On the Deformation Mechanism and Dislocation Density Evolution in A Polycrystalline Nano Copper at 10 K–700 K/108 s−1–109 s−1 Employing Molecular Dynamics Simulations

In this work, molecular dynamics (MD) simulations have been utilized to explore the effect of temperature and strain rate on the deformation mechanisms that occurs in nano grain polycrystalline Cu having special ∑3 grain boundaries along with other high and low angle grain boundaries. The temperature and strain rate ranges explored in this work are 10 K–700 K and 1 × 108 s−1–1 × 109 s−1, respectively. The results show that the yielding starts by the nucleation of the Shockley partials of \(\frac{1}{6}\) <112 > character at the ∑3 grain boundaries. Furthermore, the subsequent plastic strain is evidenced to be accommodated by the formation of stacking faults and twins. The formation of stacking faults at the expense of Shockley partials occurs at lower strain while twin formation from Shockley partials is favorable at high strain. Low temperature (10 K) deformation leads to intergranular failure via void nucleation, growth and crack propagation.