Elastic constants of three Ni-Cr dental alloys at room and elevated temperatures

Dental porcelains are fused to metals at elevated temperatures. Therefore, the development of stress that affects the stability of porcelain-fused-to-metal (PFM) systems may be influenced by the temperature dependence of the elastic constants of both materials. The sonic resonance technique was used to determine the elastic moduli for three nickel-based dental alloys. In addition to room temperature data, the temperature dependencies of the Young's modulus (Y) and the shear modulus (G) were determined up to 600 degrees C (873 degrees K). The measured values for the resonant frequencies decreased with increasing temperatures, which resulted in correspondingly low moduli. The decrement of the elastic constants over the temperature range considered is less than 10%. The change of Poisson's ratio as a function of temperature for the alloys considered is presented in this paper.