Atomistic simulation of crack propagation in CNT reinforced nanocrystalline aluminum under uniaxial tensile loading
PN Babu and S Dixit and S Pal, PHILOSOPHICAL MAGAZINE, 101, 1942-1964 (2021).
A molecular dynamics simulation-based study has been performed to examine the deformation behaviour of the predetermined parallel and perpendicular centreline cracks in CNTs embedded nanocrystalline aluminum (CNTs-NC Al) composite specimens under uniaxial loading. The hybrid potential (i.e. EAM, AIREBO, and LJ) method is adopted for carrying out the tensile deformation at three different temperatures (such as 10 K, 300 K, and 653 K). The mechanical properties are evaluated for both cases of parallel and perpendicular cracks of NC Al and CNTs-NC Al specimens. (30,30) CNT-NC Al specimen has shown superior fracture strain and ultimate tensile strength (UTS) at low temperature, whereas, higher fracture strain and lower UTS at high temperature than NC Al specimen. The mechanical properties of CNTs-NC Al nanocomposites are affected by the pre-existing crack and loading direction. The CNTs- NC Al nanocomposite specimens have exhibited the highest dislocation density compared to the NC Al specimen. The Shockley partial dislocations are a major driving factor for the parallel and perpendicular cracks of both (NC Al and CNTs-NC Al) specimens. The structural evolution and defect variation (such as stacking faults interaction with various dislocations, twin boundary, and grain boundary widening) has been elucidated during the tensile deformation of NC Al and CNT-NC Al nanocomposites.
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