Ultrashort Pulsed Laser Surface Modification of Stainless Steel 316L and Titanium Ti-6Al-4V
TWI Industrial Member Report 1174-2023 [pdf / 2080 KB]
By Andy Wilson and Christian Stadter
With the latest developments in the field of ultrashort pulse laser technology, high-energy pulses with remarkably high repetition rates are becoming readily available. Thus, new applications such as low surface energy or repellent surfaces, anti-icing surfaces, and surface preparation and cleaning prior to subsequent materials processing are emerging, as large surface areas can be processed efficiently. Key industrial sectors that this can apply to range from aerospace to automotive, consumer goods, spectroscopic equipment and medical. Although the basic mechanisms of the interaction of ultrashort pulses with matter have been researched for decades, of transfer of this knowledge to real world applications remains limited. For that reason, this work aimed to identify parameters and effects that dominate the process output of an ultrashort pulsed laser. Stainless steel 316 (SS 316L) and Ti‑6Al‑4V titanium alloy were identified as key materials with a view to future applications.
- The surface free energy of SS 316L was generally decreased compared with the unprocessed condition. Medium pulse energies seem to be most appropriate to decrease the total surface free energy.
- Ti 6Al 4V showed exclusively an increase in surface free energy due to processing with ultrashort laser pulses within the scope of this study.
- Adopting ultrashort laser processing for large scale surface modification is approximately three to five years away, according to current trends in manufacturer increases of average power and improvements in optical delivery, process monitoring and automation systems.
- Whilst this technology is not yet mature enough for adoption into existing processing facilities because of the limitations of current processing speeds, the fundamental studies show that the benefits in terms of surface energy control of SS 316L and Ti-6Al-4V.