High Temperature Oxidation Kinetics of Shot-Peened and Laser-Shock Peened Ti-Beta-21S

Isothermal oxidation tests of mechanically treated Ti-Beta-21S (TIMET, Ti–15Mo–3Nb–3Al–2Si, ASTM Grade 21) were performed under dry air at 650, 700 and 750 °C for 100 h compared to untreated samples. Two different mechanical surface treatments used: ultrasonic shot-peening (SP) laser-shock peening (LSP). The study investigates the effect both on kinetics process role atmospheric nitrogen insertion. With this aim, experiments also pure oxygen. results show that is governed by diffusion after a short transient time. Both SP LSP improve high temperature resistance in air, but not formation nitrogen-enriched layer oxide–metal interface, which promoted treatments, explains increase slowing down oxygen into metal.