[20a-224A-1~10] 3.7 Laser processing

[20a-224A-1] In-situ observation of crystal structure transition of austenitic stainless steel during laser peening using X-ray free-electron laser

〇(PC)Kohei Miyanishi¹, Yoichiro Hironaka¹, Takashi Kurita², Keisuke Shigemori¹, Takeshi Matsuoka¹, Norimasa Ozaki¹, Eisuke Miura³, Takeshi Watari², Yoshio Mizuta², Yuki Kabeya², Yoshinori Kato², Norio Kurita², Ryunosuke Kuroda³, Ryosuke Kodama¹ (1.Osaka Univ., 2.HPK, 3.AIST)

Keywords:laser peening, austenitic stainless steel, crystal structure transition

The crystal structure transitions of austenitic stainless steel under laser peening were observed using in-situ X-ray diffraction. Any structural transitions were not observed under compression whereas structural transition from the fcc structure to the hcp structure was observed in the release process from compression, and transition to the bcc structure was observed after release. These results suggest that the tensile stress in the pressure release process transforms the fcc structure to the bcc structure via the hcp structure.