Quasi-continuous laser metal 3D printing method capable of realizing regulation of nickel base alloy crystallographic texture

Abstract

The invention discloses a quasi-continuous laser metal 3D printing method capable of realizing regulation of nickel base alloy crystallographic texture. Laser output is set as a quasi-continuous lasermode, and then a laser metal 3D printing technical window is preliminarily optimized. The temperature field of a molten bath under the preliminarily optimized parameter is calculated by using a finite element heat transfer model; the temperature gradient G and the cooling rate xi of the moving boundary of the molten bath during closing of laser in a single pulse period are extracted, and the growth length L of a single pulse internal columnar dendrite is worked out according to a structure growth theoretical model; the laser parameter is optimized according to the matching rule that the ratioof the scanning speed V to pulse frequency f is 0.5-0.8L, and finally 3D printing forming is conducted according to the optimized parameter, so that a formed part with the consistent crystallographicorientation height is obtained. By regulating the heat source output mode, an effective remelting mechanism for mixed crystal or isometric crystal is introduced in the scanning direction, all columnar dendrite growth is obtained, and the consistency of grain orientation is remarkably improved.

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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