|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Materials for High Temperature Applications: Next Generation Superalloys and Beyond
||Room and Elevated Temperature Fatigue Life Improvement of ATI 718Plus Using LSP Treatment
||Micheal Antoine Kattoura, Seetha Ramaiah Mannava, Dong Qian, Vijay Vasudevan
|On-Site Speaker (Planned)
Fatigue experiments on ATI 718Plus were conducted at room and elevated temperatures (650 ˚C) to study the improvement in the fatigue life due to Laser Shock Peening (LSP). Stress controlled uniaxial fatigue tests were conducted on base-material and LSP-treated samples to determine the improvement in fatigue life. LSP created surface residual stresses around -700 MPa and increased the surface hardness by 24%. LSP improved yield strength by 16% and endurance limit by 15% at room temperature. The mechanical, thermal, and thermo-mechanical relaxation of residual stresses have been investigated. Residual stresses retained 66% of its amplitude after 140 hours at 650 ˚C. In addition, changes in the microstructure after LSP-treatment and fatigue testing at both temperatures were characterized using the Scanning Electron Microscopy, Electron Back-Scatter Diffraction and Transmission Electron Microscopy. Near surface compressive residual stresses, microstructure and hardening induced by LSP effects on improvement in fatigue life are discussed.