Measurement of local creep deformation in cross-weld specimen by optical fiber marking and remote monitoring

Creep deformation localization is a common occurrence generally found in high temperature components, typically at weldments and geometrical discontinuities. The deformation in a small region cannot be measured by a conventional displacement gage. A new technique for measuring long-term local creep deformation was developed. It uses quartz optical fiber marking, remote monitoring, and image processing. Long-term measurements of the creep deformations of base metal, weld metal, and heat-affected zone in cross-weld specimens were performed at high temperature, which verify the new technique. Strain distributions and evolutions in the weldments are obtained.