A high-performance magnesium-based composite material based on laser 3D printing and its preparation method

Abstract

The invention relates to the field of magnesium matrix composites, in particular to a high performance magnesium matrix composite based on laser 3D printing forming and a preparation method thereof. The high performance magnesium matrix composite comprises, by weight, 2-5% of monatomic silicon particles, 6-8% of LiH, 1-2% of CaH, and the balance high-purity magnesium powder. The problem of the evaporation and oxidation of magnesium alloy powder in the forming process can be effectively reduced, so as to ensure a precision forming manufacture of high performance magnesium alloy, and also a method for the preparation of magnesium alloy powder specially for laser additive manufacturing is provided.

Description

technical field [0001] The invention belongs to the field of magnesium-based composite materials, and specifically relates to a high-performance magnesium-based composite material based on laser 3D printing and a preparation method thereof. [0002] technical background [0003] Magnesium alloy is currently one of the lightest metal structural materials in industrial applications. It has high specific strength, specific stiffness, and good casting, shock absorption, cutting and dimensional stability. It has already attracted attention in the aviation industry and the automobile industry. attention. In addition, magnesium alloys have broad application prospects in the biomedical field due to their inherent biocompatibility, biodegradability, low elastic modulus, and excellent mechanical properties. However, given the hexagonal crystal structure of magnesium alloys, the formability of magnesium alloys is severely limited, especially for biomedical implants with complex and fin...

AI Technical Summary

Problems solved by technology

The boiling point of pure Mg is only 1107°C, and it is very easy to form Mg vapor in high-energy-density laser processing, which will lead to a decrease in the compactness of the final product and a loss of Mg components, which will significantly affect the formability of magnesium alloys

[0007] (2) Mg alloy is extremely prone to "oxidation reaction"

The oxidized Mg alloy powder affects the powder spreading performance and energy absorption, and the oxidized Mg alloy melt significantly reduces the wettability of the current scanning pass and the adjacent solidified metal. At the same time, under the disturbance of the laser, the oxidized impurities are very It may enter the molten pool and form holes in the solidified matrix, thereby reducing the density and mechanical properties of the sample

[0008] (3) From the perspective of forming process, Mg alloy material has low density and poor powder fluidity, so its spreadability and powder transmission performance on the powder bed are poor, resulting in uneven powder layer laying in the SLS / SLM process and LMD process Discontinuous and uniform powder spraying

When the high-energy laser beam interacts with the uneven powder layer or discontinuously conveyed powder, it will cause serious powder / melt splashing and melt "spheroidization" effect, which will affect the subsequent powder spreading, resulting in the failure of the additive manufacturing process. conduct

[0009] The two most prominent problems are the first two points, that is, the high saturated vapor pressure and the characteristics of easy oxidation, which seriously restrict the forming and mechanical properties of laser additive manufacturing magnesium alloy components.

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