An Al 11 Method for producing La3 particle reinforced magnesium matrix composite

Abstract

The application discloses an Al 11 The preparation method of the La3 particle reinforced magnesium-based composite material is to mechanically mix the lanthanum oxide particles after vacuum heat treatment with magnesium-aluminum alloy particles, and then to obtain Al 11 La3 particle reinforced magnesium-based composite material. The method is simple, and in the semi-solid injection molding process, the lanthanum oxide particles and the magnesium-aluminum alloy particles are chemically reacted to obtain Al 11 La3 intermetallic compound particles, the particle size and the morphology of which are controllable, so that the Al 11 La3 intermetallic compound particles are tightly combined with the magnesium-aluminum alloy interface and uniformly distributed in the matrix, and the integrity of the composite material is good, and the composite material has good tensile mechanical properties and good fracture elongation.

Description

Technical Field

[0001] This invention relates to an Al 11 The preparation method of La3 particle-reinforced magnesium matrix composite material belongs to the field of new materials technology. Background Technology

[0002] Magnesium-aluminum alloys are representative lightweight metallic materials with broad application prospects in the fields of digital 3C and new energy vehicles. As an alloy material successfully used on a large scale commercially, magnesium-aluminum alloys possess excellent comprehensive properties, but their inferior absolute mechanical properties limit further applications. Researchers have improved the strength of magnesium-aluminum alloy composites by adding hard particles, including hard ceramic particles such as SiC and Al2O3. However, the interfacial bonding between reinforcing particles such as SiC and Al2O3 and the alloy matrix is ​​usually poor. Under tensile loads, interfacial separation easily occurs between the reinforcing particles and the matrix, leading to composite fracture. Although adding hard particles can improve the strength of composites, it often leads to a significant decrease in elongation, thus limiting further improvement in composite strength. Furthermore, using intermetallic compounds to reinforce magnesium-aluminum alloys is also an option, but as precipitated phases, their morphology and size are difficult to control, resulting in unsatisfactory interfacial bonding.

[0003] In view of the above situation, the present invention proposes an Al 11 The preparation method of La3 particle-reinforced magnesium matrix composites involves vacuum heat treatment, mechanical mixing, and semi-solid injection molding. During the molding process, an in-situ reaction occurs to obtain Al... 11 The particle size and morphology of La3 intermetallic compound particles are controllable, and they are uniformly distributed in the matrix with tight interfacial bonding. While providing strength to magnesium-based composite materials, they also have good elongation at break. Summary of the Invention

[0004] The purpose of this invention is to provide an Al 11 A method for preparing La3 particle-reinforced magnesium matrix composites is proposed to improve the strength of the composites while simultaneously increasing the elongation at break.

[0005] This invention provides an Al 11 The preparation method of La3 particle-reinforced magnesium matrix composites involves mechanically mixing lanthanum oxide particles that have undergone vacuum heat treatment with magnesium-aluminum alloy particles, followed by semi-solid injection molding and in-situ reaction to obtain Al. 11 La3 particle-reinforced magnesium matrix composites; The specific process is as follows: Step 1: Vacuum heat treatment Lanthanum oxide particles were placed in a vacuum tube furnace and heated and held in a vacuum atmosphere, and then cooled to room temperature. Step 2: Mechanical mixing Argon was used as a protective gas, and a three-dimensional mixer was used to mechanically mix lanthanum oxide particles that had been vacuum heat-treated with magnesium-aluminum alloy particles to obtain mixed particles. Step 3: Semi-solid injection molding The mixed particles were subjected to semi-solid injection molding, followed by in-situ reaction to obtain Al. 11 La3 particle-reinforced magnesium matrix composites.

[0006] The lanthanum oxide particles have a particle size of 1-5 μm and are added at a rate of 0.5 wt%-3.0 wt% of the mass of the magnesium-aluminum alloy particles.

[0007] The mechanical mixing time is 10-30 min.

