Development on the Tensile Fatigue Test Apparatus and Strength Evaluation of Thin Metal Films

Recently, development of medical devices such as catheter and stent are advanced in the loi invasion medical field. Considering the functions of human body are affected severely by the mediczdevices, the high strength reliability of devices must be secured. In these circumstances, the thi metal film, which has high reliability of strength, is useful structural material for further developmer of low invasion medical device. As the strength characteristics of a thin film depend on thickness an formation process of itself, there is little strength database concerning a thin metal film. In this stud] a tensile fatigue testing apparatus with cyclic loading frequency up to 30 Hz and maximum loadin 8 N for the thin metal film has been developed, and thin rolled films Ti and SUS304 were evaluate on tensile and load-controlled fatigue strength. The static tensile tests give that both are also OVE the twice of the bulk material on the tensile strength, and the proof stress is high-strength with OVE 90% of tensile strength respectively. The fatigue test shows that Ti thin film has long life i comparison with the bulk material, however, the fatigue characteristic itself is similar like that bulk material.