Carbon composition and temperature dependence of relative change in length during isothermal decomposition of Fe–C austenite

Abstract

The carbon composition and temperature dependence of the relative change in length during isothermal decompos ition of Fe–C austenite has been modelled. Decomposition of austenite above and below the A₁ temperature has been considered, as well as a two-step procedure where a specimen decomposes into ferrite and carbon enriched austenite at a temperature above A₁ and is subsequently subjected to transformation below A₁ leading to ferrite and cementite. Analytical expressions have been given for the relative change in length as a function of carbon composition, isothermal decomposition temperature, and degree of transformation. Predicted changes in length have been compared with experimental results.