Shift of Creep Mechanism in Nanocrystalline NiAl Alloy.

ABSTRACT: We have examined the effects of temperature, stress, and grain size on the creep process including creep strain, crystal structure, dislocations and diffusions of nanocrystalline NiAl alloy through molecular dynamics simulations. A smaller grain size accelerates the creep process due to the large volume fraction of grain boundaries. Higher temperatures and stress levels also speed up this process in terms of dislocation changes and atom diffusion. In both primary creep and steady-state creep stages, atomic diffusion at the grain boundary could be seen and the dislocation density increased gradually, indicating that the creep mechanism at these stages is Coble creep controlled by grain boundary diffusion while accompanied by dislocation nucleation. When the model enters the tertiary creep s

SUBMITTER: Sun Z 

PROVIDER: S-EPMC6720299 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature