Stresses in thermally grown alumina scales near edges and corners.

摘要

We have investigated the residual stress near edges and corners of thermally grown alumina scales. Micro-fluorescence measurements, performed on alloys with composition Fe-5Cr-28Al (at.%, bal. Fe) oxidized at 900 C, showed a large (>50%) reduction in hydrostatic stress in the vicinity of edges and corners. Surprisingly, stress relaxation persists out to distances ten times the scale thickness from the edge. Finite element analysis calculations confirm the experimental results and provide a considerably more detailed picture of the stress distribution and its components.