CONSTITUTIVE DESCRIPTION OF CREEP IN SILICON-IRON AT HIGH-TEMPERATURES

Primary and steady state creep in a Fe-3 wt% Si solid solution was inv estigated in the temperature interval 823-973 K at applied stresses wh ich resulted in minimum creep rates of 10(-7)-10(-3) s(-1). The creep curves were described by the McVetty equation and the dependence of it s parameters on external variables was discussed. For a constitutive d escription of the curves based on the choice of the internal stress as a single internal variable, a set of constitutive equations that incl ude the experimentally found relation between the creep rate and the i nternal stress were suggested. Consequences resulting from this sugges tion for the internal stress values which follow from the analysis of the creep curves were discussed.