Applicability of an exponential law in creep of metals

Abstract

An exponential type creep equation has been developed for heat resistant steels by the authors. This equation was induced assuming both a thermally activated process for a mobile dislocation and rather high applied stress. The applicability of the new creep equation was examined for a pure iron, two kinds of Ni-base super alloys and an eutectic solder alloy in a Pb-Sn system which were tested at relatively high temperatures and under very low stresses. All of the data obtained were completely explained by the new creep equation. The data for each alloy were classified into a few groups, where a deformation mechanism may be different with each other. The new creep equation is valid for stresses higher than the half value of the slope in a logarithm of time to rupture vs. linear stress diagram.