A Laser Composite Additive Manufacturing Method Based on Pulsed Laser Controlled Melt Pool Flow

Abstract

The invention discloses a laser composite additive manufacturing method based on pulsed laser controlling molten pool flow, and belongs to the field of laser advanced additive manufacturing. The laser composite additive manufacturing method of the present invention is: using a continuous laser beam to melt the surface of the substrate and the alloy powder to form a molten pool, and at the same time, introducing a pulsed laser beam to perform synchronous impact treatment on the molten pool, and performing the process of using pulsed laser to control the molten pool Laser composite additive manufacturing process; during the manufacturing process, the pulsed laser beam is used to control the shape and flow of the molten pool, improve the flatness of the cladding surface, adjust the residual stress in the cladding layer, and reduce the anisotropy of the cladding layer performance. The present invention not only improves the forming quality and residual stress of the cladding layer, but also improves the flatness and mechanical properties of the cladding layer, which is beneficial to the improvement of production efficiency, and is suitable for continuous multi-layer overlapping or multi-layer stacking laser additive materials In manufacturing work, it is suitable for the field of laser additive manufacturing for surface remanufacturing repair or 3D printing direct forming.

Description

technical field [0001] The invention belongs to the field of advanced laser additive manufacturing, and in particular relates to a laser composite additive manufacturing method based on pulsed laser to control molten pool flow. Background technique [0002] Laser additive manufacturing technology is a comprehensive integration of material science, mechanical engineering and laser technology. It uses high-energy laser beams to focus on the substrate to form a molten pool. Metal powder is fed into the molten pool by prefabrication or coaxial powder feeding. Metal powder In the molten pool, it is fused with the matrix solution, and with the movement of the laser beam, the molten pool moves to the direction of the laser beam under the action of the surface tension of the liquid, thus gradually forming a deposition layer. This technology is of great significance for the remanufacturing of parts and the direct molding of complex parts, and is the main research direction of advance...

AI Technical Summary

Problems solved by technology

[0003] Laser additive manufacturing technology is based on the principle of discrete-stacking molding. While this technology can realize direct molding of complex structural parts, it also has the following three limitations: (1) Continuous multi-channel overlapping laser additive manufacturing process This leads to large ripples and undulations on the deposition surface, which increases the workload of subsequent processing; (2) The continuous multi-pass laser additive manufacturing process leads to uneven cyclic heating and cooling of the deposited part, and the deposition layer memory Under complex thermal stress, the cladding layer is prone to defects such as cracks and pores; (3) The directional characteristics of heat flow diffusion in the molten pool promote the directional growth of dendrites, resulting in anisotropy in the properties of the deposited layer

However, in the laser additive manufacturing process, the cooling speed is fast, and it is difficult to accurately control the forging temperature of the cladding layer, and it is difficult to accurately forge the cladding layer within the forging temperature range, and it is easy to produce irregular grain sizes in the cladding layer. Uniformity and Chilling

In addition, the above methods all use laser shock technology to impact or forge the cladding layer after cladding, and the deformation on the surface of the cladding layer is small, and the influence on the flatness of the cladding layer surface is relatively weak. Effectively reduce the workload of subsequent processing on the cladding layer surface and improve production efficiency

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