Atomistic simulation of the tension/compression response of textured nanocrystalline HCP Zr

GRACIELA BERTOLINO; MARGARITA RUDA; PASIANOT ROBERTO; DIANA FARKAS

COMPUTATIONAL MATERIALS SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 130 p. 172 - 182

0927-0256

Molecular dynamics virtual tension/compression tests were performed to study the deformation mechanisms in nanocrys-talline (15?38 nm grain size) 50 grains HCP Zr columnar samples with random [1-100] prismatic and [0001] basal tex-tures. Two different embedded atom potentials were used to model atomic interactions and to describe the relationshipbetween generalized stacking fault energies and mechanical predictions. Both potentials predict higher flow stresses incompression for both textures. Nanocrystalline Zr [0001] basal textured samples deform mainly by dislocations emissionand glide along 〈11-20〉 {1-100} and by grain boundary sliding and migration; both potentials show the same deformationmechanisms for this texture. Prism [1-100] textured samples deform mainly by twinning. Both in tensile and compres-sion tests {11-21} twins nucleate mainly at grain boundaries and sites with high stress concentration. These twins growby a shuffle mechanism. Emission and sliding of partial dislocations, grain boundary gliding and migration were alsoobserved for this texture with the main dislocations being of the 1/3 〈1-210〉 type. These basic deformation mechanismswere the same for both potentials tested. The observed quantitative differences between the predictions of both potentialsare discussed in terms of some of their basic properties.