A magnesium alloy semi-solid formed piece reinforced with a mesh titanium sheet and a manufacturing method

Abstract

The application discloses a kind of net titanium sheet reinforced magnesium alloy semi-solid forming piece and its manufacturing method, belong to metal matrix composite and semi-solid precision forming technical field.The forming piece is made of magnesium alloy matrix and embedded in its inside ultra-thin net titanium sheet, titanium wire diameter is 0.05~0.1 mm, and the whole structure piece is formed by semi-solid injection molding process once, magnesium alloy slurry fills titanium net mesh and completely wraps titanium wire, and forms three-dimensional interlocking interface bonding structure.The application also discloses the manufacturing method of the forming piece, including titanium net cleaning fixation, semi-solid slurry preparation, injection molding and pressure maintaining cooling and the like steps.The tensile strength of the obtained forming piece reaches 380~420 MPa, yield strength reaches 340~410 MPa, and elongation reaches 10%~17%, with high strength and high toughness, and process is simple, cost controllable, and suitable for large-scale industrialized production of high load light weight structural component.

Description

Technical Field

[0001] This invention relates to the field of semi-solid precision molding technology, specifically to a semi-solid molded magnesium alloy part reinforced with mesh titanium sheets and a manufacturing method thereof. Background Technology

[0002] Semi-solid injection molding is a rapidly developing advanced forming technology for magnesium alloys in recent years. Products produced using this technology have significant advantages, including fewer defects, finer grains, and excellent mechanical properties. Furthermore, it allows for near-final shaping in a single step, greatly reducing subsequent processing steps. However, conventional AZ91D magnesium alloys, after injection molding at 590℃~595℃, exhibit tensile strength of only 240~260 MPa, yield strength of only 140~160 MPa, and elongation of only 3%~5%. Such low strength levels are insufficient to meet the requirements of structural components subjected to heavy loads. To improve the mechanical properties of magnesium alloys, researchers have explored various reinforcement methods, including adding titanium particles to the alloy, coating the surface of the alloy with titanium plates, and using titanium alloy exoskeletons for reinforcement. However, each of these methods has significant drawbacks—titanium particles are prone to agglomeration, and interfacial reactions are difficult to control effectively; titanium plates only strengthen the material surface, offering limited improvement to overall mechanical properties; while titanium alloy exoskeletons provide better reinforcement, their complex manufacturing process and high production costs hinder industrial-scale mass application. Summary of the Invention

[0003] The purpose of this invention is to provide a semi-solid molded part of magnesium alloy reinforced with mesh titanium sheets and a manufacturing method thereof, which significantly improves the strength, toughness and high-temperature creep resistance of magnesium alloy, while maintaining the simplicity of the process and the controllability of cost, so that magnesium alloy can meet the application requirements of high load-bearing structural components.

[0004] To achieve the above objectives, the present invention provides a magnesium alloy semi-solid molded part reinforced with mesh titanium sheets. The molded part is composed of a magnesium alloy matrix and an ultra-thin mesh titanium sheet embedded therein. The titanium sheet and the magnesium alloy matrix are molded into an integral structural part in one step by a semi-solid injection molding process, and the magnesium alloy matrix fills the mesh of the titanium sheet and completely wraps the titanium wires.

[0005] Preferably, the diameter of the titanium wires in the ultrathin mesh titanium sheet is 0.05 to 0.1 mm.

[0006] The present invention also provides a method for manufacturing a semi-solid molded part of magnesium alloy reinforced with mesh titanium sheet, comprising the following steps: (1) selecting an ultra-thin mesh titanium sheet with a titanium wire diameter of 0.05 to 0.1 mm, cleaning its surface to remove oil and oxide layer, and obtaining a clean insert; (2) fixing the cleaned titanium mesh insert in a designated position in the cavity of a semi-solid injection molding mold; (3) adding magnesium alloy particles into the screw barrel of the injection molding machine and heating it to a semi-solid temperature range of 580 to 600°C, while using the shearing force generated by the rotation of the screw to transform the alloy into a semi-solid slurry; (4) injecting the semi-solid slurry into the mold, allowing the slurry to penetrate the mesh of the titanium mesh in a laminar flow manner and completely wrap each titanium wire; (5) cooling to room temperature after pressure holding, opening the mold and taking out the molded part.