[0008] The vacuum heat treatment temperature is greater than 600 ℃, and the holding time is greater than 10 min.

[0009] The semi-solid injection molding temperature is 590-630 ℃, the injection speed is 2-4 m / s, and the mold temperature is 220 ℃.

[0010] Beneficial effects of this invention: The method of this invention is simple. In the semi-solid injection molding process, lanthanum oxide particles and magnesium-aluminum alloy particles undergo a chemical reaction to obtain Al. 11 La3 intermetallic compound particles, making Al 11 The La3 intermetallic compound particles are tightly bonded to the magnesium-aluminum alloy interface, resulting in good overall integrity of the composite material. It achieves excellent tensile mechanical properties as well as good elongation at break. Attached Figure Description

[0011] Figure 1 SEM image of lanthanum oxide particles used in Example 1 of this invention; Among them: the SEM image magnification is 8000 times; Figure 2 : A physical image of the AZ91 magnesium alloy particles used in Embodiment 1 of this invention; Figure 3 Al prepared in Example 1 of this invention 11 SEM image of La3 particle-reinforced AZ91 magnesium matrix composite; Among them: the magnification of the SEM image is 3000 times; Figure 4 Al prepared in Example 1 of this invention 11 TEM image of La3 particle-reinforced AZ91 magnesium matrix composite; Figure 5 Al prepared in Example 1 of this invention 11Selected area electron diffraction pattern of the reinforcing phase in La3 particle-reinforced AZ91 magnesium matrix composite; Figure 6 Al prepared in Example 2 of this invention 11 SEM image of La3 particle-reinforced AZ91 magnesium matrix composite; Among them: the SEM image is magnified by 500 times; Figure 7 Al prepared in Example 1 of this invention 11 Stress-strain curve of La3 particle-reinforced AZ91 magnesium matrix composite; Figure 8 Al prepared in Comparative Example 1 of this invention 11 Stress-strain curve of La3 particle-reinforced AZ91 magnesium matrix composite. Detailed Implementation

[0012] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0013] Example 1 Al 11 Preparation method of La3 particle-reinforced AZ91 magnesium-based composite material: Lanthanum oxide particles with a diameter of 2±1 μm were heated and held at a vacuum temperature in a vacuum tube furnace under a vacuum atmosphere. The heating temperature was 600℃ and the holding time was 10 min.

[0014] Its SEM images are as follows Figure 1 As shown.

[0015] The cooled lanthanum oxide particles were mixed evenly with AZ91 magnesium alloy particles using a three-dimensional mixer to obtain mixed particles. The amount of lanthanum oxide particles added was 1.5 wt% of the mass of AZ91 magnesium alloy particles. Excess argon gas was introduced into the mixing chamber of the three-dimensional mixer as a protective gas, and the mixing time was 15 min.

[0016] The above-mentioned AZ91 magnesium alloy particles, such as Figure 2 As shown.

[0017] The above-mentioned mixed particles were subjected to semi-solid injection molding to obtain Al. 11 La3 intermetallic compound particle-reinforced AZ91 magnesium matrix composite.

[0018] The injection molding temperature is 630℃, the injection speed is 2.5 m / s, and the mold temperature is 220℃.

[0019] The Al 11 SEM images and energy dispersive spectroscopy analysis of La3 intermetallic compound particle-reinforced AZ91 magnesium matrix composites are as follows: Figure 3As shown, it can be seen that Al is present 11 La3 intermetallic compound particles are uniformly distributed within the AZ91 magnesium-based composite matrix. TEM images are shown below. Figure 4 As shown, the white particles are Al. 11 La3 intermetallic compound particles, with the darker color representing the AZ91 magnesium-based composite matrix. It can be seen that Al... 11 La3 intermetallic compound particles are generated through a reaction, and their size and morphology are the same as those of the added lanthanum oxide particles. 11 Selected area electron diffraction pattern of La3 intermetallic compound particles (selected area electron diffraction pattern) is as follows: Figure 5 As shown, this Al can be used 11 Phase identification of La3 intermetallic compound particles confirmed that they were Al3234 ... 11 La3.

