Proceedings of the Symposium on Energy Engineering Sciences (18th)

摘要

Damage nucleation, growth, and failures of metallic structural components thatoperate at high temperature are overviewed. Damage nucleation usually begins with the development of small voids at a size level at the high end of the nanoscale (50 to 500 rim). These voids begin to grow via diffusion mechanisms along the grain boundaries along with dislocation creep within the grains. Voids eventually link-up to produce micro-cracks (size 2 to 20 micrometers). Micro-cracks then link-up to produce macro-cracks, which eventually leads to component failure. Here we overview the high temperature damage development process, especially with regard to cyclic loading, which has received little attention to date. It is seen that damage development under cyclic loading develops in a fashion quite different from the constant load situation.