxed preform; the mass ratio of the nano-titanium particles to the paraffin in the paraffin preform is 1:1-2; the mass ratio of the nano-titanium particles to the paraffin in the dewaxed preform is 1:0.3-0.8;

[0042] Alloy mixing: the dewaxed preform is added into the semi-solid magnesium alloy melt under the second protective atmosphere and is stirred and mixed uniformly to make the paraffin attached to the surface of the nano-titanium particles completely escape from the melt to obtain a mixed melt;

[0043] Casting: the temperature of the mixed melt is increased by 50-80 DEG C and then the nano-titanium reinforced magnesium-based alloy is obtained by casting.

[0044] Since it is necessary to ensure that the nano-titanium particles are uniformly dispersed in the paraffin, the paraffin in the paraffin preform is generally slightly higher; under the preform dewaxing conditions defined in the present application, the part of the paraffin in the paraffin preform that is slightly more can be removed, and after part of the paraffin is removed, the combination of the paraffin and the nano-titanium particles can be more uniform, thereby ensuring that the dewaxed preform can be fully and uniformly dispersed in the magnesium alloy melt after being added into the magnesium alloy melt; mixing the dewaxed preform into the semi-solid magnesium alloy melt with appropriate viscosity can effectively avoid the nano-titanium from settling at the bottom of the magnesium alloy melt during the mixing process, and can ensure that the nano-titanium particles are uniformly dispersed in the magnesium alloy melt.

[0045] Therefore, the preparation method of the nano-titanium reinforced magnesium-based alloy provided by the embodiments of the present application can effectively avoid the problem of agglomeration of the nano-titanium particles that occurs when the nano-titanium is directly added into the magnesium alloy melt and is not easy to be dispersed uniformly, by removing the excess paraffin from the paraffin preform to obtain a dewaxed preform and mixing the paraffin preform into the semi-solid magnesium alloy melt uniformly. The nano-titanium particles are added together with the paraffin, and the paraffin can completely escape from the melt at high temperature and will not introduce impurities into the magnesium alloy. Therefore, the preparation method provided by the embodiments of the present application can prepare the nano-titanium reinforced magnesium-based alloy with uniformly dispersed nano-titanium particles.

[0046] Specifically, the preparation method comprises:

[0047] S1, preparing paraffin preform

[0048] The internal mixer is heated to 100-120°C under an inert gas protective atmosphere, paraffin chips are added, and after the paraffin is completely melted, nano-titanium particles are added, with a mass ratio of nano-titanium particles to paraffin of 1:1-2. Stirring is carried out at 100-120°C, with a rotation speed of 35-45 rpm, for 1.5-2.5 h, and after the paraffin is completely cooled, it is removed.

[0049] If the nano-titanium particles added are less, the strengthening effect on the magnesium-based alloy is weaker; if the nano-titanium particles added are more, it is not conducive to uniform dispersion in the paraffin. Therefore, if sufficient nano-titanium particles are needed to strengthen the magnesium-based alloy, and uniform dispersion of the nano-titanium particles in the paraffin is ensured, the ratio of the two should be 1:1-2; however, the ratio of paraffin is actually more, so a subsequent dewaxing step is needed.

[0050] Optionally, the paraffin is polyethylene wax (ACPE).

[0051] Optionally, the inert gas is argon;

[0052] Optionally, to better strengthen the magnesium-based alloy, the particle size of the nano-titanium particles is 1-600 nm; preferably 50-200 nm.

[0053] Preferably, the mixing process is carried out under ultrasonic treatment, with a frequency of 10-30 kHz and a power of 200-400 W.

[0054] Ultrasonic stirring is used, and the cavitation effect of ultrasonic waves is used to induce rapid formation and collapse of air bubbles in the liquid, producing a short-term high-energy microenvironment, which further disperses the agglomerated nanoparticles. The best results are obtained under the above ultrasonic conditions; if the frequency is too low, the dispersion effect is not obvious, and if the frequency is too high, the probability of particle collision increases, which may lead to further agglomeration.

