HYDROGEN--INDUCED DELAYED FRACTURE IN TiNi
TiNi形状记忆合金的氢致滞后断裂

Hydrogen-induced delayed fracture during dynamic charging of TiNi shape memory alloy, and the role of atomic hydrogen, hydrogen-induced martensite and hydride in hydrogen-induced delayed fracture have been investigated. The results show that hydrogen-induced delayed fracture in TiNi alloy could occur, and the normalized threshold stress intensity factor decreased linearly with increasing the total hydrogen concentration, i.e., KIH/KIC=2.01-0.25 LnCT. The content of hydride increased continuously during dynamic charging, and the fracture toughness of the TiNi alloy decreased gradually, which is the main cause of hydrogen-induced delayed fracture. The role of atomic hydrogen and hydrogen-induced martensite in hydrogen-induced delayed fracture was very small.