Device and method for refining structure crystalline grains in metal additive manufacturing process

Abstract

The invention provides a device and method for refining structure crystalline grains in the metal additive manufacturing process. The device comprises a main laser device and an auxiliary laser device. A main laser path and an auxiliary laser path transmit lasers to the same concentration lens through a light combination lens. The concentration lens generates a composite laser spot composed of a main laser spot and an auxiliary laser spot. The auxiliary laser spot is smaller than that of the main laser spot and can move in the main laser spot. By the adoption of the device and method for refining the structural crystalline grains in the metal additive manufacturing process, a bath is formed through the main laser spot, a key hole is formed through the auxiliary laser spot, the key hole ismade to move in a specific manner to achieve the function of stirring the bath, and therefore the structure crystalline grains are refined; the depth and shape of the key hole can be adjusted by adjusting the parameter of the auxiliary laser; the device and method for refining the structure crystalline grains in the metal additive manufacturing process have no limitation to matrix and powder adopted in the laser metal deposition process and are suitable for formation motion in any form, the situation that in the process of refining the structural crystalline grains, after one cladding layer isobtained, the track is repeated is avoided, and high efficiency is achieved.

Description

technical field [0001] The invention belongs to the field of additive manufacturing, and relates to a device and method for refining structure grains in the metal additive manufacturing process. Background technique [0002] In the field of metal additive manufacturing, Laser Melting Deposition (LMD) technology has received more and more attention. The principle of LMD technology is that in a laser processing head, the metal powder is sent to the working surface through a powder feeder, and at the same time, the laser is converged to the working surface through a collimating mirror and a focusing lens to form a molten pool, and the metal powder melts rapidly in the molten pool , After laser scanning, the molten metal powder in the molten pool will be rapidly cooled to solidify, and finally form a metal layer with a certain thickness. [0003] At present, the workpiece formed by the LMD process is mostly columnar crystals in the area close to the substrate, and the area away...

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Problems solved by technology

[0005] The object of the present invention is to provide a device and method for refining the structure and grain in the process of metal additive manufacturing in order to solve the problem that the refinement of the structure and grain in the above-mentioned prior art cannot be applied to complex forming movements and the processing efficiency is low. For any form of forming movement, it is not necessary to repeat the trajectory after cladding a layer when refining the structure and grain, which is highly efficient

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