Shock-induced plasticity in semi-coherent {111} Cu-Ni multilayers

Abstract

Using atomistic simulations, dislocation dynamics modeling, and continuum elastic-plastic stress-wave theory, we present a systematic investigation on shock-induced plasticity in semi-coherent Cu-Ni multilayers. The features of stress-wave evolutions in the multilayers, including wave-front stress attenuation and strong interfacial discontinuities, are revealed by atomistic simulations. Continuum models are proposed to explain the shockwave propagation features. The simulations provide insight into microplasticity behaviors including interactions between lattice and misfit dislocations. The formation of hybrid Lomer-Cottrell locks through the attraction and combination of lattice and misfit dislocations is a major mechanism for trapping gliding lattice dislocations at interfaces. The relationship between dislocation activity and dynamic stress-wave evolution history is explored. The hybrid Lomer-Cottrell locks can dissociate under shock compression or reverse yielding. This dissociation facilitates slip transmission. The influence of coherent stress causes direction dependency in the slip transmission: a lattice dislocation is transmitted more smoothly across an interface from Ni to Cu than from Cu to Ni. The interaction forces between lattice and misfit dislocations are calculated using dislocation dynamics code. Lattice dislocation nucleation from semi-coherent interfaces under shock compression is also reported.

Enhanced co-deformation of a heterogeneous nanolayered Cu/Ni composite

“…2(c). This phenomenon has also been observed by Chen et al 39 and Xiang et al 42,43 In addition, there exists a slight difference in the size of networks for NLs with different layer thicknesses. In the following analysis, the FCC and other atoms are deleted in all the models for the sake of a clearer observation of the microstructure.…”

Inapparent Strengthening Effect of Twin Interface in Cu/Pd Multilayered Films with a Large Lattice Mismatch

“…Nanostructured metallic multilayered films have attracted much attention due to their excellent mechanical properties [1][2][3]. Therefore, the relationship between their mechanical properties and microstructure parameters, and the optimization of these properties, are the hottest topics in this context of recent years [3][4][5][6].…”

Molecular dynamics simulation of the heterostructure of the CoCrFeMnNi high entropy alloy under an impact load

“…The interaction between the reflected wave and the incident wave results in a decrease in the velocity of the shock wave. When the shock wave crosses the Ni/HEA heterostructure interface, it forms a compressed wave, and the velocity of the compressed wave is higher than that of the incident wave [36,37].…”

“…When the shock wave reaches the interface of the HEA/Ni heterostructure, it undergoes partial reflection, resulting in the formation of a reflected wave. The interaction between the reflected wave and the incident wave leads to a change in shock pressure at the interface [36,37]. The detailed discussion will be presented in section 3.4.…”