CN-121972679-A - Additive manufacturing method of TiAl alloy material with three-dimensional overlapped microstructure

CN121972679ACN 121972679 ACN121972679 ACN 121972679ACN-121972679-A

Abstract

The invention relates to the technical field of metal material manufacturing, in particular to an additive manufacturing method of a TiAl alloy material with a three-dimensional overlapped microstructure, which comprises the steps of preheating a forming substrate to a set temperature, preserving heat, scanning TiAl alloy powder which is laid on the forming substrate layer by layer according to a preset scanning path, and respectively carrying out fixed-point scanning melting on the TiAl alloy powder which is laid on the forming substrate layer by adopting a continuous electron beam and a continuous electron beam overlapped pulse electron beam in a corresponding low-energy scanning area and a high-energy scanning area to obtain the TiAl alloy material with the three-dimensional overlapped microstructure, wherein the scanning speed is more than or equal to 1000mm/s. The additive manufacturing method of the TiAl alloy material with the three-dimensional overlapped microstructure aims at solving the problem of how to simultaneously improve the high strength and high crack expansion resistance of the TiAl alloy material.

Inventors

CHEN WEI
YANG YANG
XING YISI
Lin Bochao

Assignees

中国航空制造技术研究院

Dates

Publication Date: 20260505
Application Date: 20260109

Claims (10)

1. A method for additive manufacturing of a TiAl alloy material having a three-dimensional network microstructure, the method comprising the steps of: Preheating a forming substrate to a set temperature and preserving heat; According to a preset scanning path, continuous electron beams and continuous electron beam superposition pulse electron beams are adopted to respectively perform fixed-point scanning melting on TiAl alloy powder which is paved on the forming substrate layer by layer in a corresponding low-energy scanning area and a high-energy scanning area, so as to obtain the TiAl alloy material with the three-dimensional overlapped microstructure, wherein the scanning speed is more than or equal to 1000mm/s.
2. The additive manufacturing method of the TiAl alloy material with the three-dimensional stacked micro-structure according to claim 1, wherein the continuous electron beam and the continuous electron beam stacked pulse electron beam are adopted to respectively perform fixed-point scanning melting of a low-energy scanning area and a high-energy scanning area corresponding to the Tial alloy powder layer by layer laid on the forming substrate according to a preset scanning path, so as to obtain the TiAl alloy material with the three-dimensional stacked micro-structure, specifically: And according to the scanning path, adopting the continuous electron beam to scan and melt the low-energy scanning area, and adopting the continuous electron beam to overlap the pulse electron beam to scan and melt the high-energy scanning area so as to obtain a grid-type energy input mode, thereby obtaining the TiAl alloy material with the three-dimensional grid-overlapping microstructure.
3. The method for manufacturing the additive of the TiAl alloy material with the three-dimensional stacked network microstructure according to claim 1, wherein the simultaneous output of the continuous electron beam and the pulsed electron beam is realized by adopting a composite bias power supply device, the composite bias power supply device comprises a pulse bias circuit and a disconnecting switch positioned at the output end of the pulse bias circuit, and the switching of the pulse bias is realized by utilizing the disconnecting switch.
4. The method of additive manufacturing of TiAl alloy material with three-dimensional network microstructure of claim 3 wherein the pulsed bias power is always on during processing.
5. The method for manufacturing the additive of the TiAl alloy material with the three-dimensional stacked network microstructure according to claim 3, wherein the pulse bias circuit is formed by connecting a bias basic value generating circuit and a bias pulse generating circuit which are mutually independent in series, When the bias base value generating circuit and the bias pulse generating circuit are operated, pulse bias is generated to realize simultaneous output of the continuous electron beam and the pulse electron beam.
6. The method of additive manufacturing of TiAl alloy materials with three-dimensional network microstructure of claim 5 wherein the pulse bias circuit has two modes of operation: When the bias voltage basic value generating circuit and the bias voltage pulse generating circuit both output voltages, the output voltage U0 of the rectifying and filtering circuit is measured, and the bias voltage basic value generating circuit output voltage U1 and the bias voltage pulse generating circuit output voltage U2 are connected in series and are input in parallel by the same given signal, when the basic value circuit output voltage U1 reduces the set voltage value In the case of U, the corresponding U2 is increased at the same time U, the bias voltage u0=u1+u2 is measured at the output end to be a stable and unchanged direct current voltage; when the bias voltage basic value generating circuit has output voltage and the output voltage of the bias pulse generating circuit is zero, the output voltage of the bias pulse generating circuit is 0V, and the output end voltage of the rectifying and filtering circuit is the basic value voltage output.
7. The method of additive manufacturing of TiAl alloy material with three-dimensional network microstructure of claim 3 wherein the isolating switch is a high voltage resistant MOSFET device.
8. The method for additive manufacturing of a TiAl alloy material having a three-dimensional stacked microstructure according to claim 3, wherein the electron gun outputs the composite energy of the continuous electron beam and the pulsed electron beam when the isolating switch is turned on, and the electron gun outputs only the continuous energy supplied by the continuous electron beam when the isolating switch is turned off.
9. The additive manufacturing method of the TiAl alloy material with the three-dimensional stacked network microstructure, which is disclosed in claim 1, is characterized in that parameters of the continuous electron beam are 8-13 mA of current, 50-70 kV of accelerating voltage and 1000-1500 mm/s of scanning rate.
10. The additive manufacturing method of the TiAl alloy material with the three-dimensional stacked network microstructure, which is disclosed in claim 1, is characterized in that parameters of the pulsed electron beam are that current is 5-10 mA, and duty ratio is 10% -20%.

