Fatigue strength properties of titanium (grade 2) at cryogenic temperatures

Knowledge of fatigue strength properties of materials is very crucial in the design of a mechanical system failing which the entire system can fail prematurely. Reliable data of strength properties of many engineering materials are not available at cryogenic temperatures. Available room temperature data cannot be extrapolated down to cryogenic temperature zone since many of the mechanical properties change abruptly. In this experimental study, a rotating beam fatigue testing machine suitable for both room and cryogenic temperatures has been designed and developed to determine fatigue strength properties of materials which are frequently used in cryogenic engineering applications. Tests are conducted within an insulated cryogenic chamber. Desired cryogenic temperatures down to 77K are maintained by circulation of pressurized liquid nitrogen with the help a solenoid valve and a PID controller. Fatigue strength properties of titanium (grade 2) are determined both at room and cryogenic temperatures and analyzed.