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Jiang, L.*; Oshima, Nagayasu*; O'Rourke, B. E.*; Suzuki, Ryoichi*; Harada, Yoshihisa*; Suzuki, Takayuki*; Takatsu, Shuhei*; Hirade, Tetsuya; Takai, Kenichi*
no journal, ,
Positron annihilation spectroscopy (PAS) is a sensitive method for detection of defects such as vacancies, vacancy clusters and nano-voids. The positron probe microanalyzer (PPMA) in AIST can investigate defect distribution of materials using a scanning positron microbeam. For the application of the PPMA for analysis of such materials it is important to consider the defects introduced during the sample preparation. we are investigating two kinds of sample preparation process, electrical discharge machining (EDM) and colloidal silica polishing after EDM. We are studying the depth dependence of the density of the defects induced by these processes in various metals, including SUS316L, using PAS.
Jiang, L.*; O'Rourke, B. E.*; Harada, Yoshihisa*; Takatsu, Shuhei*; Ito, Kenji*; Okubo, Masataka*; Hirade, Tetsuya; Uedono, Akira*; Suzuki, Ryoichi*; Takai, Kenichi*; et al.
no journal, ,
We are studying the depth dependence of the density of the defects induced by the electrical discharge machining (EDM) in SUS316L, using the electron probe microanalysis (EPMA), Positron annihilation lifetime spectroscopy (PALS) and X-ray diffraction (XRD). EPMA results show a large change in the composition over the first 10 
m. This layer can be assumed to correspond to the recast layer. PALS and XRD results suggest a defect layer with a thickness of around 50 m. This depth can be assumed to correspond to the heat affected zone where dislocations and vacancy clusters exists. For PALS (and other methods) analysis, it is recommended to remove the topmost 100 m of the samples by chemical polishing after EDM.