TiNi超弾性合金細線の疲労寿命におよぼす応力繰返し速度と水素環境の影響

抄録

In this study, the fatigue behavior of TiNi Super Elastic Alloy under hydrogen environments were investigated by using thin wires with the diameter of 0.7 mm. Fatigue tests with stress ratio of R = 0.1 were conducted in two environments: in air and NaOH solution with hydrogen charging (current density J = 127 mA/mm²).Frequency were 2Hz and 10Hz. Fatigue life decreased in hydrogen environments than that in air. Frequency does not effect of the fatigue life in air, while fatigue life in hydrogen environment are time deperdent in the region of low stress amplitude. In microscopic observation, brittle surface layer was formed and surface spalling occurred only for J = 127 mA/mm².