EFFECT OF LOCAL STRAIN AND GND DENSITY ON CRACK INITIATION IN ALLOY 600

摘要

In this work, strain and geometric necessarydislocation (GNDs) have been measured around variousgrain boundaries after subjected to a 4-point bend test insimulated PWR primary water conditions, with the aim ofclarifying which local conditions trigger SCC initiation.Three different regions are compared: in a cracked grainboundary, the cracked and the uncracked portions arecompared to a similar grain boundary in the as-receivedmaterial. l. To study this, “on-axis” Transmission KikuchiDiffraction (TKD) with a step size of 1 nm followed byGND analysis and cross-correlation based strainmapping, was performed. Results together with adiscussion on the limitations of the approach will bepresented.