Kinetic Modelling of the Influence of Particles on Creep Strength

摘要

The influence of particles on creep strength isstudied for an austenitic stainless steel strengthened with TiC-particles in the temperature interval 550-800 deg C. At lowertemperatures, when the dislocations cannot climb over theparticles, the Orowan mechanism dominates. At highertemperatures, the increase in strength is limited by climb. Atintermediate stresses both climb and the Orowan mechanismsare active. By kinetically analysing the time it takes for theparticles to be climbed, the role of the two mechanisms can beclarified. Smaller particles will first be overcome with climb,while larger ones have to be surounded with Orowan loops,which considerably contribute to strength. At low stresses, allparticles are overcome with climb, and the strengtheningcontribution is small. Particle coarsening is described with amulti-component model.