[0055] S2, dewaxing the preform

[0056] The paraffin preform is placed in a tube furnace for dewaxing treatment, and under a first protective atmosphere, it is heated to 380-420°C for 120-180 min, held for 28-32 min, then heated to 530-570°C for 60-90 min, held for 55-65 min, and then naturally cooled to obtain a dewaxed preform.

[0057] After dewaxing treatment, the mass ratio of the nano-titanium particles to the paraffin in the dewaxed preform is 1:0.3-0.8, for example 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, or 1:0.8.

[0058] Optionally, the first protective atmosphere is an argon atmosphere.

[0059] The proper gradient temperature dewaxing can ensure sufficient and uniform removal of excess paraffin wax; if the dewaxing temperature is too low or the dewaxing time is too short, the excess paraffin wax cannot be effectively removed, resulting in defects such as pores and inclusions in the ingot; if the dewaxing temperature is too high or the dewaxing time is too long, too much paraffin wax is removed, which cannot provide good dispersion effect.

[0060] S3, crushing the dewaxed preform

[0061] The prepared dewaxed preform is crushed into granules with a particle size of 1-5 mm, and the dewaxed preform added into the magnesium alloy melt in the subsequent step is also granules with a particle size of 1-5 mm, which facilitates uniform dispersion of the nano titanium into the melt.

[0062] S4, alloy mixing

[0063] The vacuum stirring furnace is evacuated, argon is introduced when the vacuum degree in the furnace is lower than 100 Pa, the pressure relief valve of the vacuum stirring furnace is opened when the pressure reaches atmospheric pressure, argon is introduced while the exhaust is carried out, and the micro-positive pressure state of ≤0.03 MPa is maintained in the furnace at all times; optionally, the second protective atmosphere is an argon atmosphere, or a mixed atmosphere of titanium dioxide and sulfur hexafluoride with reducing properties.

[0064] The resistance furnace is heated to 750℃, and the magnesium alloy is completely melted into a liquid state;

[0065] The temperature of the liquid magnesium alloy is reduced to the semi-solid temperature range of 550-650℃ (for magnesium alloys with different compositions, the corresponding temperature range is slightly different within the above range; for example, for AZ91 magnesium alloy, the semi-solid temperature is generally around 580℃); under the condition of unidirectional stirring, the dewaxed preform is added to the semi-solid magnesium alloy, the stirring speed is 300-500 r / min (for example, 300 r / min, 400 r / min or 500 r / min), and the addition method is slow addition, and the complete addition time is controlled within 10 min.

[0066] After the granular preform is completely added, forward and reverse stirring or variable speed stirring is adopted, the stirring time is 10-60 min (for example, 10 min, 20 min, 30 min, 40 min or 60 min), the stirring speed is 300-1200 r / min (for example, 300 r / min, 500 r / min, 800 r / min, 1000 r / min or 1200 r / min), and the paraffin wax attached to the surface of the Ti particles volatilizes into gas and escapes from the melt.

[0067] S5, casting

[0068] The semi-solid mixed melt after stirring is heated to 50-80℃ (for example, 50℃, 60℃, 70℃ or 80℃), the heating rate is controlled to be 10-30℃ / min (for example, 10℃ / min, 20℃ / min or 30℃ / min), and the stirring speed is controlled to be 400-1000r / min (for example, 400r / min, 600r / min, 800r / min or 1000r / min) during the heating process. After heating, the nano-titanium reinforced magnesium-based alloy is poured into a mold and cooled to obtain the nano-titanium reinforced magnesium-based alloy.

[0069] The nano-titanium reinforced magnesium-based alloy prepared by the preparation method provided in the embodiments of the present application has uniform dispersion of nano-titanium in the magnesium-based alloy, and has beneficial mechanical properties.

[0070] The mechanical equipment provided in the embodiments of the present application is prepared by using the nano-titanium reinforced magnesium-based alloy provided in the embodiments of the present application, and the nano-titanium reinforced magnesium-based alloy has good mechanical properties, so that the mechanical equipment has good performance.

