Open AccessAtomistic simulation of mechanical properties of martensitic transformation under dynamic compression
Author(s) -
Jian-Li Shao,
Qin Cheng-Sen,
Pei Wang
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.1936
Subject(s) - materials science , softening , nucleation , slip (aerodynamics) , diffusionless transformation , slipping , stress (linguistics) , compression (physics) , condensed matter physics , stress relaxation , crystal twinning , phase (matter) , martensite , composite material , thermodynamics , microstructure , structural engineering , creep , physics , linguistics , philosophy , engineering , quantum mechanics
Molecular dynamics simulation MD was used to investigate the microscopic mechanism of martensitic transformations in Fe single crystals driven along 001 orientation by an accelerating piston. Simulated results revealed that the above compression process can be divided into five stages, namely the elastic compression, softening of elastic ratio, phase transformation bcc to hcp, over-relaxation of stress and elastic compression of high-pressure phase. The slipping laws of atoms and properties of stress are analysed in detail. Atoms can only slip along longitudinal direction under elastic compression, and when the longitudinal stress is beyond 10 GPa, local atoms begin to slip along lateral direction and form embryos, which is just the microscopic nature of the softening of elastic ratio.The stacking fault fcc is a more steady origin of crystal nucleation than the twin boundary. After the phase transformation, the atoms undergo an over-relaxation of stress i.e., the lateral stress is larger than the longitudinal stress, and this state disappears when the longitudinal stress is beyond about 36 GPa.