Plastically-Induced Volume Deformation of Nanocrystalline α-Fe with a <110> Columnar Structure

Metals

I. Aldazabal¹  J. Aldazabal²  J. Gil Sevillano² 

[1] Centro de Física de Materiales (CSIC-UPV/EHU)-MPC, P. Manuel de Lardizabal 5, E-20018 San Sebastián, Spain;TECNUN—University of Navarra, P. Manuel de Lardizabal 13, E-20018 San Sebastián, Spain;

关键词: plastic volume invariance;    plastic volume deformation;    nanocrystalline iron;    molecular dynamics simulations;    size effects;   

DOI  :  10.3390/met10121649

来源: DOAJ

【 摘 要 】

Volume changes accompanying the plastic deformation at 300 K of nanocrystalline samples of α-Fe with a columnar grain structure possessing a $\langle 1\overline{1}0\rangle$ random fiber texture has been obtained from molecular dynamics (MD) simulations. The samples were strained in tension along the common axial direction of the columnar grains. After removal of the elastic volume change, the evolution of plastic volume strain was obtained. Small but non-negligible volume dilations or contractions are observed depending on size (samples of very small grain size show volume contraction). The rate of volume change is high during the first 10% plastic deformation and continues at a low pace thereafter; the first 10% deformation represents a transient in the stress–strain behavior too. The complex behavior observed is reasonably explained by the superposition of contributions from different plastically-induced structural changes to the mass density change: Mainly from changes of grain size, grain boundary structure, dislocation density and density of point-defects. The results are of interest for the development of crystal plasticity theories not restricted by the volume conserving assumption.

【 授权许可】

Unknown