Laser Fusion of Aluminum Powder Coated with Diamond Particles via Selective Laser Melting - Powder Preparation and Synthesis Description
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2021-10-05 |
| Journal | Coatings |
| Authors | Alexander S. Shinkaryov, D. Yu. Ozherelkov, Ivan A. Pelevin, С. А. Еремин, V. N. Anikin |
| Institutions | National University of Science and Technology, Skolkovo Institute of Science and Technology |
| Citations | 15 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This study investigates the synthesis of aluminum-diamond Metal Matrix Composites (MMC) using Selective Laser Melting (SLM) to achieve enhanced mechanical properties.
- Core Value Proposition: Successful fabrication of AlSi10MgCu matrix composite reinforced with 500 nm diamond particles, yielding material with microhardness significantly exceeding standard SLM aluminum alloys.
- Powder Preparation: AlSi10MgCu powder (D50 = 43 µm) was uniformly coated with 0.67 wt% nanodiamond particles via mechanical mixing in a roller mill.
- Achieved Hardness: Maximum microhardness reached 172 ± 5 HV50, which is substantially higher than the 95-105 HV of high-pressure die-cast AlSi10Mg and the 150-155 HV of standard SLM AlSi10MgCu.
- Optimal Processing Window: Optimal SLM parameters were found to correspond to a Laser Energy Density (LED) range of 1.40-2.0 J/mm2, crucial for balancing sufficient melting with minimizing defects.
- Phase Transformation: XRD analysis confirmed the formation of aluminum carbide (Al4C3) due to the graphitization and subsequent reaction of nanodiamonds with the aluminum matrix during the high-temperature SLM process.
- Process Challenge: High laser energy density (LED > 2.7 J/mm2) caused excessive graphitization, leading to structural defects, microcracks, and sample destruction, highlighting the sensitivity of nanodiamond additives to thermal input.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Matrix Alloy Composition | 87% Al, 10.7% Si, 0.5% Mg, 0.7% Cu | wt % | AlSi10MgCu |
| Matrix Powder Median Diameter (D50) | 43 | µm | Initial AlSi10MgCu powder |
| Diamond Particle Size (Average) | 500 | nm | Reinforcement additive |
| Diamond Content | 0.67 | wt % | In composite powder |
| Maximum Microhardness | 172 ± 5 | HV50 | Achieved at LED 1.40 J/mm2 (Sample 10) |
| Optimal LED Range | 1.40-2.0 | J/mm2 | Recommended for dense, hard composite |
| Laser Power (P) Range Tested | 250-370 | W | SLM process input |
| Scanning Speed (V) Range Tested | 850-1650 | mm/s | SLM process input |
| Laser Energy Density (LED) Range Tested | 1.17-3.35 | J/mm2 | Calculated process variable |
| Powder Layer Thickness | 50 | µm | Fixed SLM parameter |
| Hatch Distance (h) | 0.13 | mm | Fixed SLM parameter |
| Laser Spot Size | 80 | µm | Fixed SLM parameter |
| Diamond Hardness (Reference) | ~100 | GPa | Carbon allotrope property |
| Diamond Thermal Conductivity (Reference) | up to 2200 | W/(m K) | Carbon allotrope property |
| Residual Oxygen Content | less than 0.2 | vol. % | Argon atmosphere requirement |
| Carbide Phase Detected | Al4C3 | N/A | Formed during SLM process |
Key Methodologies
Section titled “Key Methodologies”The Al-C composite was prepared and synthesized using a combination of mechanical coating and Selective Laser Melting (SLM).
- Nanodiamond Preparation: Nanodiamonds were synthesized via detonation of a condensed explosive mixture (TNT/RDX ratio 1.5). Non-diamond carbon was removed via a two-stage acid and water washing process.
- Composite Powder Coating: AlSi10MgCu powder was mechanically mixed with 500 nm diamond particles (0.67 wt%) using a laboratory roller mill (drum speed 48 rpm). This process ensured the aluminum particles were covered by several diamond monolayers without grinding.
- SLM Synthesis: Samples (10 x 10 mm, 300 µm thickness) were printed on an SLM Solutions 280 HL 3D printer.
- Atmosphere: Argon gas was used to maintain a low residual oxygen content (less than 0.2 vol.%).
- Scanning Strategy: A 67° rotation was applied layer-to-layer, building samples in the Z-axis direction.
- Fixed Parameters: Layer thickness (50 µm), hatch distance (130 µm), and laser spot size (80 µm).
- Variable Parameters: Laser Power (250-370 W) and Scanning Speed (850-1650 mm/s) were varied to test a wide range of Laser Energy Densities (1.17-3.35 J/mm2).
- Microstructural and Phase Analysis:
- Powder Characterization: TEM (particle size/shape), XRD (initial diamond phase), and Raman spectroscopy (diamond coating confirmation).
- Printed Sample Characterization: SEM/EDX (carbon presence, chemical distribution), XRD (phase identification, confirming Al4C3), and XPS (surface elemental composition and oxide analysis, using Ar+ ion etching for depth profiling).
- Mechanical Testing: Microhardness was tested using the Vickers method (HV50) with a loading test force of 490.3 N.
Commercial Applications
Section titled “Commercial Applications”This research focuses on developing high-performance Metal Matrix Composites (MMC) using additive manufacturing, targeting industries requiring superior strength-to-weight ratios and wear resistance.
- Aerospace and Defense: Fabrication of lightweight, high-specific-strength components where Al-matrix composites (AMC) are critical for fuel efficiency and structural integrity.
- Automotive Industry: Production of high-wear-resistant parts and components, leveraging the hardness provided by the diamond/carbide reinforcement.
- Advanced Tooling and Machining: Manufacturing complex metal-bonded diamond cutting and drilling tools. SLM overcomes traditional powder metallurgy limitations by achieving higher matrix-to-diamond holding forces and enabling intricate geometries.
- Thermal Management Systems: Utilizing the high thermal conductivity of diamond additives for developing efficient heat sinks and thermal interface materials in high-power electronic devices.
- Additive Manufacturing (SLM): Expanding the material portfolio for SLM technology, enabling the creation of new composite materials with tailored microstructures and properties previously unattainable by conventional methods.
View Original Abstract
This work aims to study the possibility of obtaining Al-C composite from AlSi10MgCu aluminum matrix with the addition of 500 nm-sized diamond particles by selective laser melting (SLM) process. Al-C composite powder was prepared by mechanical mixing to form a uniform cover along the surface of aluminum particles. The diamond content in the resulting AlSi10MgCu-diamond composite powder was equal to 0.67 wt %. The selection of the optimal SLM parameters for the obtained composite material is presented. For materials characterization, the following methods were used: scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was applied after SLM printing for a detailed investigation of the obtained composites. The presence of carbon additives and the formation of aluminum carbides in the material after the SLM process were demonstrated.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
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