Creep and Sagging of Dental Alloys

Abstract

Creep is defined as the permanent deformation of a material when subjected to stresses below the yield strength as a function of time and temperature. Creep is normally an undesirable phenomenon and is often a limiting factor in the lifetime of a material.

The temperature range in which creep deformation may occur differs in various materials. Creep deformation generally occurs when a material is stressed at a temperature near its melting point. If a metal is held at a temperature near its melting point, over a period of time at stresses well below the material’s yield strength, permanent deformation can take place and the resulting strain will increase over time. The effects of creep deformation generally become noticeable at approximately 35% of the melting point for metals.