Grain size control in laser based additive manufacturing of metallic articles

Patent metadata

Field	Value
Publication number	US-2018200798-A1
Application number	US-201715409483-A
Country	US
Kind code	A1
Filing date	Jan 18, 2017
Priority date	Jan 18, 2017
Publication date	Jul 19, 2018
Grant date	—

Abstract

An additively manufactured alloy component has a first portion formed of the alloy and having a first grain size, and a second portion formed of the alloy and having a second grain size smaller than the first grain size. In an embodiment, the alloy component is an alloy turbine disk, the first portion is a rim region of the alloy turbine disk, and the second portion is a hub region of the alloy turbine disk. The first and second grain sizes may be achieved by controllably varying the laser power and/or scan speed during additive manufacturing.

First claim

1 . An additively manufactured alloy component comprising:
a first portion formed of an alloy and having a first grain size; and a second portion formed of the alloy and having a second grain size smaller than the first grain size.

2 . The additively manufactured alloy component of claim 1 , wherein the alloy component is an alloy turbine disk, the first portion is a rim region of the alloy turbine disk, and the second portion is a hub region of the alloy turbine disk.

3 . The additively manufactured alloy component of claim 2 , wherein the rim region is from about 10 percent to about 25 percent of the total area of the disk.

4 . The additively manufactured alloy component of claim 2 , wherein the hub region is from about 50 percent to about 80 percent of the total area of the disk.

5 . The additively manufactured alloy component of claim 1 , wherein the alloy is selected from a group consisting of nickel based alloys, cobalt based alloys, iron based alloys, mixtures of nickel based alloys, cobalt based alloys and iron based alloys, and titanium alloys.

6 . The additively manufactured alloy component of claim 5 , wherein the alloy is Inconel 718.

7 . The additively manufactured alloy component of claim 1 , wherein the first grain size is greater than 40 microns.

8 . The additively manufactured alloy component of claim 1 , wherein the second grain size is between 10 nanometers and 30 microns.

9 . The additively manufactured alloy component of claim 1 , further comprising a third portion between the first portion and the second portion with a grain size that is graded from the first grain size to the second grain size.

10 . The additively manufactured component of claim 1 wherein the first portion is formed by additive manufacturing and the second portion is formed by deformation processing and wherein the two portions are joined during additive manufacturing of the first portion.

11 . The additively manufactured component of claim 1 wherein the first portion is formed by casting and the second portion is formed by additive manufacturing and wherein the two portions are joined during additive manufacturing of the second portion.

12 . A method of additively manufacturing an alloy turbine disk having a first rim portion with a first grain size and a second hub portion with a second grain size smaller than the first grain size, the method comprising:
forming a layer of alloy powder on a build platform; forming a first fused rim region of the layer of alloy powder with the first grain size by scanning the first fused rim region with a laser at a first laser power and a first scan speed; forming a second fused hub region of the layer of alloy powder with the second grain size by scanning the second fused hub region with the laser at a second laser power and a second scan speed, wherein the second laser power is lower than the first laser power and/or the second scan speed is faster than the first scan speed; and repeating the process in a layer by layer fashion until the alloy turbine disk is formed.

13 . The method of claim 12 further comprising:
forming a fused transition region with a grain size gradient in the layer of alloy powder between the first fused region and the second fused region while changing the laser power from the first laser power to the second laser power and/or changing the scan speed from the first scan speed to the second scan speed.

14 . The method of claim 12 , wherein the build platform is a pre-formed rim region of the alloy turbine disk.

15 . The method of claim 12 , wherein the build platform is a pre-formed hub region of the alloy turbine disk.

16 . The method of claim 14 , wherein the rim region is formed with a grain size greater than 40 microns.

17 . The method of claim 15 , wherein the hub region is formed with a grain size between 10 nanometers and 30 microns.

18 . The method of claim 12 , wherein the alloy powder is selected from a group consisting of nickel based alloys, cobalt based alloys, iron based alloys, mixtures of nickel based alloys, cobalt based alloys and iron based alloys, and titanium alloys.

19 . The method of claim 14 , wherein the rim region is from about 10 percent to about 25 percent of the total area of the disk.

20 . The method of claim 15 , wherein the hub region is from about 50 percent to about 80 percent of the total area of the disk.

Assignees

• United Technologies Corp

Inventors

• Sharon John A
• Viens Daniel V
• El-Wardany Tahany Ibrahim
• Srinivasan Gajawalli V
• Sangiovanni Joseph J
• Acharya Ranadip

Classifications

• B22F10/22

  Direct deposition of molten metal · CPC title

• B22F10/64

  by thermal means (control of energy beam parameters for post heating B22F10/364) · CPC title

• B22F10/36

  of energy beam parameters · CPC title

• B22F10/38

  to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures · CPC title

• B22F12/49

  Scanners · CPC title