Sessile dislocations by reactions in NiAl severely deformed at room temperature

Author(s)
D. Geist, C. Gammer, C. Rentenberger, H. P. Karnthaler
Abstract

B2 ordered NiAl is known for its poor room temperature (RT) ductility; failure occurs in a brittle like manner even in ductile single crystals deforming by single slip. In the present study NiAl was severely deformed at RT using the method of high pressure torsion (HPT) enabling the hitherto impossible investigation of multiple slip deformation. Methods of transmission electron microscopy were used to analyze the dislocations formed by the plastic deformation showing that as expected dislocations with Burgers vector a <1 0 0 > carry the plasticity during HPT deformation at RT. In addition, we observe that they often form a <1 1 0 > dislocations by dislocation reactions; the a <1 1 0 > dislocations are considered to be sessile based on calculations found in the literature. It is therefore concluded that the frequently encountered 3D dislocation networks containing sessile a <1 1 0 > dislocations are pinned and lead to deformation-induced embrittlement. In spite of the severe deformation, the chemical order remains unchanged.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Lawrence Berkeley National Laboratory
Journal
Journal of Alloys and Compounds
Volume
621
Pages
371-377
No. of pages
7
ISSN
0925-8388
DOI
https://doi.org/10.1016/j.jallcom.2014.09.226
Publication date
02-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
103042 Electron microscopy, 103018 Materials physics, 210004 Nanomaterials
Keywords
ASJC Scopus subject areas
Mechanics of Materials, Mechanical Engineering, Metals and Alloys, Materials Chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/sessile-dislocations-by-reactions-in-nial-severely-deformed-at-room-temperature(3846d5ee-05d8-41d8-8f51-80a69c134618).html