Ultrafast visualization of incipient plasticity in dynamically compressed matter
Mianzhen Mo, Minxue Tang, Zhijiang Chen, James R. Peterson, Xiaozhe Shen, Jon K. Baldwin, Mungo Frost, Mike Kozina, Alexander H. Reid, Yongqiang Wang, E Juncheng, Adrien Descamps, Benjamin K. Ofori-Okai, Renkai Li, Sheng‐Nian Luo, Xijie Wang, S. H. Glenzer
Abstract
Plasticity is ubiquitous and plays a critical role in material deformation and damage; it inherently involves the atomistic length scale and picosecond time scale. A fundamental understanding of the elastic-plastic deformation transition, in particular, incipient plasticity, has been a grand challenge in high-pressure and high-strain-rate environments, impeded largely by experimental limitations on spatial and temporal resolution. Here, we report femtosecond MeV electron diffraction measurements visualizing the three-dimensional (3D) response of single-crystal aluminum to the ultrafast laser-induced compression. We capture lattice transitioning from a purely elastic to a plastically relaxed state within 5 ps, after reaching an elastic limit of ~25 GPa. Our results allow the direct determination of dislocation nucleation and transport that constitute the underlying defect kinetics of incipient plasticity. Large-scale molecular dynamics simulations show good agreement with the experiment and provide an atomic-level description of the dislocation-mediated plasticity.