Abstract
Young’s modulus, rigidity modulus and thermal expansion in the palladium-gold system were measured at low and high temperatures after various heat-treatments and cold works. It has been found that the temperature coefficients of Young’s modulus and rigidity modulus of palladium-gold alloys annealed at 1000°C for 1 hr show a negative minimum value of −3.0×10−5 at a composition of 50% gold. However, the minimum turns to a positive value of 2.8×10−5 when heated at 360°C for 15 hr after water quenching from 1000°C or cold reducing of 96%. And the thermal expansion coefficient of palladium-gold alloys annealed at 1000°C for 1 hr has a minimum at composition of 48% gold. This minimum corresponds to the maximum temperature coefficient of Young’s modulus or rigidity modulus in the palladium-gold alloys. Moreover, the hardness of these alloys heated at 360°C for 15 hr after water quenching or cold working is about two times that in the annealed state. These alloys were named “PALLAGOLD” which is a abbreviation of palladium-gold alloy.
