S. Chen, H. H. Kwon, N. Mitchell, University of Texas at Austin, Austin, TX; Y. Guo, The University of Alabama, Tuscaloosa, AL
Laser shock peening is a technology that a laser beam is used to create a shockwave, which then in turn “dents” the target material, creating a compressive residual stress in the surface of various metallic components. There are several advantages associated with laser shock peening. The primary advantage is that when a series of dents are made in the material in a regular pattern, which may act as lubricant reservoir for improved sliding/rolling performance. In addition, the fatigue life of the material can also be greatly improved. A sample that has been treated with laser shock peening will generally have a superior fatigue life that is on the order of several times longer than those of non-treated surfaces. In addition, laser shock peening can improve the corrosion resistance of a specimen, as well as several other properties. Here we report our experimental investigation of sub-micron scale laser shock peening of Aluminum (Al) and Ti-6Al-4V (Ti) surfaces. A Nd:YAG laser (355 nm wavelength, 10 ns pulse width) was used. The metal surfaces were coated with a layer of alumina foil as a sacrificial layer. The sample was then immersed in water. The laser beam was focused on the alumina foil surface to generate the shock wave. Micro and sub-micron dents were generated in Al and Ti samples surfaces. The dent size dependence on the laser energy/intensity was also investigated. Both scanning electron microscopy and atomic force microscopy were used to characterize the surface topography.
Summary: Laser shock peening is a technology that a laser beam is used to create a shockwave, which then in turn “dents” the target material, creating a compressive residual stress in the surface of various metallic components. There are several advantages associated with laser shock peening. The primary advantage is that when a series of dents are made in the material in a regular pattern, which may act as lubricant reservoir for improved sliding/rolling performance. In addition, the fatigue life of the material can also be greatly improved. A sample that has been treated with laser shock peening will generally have a superior fatigue life that is on the order of several times longer than those of non-treated surfaces. In addition, laser shock peening can improve the corrosion resistance of a specimen, as well as several other properties. Here we report our experimental investigation of sub-micron scale laser shock peening of Aluminum (Al) and Ti-6Al-4V (Ti) surfaces. A Nd:YAG laser (355 nm wavelength, 10 ns pulse width) was used. The metal surfaces were coated with a layer of alumina foil as a sacrificial layer. The sample was then immersed in water. The laser beam was focused on the alumina foil surface to generate the shock wave. Micro and sub-micron dents were generated in Al and Ti samples surfaces. The dent size dependence on the laser energy/intensity was also investigated. Both scanning electron microscopy and atomic force microscopy were used to characterize the surface topography.
