Apparatus and method for direct writing of single crystal super alloys and metals

Patent metadata

Field	Value
Publication number	US-2016258045-A1
Application number	US-201514836494-A
Country	US
Kind code	A1
Filing date	Aug 26, 2015
Priority date	Aug 26, 2014
Publication date	Sep 8, 2016
Grant date	—

Abstract

Apparatus and methods for direct writing of single crystal super alloys and metals are provided. In one method, a substrate is heated to a pretermined temperature below its melting point, and a laser is used to form a melt pool on a surface of a substrate. The substrate is positioned on a base plate, and the laser and the base plate are movable relative to each other, with the laser being used for direct metal deposition and the substrate is heated to a temperature below its melting point. A superalloy powder is introduced to the melt pool, and the temperature of the melt pool is controlled to maintain a predetermined thermal gradient on a solid and liquid interface of the melt pool so as to form a single crystal deposit on the substrate.

First claim

What is claimed is:

1 . A method for direct writing of single crystal super alloys and metals, the method comprising:
heating a substrate to a predetermined temperature below its melting point; using a laser to form a melt pool on a surface of the substrate, wherein the substrate is positioned on a base plate, and wherein the laser and the base plate are movable relative to each other, the laser being used for direct metal deposition; introducing a superalloy powder to the melt pool; and controlling the temperature of the melt pool to maintain a predetermined thermal gradient on a solid and liquid interface of the melt pool so as to form a single crystal deposit on the substrate.

2 . The method of claim 1 , wherein the laser has a variable power source, and wherein controlling the temperature of the melt pool comprises:
adjusting the variable power source of the laser.

3 . The method of claim 1 , wherein the laser has a variable power output controllable by a laser power controller, and wherein controlling the temperature of the melt pool comprises:
measuring the temperature of the melt pool; receiving the temperature measured at a controller; comparing the temperature measured to a reference temperature; and adjusting the variable power output of the laser.

4 . The method of claim 3 , wherein the temperature measured is lower than the reference temperature, and wherein adjusting the variable power output of the laser comprises:
increasing the variable power output of the laser.

5 . The method of claim 4 , wherein increasing the variable power output of the laser comprises:
increasing the voltage supplied by the laser power controller.

6 . The method of claim 3 , wherein the temperature measured is higher than the reference temperature, and wherein adjusting the variable power output of the laser comprises:
decreasing the variable power output of the laser.

7 . The method of claim 6 , wherein decreasing the variable power output of the laser comprises:
decreasing the voltage supplied by the laser power controller.

8 . The method of claim 1 , wherein the laser and the base plate are movable in 3 directions with respect to each other.

9 . The method of claim 1 , further comprising:
moving the laser in a horizontal plane with respect to the substrate.

10 . The method of claim 1 , further comprising:
moving the base plate in a vertical direction with respect to the laser.

11 . An apparatus for direct writing of single crystal super alloys and metals comprising:
a laser having a power output; a base plate configured for holding a substrate thereon; a DMD head configured to supply a stream of superalloy powder onto the substrate; an induction heating source positioned to heat the substrate on the base plate to a predetermined temperature; and a controller for controlling the power output of the laser to maintain the predetermined temperature, wherein the controller is responsive to a measured temperature of at least one of a melt pool on the substrate and the superalloy powder.

12 . The apparatus of claim 11 , further comprising:
a pyrometer configured to measure the temperature of the at least one of the melt pool on the substrate and the superalloy powder.

13 . The apparatus of claim 12 , wherein the pyrometer is in communication with the controller.

14 . The apparatus of claim 13 , wherein the laser has a variable power output controlled by a laser power controller.

15 . The apparatus of claim 14 , wherein the laser power controller is in communication with the controller.

16 . The apparatus of claim 11 , wherein the laser passes through the DMD head onto the substrate to form a melt pool.

17 . The apparatus of claim 11 , wherein the laser and the base plate are movable in 3 directions with respect to each other.

18 . The apparatus of claim 11 , wherein the laser is movable in a horizontal plane with respect to the substrate.

19 . The apparatus of claim 11 , wherein the base plate is movable in a vertical direction with respect to the laser.

Assignees

• Gen Electric
• Univ Michigan Regents

Inventors

• Carter Jr William Thomas
• Rockstroh Todd Jay
• Konitzer Douglas Gerard
• Mazumder Jyotirmoy
• Choi Jeongyong

Classifications

• B23K26/083

  Devices involving movement of the workpiece in at least one axial direction · CPC title

• B23K26/144

  the fluid stream containing particles, e.g. powder · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• B23K2103/08

  Non-ferrous metals or alloys · CPC title

• B23K26/34

  Laser welding for purposes other than joining · CPC title