Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Dislocation Confinement and Ultimate Strength in Nanoscale Metallic Multilayers Qizhen Li and Peter M. Anderson
 

Summary: Dislocation Confinement and Ultimate Strength in Nanoscale Metallic Multilayers
Qizhen Li and Peter M. Anderson
Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, U.S.A.
ABSTRACT
In nanostructured metallic multilayers, hardness and strength are greatly enhanced compared
to their microstructured counterparts. As layer thickness is decreased, three different regions are
frequently observed: the first region shows Hall-Petch behavior; the second region shows an
even greater dependence on layer thickness; and the third region exhibits a plateau or softening
of hardness and strength. The second and third regions are studied using our discrete dislocation
simulation method. This method includes the effects of stress due to lattice mismatch, misfit
dislocation substructure, and applied stress on multilayer strength. To do so, we study the
propagation of existing threading and interfacial dislocations as the applied stress is increased to
the macroyield point. Our results show that in region 2, dislocation propagation is confined to
individual layers initially. This "confined layer slip" builds up interfacial content and
redistributes stress so that ultimately, the structure can no longer confine slip. The associated
macroyield stress in this region depends strongly on layer thickness. In region 3, layers are so
thin that confined layer slip is not possible and the macroyield stress reaches a plateau that is
independent of layer thickness.
INTRODUCTION
An increase in strength is observed frequently in multilayered structures with a decrease of

  

Source: Anderson, Peter M. - Department of Materials Science and Engineering, Ohio State University

 

Collections: Materials Science