A quasi-continuous laser metal 3D printing method to realize the crystallographic texture control of nickel-based alloys

Abstract

The invention discloses a quasi-continuous laser metal 3D printing method that realizes the regulation and control of the crystallographic texture of nickel-based alloys. Firstly, the laser output is set to the quasi-continuous laser mode, and then the laser metal 3D printing process window is initially optimized; The heat transfer model calculates the molten pool temperature field under the preliminary optimization parameters; extracts the temperature gradient G and cooling rate ξ of the molten pool moving boundary during the laser off period in a single pulse period, and calculates the columnar branch in a single pulse according to the tissue growth theoretical model Crystal growth length L; according to the matching principle that the ratio of scanning speed V to pulse frequency f is equal to 0.5-0.8L, the laser parameters are optimized, and finally 3D printing is carried out according to the optimized parameters to obtain formed parts with highly consistent crystallographic orientation. The present invention introduces an effective remelting mechanism for miscellaneous crystals or equiaxed crystals along the scanning direction by modulating the heat source output, thereby obtaining growth of all columnar dendrites and significantly improving the consistency of grain orientation.

Description

technical field [0001] The invention relates to the field of laser metal material processing, in particular to a quasi-continuous laser metal 3D printing method for realizing the crystallographic texture regulation of nickel-based alloys. Background technique [0002] Crystallographic texture can make full use of the anisotropy of the crystal itself, and on the basis of maintaining the original traditional characteristics of engineering materials, the necessary performance can be significantly improved in a specific direction, which plays an important role in improving the performance of materials. For example, in nickel-based high-temperature turbine blades under high-temperature-stress service environment, the grain boundary perpendicular to the stress axis is the main crack source, but through certain control (such as directional solidification), the <100> orientation almost parallel to the principal stress axis direction can be obtained Columnar grain structure (el...

AI Technical Summary

Problems solved by technology

At present, there is still a lack of methods to effectively control the growth of dendrite structure and solidification texture (such) in the process of metal 3D printing.

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