[0071] The features and properties of the present application are further described in detail below in combination with embodiments.

[0072] Embodiment 1

[0073] The preparation method of the nano-titanium reinforced magnesium-based alloy provided in the present embodiment is as follows:

[0074] The internal mixer is heated to 110℃ under an argon atmosphere, polyethylene wax chips are added, and after the polyethylene wax is completely melted, nano-titanium particles are added, the mass ratio of the nano-titanium particles to the paraffin is 1:1, and the particle size of the nano-titanium particles is 50-200nm. Stirring is carried out at 110℃, the stirring speed is 40rpm, and the stirring time is 2h. The stirring process is carried out under ultrasonic treatment conditions, the frequency of the ultrasonic wave is 20KHz, and the power is 300W. After the paraffin is completely cooled, the paraffin preform is obtained.

[0075] The paraffin preform is placed in a tube furnace for dewaxing treatment, heated to 400℃ under an argon atmosphere for 150min and kept for 30min, and then heated to 550℃ for 75min and kept for 60min, and then naturally cooled to obtain a dewaxed preform. After dewaxing, the dewaxed preform is obtained, and the ratio of the nano-titanium particles to the paraffin in the dewaxed preform is 1:0.6.

[0076] The prepared dewaxed preform is crushed into a particle size of 1-5mm.

[0077] The vacuum stirring furnace is vacuumized, when the vacuum degree in the furnace is lower than 100 Pa, argon is introduced, when the pressure reaches the atmospheric pressure, the pressure reducing valve of the vacuum stirring furnace is opened, the second protective atmosphere is introduced and the exhaust is carried out, the micro-positive pressure state of ≤0.03 MPa is kept in the furnace. The resistance furnace is heated to 750 ℃, the magnesium alloy (AZ91) is completely melted into liquid state; the temperature of the liquid magnesium alloy is reduced to semi-solid temperature (580 ℃); the dewaxed preform is slowly added into the semi-solid magnesium alloy under the condition of unidirectional stirring, the stirring speed is 400 r / min. After the granular preform is completely added, the forward and reverse stirring is adopted, the stirring time is 30 min, the stirring speed is 500 r / min, the paraffin attached to the surface of the Ti particle is volatilized into gas and escapes from the melt.

[0078] The semi-solid mixed melt after stirring is heated to 650 ℃ with the temperature increasing by 70 ℃, the heating rate is 20 ℃ / min, the stirring speed is 800 r / min during the heating process. After heating, it is poured into a mold, and a nano titanium reinforced magnesium-based alloy is obtained after cooling.

[0079] Example 2

[0080] The preparation method of the nano titanium reinforced magnesium-based alloy provided in the embodiment is as follows:

[0081] The internal mixer is heated to 100 ℃ under the argon atmosphere, the polyethylene wax chip is added, after the polyethylene wax is completely melted, the nano titanium particles are added, the mass ratio of the nano titanium particles to the paraffin is 1:2, the particle size of the nano titanium particles is 50-200 nm. Stirring is carried out at 110 ℃, the speed is 35 rpm, the stirring time is 1.5 h, the stirring process is carried out under the ultrasonic treatment condition, the frequency of the ultrasonic wave is 10 KHz, the power is 400 W, after the paraffin is completely cooled, the paraffin preform is taken out.

[0082] The paraffin preform is placed in a tube furnace for dewaxing treatment, heated to 380 ℃ under the argon atmosphere for 180 min and kept for 32 min; continuously heated to 570 ℃ for 60 min and kept for 55 min, and then naturally cooled to obtain the dewaxed preform. The dewaxed preform is obtained after dewaxing, the mass ratio of the nano titanium particles to the paraffin in the dewaxed preform is 1:0.6.

[0083] The prepared dewaxed preform is crushed into a particle size of 1-5 mm.

