Creep

Abstract

The creep behavior of MMCs is of great significance, since in many structural and nonstructural applications, these materials will be subjected to constant stress (or strain) for long periods of time, at temperature above half of the homologous temperature (homologous temperature is the temperature of interest divided by melting point, both in K; i.e., T/T_m). Most materials exhibit three distinct stages of creep: (1) primary creep, (2) secondary or steady-state creep, and (3) tertiary creep. In primary creep, the strains are relatively small. In the secondary or steady-state regime, a linear relationship exists between the strain and time (constant strain rate). This is believed to be a result of the combination of hardening and recovery mechanisms during creep. Finally, in the tertiary regime, the material undergoes cavitation and void growth, which is manifested in terms of a very rapid increase in strain with time.