Partial dislocations associated with NbC precipitation in austenitic stainless steels

Abstract

Abstract A systematic electron microscope investigation has been made of the partial dislocations bounding stacking faults in niobium-containing austenitic stainless steels. Observations of contrast for various reflecting conditions are explained on the basis of calculations carried out using the two-beam dynamical theory of Howie and Whelan, and it is concluded that the outer partials are Franks, the inner partials are Shockleys, and the faults are extrinsic. The invisibility criteria given by Howie and Whelan for partials are extended and a mechanism of NbC precipitation causing growth of the faults is proposed.