[0084] The vacuum stirring furnace is vacuumized, when the vacuum degree in the furnace is lower than 100 Pa, argon is introduced, when the pressure reaches the atmospheric pressure, the pressure reducing valve of the vacuum stirring furnace is opened, the second protective atmosphere is introduced and the exhaust is carried out, the micro-positive pressure state of ≤0.03 MPa is kept in the furnace. The resistance furnace is heated to 750 ℃, the magnesium alloy (AZ91) is completely melted into liquid state; the temperature of the liquid magnesium alloy is reduced to semi-solid temperature (580 ℃); the dewaxed preform is slowly added into the semi-solid magnesium alloy under the condition of unidirectional stirring, the stirring speed is 300 r / min. After the granular preform is completely added, the forward and reverse stirring is adopted, the stirring time is 10 min, the stirring speed is 1200 r / min, the paraffin attached to the surface of the Ti particle is volatilized into gas and escapes from the melt.

[0085] The semi-solid mixed melt after stirring is heated to 660 ℃ with the temperature increase of 80 ℃, the heating rate is 10 ℃ / min, the stirring speed is 400 r / min during the heating process. After heating, it is poured into a mold, and a nano titanium reinforced magnesium-based alloy is obtained after cooling.

[0086] Example 3

[0087] The preparation method of the nano titanium reinforced magnesium-based alloy provided in the embodiment is specifically as follows:

[0088] The internal mixer is heated to 120 ℃ under the argon atmosphere, the polyethylene wax chip is added, after the polyethylene wax is completely melted, the nano titanium particle is added, the mass ratio of the nano titanium particle to the paraffin is 1:1.5, the particle size of the nano titanium particle is 50-200 nm. The stirring is carried out at 120 ℃, the speed is 35 rpm, the stirring time is 2.5 h, the stirring process is carried out under the ultrasonic treatment condition, the frequency of the ultrasonic wave is 30 KHz, the power is 200 W, after the paraffin is completely cooled, the paraffin preform is taken out.

[0089] The paraffin preform is placed in a tube furnace for dewaxing treatment, under the argon atmosphere, the temperature is increased to 420 ℃ for 120 min, the temperature is kept for 28 min, the temperature is continuously increased to 530 ℃ for 90 min, the temperature is kept for 60 min, and then the natural cooling is carried out to obtain the dewaxed preform. After dewaxing, the dewaxed preform is obtained, the mass ratio of the nano titanium particle to the paraffin in the dewaxed preform is 1:0.6.

[0090] The prepared dewaxed preform is crushed into a particle size of 1-5 mm.

[0091] The vacuum stirring furnace was evacuated, when the vacuum degree in the furnace was lower than 100 Pa, argon was introduced, when the pressure reached the atmospheric pressure, the pressure reducing valve of the vacuum stirring furnace was opened, the second protective atmosphere was introduced and the exhaust was carried out, the micro-positive pressure state of ≤0.03 MPa was maintained in the furnace. The resistance furnace was heated to 750 ℃, the magnesium alloy (AZ91) was completely melted into liquid state; the temperature of the liquid magnesium alloy was reduced to semi-solid temperature (580 ℃); the dewaxing preform was slowly added to the semi-solid magnesium alloy under the condition of unidirectional stirring, the stirring speed was 500 r / min. After the granular preform was completely added, the forward and reverse stirring was adopted, the stirring time was 60 min, the stirring speed was 300 r / min, the paraffin attached to the surface of the Ti particles volatilized into gas and escaped from the melt.

[0092] The semi-solid mixed melt after stirring was increased by 50 ℃ to reach 630 ℃, the temperature increasing rate was 30 ℃ / min, the stirring speed was 1000 r / min during the temperature increasing process. After the temperature increasing, the nano titanium reinforced magnesium-based alloy was obtained by pouring into a mold and cooling.

[0093] Example 4

[0094] The embodiment is basically the same as example 1, the difference is only that the ultrasonic treatment is not carried out.

