Study of Lattice Rotation in Expanded Austenite

Alice Bastos da Silva Fanta
Project coordinators: Thomas L. Christiansen, Marcel A. J. Somers

The aim of this project is to study lattice rotation in differently oriented grains after surface hardening of stainless steel. Improvements in tribological performance of austenitic stainless steel without compromising corrosion behaviour can be achieved by low temperature (< 550°C) gaseous carburising and /or nitriding the surface. The microstructural feature responsible for enhanced wear resistance is the formation of a supersaturated solution of carbon or nitrogen in austenite, so-called expanded austenite. In this project we focus on electron backscatter diffraction (EBSD) studies of the microstructural changes induced by the incorporation of nitrogen and/or carbon in austenitic stainless steel by low temperature gaseous processes. The microstructure of the samples will be characterized before and after surface treatment with respect to their crystallographic orientation and local misorientation. The dependence of the lattice rotation on the grain orientation and texture development will be studied on samples that differ in interstitial content and layer thickness. Furthermore the influence of different grain orientation on the lattice rotation of its neighbouring grains will be addressed.

                 

SEM micrograph of the sample surface after nitrogen incorporation. 

Alice Bastos da Silva Fanta
Seniorforsker
DTU Cen
45 25 64 69