Patent ID: 11872625
Assignee: CENTRAL SOUTH UNIVERSITY
Field: Materials, metallurgy (Chemistry)
Classification: CPC B  Y | IPC B

Claim 0:
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 D10 of 15-20 μm, a D50 of 25-31 μm, and a D90 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)*Tre° 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)*Tre° C. for a time of 10-20 min,
Where the Tre is the recrystallization temperature of the alloy, expressed in ° C.