A method for improving the toughness of additively manufactured prototypes

Abstract

The present invention provides a method for improving the toughness of additively manufactured samples, which includes the following steps: (1) single-pass forming process: obtain single-pass morphology under different laser forming processes, and select forming conditions corresponding to continuous and uniform melt paths; 2) Change the laser scanning strategy to print a cuboid with different scanning line spacing; (3) Cut a small square from the end of the cuboid, grind the six sides of the small square and conduct a density experiment to obtain the density; After the annealing treatment of the cuboid of the small square, it is processed into a tensile strip by wire cutting, and the stress-strain curve and toughness value of the printed part are obtained through the tensile test; (5) Analyze the fracture morphology of the stretched strip, and select a reasonable scan Line spacing value for strong, tough prints. This method improves the energy distribution of the laser acting on the material, reduces thermal stress, and is conducive to obtaining printed samples with high surface precision and good toughness; it is simple and easy to implement, and is conducive to meeting the needs of the 3D printing industry.

Description

technical field [0001] The invention belongs to the technical field of material preparation and processing, and in particular relates to a method for improving the toughness of additive manufacturing samples. Background technique [0002] Additive manufacturing technology, commonly known as 3D printing, is a green and intelligent manufacturing technology, known as one of the carriers of the "third industrial revolution". Compared with traditional subtractive and equal material processing methods, additive manufacturing technology has the advantages of fast flexibility, material saving, and personalized customization. It has obvious advantages in the processing of high melting point, traditional difficult-to-machine materials and complex shape parts. . At present, titanium alloys, stainless steels, cobalt-chromium alloys, and high-temperature alloys manufactured by additive manufacturing have been widely used in aerospace, medical and industrial production. In the additive ...

AI Technical Summary

Problems solved by technology

However, since the printing process is a process of rapid melting and subsequent rapid solidification, the temperature gradient and thermal stress in this process are large, which will lead to microscopic defects such as cracks in the printed part, anisotropic mechanical properties, and low toughness.

[0003] In the prior art, the residual stress of the printed part is usually reduced and the mechanical properties are improved by preheating the printing base plate, annealing the printed part, laser remelting during the printing process, and optimizing the composition of the printing raw material; however, due to the preheating of the powder bed base plate The heat temperature is not high, laser remelting will reduce printing efficiency, other elements may be introduced into the optimization of raw material composition, and annealing treatment cannot completely eliminate microscopic defects.

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