Mechanism for beneficial effect of boron addition on creep resistance of 9-12% chromium steels

Paper i proceeding, 2006

Energy filtered transmission electron microscopy has been used to study two similar steels after long time aging, with different boron additions, to measure the effect of B on coarsening rate of M23Ce precipitates. The mechanism behind the effect of boron could either be a drastic decrease in the energy of the interface between M23C6 and matrix or a decrease in flux of atoms from a shrinking precipitate to a growing one. We suggest that the latter mechanism is operating, based on atom probe (APFIM) measurements of boron solubility in the matrix and the detection of Mo-B clustering.