An Analysis of High Temperature Metal Creep—Part II: A Constitutive Formulation and Verification

A phenomenological development of a constitutive equation is presented for the high temperature viscoplastic flow of a metal. The development rests on a viscoelasticity foundation but incorporates several features of a classical metals theory. The one dimension representation is developed using the creep response, strain rate response, and stress rate response of wrought Udimet 700 at 926.7°C (1700°F). The strain response to several cyclic stress histories is successfully predicted using the model. A three dimensional theory is proposed.