| AVS 64th International Symposium & Exhibition | |
| Applied Surface Science Division | Thursday Sessions |
| Session AS-ThP |
| Session: | Applied Surface Science Poster Session |
| Presenter: | Harry Meyer, Oak Ridge National Laboratory |
| Authors: | H.M. Meyer, Oak Ridge National Laboratory D. Leonard, Oak Ridge National Laboratory A. Sabau, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Lightweight materials, such as aluminum alloys, find increasing use in both automotive and aerospace applications. A key requirement for their use is effective surface cleaning and texturing techniques to improve the quality of the structural components. Work at ORNL focuses on the a novel surface treatment method using laser interferometry produced by two beams of a pulsed Nd:YAG laser. Operating at 10Hz of frequency, this technique has been used to clean aluminum surfaces, and at the same time creating periodic and rough surface structures. The influences of beam size, laser fluence, wavelength, and pulse number per spot are currently under investigation. Metallic aluminum is very reactive with atmospheric oxygen and quickly forms a native oxide surface layer. This layer of oxide on the surface can affect further manufacturing processes, such as welding, and must be removed prior to any joining step. Without proper surface preparation, seams and joints are susceptible to increased wear, degradation and, in some cases, catastrophic failure. There are many methods for removing aluminum surface oxides, including mechanical (i.e. abrasive wear) and chemical stripping, generally used for complex part geometries. Despite its effectiveness, chemical stripping also introduces higher costs associated with environmental protection and hazardous-waste management. Aluminum and aluminum alloy surfaces can be cleaned using high-energy laser pulses (nanoseconds to milliseconds range) and is accomplished mainly by surface melting and ablation. This method is a non-contact process without abrasion and chemical impact and the controllability offered by using lasers enables high-precision removal of surface oxides and other contaminants in the range from sub-micrometers to several millimeters. The process being optimized at ORNL is using a 2-beam method that not only cleans the surface for joining but textures the surface in a periodic manner. This poster present preliminary surface characterization results for the cleaning of Al-alloy surfaces. Results from optical and electron microscopies, scanning Auger microanalysis, x-ray photoelectron spectroscopy, and contact angle measurements on as received and laser–treated Al-2024 alloy surfaces will be shown. This abstract has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.