[0095] Comparative Example 1

[0096] The comparative example is basically the same as example 1, the difference is only that during the alloy mixing process, after the magnesium alloy is completely melted, it is not cooled to semi-solid state, the dewaxing preform is directly added to the melted magnesium alloy melt, the feeding and stirring mode is the same as example 1, after the stirring is completed, it is not heated and directly casted.

[0097] Comparative Example 2

[0098] The comparative example is basically the same as example 1, the difference is only that the preform dewaxing step is not carried out; the paraffin preform is directly crushed into granules and then added to the magnesium alloy melt instead of the dewaxing preform.

[0099] Comparative Example 3

[0100] The comparative example is basically the same as example 1, the difference is only that the ratio of nano titanium particles to paraffin in the prepared paraffin preform is 5:3; the preform dewaxing step is not carried out; the paraffin preform is directly crushed into granules and then added to the magnesium alloy melt instead of the dewaxing preform.

[0101] Example 1

[0102] The microstructure photographs of the cross section of the cast ingot prepared in the example and the comparative example are shown in the following figures, Figures 1-4 The microstructure photographs of the cast ingot prepared in example 1-4 of the application are shown in the following figures, Figures 1-3The microstructure of the ingot prepared in Comparative Examples 1-3. As can be seen from the figure, the nano-titanium particles in Example 1-3 are almost not aggregated in the ingot, and have good dispersibility; while the nano-titanium particles in each of the comparative examples are obviously aggregated, and have poor uniformity of dispersion; and the ingot prepared in Example 4 has holes due to not being subjected to ultrasonic dispersion.

[0103] Example 2

[0104] The mechanical properties of the nano-titanium reinforced magnesium-based alloy prepared in each of the examples and comparative examples were tested, the tensile samples were designed according to GB228-2010, and the tensile mechanical property test was performed by using a CMT-6305-300KN universal testing machine, and the test results were recorded in Table 1.

[0105] Table 1: Mechanical property test of each example and comparative example

[0106] Group Tensile strength Yield strength Elongation at break Example 1 193 147 12.6 Example 2 210 165 13.4 Example 3 190 157 12.0 Example 4 189 145 11.5 Comparative Example 1 163 129 7.2 Comparative Example 2 170 135 8.3 Comparative Example 3 187 133 9.6

[0107] As can be seen from the above table, the nano-titanium reinforced magnesium-based alloy prepared in each of the examples has better mechanical properties, and especially Examples 1-3 are the best. Comparing Example 1 with Example 4, the mechanical properties of Example 1 are better, which indicates that the proper ultrasonic treatment in the preparation process of the paraffin preform is beneficial to the more uniform dispersion of the nano-titanium particles, so that a magnesium-based alloy with better performance is prepared; comparing Example 1 with Comparative Example 1, the magnesium-based alloy prepared in Comparative Example 1 has significantly poorer performance, which indicates that when the dewaxed preform is added to the alloy, the semi-solid state of the alloy is beneficial to the uniform dispersion of the nano-titanium, so that a magnesium-based alloy with good performance is obtained; comparing Example 1 with Comparative Examples 2 and 3, the performance of Comparative Examples 2 and 3 is significantly poorer, which indicates that the paraffin preform is prepared by using slightly more paraffin in advance, and then part of the excess paraffin in the paraffin preform is removed, which can ensure that the nano-titanium is uniformly dispersed in the magnesium alloy melt, so that a nano-titanium reinforced magnesium-based alloy with excellent mechanical properties is obtained.

[0108] In summary, the preparation method of the nano-titanium reinforced magnesium-based alloy provided by the present application can effectively avoid the problem of aggregation of nano-titanium particles which is not easy to disperse uniformly when the nano-titanium is directly added to the magnesium alloy melt, by removing the excess paraffin from the paraffin preform, and then adding the paraffin preform to the semi-solid magnesium alloy melt and mixing uniformly. The nano-titanium particles are added together with the paraffin, and the paraffin can completely escape from the melt at high temperature, and will not introduce impurities into the magnesium alloy, so that the preparation method provided by the examples of the present application can prepare a reinforced magnesium-based alloy with uniformly dispersed nano-titanium.

