Method for preparing in-situ particle reinforced magnesium base compound material

Technical Field

The invention relates to an in-situ particle-enhanced process for the preparation of magnesium-based composite material, especially a kind of using the ultrasonic chemical process for preparing in-situ particle-enhanced method of mg-based composite material.

Background Art

In recent years, because of the environment, energy and other concerns, magnesium-base composite material become hot spots in the field of material study. Mg-based composite material has the advantages of high specific strength, specific rigidity, good castability and dimensional stability, resistance to electromagnetic interference and shielding property, a good damping performance, vibration damping performance is good, small influence on the environment, pollution-free, its waste recycling utilization factor is as high as 85%, therefore in the aerospace, automotive, computer, network, communication is widely applicable to the fields of prospects. The present preparation of magnesium-base composite material is mainly applied to enhance additional particles or fibers. However, additional strengthening particles in preparation of the composite material of the large particle size of the reinforcing phase, particles of poor wettability with the substrate, are relatively poor mechanical property of composite material; fiber-reinforced composite material preparation process is complicated, the cost is high, in actual production is restricted in application. In-situ preparation of composite material is that, in recent years, development of the preparation method, the particle size of the fine, interface bonding is good, the characteristic of high performance material, in the preparation of aluminum-based composite material the more successful.

The document search of the prior art found, process for the preparation of magnesium-based composite material have been a number of literature reports, such as China Patent number: CN101148722, the name: "in-situ self-generation aluminum nitride and magnesium two silicon reinforced magnesium-base composite material and its preparation method". The technology of this Patent is characterized in that the the stirring casting method and in-situ reaction together, the preparation of lightweight, high-strength, high-elasticity modulus magnesium-based composite material. However, only by utilizing the method for stirring the melt cannot be specified enhancing phase, at the same time enhancement phase in the distribution of the substrate is not uniform, therefore, this kind of preparation method has certain limitations.

Content of the invention

The purpose of this invention is for the deficiency of the prior art, to provide an in-situ particle-enhanced process for the preparation of magnesium-based composite material. In the course of preparing the melt by using ultrasonic wave, caused by the acoustic cavitation and sonic flow the mechanical effect stirring, dispersing, degassing, impact damage, fatigue damage calorifics and overall heating effect, the local heating effect of the bowing, cast microstructure of the composite material, the mechanical performance of the composite material.

This invention is realized through the following technical scheme, the intermediate alloy Al-Si in magnesium alloy into molten, then utilize the high-energy ultrasound acting on the melt, the melt static after the final casting molding.

The invention relates to in-situ particle-enhanced process for the preparation of magnesium-based composite material, comprising the following steps:

(1) the SF₆ and CO₂ under the conditions of mixed gas protected, the magnesium-aluminum-alloy raw material is completely melted;

(2) then the magnesium-aluminum alloy is pressed in in the middle Al-Si in the melt, and thermal insulation, in order to guarantee the Si and the magnesium-aluminum alloy in the melt complete reaction mg, at the same time, the ultrasonic probe is inserted into the melt to be processed;

(3) after the completion of treatment, to remove the surface scum, and casting in a metal mold, to obtain in-situ mg₂ Si Authigenic particle-reinforced magnesium-base composite material.

Step (1) in, the melting, the temperature control in the 680-720 [...].

Step (1) in, the SF₆ and CO₂ mixed gas, wherein the SF₆ volume 1-3%, CO₂ for the rest.

Step (2) in, the heating, its temperature rises to the 700-740 [...].

Step (2) in, the thermal insulation, its time is 10-20 minutes.

Step (2) in, the ultrasonic processing, power control in the 0.4-2.0KW.

Step (2) in, the ultrasonic processing, its processing time is 5-15 minutes, processing mode is a continuous processing.

The beneficial effects of the invention are: the invention in order to AZ91 magnesium alloy and Al-Si alloy as the raw materials, using high energy ultrasonic and the method of combining the in-situ reaction, the successfully prepared mg₂ Si particle-reinforced magnesium-base composite material. Because mg₂ Si particles are in the ultrasonic treatment process in the magnesium alloy through chemical reaction generated in situ in the basal body, good compatibility of the interface with the substrate, the particle size of the wild controllable, enhanced, and the like is uniformly distributed, thus preparing the mg-based composite material has good mechanical and physical properties of the; traditional outside addition effectively avoided when preparing the composite material by limiting the size of the reinforcing phase, the enhancement phase is not good to combine with the host, enhance the phase distribution is uneven, and the like; the ultrasonic chemical method, also by mg₂ Si the original chinese character shapesharp corniformis into the and, at the same time; the size of the particles obtained, to prepare the magnesium-based composite material and opens up a new way.

Description of drawings

Figure 1 embodiment is 1 the mg₂ Si particle-enhanced photo organization of mg-based composite material

Mode of execution

example by this of execution of this invention the technical scheme of the invention implement, provides detailed and specific embodiment of the process of operation, the scope of protection of the present invention, however, is not limited to the following embodiments.

Embodiment 1

In 3vol. %SF₆ + 97vol. %CO₂ under the conditions of mixed gas protection, the AZ91D alloy ingot (80 wt. %) in the 680 [...] is completely melted, then the intermediate alloy Al-Si (20 wt. %) in the melt is pressed, then the temperature rise to the 700 [...] , and thermal insulation 20 minutes, the ultrasonic probe is inserted into the melt to be processed, the ultrasonic power setting for 2KW, continuous treatment of 5 minutes. Finally removing the dross on the surface of the metal mold for casting the obtained after solidification in 11vol %Mg₂ Si/AZ91D composite material. The resulting in-situ mg₂ Si particle reinforced magnesium-base composite material organization of photographs as shown in Figure 1, the room temperature tensile strength is 230 MPa, tensile strength is 150 °C 202 MPa.

Embodiment 2

In 2vol. %SF₆ + 98vol. %CO₂ under the conditions of mixed gas protection, the AZ91D alloy ingot (85 wt. %) in the 700 [...] is completely melted, then the Al-Si intermediate alloy (15 wt. %) in the melt is pressed, then the temperature rise to the 720 [...] , and thermal insulation 15 minutes, the ultrasonic probe is inserted into the melt to be processed, the ultrasonic power setting for 1.6KW, continuous processing of 8 minutes. Finally removing the dross on the surface of the metal mold for casting the obtained after solidification in 8vol %Mg₂ Si/AZ91D composite material, the resulting mg₂ Si particle reinforced magnesium-base composite material tensile strength at room temperature of the: 215 MPa, tensile strength is 150 °C 188 MPa.

Embodiment 3

In 1vol. %   SF₆ + 99vol. %   CO₂ under the conditions of mixed gas protection, the AZ91D alloy ingot (90 wt. %) in the 720 [...] is completely melted, then the intermediate alloy Al-Si (10 wt. %) in the melt is pressed, then the temperature rise to the 740 [...] , and thermal insulation 10 minutes, the ultrasonic probe is inserted into the melt to be processed, the ultrasonic power setting for 0.4KW, continuous treatment of 15 minutes. Finally removing the dross on the surface of the metal mold for casting the obtained after solidification in 5vol %Mg₂ Si/AZ91D composite material, the resulting mg₂ Si particle reinforced magnesium-base composite material tensile strength at room temperature to 208 MPa, tensile strength is 150 °C 175 MPa.