Fatigue Life Improvement with Surface Treatments other than Shot Peening

Efforts proposed in this program are focused on the development of next-generation laser peening surface treatment technology, which may be used as an alternative to conventional metal shot peening. The proposed program involves the development of enhanced laser peening equipment and procedures, which combine the objectives of an affordable process with high productivity and effectiveness in terms of treating structures and components to achieve deep compressive residual stresses. The proposed technology will be universally applicable to a wide variety of materials, including high-strength carburized steels, and to a wide variety of components such as aerospace gears and other propulsion system components. Laser peening has emerged as the leading technology for imparting deep compressive residual stresses with precise process control on fatigue-critical parts. Achieving deep compressive residual stresses (in excess of 0.040 inches or 1 mm) is particularly important for carburized gear steels. The developments proposed under this program have the potential to reduce the cost of laser peening by an additional 25 percent to 50 percent and enable the development of smaller, more affordable laser peening systems, which could be deployed in industrial environments or at military depots. BENEFITS: A successful outcome for the Phase I program will lead to significant reductions in the cost of the laser peening and expansion of laser peening applications. The use of next generation laser peening equipment and procedures will result in lower captial equipment and maintenance costs, leading to significant process cost reductions. This cost reduction will allow many military components to be laser peened affordably, taking full advantage of the fatigue performance benefits offered by this process.