[0020] Example 2 This Example 2 is basically the same as Example 1, except that the added lanthanum oxide particles were not subjected to heat treatment.

[0021] Lanthanum oxide particles with a particle size of 2±1 μm were mixed with AZ91 magnesium alloy particles using a three-dimensional mixer to obtain mixed particles. The amount of lanthanum oxide particles added was 1.5 wt% of the mass of AZ91 magnesium alloy particles. Excess argon gas was introduced into the mixing chamber of the three-dimensional mixer as a protective gas, and the mixing time was 15 min.

[0022] The above-mentioned mixed particles were subjected to semi-solid injection molding to obtain AZ91 magnesium-based composite material.

[0023] The injection molding temperature is 630℃, the injection speed is 2.5 m / s, and the mold temperature is 220℃.

[0024] Its SEM images are as follows Figure 6 As shown, obvious defects such as pores are present in the AZ91 magnesium-based composite material.

[0025] In summary, Example 1, by heating and holding the lanthanum oxide particles, allows them to chemically react with AZ91 magnesium alloy particles during the casting process, generating stable Al. 11 La3 intermetallic compounds, as effective particulate reinforcing phases, improve the mechanical properties of AZ91 magnesium-based composites.

[0026] Comparative Example 1

[0027] This comparative example is basically the same as Example 1, except that lanthanum oxide particles were not added.

[0028] AZ91 magnesium alloy particles are semi-solid injection molded to obtain AZ91 magnesium alloy material.

[0029] The injection molding temperature is 630℃, the injection speed is 2.5 m / s, and the mold temperature is 220℃.

[0030] The composite materials obtained in Comparative Example 1 and Example 1 were subjected to tensile tests according to national standards GB / T22315-2008 and GB / T 228.1-2010. The obtained stress-strain curves are shown below. Figure 7 As shown, the yield strength, ultimate tensile strength, and elongation at break of the composite material in Example 1 are significantly improved.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An Al 11 The method for preparing La3 particle-reinforced magnesium matrix composites is characterized by: The preparation method involves mechanically mixing lanthanum oxide particles that have undergone vacuum heat treatment with magnesium-aluminum alloy particles, followed by semi-solid injection molding and in-situ reaction to obtain Al. 11 La3 particle-reinforced magnesium matrix composites; The specific process is as follows: Step 1: Vacuum heat treatment Lanthanum oxide particles were placed in a vacuum tube furnace and heated and held in a vacuum atmosphere, and then cooled to room temperature. Step 2: Mechanical mixing Argon was used as a protective gas, and a three-dimensional mixer was used to mechanically mix lanthanum oxide particles that had been vacuum heat-treated with magnesium-aluminum alloy particles to obtain mixed particles. Step 3: Semi-solid injection molding The mixed particles were subjected to semi-solid injection molding, followed by in-situ reaction to obtain Al. 11 La3 particle-reinforced magnesium matrix composites.

2. An Al according to claim 1 11 The method for preparing La3 particle-reinforced magnesium matrix composites is characterized by: The lanthanum oxide particles have a particle size of 1-5 μm and are added at a rate of 0.5 wt%-3.0 wt% of the mass of the magnesium-aluminum alloy particles.

3. An Al according to claim 1 11 The method for preparing La3 particle-reinforced magnesium matrix composites is characterized by: The mechanical mixing time is 10-30 min.

4. An Al according to claim 1 11 The method for preparing La3 particle-reinforced magnesium matrix composites is characterized by: The vacuum heat treatment temperature is greater than 600 ℃, and the holding time is greater than 10 min.

5. An Al according to claim 1 11 The method for preparing La3 particle-reinforced magnesium matrix composites is characterized by: The semi-solid injection molding temperature is 590-630 ℃, the injection speed is 2-4 m / s, and the mold temperature is 220 ℃.

Images