# US 2022/0033946 A1 · Composition design optimization method of aluminum alloy for selective laser melting

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- Number: US 2022/0033946 A1
- Document ID: US20220033946A1
- Status: Published application
- Kind: A1
- Application number: 17/386,202
- Filed: 2021-07-27
- Published: 2022-02-03
- Earliest claimed: 2020-07-28
- Assignees: Central South University
- Applicants: Central South University
- Inventors: Zhiyong CAI; Richu WANG
- Web page: https://patentgrep.com/patent/US20220033946A1

## CPC

- C22F 1/04: of aluminium or alloys based thereon
- B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
- B22F 10/31: Calibration of process steps or apparatus settings, e.g. before or during manufacturing
- B22F 10/38: to achieve specific product aspects, e.g. surface smoothness, density, porosity or hollow structures
- B22F 10/64: by thermal means (control of energy beam parameters for post heating B22F10/364)
- B22F 10/80: Data acquisition or data processing
- B23K 26/0006: {taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence)}
- B23K 26/34: Laser welding for purposes other than joining
- B23K 26/342: Build-up welding
- B23K 26/354: by melting
- B23K 31/12: relating to investigating the properties, e.g. the weldability, of materials
- B33Y 10/00: Processes of additive manufacturing
- B33Y 40/20: Post-treatment, e.g. curing, coating or polishing
- B33Y 50/00: Data acquisition or data processing for additive manufacturing
- B33Y 50/02: for controlling or regulating additive manufacturing processes
- B33Y 70/00: Materials specially adapted for additive manufacturing
- C22F 1/002: {by rapid cooling or quenching; cooling agents used therefor}
- B22F 2003/248: {Thermal after-treatment}
- B22F 2301/052: Aluminium
- B23K 2103/10: Aluminium or alloys thereof
- Y02P 10/25: Process efficiency
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A composition design optimization method of aluminum alloy for selective laser melting, including the following steps: S1: making alloy ingots with different composition; S2: pre-treating and processing the alloy ingots to obtain alloy sample blocks with different composition; S3: twice laser surface scanning treatment; S4: treating the alloy sample blocks by induction heating and quenching; S5: inspecting surface morphology, microstructure and properties of second laser melting layer of each alloy sample block, to determine whether the alloy sample blocks are suitable for selective laser melting process and optimize alloy composition.

## Claims

### Claim 1

A composition design optimization method of aluminum alloy for selective laser melting, comprising the following steps:
S1: preparing raw materials according to different designed formulas, and making alloy ingots with different composition;
S2: pre-treating and processing the alloy ingots to obtain alloy sample blocks with different composition;
S3: using high-energy laser beam perform on surface of each alloy sample block for first laser scanning to form a first laser melting layer on the surface thereof, then using high-energy laser beam again to perform on area of the first laser melting layer for second laser scanning to form a second laser melting layer;
S4: treating the alloy sample blocks from the step S3 by induction heating and quenching;
S5: inspecting surface morphology, characterizing and testing microstructure and properties of the second laser melting layer of each alloy sample block from the step S4, to determine whether the alloy sample blocks are suitable for selective laser melting process and optimize composition of the alloy sample blocks.

### Claim 2 (depends on 1)

The composition design optimization method of claim 1, wherein in the step S3, when the alloy sample blocks are completely cooled after the first laser scanning, the second laser scanning is performed.

### Claim 3 (depends on 2)

The composition design optimization method of claim 2, wherein in the step S3, a center of the laser beam of the second laser scanning is scanned along centers of two molten pools formed in the first laser melting layer.

### Claim 4 (depends on 3)

The composition design optimization method of claim 3, wherein in the step S3, before the first laser scanning, the surface of each alloy sample block is subjected to laser scanning pretreatment, and then process parameters of the first laser scanning and the second laser scanning are determined by observing state of a laser surface melting layer obtained by the laser scanning pretreatment.

### Claim 5 (depends on 4)

The composition design optimization method of claim 4, wherein in the step S3, steps of the first laser scanning and the second laser scanning comprise: placing the alloy sample blocks in prefabricated fixtures of a selective laser melting equipment, and setting scanning speed to 10-600 mm/s, laser power to 50-300 W, and scanning spacing to 0.05-0.1 mm for scanning.

### Claim 6 (depends on 5)

The composition design optimization method of claim 5, wherein in the step S3, the prefabricated fixtures are grooves machined on a substrate of the selective laser melting equipment, matching dimensions of the alloy sample blocks, with a height of 2 mm.

### Claim 7 (depends on 6)

The composition design optimization method of claim 6, wherein the step S4 specifically comprises: transferring the alloy sample blocks from the step S3 to a high-frequency induction furnace, using the high-frequency induction furnace for heating with a heating temperature of 450-550° C., and holding time of 5-60 seconds, and quenching the alloy sample blocks with water to room temperature after holding.

### Claim 8 (depends on 7)

The composition design optimization method of claim 7, wherein in the step S1, making each alloy ingot comprises: preparing raw materials, mixing pure metals, master alloys and smelting aids, and then smelting to obtain an alloy melt; a method of smelting is any one of resistance furnace smelting, induction smelting, and vacuum smelting; then casting the alloy melt with a mold with a flat cavity to form a slab-shaped alloy ingot.

### Claim 9 (depends on 8)

The composition design optimization method of claim 8, wherein in the step S2, pre-treating and processing each alloy ingot comprises: homogenizing the alloy ingot, and then processing and cutting the alloy ingot to form a round alloy sample block with a thickness of 5-10 mm and a diameter of 20-30 mm.

### Claim 10 (depends on 9)

The composition design optimization method of claim 9, wherein in the step S5, according to cracking degree, pore size, morphology and microstructure uniformity of the second laser melting layer of each alloy sample block, whether the alloy sample block with designed formula is suitable for selective laser melting process is evaluated, and microstructure and properties of the second laser melting layer of the alloy sample block and alloy powder with the same formula after selective laser melting are compared, to optimize composition of aluminum alloy for selective laser melting process.