Why nanoprojectiles work differently than macroimpactors: the role of plastic flow.
Atomistic simulation data on crater formation due to the hypervelocity impact of nanoprojectiles of up to 55 nm diameter and with targets containing up to 1.1×10(10) atoms are compared to available experimental data on μm-, mm-, and cm-sized projectiles. We show that previous scaling laws do not hold in the nanoregime and outline the reasons: within our simulations we observe that the cratering mechanism changes, going from the smallest to the largest simulated scales, from an evaporative regime to a regime where melt and plastic flow dominate, as is expected in larger microscale experiments. The importance of the strain-rate dependence of strength and of dislocation production and motion are discussed.
Fachbereich Physik und Forschungszentrum OPTIMAS, Universität Kaiserslautern, Kaiserslautern, Germany.
Christian
C
Anders
Eduardo M
EM
Bringa
Gerolf
G
Ziegenhain
Giles A
GA
Graham
J Freddy
JF
Hansen
Nigel
N
Park
Nick E
NE
Teslich
Herbert M
HM
Urbassek