Influence of crystallographic orientation and layer thickness on fracture behavior of Ni/Ni3Al multilayered thin films

Ni / Ni3Al multilayers have been deposited epitaxially and non-epitaxially by UHV magnetron sputtering on < 001 > NaCl substrates. Two interfacial ori entations were achieved: {001} Ni // {001} Ni3Al, < 100 > Ni // < 100 > Ni3 Al and {111} Ni // {111} Ni3Al, < 110 > Ni // < 110 > Ni3Al Under in-plane tensile loading, < 001 >, oriented multilayers exhibit ductile fracture sur face features but < 111 > oriented multilayers of the same layer thickness are predominantly brittle. For each orientation, the fracture surface featu res from 20 nm thick Ni and Ni3Al layers appear to be as ductile or more du ctile than those from 120 nm thick layers, but the plastic deformation appe ars to be more localized. (C) 2001 Acta Materialia Inc. Published by Elsevi er Science Ltd. All rights reserved.