Thermomechanical properties of iron: Viscoplasticity of ferrite and of austenite-ferrite mixtures

The available data on secondary deep in creep tests and on maximum stress in hot deformation tests obtained for delta and alpha ferrite have been reviewed and expressed in the form of the equation epsilon = K(sigma/E)(Pc) sinh(V sigma/RT) exp(-Q(c);RT) with P-c = 2.5, V = 0.0013 m(3) mol(-1), and K = 2.6 x 10(17) s(-1), E and Q(c) bring temperature dependent functions. The approximate range of validity is Z = epsilon exp (Q(c)/RT) approximate to 10(1)-10(11) s(-1). Together with the corresponding equation for austenite the data can be used to predict the viscoplastic behaviour of austenite-ferrite mixtures. (C) 1996 The Institute of Materials.