Characterisation of precipitates in a stainless maraging steel by three-dimensional atom probe and small-angle neutron scattering

Abstract

Two complementary techniques, namely three-dimensional atom probe and small-angle neutron scattering, were employed to study precipitation phenomena in a stainless maraging steel (Fe-12.3 %Cr-8.9%Ni-0.6 %Si-1 %Mo-0.6 %Al-0.8%Ti, wt.%) during ageing at 475 °C. Atom probe investigations revealed the precipitation of a single Ni-rich phase exhibiting an average particle diameter of 2.5 nm after 12 h. After ageing for 100 h these precipitates had grown to an average size of 4 nm. In addition, needle-or plate-like Ni-rich precipitates larger than 15 nm were present. Their compositions differ mainly in the amount of Fe, Ni and Ti. Furthermore, Cr-rich precipitates were observed. The size ranges and the number densities of the precipitates match well with those observed by small-angle neutron scattering.

Sonochemical formation of metal sponges

“…Sharp tips were prepared using standard techniques by electrolytical polishing as described in ref. 62. Samples after solution sonochemical treatment were investigated.…”