Influence of Thermal Cycling on the Fatigue Strength of the Interface between Ag-Pd Alloys and Hydrothermal Ceramics

Svrha ovoga rada bila je istražiti utjecaj termocikliranja na dinamičku izdržljivost spoja Ag-Pd slitine i hidrotermalne keramike. Istraživanje je obavljeno na 48 uzoraka Ag-Pd slitine izrađenih u obliku pločica 45x12x4 mm na koje je napečena 2 mm debela hidrotermalna keramika. Uzorci su podijeljeni u dvije skupine. Prva skupina uzoraka odmah je nakon izrade bila dinamički opterećivana, druga je skupina uzoraka prije dinamičkih opterećenja termociklirana na temperaturama 0 °C i 55 °C 1000 puta. Mjerenje dinamičke izdržljivosti provedeno je modificiranom metodom po Schwickerathu u Amslerovu visokofrekventnom pulzatoru. Izmjerene su veće vrijednosti maksimalne dinamičke izdržljivosti za netermociklirane uzorke u iznosu od 850N, dok su utvrđene manje vrijednosti maksimalne dinamičke izdržljivosti za termociklirane uzorke od 550N. Statistički značajna razlika pronađena je između graničnih opterećenja Fg i broja ciklusa n za obje istraživane skupine uzoraka.The purpose of the present paper was to investigate the influence of thermocycling on the fatigue strength of the Ag-Pd alloy and hydrothermal ceramics interface. The investigation was performed on 48 samples made o f Ag-Pd alloy frames (45x12x4 mm) on which the hydrothermal ceramics were fused (25x12x2 mm). The specimens were divided into two groups. The first group o f samples was dynamically loaded immediately after working, while the other group o f samples was thermocycled (1000 times at 0 °C and 55 °C) before dynamic loading. The dynamic loading tests were carried out by using the modified three- -point load method by Schwickerath in Amsler’s high-frequency pulsator. The determined dynamic loading limit was up to 550N for thermocycled samples, and up to 850N for non-thermocylied samples. A statistically significant difference between maximal dynamic forces and the number o f loading cycles for both groups o f samples was determined