Effect of recovery process on the efficiency of nano-diamond synthesis by shock compression

Mechanical characterization of reinforced vertically-aligned carbon nanotube array synthesized by shock-induced partial phase transition: insight from molecular dynamics simulations

“…At the third stage, performing an NVT ensemble with a timestep of 0.25 fs, the shock-compressed samples are quenched at the rate of 10 14 K s −1 to the ambient temperature of 300 K. Afterward, the samples are depressurized to the ambient pressure of 1 bar by using an NPT ensemble with a timestep of 0.5 fs. The efficiency of these recovery parameters to preserve sp 3 content in the structure is examined in previous studies [35]. The quenching stage and its cooling rate play a crucial role in the final molecular structure of the shocked structure and it has been widely studied by researchers [35,42].…”

“…The efficiency of these recovery parameters to preserve sp 3 content in the structure is examined in previous studies [35]. The quenching stage and its cooling rate play a crucial role in the final molecular structure of the shocked structure and it has been widely studied by researchers [35,42]. It should be emphasized that higher cooling rates lead to higher rates of diamond phase preservation while insufficient cooling rates can wipe out the sp 3 hybridization almost completely [43].…”

“…Although NEMD approach gives comprehensive information on the transient state of the shockwave formation and propagation, it requires very large systems with numerous atoms which makes the simulations to be highly time-consuming with extensive computational cost [34]. Comparing to NEMD, in the Hugoniostat method, which applies the Rankine-Hugoniot equations to study the steady-state of shockwave propagation, the simulations have been conducted in a shorter time and also with a much less number of atoms [35]. Studies have ensured an appropriate agreement between the results obtained by both methods, however, it is noted that the Hugoniostat method is much more preferred to get the final steady-state shocked structure due to its computational efficiency and technical feasibility [36].…”