The Influence of Alloying Elements on the Carbon Activity in Steel

摘要

An experimental method to determine the C activity in various solid solutions was developed. Samples of the solid solutions and an Fe-C reference sample were equilibrated with respect to C content by annealing them in a H2 - CH4 gas mixture in a closed cell. The C content of each sample was determined, and the C activity was obtained from the C content of the reference sample and well established data for the dependence of C activity on C content in Fe-C alloys. The influence of vanadium on the activity of carbon in austenitic Fe-C-V alloys at 1000C was determined by this technique. A general semi-empirical correlation was developed to describe the dependence of the activity coefficient of C on the composition of ternary austenitic iron-base alloys containing interstitial carbon and a substitutional solute. The correlation is particularly useful in predicting the partitioning of C between various alloys. (Author)