[0109] The above merely describes the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of producing a nano-titanium reinforced magnesium-based alloy, characterized by, Comprising: Dewaxing of the preform: heat treating the paraffin wax preform uniformly dispersed with nano-titanium particles under a first protective atmosphere to remove part of the paraffin wax to obtain a dewaxed preform; the mass ratio of the nano-titanium particles to the paraffin wax in the paraffin wax preform is 1:1-2; the mass ratio of the nano-titanium particles to the paraffin wax in the dewaxed preform is 1:0.3-0.8; Alloy mixing: adding the dewaxed preform into a semi-solid magnesium alloy melt under a second protective atmosphere to mix uniformly to make the paraffin wax attached to the surface of the nano-titanium particles completely escape from the melt to obtain a mixed melt; Casting: casting after increasing the temperature of the mixed melt by 50-80℃ to obtain a nano-titanium reinforced magnesium-based alloy.

2. The production method according to claim 1, characterized by, Before the preform dewaxing step, further comprising: Mixing nano-titanium particles and paraffin wax under an inert gas protective atmosphere to obtain a paraffin wax preform, the mass ratio of the nano-titanium particles to the paraffin wax is 1:1-2, and the mixing is uniform at 100-120℃.

3. The production method according to claim 2, characterized by, The inert gas is argon.

4. The preparation method according to claim 2, characterized in that, The mixing mode of the nano-titanium particles and the paraffin wax is stirring at a speed of 35-45 rpm for 1.5-2.5 hours.

5. The preparation method according to claim 2, characterized in that, The mixing process of the nano-titanium particles and the paraffin wax is carried out under ultrasonic treatment, the frequency of the ultrasonic wave is 10-30 KHz, and the power is 200-400 W.

6. The method of claim 1, wherein, The particle size of the nano-titanium particles in the paraffin wax preform is 1-600 nm.

7. The production method according to claim 6, wherein The particle size of the nano-titanium particles in the paraffin wax preform is 50-200 nm.

8. The method of claim 1, wherein, The heat treatment mode is: placing the paraffin wax preform in a 380-420℃ oven for 28-32 min, increasing the temperature to 530-570℃ for 55-65 min.

9. The method of claim 1, wherein, The dewaxed preform added to the semi-solid magnesium alloy melt is a granular material. During the process of adding the dewaxed preform to the semi-solid magnesium alloy melt, the stirring speed is 300-500 r / min, and the stirring mode is unidirectional stirring. After adding the dewaxed preform to the semi-solid magnesium alloy melt, forward and reverse stirring or variable speed stirring is adopted, the stirring speed is 300-1200 r / min, and the stirring time is 10-60 min to obtain the mixed melt.

10. The method of claim 9, wherein, The alloy mixing step is carried out in a melting device, and during the alloy mixing step, the melting device always maintains a micro-positive pressure state of ≤0.03 MPa.

11. The method of claim 1, wherein, In the casting step, the process of increasing the temperature of the mixed melt to 600-720℃ is carried out under stirring at a speed of 400-1000 r / min.

12. The method of claim 1, wherein, The temperature increasing rate of the process of increasing the temperature of the mixed melt is 10-30℃ / min.

13. The method of claim 1, wherein, In the alloy mixing step, the semi-solid magnesium alloy melt is obtained by heating a magnesium alloy to complete melting and then reducing the temperature to 550-650℃.

14. The method of claim 1, wherein, The first protective atmosphere is an argon atmosphere.

15. The method of claim 1, wherein, The second protective atmosphere is an argon atmosphere or a mixed atmosphere of carbon dioxide and sulfur hexafluoride.

16. A nano-titanium reinforced magnesium-based alloy, characterized in that, The nano-titanium reinforced magnesium-based alloy is prepared by the preparation method of any one of claims 1-15.

17. A mechanical device, characterized by The nano-titanium reinforced magnesium-based alloy is prepared by the preparation method of claim 16.

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