Component Surface Treatments for Engine Fatigue Enhancement

The feasibility of improving damage tolerance of the F119 4th stage compressor IBR blades with low plasticity burnishing (LPB) was successfully demonstrated in Phase I. Fatigue results for Ti-6246 blade-edge specimens showed LPB completely mitigated FOD upto 0.03 in. deep and provided an endurance limit above the Kt=3 design limit for massive FOD up to 0.1 in. deep. In Phase II, the leading edge and blade tip compressive residual stress distributions will be designed for the blade geometry and appliedstresses to provide maximum achievable damage tolerance with minimal distortion and equilibrating tension in the core of the blade. CNC processing code will be developed first for single blade processing of the leading edge and tip. The residual stressdistributions achieved and their thermal and mechanical stability will be tested relative to conventional shot peening. The HCF performance and damage tolerance achieved will be documented. CNC code and tooling for LPB processing of full-scale IBRs willthen be developed and demonstrated. The design of an automated production facility for LPB processing full IBRs in manufacturing and repair and in process quality control will be addressed for transition to production in Phase III.