Advancing Aerospace Manufacturing: Optimizing Spherical Titanium Powder For 3D Printing Applications

Summary:

This project investigates the application of spherical titanium powder in advanced 3D printing for aerospace components. The aim is to optimise the powder properties and printing parameters to improve the mechanical performance of additively manufactured titanium parts. The methodology involves synthesising spherical titanium powder by gas atomisation, characterising its morphology and particle size distribution, and conducting a range of 3D printing experiments with varied process parameters. The printed samples undergo tensile, fatigue, hardness and impact tests, as well as microstructural analyses using light microscopy, scanning electron microscopy and X‑ray computed tomography. This study quantifies improvements in part density and surface finish, thereby addressing the demand for lightweight, high‑strength materials in aerospace.

Background:

The aerospace industry continually seeks innovative manufacturing methods to improve performance and fuel efficiency. Additive manufacturing, particularly 3D printing with metal powders, enables the production of complex, lightweight components with enhanced mechanical performance. Titanium alloys are used because they offer a high strength-to-weight ratio, corrosion resistance and excellent high temperature performance. Spherical powder technology is crucial as the shape, size distribution and flow behaviour directly affect the consistency and overall quality of the printed parts. This project focuses on optimising spherical titanium powder for aerospace applications, aiming to improve the properties of 3D‑printed components.

Methodology:

Our approach comprises several key phases:

1. Powder Synthesis:

High‑purity titanium is melted and atomised using inert gas nozzles. Gas atomisation parameters, such as gas pressure, melt temperature and nozzle design, are adjusted. Multiple runs are performed to obtain an optimal particle morphology and size distribution.

2. Powder Characterisation:

Particle size distribution is determined by laser diffraction analysis. The morphology is examined using scanning electron microscopy (SEM). The chemical composition is measured with X‑ray fluorescence spectroscopy (XRF). Flow behaviour is assessed by a Hall flowmeter and angle of repose tests. Both apparent and tap density are recorded.

3. 3D‑Printing Experiments:

A 3D metal printer equipped with a 500‑W fibre laser is used. Printing parameters such as laser power, scan speed, layer thickness, hatching distance and powder bed temperature are varied. For each parameter set, standard samples including tensile bars and fatigue specimens are printed.

4. Post‑Processing and Heat Treatment:

Printed samples are subjected to heat treatment for stress relief. A subsequent hot isostatic pressing (HIP) is applied to reduce porosity and improve mechanical performance.

5. Mechanical Testing and Microstructural Analysis:

Tensile tests determine yield strength, ultimate tensile strength and elongation. Fatigue tests assess cyclic performance. Hardness is measured and impact toughness is evaluated. Microstructural analysis is undertaken using light microscopy and SEM. Internal defects and porosity are examined by X‑ray computed tomography.

Results and Discussion:

Preliminary results indicate that powder sizes between 15–45 μm produce a better surface finish and increased part density. Excessively fine powders reduce flow behaviour and raise the risk of agglomeration. Optimisation of the laser parameters demonstrates that balancing high energy density against moderate scan speeds is essential to attain the desired microstructure and mechanical properties. The optimised parts display tensile strengths comparable to those of titanium wrought alloys. Rapid solidification during 3D printing leads to a fine, needle‑like α'-martensitic structure. Subsequent heat treatments convert this structure into an α+β phase, thereby enhancing ductility without a notable reduction in strength.

Challenges and Future Work:

Despite promising outcomes, several challenges remain in fully optimising spherical titanium powder for aerospace applications:

1. Powder Recycling: High titanium powder costs demand efficient recycling methods. Future work will quantify the effects of repeated powder reuse on particle properties and printed part quality.

2. Scalability: Transitioning from small test samples to full‑scale aerospace components is challenging. Future work will develop scaling algorithms for the printing parameters.

3. Anisotropy: 3D‑printed titanium parts exhibit some anisotropy in mechanical performance. Research will focus on reducing this effect by modifying scanning strategies and post‑processing techniques.

4. Qualification and Certification: Aerospace applications require strict qualification protocols. We plan to collaborate with industry partners such as Oceania International LLC to develop test protocols and generate data required for certification.

Potential Impacts:

The optimisation of spherical titanium powder for 3D printing can have several impacts on the aerospace sector:

1. Weight Reduction: The production of intricately designed, topology‑optimised components can result in significant weight savings in aircraft structures, thereby reducing fuel consumption.

2. Supply Chain Flexibility: On‑demand production of replacement parts may reduce storage costs and aircraft downtime.

3. Design Freedom: Engineers can investigate innovative designs that were previously impractical, thereby enhancing the performance of aircraft systems.

4. Material Efficiency: Additive manufacturing produces less waste than subtractive processes, which supports sustainability targets in aerospace.

5. Rapid Prototyping: Shorter development cycles can accelerate innovation and reduce the time-to‑market for new designs.

In summary, this project demonstrates a significant step in applying spherical powder technology for aerospace applications. By optimising the titanium powder properties and corresponding 3D printing parameters, the project establishes a foundation for extended additive manufacturing applications in aerospace, leading to lighter, stronger and more efficient components.

This is a contribution for the SAM Scholarship 2024 on the subject of spherical powder, composed by Antonio Zuquilanda.

Biography:

Antonio Zuquilanda is a dedicated student pursuing a Bachelor’s degree in Political and Economic Sciences at the University of Connecticut with a perfect score of 4.0. His academic journey began at Manchester Community College, where he graduated Summa Cum Laude with an Associate degree in Liberal Arts & Sciences. Although he formally studied social sciences, he has actively pursued opportunities in STEM, particularly in materials science. His motivation for this project arises from a desire to integrate his understanding of politics and economics with quantitative advances in aerospace technology. Antonio’s diverse experience, including internships in strategic planning and project management, positions him to approach spherical powder technology from an interdisciplinary perspective.