[0007] Preferably, the magnesium alloy particles are AZ91D magnesium alloy.

[0008] Preferably, in step (4), the injection speed is 2.0 to 2.5 m / s and the mold temperature is 230 to 280°C.

[0009] Preferably, the titanium mesh has a mesh size of 0.2 to 0.4 mm and a porosity of 40 to 50%.

[0010] Preferably, the resulting molded part has a tensile strength of 380–420 MPa, a yield strength of 340–410 MPa, and an elongation of 13%–17%.

[0011] This invention provides a semi-solid molded magnesium alloy part reinforced with mesh titanium sheets and its manufacturing method. In this technical solution, firstly, the mesh titanium sheets and the magnesium alloy matrix interweave in three-dimensional space, forming a three-dimensional interlocking interface structure. This structure enables the interface tensile strength to reach 147.8 MPa and the shear strength to reach 110.5 MPa, far exceeding that of traditional planar interfaces, making the molded part less prone to delamination or interface failure during use. Secondly, the tensile strength of the molded part is increased from the conventional 240–260 MPa to 380–420 MPa, and the yield strength is increased from 140–160 MPa to 340–410 MPa, representing a strength increase of over 80%, which meets the requirements for high-load-bearing structural components. Thirdly, the elongation of the molded part is increased from the conventional 3%–5% to 10%–17%, and the material exhibits significant toughness characteristics. Especially when using 0.05 mm fine titanium wire, the elongation can reach 13%–17%, with a particularly outstanding toughening effect.

[0012] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0013] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0014] The AZ91D magnesium alloy particles used in this embodiment are commercially available products, and their chemical composition conforms to standard proportions. The industrial pure titanium mesh is a commercially available woven titanium wire mesh with a regular square or diamond-shaped mesh arrangement. The titanium mesh needs to be surface cleaned before use to remove residual oil and natural oxide layers from the rolling or weaving process.

[0015] Example 1 (0.05 mm titanium mesh + AZ91D) Industrial pure titanium mesh with a diameter of 0.05 mm, a mesh size of 0.2 mm, and a porosity of 40% was selected as the reinforcing insert. First, the surface of the titanium mesh was cleaned to remove oil and oxide layers. The treated titanium mesh was then accurately fixed in the center of the cavity of a semi-solid injection molding mold. AZ91D magnesium alloy granules were added to the screw barrel of the injection molding machine and heated to 595℃. The shear force generated by the screw rotation transformed the alloy into a semi-solid slurry with good thixotropic properties. The semi-solid slurry was then injected into the mold at a speed of 2.2 m / s, with the mold temperature controlled at 240℃. The slurry smoothly filled the cavity in a laminar flow state, fully penetrating all the mesh openings of the titanium mesh and completely encapsulating each titanium wire. After holding under pressure for a period of time and cooling to room temperature, the mold was opened and the molded part was removed.

[0016] Tests showed that the molded parts obtained in this embodiment have a tensile strength of 380–420 MPa, a yield strength of 340–410 MPa, and an elongation of 13%–17%.

[0017] Example 2 (0.1 mm titanium mesh + AZ91D) The operation steps are basically the same as in Example 1. The only difference is that an industrial pure titanium mesh with a titanium wire diameter of 0.1 mm is used. The mesh size, porosity, injection temperature, injection speed, mold temperature and other parameters are consistent with those in Example 1.

[0018] Tests showed that the molded part obtained in this embodiment has a tensile strength of 410-450 MPa, a yield strength of 380-450 MPa, and an elongation of 10%-13%.

[0019] Comparative example (conventional AZ91D semi-solid injection molded part) Comparative samples were prepared using the same AZ91D magnesium alloy particles as in Example 1, on the same semi-solid injection molding equipment, and according to a conventional semi-solid injection molding process (without any inserts). The injection temperature was 595°C, the injection speed was 2.2 m / s, the mold temperature was 240°C, and the molded parts were removed after holding pressure and cooling.

