NDT

LaserPeening Improves Blade Life

We've all seen demonstrations where laser beams have been used to cut various metals "like butter." LSP Technologies (www.lspt.com) has found another and much more constructive use for the power of light: it makes metal stronger. The LaserPeen process uses a high-energy pulsed laser to drive a high-amplitude shock wave into a material surface. The process creates a residual compression stress area deep within the part's surface. These compression surface stresses inhibit the initiation and propagation of cracks in high-stress areas and make the blades much more resistant to metal fatigue and foreign object damage.

The depth and magnitude of the residual stresses depend upon the material and LSPT's LaserPeen processing conditions, which can be tailored for specific applications. The company states that the effects are seen typically five to ten times the depth of standard metal shot peening.

The process is particularly effective in controlling cracking and fatigue failure problems in titanium alloy fan and compressor blades. To date the LaserPeening technology has been used effectively to prevent cracking in the turbine blades used in the engines of a variety of U.S. Air Force aircraft including the B-1 and F-16. Plans are also underway to use it during production of engine fan blades for the F/A-22 and Joint Strike Fighter.

A company spokesperson said that as the technology matures, there are plans to offer it to the commercial segment of the aviation industry.