New Description of Steady-State Creep Rate, Yield Stress, Stress Relaxation and Their Interrelation
The steady-state creep rate increases with temperature according to the Arrhenius equation and its increase with applied stress is mostly described by the power law. Combining both these laws, equation ) exp( RT Qa n − µ s e& is obtained, where apparent activation energy a Q and stress sensitivity parameter n are considered to be constants. But most measurements show some dependence of activation energy on applied stress and of stress sensitivity parameter on temperature. An equation respecting these facts is derived in the paper and verified using some published results of creep tests. Based on this derived equation, the dependence of yield stress on temperature and strain rate and an equation describing the relaxation curves are deduced.
J. Kohout "New Description of Steady-State Creep Rate, Yield Stress, Stress Relaxation and Their Interrelation", Materials Science Forum, Vol. 482, pp. 319-322, 2005