Paper Title:
Molecular Dynamics Simulation of Nanocrystalline Tantalum under Uniaxial Tension
  Abstract

Using molecular dynamics (MD) simulation, we have investigated the mechanical properties and the microstructural evolution of nanocrystalline tantalum (NC-Ta, grain size from 3.25 nm to ~13.0 nm) under uniaxial tension. The results show the flow stress at a given offset strain decreases as the grain size is decreased within the grain size regime studied, implying an inverse Hall-Petch effect. A strain rate sensitivity of ~0.14, more than triple that of coarse-grain Ta, is derived from the simulation results. Twinning is regarded to be a secondary deformation mechanism based on the simulations. Similar to nanocrystalline iron, stress-induced phase transitions from body-centered cubic (BCC) to face-centered cubic (FCC) and hexagonal close-packed (HCP) structures take place locally during the deformation process, The maximum fraction of FCC atoms varies linearly with the tensile strength. We can thus conclude that a critical stress exists for the phase transition to occur. It is also observed that the higher the imposed strain rate, the further delayed is the phase transition. Such phase transitions are found to occur only at relatively low simulation temperatures, and are reversible with respect to stress.

  Info
Periodical
Solid State Phenomena (Volume 139)
Edited by
Veena Tikare, Graeme E. Murch, Frédéric Soisson and Jeung Ku Kang
Pages
83-88
DOI
10.4028/www.scientific.net/SSP.139.83
Citation
Z. L. Pan, Y. L. Li, Q. M. Wei, "Molecular Dynamics Simulation of Nanocrystalline Tantalum under Uniaxial Tension", Solid State Phenomena, Vol. 139, pp. 83-88, 2008
Online since
April 2008
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Julia Ivanisenko, Ian MacLaren, Ruslan Valiev, Hans Jorg Fecht
Abstract:Recent studies of nanocrystalline materials have often found that the deformation mechanisms are radically different to those in...
439
Authors: Wei Guo Guo
Abstract:In the present paper, in order to better understand the third type “dynamic strain aging” occurring during the plastic flow of metals, the...
823
Authors: Yoshihiro Kubota, Ryosuke Matsumoto, Michihiko Nakagaki
Abstract:In recent years, nano-crystalline materials have attracted many researchers’ attention, but the fracture mechanism has not been fully...
985
Authors: Yong Jun Lan, C. Pinna
Chapter 5: Annealing
Abstract:An integrated crystal plasticity-phase field model has been developed to simulate the static recrystallisation textures of both Face-Centred...
663
Authors: Yan Zhang, Yan Zhao, Fu Cheng Zhang
Chapter 1: Materials Design
Abstract:Phase boundary is an important kind of interfaces for the dual-phase metals. Orientation relationship (OR) is a crucial factor affecting the...
601