[0020] Tests showed that the tensile strength of the molded parts obtained by the comparative method was 240–260 MPa, the yield strength was 150–160 MPa, and the elongation was 3%–5%.

[0021] The tensile strength of Example 1 of the present invention (using a 0.05 mm titanium mesh) is 380–420 MPa, the yield strength is 340–410 MPa, and the elongation is 13%–17%. The tensile strength of Example 2 of the present invention (using a 0.1 mm titanium mesh) is 410–450 MPa, the yield strength is 380–450 MPa, and the elongation is 10%–13%.

[0022] As can be seen from the above data, compared with the comparative example without reinforcement, the two embodiments of the present invention achieve comprehensive and significant improvements in tensile strength, yield strength, and elongation. Specifically, the tensile strength is increased by 50%–80%, the yield strength by over 100%, and the elongation by over 200%. Of particular note is that the present invention significantly improves strength without sacrificing plasticity; on the contrary, it achieves a simultaneous improvement in strength and toughness, which is a significant technological breakthrough in the field of metal matrix composites.

[0023] Comparing Examples 1 and 2 reveals that using 0.05 mm fine titanium wire significantly improves elongation (13%–17%) compared to 0.1 mm titanium wire (10%–13%), while tensile strength is slightly lower (380–420 MPa vs. 410–450 MPa). This indicates that finer titanium wires have less cutting effect on the matrix, which helps maintain and improve the material's plasticity; while thicker titanium wires provide stronger load-bearing capacity, further enhancing tensile strength. This principle suggests that the present invention can adapt to different application scenarios with varying performance requirements by adjusting the titanium wire diameter—finer titanium wires are preferred for applications requiring higher toughness, while thicker titanium wires are preferred for applications requiring higher strength.

[0024] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0025] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0026] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A semi-solid molded magnesium alloy part reinforced with mesh titanium sheets, characterized in that, The molded part consists of a magnesium alloy matrix and an ultra-thin mesh titanium sheet embedded therein. The titanium sheet and the magnesium alloy matrix are molded into an integral structural part in one step by a semi-solid injection molding process, and the magnesium alloy matrix fills the mesh of the titanium sheet and completely wraps the titanium wire.

2. The semi-solid magnesium alloy part reinforced with mesh titanium sheets according to claim 1, characterized in that, The diameter of the titanium wires in the ultrathin mesh titanium sheet is 0.05–0.1 mm.

3. A method for manufacturing a semi-solid magnesium alloy part reinforced with mesh titanium sheets, characterized in that, Includes the following steps: (1) Select ultra-thin mesh titanium sheets with a titanium wire diameter of 0.05-0.1 mm, clean their surface to remove oil and oxide layer, and obtain a clean insert; (2) Fix the cleaned titanium mesh insert in the designated position of the cavity of the semi-solid injection molding mold; (3) Add magnesium alloy particles to the screw barrel of the injection molding machine and heat it to the semi-solid temperature range of 580-600℃. At the same time, the alloy is transformed into a semi-solid slurry by the shearing force generated by the rotation of the screw; (4) Inject the semi-solid slurry into the mold, so that the slurry penetrates the mesh of the titanium mesh in a laminar flow manner and completely wraps each titanium wire; (5) After holding the pressure, cool to room temperature, open the mold and take out the molded part.

4. The manufacturing method according to claim 3, characterized in that, The magnesium alloy particles are AZ91D magnesium alloy.

5. The manufacturing method according to claim 3, characterized in that, In step (4), the injection speed is 2.0 to 2.5 m / s and the mold temperature is 230 to 280°C.

6. The manufacturing method according to claim 3, characterized in that, The titanium mesh has a mesh size of 0.2–0.4 mm and a porosity of 40–50%.

7. The manufacturing method according to claim 3, characterized in that, The resulting molded parts have a tensile strength of 380–420 MPa, a yield strength of 340–410 MPa, and an elongation of 13%–17%.