Understanding the plasticity contributions during laser-shock loading and spall failure of Cu microstructures at the atomic scales

• Published in: Computational materials science 2021-10, Vol.198 (C), p.110668, Article 110668
• Main Authors: Echeverria, Marco J., Galitskiy, Sergey, Mishra, Avanish, Dingreville, Remi, Dongare, Avinash M.
• Format: Article
• Language: English
• Subjects: Laser-shock; Molecular dynamics; Plasticity; Spall; Virtual diffraction
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2021.110668

[Display omitted] •Laser shock compression and spall failure behavior is modeling using a hybrid atomistic-continuum model that combines molecular dynamics simulations with a continuum two-temperature model.•The spall failure behavior is observed to vary with loading parameters (laser fluence) that affects the plasticity contributions during shock compression and also the temperatures generated at the spall plane.•The spall strength at the extremely high strain rates generated (109 s−1) using laser shock are largely affected by the temperatures generated as compared to the shock pressures generated at the spall plane.•Simulated X-ray diffraction (XRD) and selected area electron diffraction (SAED) on atomic scale microstructures is carried out to identify the contributions from density of dislocations, stacking faults, and deformation twins, to the peak shift, peak splitting, and peak broadening behavior in diffractograms. A hybrid atomic-scale and continuum-modeling framework is used to study the microstructural evolution during the laser-induced shock deformation and failure (spallation) of copper microstructures. A continuum two-temperature model (TTM) is used to account for the interaction of Cu atoms with a laser in molecular dynamics (MD) simulations. The MD-TTM simulations study the effect of laser-loading conditions (laser fluence) on the microstructure (defects) evolution during various stages of shock wave propagation, reflection, and interaction in single-crystal (sc) Cu systems. In addition, the role of the microstructure is investigated by comparing the defect evolution and spall response of sc-Cu and nanocrystalline Cu systems. The defect (stacking faults and twin faults) evolution behavior in the metal at various times is further characterized using virtual in situ selected area electron diffraction and x-ray diffraction during various stages of evolution of microstructure. The simulations elucidate the uncertain relation between spall strength and strain-rate and the much stronger relation between the spall strength and the temperatures generated due to laser shock loading for the small Cu sample dimensions considered here.