A Comprehensive Creep Model For Advanced 9-10% Cr Ferritic Steels

This article presents the findings of recent studies on creep of advanced 9-10% Cr ferritic steels. It is shown that the obstacles that fundamentally control creep in these steels are nano-scale MX carbonitrides whose time dependent coarsening leads to weakening. The second crucial factor in creep strengthening is the subgrain structure that results from martensitic transformation. The boundaries in this structure produce a hack-stress through an anelastic bowing mechanism. A quantitative model that takes these microstructural features into account is shown to be able to predict the long-term creep behavior of ferritic steels. (C) 2013 The Authors. Published by Elsevier Ltd.