Method for eliminating cracks in rené 104 nickel-based superalloy prepared by laser additive manufacturing

Patent metadata

Field	Value
Publication number	US-11872625-B2
Application number	US-201817254303-A
Country	US
Kind code	B2
Filing date	Aug 30, 2018
Priority date	Jul 27, 2018
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

The present disclosure relates to the field of additive manufacturing and superalloys, particularly to a method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing. For solving the problem that cracks are easily generated during laser additive manufacturing of René 104 nickel-based superalloy with high content of Al and Ti (Al+Ti>5 wt. %), generation of large-size cracks inside a fabricated part is suppressed by means of designing laser forming parameters and a partition scanning strategy; then stress relief annealing is performed to completely eliminate residual stress inside the fabricated part; and a spark plasma sintering process is performed to eliminate cracks inside the fabricated part and suppress the growth of grains during the sintering process.

First claim

What is claimed is:

1. A method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing, wherein the method comprising the following steps:
Step 1: preparation before the laser additive manufacturing, comprising
According to a shape of a required part, designing a three-dimensional model of the part by using a three-dimensional design software, and then importing the three-dimensional design model into the laser additive manufacturing equipment; and after auto-slicing by the software, importing data of each slice layer into the laser additive manufacturing system;
Step 2: additive manufacturing by selective laser melting, comprising
Laying the René 104 nickel-based superalloy powder, then using a laser to selectively melt the powder bed according to information of the slice layer, wherein scanning methods include a contour scanning and a solid scanning, and for scanning of each layer, the contour scanning is carried out first, then the solid scanning is carried out, where the solid scanning adopts a partition scanning strategy, and then contour scanning is carried out again; the whole step consists of powder laying and laser melting processing;
The René 104 nickel-based superalloy powder has a particle size of 15-53 μm, a D 10 of 15-20 μm, a D 50 of 25-31 μm, and a D 90 of 40-48 μm;
Where the parameters of the contour scanning are as follows: a laser spot diameter of 0.08-0.1 mm, a laser power of 100 W-150 W, and a scanning speed of 1000-1400 mm/s;
Where the parameters of the solid scanning are as follows: a laser power of 200 W-250 W, a laser spot diameter of 0.10-0.13 mm, a scanning speed of 450-650 mm/s, a scanning pitch of 0.08-0.14 mm, and a thickness of the laid powder layer being 30-35 μm; and
The partition scanning strategy is as follows: dividing a solid area of each slice layer into multiple zones, and then scanning and melting every zone by the laser in turn; and the partition scanning strategy includes a stripe scanning strategy and/or a chessboard scanning strategy;
Where the parameters for the stripe scanning strategy are as follows: a stripe width of 6-8 mm, and an overlap between stripes being 0.1-0.15 mm; and
Where the parameters for the chessboard scanning strategy are as follows: a chessboard size of 4-6 mm, an overlap between chessboards being 0.08-0.12 mm, and laser scanning directions of adjacent chessboards being perpendicular to each other;
Step 3: repeating step 2 until the whole part is printed on a substrate, and then separating the printed part from the substrate to obtain a fabricated part;
Step 4: heat-treating the fabricated part by a stress relief annealing at a temperature of (0.3-0.4)*T re ° C. for a time of 1-3 hrs; and
Step 5: spark plasma sintering the fabricated part heat-treated by the stress relief annealing at a temperature of (0.8-0.9)*T re ° C. for a time of 10-20 min,
Where the T re is the recrystallization temperature of the alloy, expressed in ° C.

2. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein the René 104 nickel-based superalloy contains Al and Ti, and Al+Ti is present in an amount of 5 wt. % or more based on the total weight of the René 104 nickel-based superalloy.

3. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein the substrate for printing is a stainless steel substrate or the same type of nickel-based superalloy; and the substrate is preheated to a temperature of 100-200° C. before printing.

4. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein during the laser additive manufacturing process, inert protective gas such as argon or nitrogen needs to be introduced into the working chamber of the equipment to ensure an oxygen content in the working chamber less than 0.1%.

5. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein the stress relief annealing is carried out under a protective gas atmosphere; during the stress relief annealing, the temperature is raised to an annealing temperature at a heating rate of 5-15° C./min, and held for 1-3 hrs; and then the alloy is cooled within the furnace.

6. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 5 , wherein during the stress relief annealing, the protective gas atmosphere is selected from at least one of argon and nitrogen.

7. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein during spark plasma sintering, the heating rate is controlled to 50-100° C./min, and the cooling rate is controlled to 50-100° C./min.

8. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein during spark plasma sintering, a pressure is controlled to 30-50 MPa.

9. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein during spark plasma sintering, a sintering temperature is controlled to 1020° C. or less.

10. The method for eliminating cracks in René 104 nickel-based superalloy prepared by laser additive manufacturing according to claim 1 , wherein after treatments of the stress relief annealing and the spark plasma sintering in turn, a tensile strength of the René 104 nickel-based superalloy is 1.6-2.0 times of that before the treatments.

Assignees

• Univ Central South

Inventors

• Liu Zuming
• Peng Kai
• Lv Xueqian
• Zhao Fan
• Li Quan
• Wei Bing

Classifications

• B22F10/28 Primary

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F3/24

  After-treatment of workpieces or articles {(B22F3/1146 takes precedence)} · CPC title

• B22F10/36

  of energy beam parameters · CPC title

• B22F10/366

  Scanning parameters, e.g. hatch distance or scanning strategy · CPC title