THE EFFECT OF CRYSTALLOGRAPHIC ORIENTATION ON THE DEFORMATION MECHANISMS OF NiAI NANOFILMS UNDER TENSION

KA Krylova and RI Babicheva and K Zhou and AM Bubenchikov and EG Ekomasov and SV Dmitriev, REVIEWS ON ADVANCED MATERIALS SCIENCE, 57, 26-34 (2018).

DOI: 10.1515/rams-2018-0044

Molecular dynamics is applied to study the effect of crystallographic orientation on the plastic deformation mechanisms and mechanical properties of NiAI intermetallic nanofilms subjected to uniaxial tension. It is observed that the deformation mechanisms qualitatively depend on the crystallographic orientation of the nanofilms with respect to the loading direction. Plastic deformation of the nanofilms along 557 crystallographic direction is associated with the edge dislocation sliding in the slip system 001(110). As for the nanofilms stretched along 554 and 111 directions, their deformation occurs first through the dislocation sliding followed by the formation of (112)11 (1) over bar twins. Uniaxial tension of the nanofilms along 559 and 55 11 leads to the nucleation and growth of a martensitic phase followed by their rupture along an interface. The maximum (minimum) strength of 9.9 (7.0) GPa is observed for the nanofilms stretched along the 559 (554) crystallographic direction, while the largest (smallest) strain to failure of 27 (15)% is for 559 (55 11). Various deformation mechanisms of the nanofilms are explained through computing the Schmid factor for the operational slip system. The results indicate that the crystallographic orientation is among the key parameters controlling the deformation mechanisms and mechanical properties of intermetallic nanofilms.

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