Description

Additive manufacturing method of TiAl alloy material with three-dimensional overlapped microstructure Technical Field The invention relates to the technical field of metal material manufacturing, in particular to an additive manufacturing method of a TiAl alloy material with a three-dimensional overlapped microstructure. Background The electron beam selective melting additive manufacturing technology is a novel manufacturing technology very suitable for processing brittle materials, and the technology for developing TiAl alloy parts has been applied to the aerospace field. The electron beam equipment core device for electron beam selective melting at present mainly comprises a high-voltage power supply and an electron gun, wherein the high-voltage power supply consists of an accelerating power supply, a cathode heating power supply and a bias power supply, and the energy is output by continuous electron beams in the forming process. The high-voltage power supply adopts an inverter circuit principle to convert 380V alternating current into electron gun energy output to provide the required 60KV direct current high voltage. The pulse electron beam selective melting technology is to modulate beam current into pulse form for energy output. At the same average power, pulsed electron beam selective melting has a greater energy density and greater penetration than conventional continuous beam electron selective melting. The active TiAl alloy structure is mostly an equiaxed crystal or lamellar structure, and the alloy material with the two structure characteristics has advantages and disadvantages in performance. The TiAl alloy material with equiaxed grain structure has higher strength but poor crack propagation resistance, while the TiAl alloy with lamellar structure is opposite to the former. Accordingly, the inventors provide a method of additive manufacturing of TiAl alloy materials having a three-dimensional network microstructure. Disclosure of Invention (1) Technical problem to be solved The embodiment of the invention provides an additive manufacturing method of a TiAl alloy material with a three-dimensional overlapped microstructure, which solves the technical problem of how to simultaneously improve the high strength and high crack expansion performance of the TiAl alloy material. (2) Technical proposal The invention provides an additive manufacturing method of a TiAl alloy material with a three-dimensional overlapped microstructure, which comprises the following steps of: Preheating a forming substrate to a set temperature and preserving heat; According to a preset scanning path, continuous electron beams and continuous electron beam superposition pulse electron beams are adopted to respectively perform fixed-point scanning melting on TiAl alloy powder which is paved on the forming substrate layer by layer in a corresponding low-energy scanning area and a high-energy scanning area, so as to obtain the TiAl alloy material with the three-dimensional overlapped microstructure, wherein the scanning speed is more than or equal to 1000mm/s. Further, according to a preset scanning path, continuous electron beams and continuous electron beam superposition pulse electron beams are adopted to respectively perform fixed-point scanning melting on TiAl alloy powder which is laid on the forming substrate layer by layer in a corresponding low-energy scanning area and a high-energy scanning area, so as to obtain the TiAl alloy material with the three-dimensional network-superposed microstructure, which specifically comprises the following steps: And adopting the continuous electron beam to scan and melt all forming areas with low energy, and adopting the continuous electron beam to superimpose the pulse electron beam to scan and melt the high energy scanning areas so as to obtain a grid energy input mode and obtain the TiAl alloy material with the three-dimensional superimposed microstructure. Further, the simultaneous output of the continuous electron beam and the pulsed electron beam is realized by adopting a composite bias power supply device, wherein the composite bias power supply device comprises a pulse bias circuit and a disconnecting switch positioned at the output end of the pulse bias circuit, and the switching of the pulse bias is realized by utilizing the disconnecting switch. Further, the pulse bias power is always on during processing. Further, the pulse bias circuit is formed by connecting a bias basic value generating circuit and a bias pulse generating circuit which are mutually independent in series, When the bias base value generating circuit and the bias pulse generating circuit are both operated, a pulse bias is generated to realize simultaneous output of the continuous electron beam and the pulsed electron beam. Further, the pulse bias circuit has the following two operation modes: when the bias voltage basic value generating circuit and the bias voltage pulse generating circuit both output voltag