Effect of Cr content on the crystal structure and lattice dynamics of FCCFe-Cr-Ni-N austenitic alloys

The present study investigates the effect of chromium additions on interato mic bonding in nitrogen austenitic steers Fe-xCr-11Ni-0.5N (x=15-29 wt.%). A Linear increase of the fee lattice parameter with increasing chromium con tent was found. In inelastic neutron scattering measurements, a softening o f the metal frequency spectrum in the low energy region was observed, but t he second moment of metal atom frequency distribution did not depend on the chromium content. These changes are in disagreement with theoretical predi ctions and an connected with contributions from the many-body forces and wi th modification of the electronic states by chromium. Furthermore, a decrea se of the nitrogen peak width with increasing Cr content was found. Such a behaviour is caused by nitrogen-induced short-range ordering of chromium at oms. (C) 1999 Published by Elsevier Science S.A. All rights reserved.