Laser shock peening improves fatigue and durability of aircraft structures

Columbus, OH - University of Cincinnati (UC) researchers and Airbus engineers have developed a laser shock peening (LSP) technology in which several lasers simultaneously focus beams of infrared light on sections of aluminum, titanium, or nickel-based superalloy components, as published by the American Society for Metals. The beams deeply compress and change the structure, altering the physical and mechanical properties and increasing strength, durability, and corrosion resistance.

When the metal is processed, a ridged, geometric grid patterns its surface; that's the section of the sample that is enhanced for fatigue and corrosion resistance. Each sample goes through a rigorous series of manipulations and tests for stress, heat, and environmental effects. Structural and chemical properties are assessed right down to its nanostructure.

UC is said to be the only university in the United States to offer LSP for use in research and development and prototyping efforts through the Ohio Center for Laser Shock Processing for Advanced Materials and Devices. The center was recently established with a $3 million grant from the State of Ohio Third Frontier Program. General Electric, which developed and patented the process, gifted its original equipment and know-how to the university in 2005.

"Critical aircraft components are subjected in service to high stresses, fatigue, and corrosion. We hypothesize that the LSP processes impart deep, compressive, residual stresses to these components, strengthening the metal in a very deliberate way, which makes it less likely to fail," explains S.R. 'Manny' Mannava, professor in the department of mechanical and materials engineering in the College of Engineering and Applied Science.

"When we have confirmed that the metal itself won't fail due to fatigue, cracking, or corrosion, we will fortify huge pieces of metal for use in prototypes and, eventually, mass production," says Vijay K. Vasudevan, professor in the department of mechanical and materials engineering in the College of Engineering and Applied Science. "We will also conduct basic research to understand the effects of the process on material behavior, in order to optimize the process for specific future applications."