28 Jul 2025
Dublin group develops Laser Ablation Particle Acceleration & Observation system to watch 10-60μm particles crashing at 1 km/s.
Researchers from Trinity College Dublin’s School of Engineering (TCD) have built a powerful new machine that reveals precisely what happens when tiny particles hit a surface at extremely high speeds. It is said to be the only machine like it in Europe, and it has taken more than two years to design and build.
The Laser Ablation Particle Acceleration and Observation (LAPAO) machine, built by Trinity’s Science & Technology in Advanced Manufacturing (STAM) research group, uses a laser to fire particles of 10 to 60 μm in size at speeds of up to 1 km per second (or about three times faster than a bullet). A dedicated camera, taking a billion pictures per second, then captures how these particles behave when they impact a surface, helping top answer the questions do they stick, bounce, or break?
Answers to these questions are important, says the team at TCD, because they can help engineers understand how to make better materials and coatings, such as for aircraft parts, medical implants, or protective layers for machinery. The process the development team is improving is called “Cold Spray”, which is a way of printing or repairing metal parts without needing to melt them.
LAPAO ‘a game-changer’
Until now, the TCD researchers could only guess at solutions based on computer models. With the LAPAO machine, they report that they can finally see what is really happening, described as “a game-changer for how to design and manufacture advanced materials”.
Leo Devlin, Ph.D. Candidate in Trinity’s School of Engineering, and a key member of the STAM team, said, “Thanks to our machine we can now obtain material parameters for micro-particles undergoing ultra-high strain rate plastic deformation, which is something that modelers have been attempting to predict for a very long time. Due to software limitations, however, they have not been able to predict particle behavior with a high enough degree of accuracy.
He added, “With this machine we can visualize real material interactions for a wide range of particle and substrate materials in minutes, which will aid us in understanding and optimizing the cold spray process for specific materials. To date, the machine has been used to find the critical velocity for a range of materials such as aluminum, Ti64, and high entropy alloy, which are used in the electrical and automotive industries as coatings which can lead to lightweight parts with more desirable material properties such as high wear and corrosion resistance.”
Over the past few years, cold spray technology has evolved into advanced variants such as laser-assisted and electromagnetism-assisted cold spray, to improve the microstructure and performance of deposited materials. Cold spray enables the formation of coatings, typically metallic, over a substrate material.
The technique is said to be highly useful as it does not require engineers to reach the melting temperature of materials to combine the coatings and substrates. Plastic deformation is key in this process; each tiny particle deforms on impact and triggers a complex bonding process that results in substrate adhesion and in particle-particle adhesion after a first deposition layer is formed.
“Today, beyond its traditional use in the aerospace industry, cold spray is also being applied in the nuclear, automotive, and broader manufacturing sectors,” said Prof. Shuo Yin, from the STAM team in Trinity. “In addition, this new machine can also be used to simulate other high-velocity microscale impact events, such as debris impacts on satellites in space, which is a growing problem with ever-increasing junk material orbiting Earth along with very important — and expensive — equipment.”
Prof. Rocco Lupoi, from the STAM team in Trinity, said, “Any particle impact can now be studied using any real shape, and we are already using this technology in a project called MadeCold, which is developing a new type of cold spray based upon electrostatic acceleration of single particles. LAPAO is now providing clear indications about the precise velocity needed for bonding and giving us key information about the relationship between particle material and morphology.”