長時間時効したステンレス鋼中の水素集積サイトのトリチウム透過電顕オートラジオグラフィによる観察

抄録

Behavior of hydrogen accumulation in a long-term aged of austenitic stainless steel SUS316 was investigated by tritium transmission electron microscopic (TEM) autoradiography. The thin foil specimens were exposed either immediately after the electrolytic charging of tritium at 253 K (diffusing tritium) or after hold at the room temperature for three days (non-diffusing tritium). Tritium TEM autoradiographs were observed by changing the inclination of the specimen. Chromium carbide (Cr₂₃C₆) was precipitated along the grain boundary and within the matrix. Blackened silver particles of large number were observed around the chromium carbide (Cr₂₃C₆) and its circumference.
On the other hand, tritium TEM autoradiographs of the specimen held at room temperature for three days were revealed at the noncoherent interfaces of chromium carbide (Cr₂₃C₆) precipitated along the grain boundary and within the matrix. But they were not observed at better coherent interfaces of chromium carbide (Cr₂₃C₆). The amount of diffusing hydrogen were about seven times larger compared with those of non-diffusing hydrogen.